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Low Voltage Definition
Low Voltage QRS Differential
Differential for Non-conducted P-waves (P:QRS > 1, a.k.a “electrocardiographic polyuria”)
Narrow vs. wide complex QRS in setting of complete heart block
Take home Points
Post “seizure” & syncope ECG
When the history and physical exam do not suggest a diagnosis, always think of the following differentials when interpreting the ECG of patients with syncope or new-onset seizures:
ECG findings in severe hypokalemia
Review Key Teaching Points
The 5 Step Approach to ECG Interpretation
Find a method and master it!
Run through the differentials when you encounter abnormalities!
Differential for Prolonged QTc Interval
Quick Evaluation of the QT-interval
T-waves should end before the midpoint of the R-R interval.
Beware of a prolonged QT when the T-waves end after ½ the R-R wave distance!
Causes of prolonged QT-interval summary
Poor R-wave Progression Differential
Low Voltage Definition
Low Voltage QRS Differential
Rate: ~ 45 ventricular and regular
Rhythm: Atrial fibrillation with complete heart block and junctional escape rhythm
Axis: Normal
ST segments / T waves: Slurred downsloping of the ST-segment with Salvador Dali moustache appearance
Digoxin
Rate: ~ 79 ventricular
Rhythm: Normal sinus rhythm
Axis: Normal
Intervals: PR & QRS are normal, QTc is short
Enlargement: None
ST segments / T waves: ST-segment elevation in V1/V2
Systematic approach to ECGs
Causes of ST-segment Elevation
Take home points
References
Nishi SPE, Barbagelata NA, Atar S, et al. Hypercalcemia-induced ST-segment elevation mimicking acute myocardial infarction. Journal of Electrocardiology 2006;39(3):298–300. PMID: 16777515
Littmann L, Taylor L, Brearley WD. ST-segment elevation: a common finding in severe hypercalcemia. Journal of Electrocardiology 2007;40(1):60–2. PMID: 17027838
Rate: ~ 50
Rhythm: Junctional
Axis: Normal
P waves: inverted in lead II and aVF, v4, V5, V6. Not sinus rhythm.
Intervals: Short PR, Normal QRS, Normal QT
ST segments / T waves: STE isolated in lead III, STD in Iead I and aVL
Normal Sinus Rhythm
History is still the key predictor of ACS!
Clinical factors that INCREASE the likelihood of ACS:
Bonus Pearl: CP patients who have RE2D flags (Radiation, Exertion, Emesis, Diaphoresis) are high risk for ACS.
Clinical factors that DECREASE the likelihood of ACS:
ECG Pearls:
References:
Rate: Sinus tachycardia ~ 100
Rhythm: Regular
Axis: Normal
Intervals: Borderline 1st degree AV Block, Prolonged QT-interval
ST-segments: Inferior and anterolateral depressions and down-slopping
T-waves: Biphasic t-waves that lead to U-waves
Quick Evaluation of the QT-interval
T-waves should end before the midpoint of the R-R interval.
Beware of a prolonged QT when the T-waves end after ½ the R-R wave distance.
Differential for Prolonged QT
ECG Findings in Severe Hypokalemia
The 5 Step Approach to ECG Interpretation
Run through the differentials when you encounter abnormalities!
Differential for Non-conducted P-waves (P:QRS > 1)
ECG Bonus Pearl:
3-step approach to diagnosing AV Blocks
The answer usually lies in the PR-interval!
Case Interpretation
Case 1 – Rate and Rhythm – Sinus tachycardia ~145 bpm (atrial), Mobitz I with 7:6 AV conduction, Ventricular Rate ~125
Case 2 – Rate and Rhythm – Sinus tachycardia ~100 bpm (atrial), Mobitz II conduction (advanced AV Block), Ventricular Rate ~ 40-45
Differential for Non-conducted P-waves (P:QRS > 1)
ECG Bonus Pearl:
3-step approach to diagnosing AV Blocks
The answer usually lies in the PR-interval!
Rhythm – Sinus tachycardia, complete heart block, junctional escape rhythm at rate of ~ 40
3-step approach to diagnosing AV Blocks
The answer usually lies in the PR-interval!
Differential for Non-conducted P-waves (P:QRS > 1)
Before diagnosing Mobitz blocks, be certain that the P-P interval is REGULAR, an irregular P-P interval may be simply caused by non-conducted PAC’s.
The 5 Step Approach to ECG Interpretation
Run through the differentials when you encounter abnormalities!
Key Teaching Points
Differential diagnosis of leftward axis
Causes of QRS Prolongation
Take home point:
Beware of pseudo- ST deviation in patients with BBB. Measure our the QRS duration and make sure you are not confusing the QRS with the ST-segment!
ECG Bonus Pearl: Fascicular blocks
| Type of Fascicular Block | LAFB | LPFB |
| Axis | Left Axis Deviation | Right Axis Deviation |
| Leads I & aVL |  |
 |
| Lead II |  |
 |
Bifascicular Block
Trifascicular Block
Take-home Points:
Sgarbossa criteria appear to predict acute MI in patients with pacemakers. The criteria have low sensitivity but are very specific. Criteria C (excessively discordant ST-segment elevation) seem to be most specific in patients with pacemakers.
Reference
References:
Take-home points:
Reference:
Final Class IIB Take-home points
Share the literature and be an advocate for your patients!
Concordant STE ≥ 1mm (in any lead) = Most specific for MI
Concordant STD ≥ 1mm in V1, V2, or V3 = Specific for MI
Discordant STE ≥ 5mm = Less specific for MI
4. Non-STE ACS (Class IA in national guidelines)
Take-home points:
Both physicians and ECG machines tend to over-call atrial fibrillation. This leads to patients being anticoagulated inappropriately and can cause bad outcomes! If the rhythm is regularly irregular it is not atrial fibrillation, consider PAC’s and 2nd degree AV blocks.
Subtle early signs of ischemia
Take-home Points:
Differential for Prolonged QT-Interval
ECG findings in severe hypokalemia
Ashman Phenomenon
Takehome Points
ECG findings in Hyperkalemia
Take-home points
ECG findings in Hyperkalemia
Take-home points
Hyperkalemia can do just about anything it wants to the ECG!
ECG findings in Pericarditis vs. STEMI
Know the differences in ECG findings & use a stepwise approach
Step 1. Factors that stronglysuggest STEMI:
Look for the factors that rule in STEMI before thinking pericarditis!
Step 2. Factors that suggest pericarditis (only after step 1):
When in doubt…do serial ECGs and consider CATH!
Take-home Points
Chest pain + (vomiting, radiation of pain, diaphoresis, or exertional worsening) is predictive of ACS
If you did not see the Brugada Syndrome Part I, please review the March 26, 2018 case
The Brugada Syndrome Part II
The Brugada Pattern: ECG findings
The Brugada Syndrome: Diagnosis
Take-home points:
References
Martini B, Nava A, Thiene G, et al. Ventricular fibrillation without apparent heart disease: description of six cases. Am Heart J. 1989 Dec;118(6):1203-9. PMID: 2589161.
Subtle early signs of ischemia
Riley, et al. Am Heart J 2013. PMID: 23237133
Millard, et al. Ann Noninvasive Electrocardiol 2017. PMID: 28044391
Take-home points:
Get serial ECG’s in suspected ACS!
Reference:
Left Bundle Branch Block
Sgarbossa Criteria
Take-home Points:
References:
ST-segment elevation in aVR with ST-segment depression in multiple other leads
References:
ECG findings in Hyperkalemia
Reference:
Durfey N, et al. Severe Hyperkalemia: Can the Electrocardiogram Risk Stratify for Short-term Adverse Events? WJEM 2017. PMID:28874951
Causes of Rightward Axis Deviation
Take-home Points:
Take-home Points:
Rapid atrial tachydysrhythmias often produce ST segment elevation in aVR but do not correlate with CAD
Lewis Lead
Take-home Points:
Brugada syndrome
The Brugada Pattern: ECG findings
The Brugada Syndrome: Diagnosis
Take-home Points:
T-waves should end before the midpoint of the R-R interval.
Beware of a prolonged QT when the T-waves end after ½ the R-R wave distance.
Differential for Prolonged QT (Greatest concern when QTc > 500ms)
ECG Findings in Severe Hypokalemia
Take-home points:
Pericardial effusion
Classic teaching
Low Voltage Definition
Low Voltage QRS Differential
Take home Points
Differential for Non-conducted P-waves (P:QRS > 1, a.k.a “electrocardiographic polyuria”)
Fascicular Block Definitions
Left anterior fascicular block (LAFB)
Left posterior fascicular block (LPFB)
Bifascicular Block
Trifascicular Block
Take Home Points:
When you see electrocardiographic polyuria…map out the P-waves and look closely at the PR-interval
Differential for Non-conducted P-waves (P:QRS > 1, a.k.a “electrocardiographic polyuria”)
Narrow vs. wide complex QRS in setting of complete heart block
Take Home Points:
When you see electrocardiographic polyuria…map out the P-waves and look closely at the PR-interval
Case 1 Pearls
Clues to RV Infarction on the 12-lead ECG
Case 2 Pearls
Left Bundle Branch Block
Sgarbossa Criteria
Case 3 Pearls
When the history and physical exam do not suggest a diagnosis, always think of the following differentials when interpreting the ECG of patients with syncope:
Case 4 Pearls
New T-wave inversion in aVL may be a reciprocal change
The 3 Causes of Narrow-Complex & Regular Tachycardia
To differentiate…always look at what the atrium is doing
(V1 typically best lead to look for atrial activity)
Some causes of ST-elevation in aVR (“global cardiac ischemia”)
Case 2 Pearl
Differential for Non-conducted P-waves (P:QRS > 1)
Case 3 Pearl
Characteristics of a normal sinus rhythm
Causes of Widening of the QRS-complex
Causes of Rightward Axis Deviation
Na+ channel blocker toxicity
Take Home Points:
Differential diagnosis for regular wide complex tachycardia (RWCT)
Differential diagnosis for regular really wide complex tachycardia (RRWCT)
Take Home Points:
Differential Diagnosis for Prolonged QTc Interval
Differential Diagnosis for T-wave inversions
New T-wave inversion or ST-segment down sloping in aVL may be an early reciprocal change that precedes inferior STEMI
Causes of ST-segment Elevation
Take home points:
References
2014 AHA/ACC Guideline for the Management of Patients with Non-ST-Elevation Acute Coronary Syndromes (Class IA)
An urgent/immediate invasive strategy (within 2 hours) is indicated for non-STE-ACS patients that:
Take-home Points:
Reference:
Amsterdam EA, Wenger NK, Brindis RG, et al. 2014 AHA/ACC Guideline for the Management of Patients with Non-ST-Elevation Acute Coronary Syndromes: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol. 2014;64(24):e139–228. PMID: 25260718.
Take-home Points:
New T-wave inversion or ST-segment down sloping in aVL may be an early reciprocal change that precedes inferior STEMI
Post-syncope ECG
When the history and physical exam do not suggest a diagnosis, always think of the following differentials when interpreting the ECG of patients with syncope:
Differential Diagnosis for T-wave inversions
Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy
Take home Points
References:
ECG findings in Hyperkalemia
Take home Points
References:
Causes of ST-segment Elevation
Intracranial hemorrhage (ICH) & cardiac arrest
Take home Points
References:
Causes of ST-segment Elevation
Take home points:
References
2014 AHA/ACC Guideline for the Management of Patients with Non-ST-Elevation Acute Coronary Syndromes (Class IA)
An urgent/immediate invasive strategy (within 2 hours) is indicated for non-STE-ACS patients that:
Take-home Points:
Reference:
Amsterdam EA, Wenger NK, Brindis RG, et al. 2014 AHA/ACC Guideline for the Management of Patients with Non-ST-Elevation Acute Coronary Syndromes: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol. 2014;64(24):e139–228. PMID: 25260718.
Take-home Points:
New T-wave inversion or ST-segment down sloping in aVL may be an early reciprocal change that precedes inferior STEMI
Post-syncope ECG
When the history and physical exam do not suggest a diagnosis, always think of the following differentials when interpreting the ECG of patients with syncope:
Differential Diagnosis for T-wave inversions
Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy
Take home Points
References:
Causes of ST-segment Elevation
Intracranial hemorrhage (ICH) & cardiac arrest
Take home Points
References:
Causes of Rightward Axis Deviation
Causes of Widening of the QRS-complex
Take home Points
Wide complex tachycardia: ventricular tachycardia mimics
Differential for ST-segment elevation in aVR (with multilead ST-depression)
Take-home Points:
References:
O’Gara PT, Kushner FG, Ascheim DD, et al. 2013 ACCF/AHA Guideline for the Management of ST-Elevation Myocardial Infarction. J Am Coll Cardiol. 2013;61(4):e78–e140. PMID: 23256914.
Differential for ST-segment elevation in aVR (with multilead ST-depression)
ECG findings in Pulmonary Embolism
Question 1. List up to 16 causes of ST-segment elevation (1 point for every 3 you list; bonus point for all 16; max 6 points).
16 causes of ST-segment Elevation
Question 2. Name 6 causes of ST-segment elevation in lead aVR that are NOT related to an acute coronary occlusion (i.e. not left main, triple vessel, or proximal LAD artery disease). (max 3 points)
Differential for ST-segment elevation in aVR (with multilead ST-depression)
Question 3. Name 4 ECG signs of right heart strain that might be found on the ECG of a patient with massive PE. Note that sinus tachycardia is too nonspecific…don’t bother listing that! (max 2 points)
ECG findings in Pulmonary Embolism
Question 4. Name causes for a rightward axis (1 point for every 3 you list; max 3 points)
Causes of Rightward Axis Deviation
Question 5. A 38-year-old man presents with sharp chest pain and the ECG below is obtained. In deciding between STEMI vs. pericarditis, name 2 findings which strongly favor the correct diagnosis over the other. (2 points)
ECG findings in Pericarditis vs. STEMI
Know the differences in ECG findings & use a stepwise approach
Step 1. Factors that strongly favor STEMI:
Look for the factors that rule in STEMI before thinking pericarditis!
Step 2. Factors that suggest pericarditis (only after step 1):
When in doubt…do serial ECGs and consider CATH!
Question 6. A 45-year-old woman presents feeling weak, with the ECG shown below. What is the diagnosis? (1 point) Name 4 typical ECG findings associated with the diagnosis. (2 points)
ECG findings in severe hypokalemia
Question 7. A 62-year-old male with history of CAD presents with palpitations. BP is 115/60. He has no pain, minimal dyspnea, clear lungs, and normal mental status. Electrolytes are normal. What is the ECG diagnosis? (1 point) What is the DRUG of choice? (1 point)
Ventricular Tachycardia (VT)
Question 8. A 37-year-old man presents with chest pain and the ECG below. What is the diagnosis (2 points)
Large pulmonary embolism! There is right axis deviation, sinus tachycardia, ST-segment elevation in aVR, and T-wave inversions in anterior and inferior leads. Pay attention to axis, as right axis deviation can help distinguish massive PE from STEMI.
Question 9. A 31-year-old male presents after a near-syncopal episode. His ECG is shown below. What is the diagnosis (1 point) What is the diagnostic test of choice (1 point) The patient insists on being discharged but will follow up with cardiology in 3 days. What is the optimal outpatient management until follow up? (1 point)
Hypertrophic obstructive cardiomyopathy (HOCM)
Question 10. A 54-year-old man presents with chest pain and the ECG noted below. What is the full ECG diagnosis? (2 points)
Sinus rhythm with inferior and right ventricular STEMI
Question 11. A 50-year-old woman presents with mild dyspnea. Nurses noted ~ 10 seconds of an unusual rhythm disturbance on the monitor and they obtained a 12-lead ECG off the monitor, noted below. What is the diagnosis? (1 point) What would be the treatment if this finding persisted? (1 point)
Artifact, no treatment necessary.
Question 12. A 58-year-old man presents with chest pain and the ECG noted below. What is the full ECG diagnosis? (3 points)
Sinus Tachycardia with Mobitz I AV conduction, inferior and posterior STEMI
Question 13. A 64-year-old male presents with palpitations and lightheadedness. ECG is below. What is the optimal treatment? (2 points)
Treatment for hyperkalemia. The QRS is too wide and ventricular rate too slow to be ventricular tachycardia.
Question 14. A 65-year-old woman presents after a syncopal episode. with palpitations and lightheadedness. ECG is below. What is the optimal treatment? (2 points)
Sinus tachycardia with complete heart block and junctional escape rhythm, left posterior fascicular block with inferior-lateral ischemia.
Causes of Rightward Axis Deviation
Causes of Rightward Axis + ST-segment elevation mimicking STEMI (usually does not produce rightward axis)
ECG findings in Hyperkalemia
ECG findings in PE associated with hemodynamic instability and increased morbidity and mortality (not specific for PE)
Final take-home points:
References:
Shopp JD, Stewart LK, Emmett TW, Kline JA. Findings From 12-lead Electrocardiography That Predict Circulatory Shock from Pulmonary Embolism: Systematic Review and Meta-analysis. Acad Emerg Med 2015;22(10):1127–37. PMID:26394330
Dibgy,GC, Kulka P, Zhan ZQ, et al. The value of electrocardiographic abnormalities in the prognosis of pulmonary embolism: a consensus paper. Ann Noninvasive Electrocardiol 2015. May;20(3):207-23. PMID:25994548
Kukla P, McIntyre WF, Fijorek K, et al. Electrocardiographic abnormalities in patients with acute pulmonary embolism complicated by cardiogenic shock. Am J Emerg Med 2014;32(6):507–10. PMID:24602894
Zhan Z-Q, Wang C-Q, Nikus KC, et al. Electrocardiogram patterns during hemodynamic instability in patients with acute pulmonary embolism. Ann Noninvasive Electrocardiol 2014;19(6):543–51.PMID:24750207
Abarca E, Baddi A, Manrique R. ECG manifestations in submassive and massive pulmonary embolism. Report of 4 cases and review of literature. Journal of Electrocardiology 2014;47(1):75–9. PMID:23890684
Differential for Left Axis Deviation
Left anterior fascicular block (LAFB)
|
Type of Fascicular Block |
LAFB |
LPFB |
|
Axis |
Left Axis Deviation | Right Axis Deviation |
| Leads I & aVL |  |
 |
| Lead III | |
|
Take-home points:
Wellens’ Syndrome
Take home Points
Beware Wellens’ syndrome & Wellens’ waves
References:
De Zwaan C, Bär FW, Wellens HJ. Characteristic electrocardiographic pattern indicating a critical stenosis high in left anterior descending coronary artery in patients admitted because of impending myocardial infarction. Am Heart J, 1892 Apr;103(4 Pt 2):730-6. PMID: 6121481
Does Gastro-Esophageal Reflux Provoke the Myocardial Ischemia in Patients with CAD?
Take home Points
LVH with repolarization abnormality (“strain”)
LVH with strain vs. Cardiac Ischemia
Take home Points
Monomorphic Ventricular Rhythm Nomenclature
Ventricular Tachycardia Pearls
Take home Points
Take home Points
Take home Points
What do you do when ST-segment elevation in STEMI resolved before cath lab activation (spontaneously or with medical treatment?
Reference:
Ownbey M, Suffoletto B, Frisch A, et al. Prevalence and interventional outcomes of patients with resolution of ST-segment elevation between prehospital and inhospital ECG. Prehosp Emerg Care, 2014 Apr-Jun;18(2):174-9. PMID: 24400994
Take home Points
Differential for Prolonged QT-Interval
Take home Points
New T-wave inversion or ST-segment down sloping in aVL or V2 may be an early reciprocal change that precedes inferior STEMI
Take home Points
Differential for Non-conducted P-waves (P:QRS > 1, a.k.a “electrocardiographic polyuria”)
Take home Points
Low Voltage Definition
Low Voltage QRS Differential
Take home Points
Causes of Widening of the QRS-complex
Wolff-Parkinson-White Syndrome with Atrial Fibrillation
Take Home Points:
WPW + Atrial Fibrillation
References:
de Winter T-waves
Take Home Points:
De Winter T-waves
References:
aVR – The forgotten 12th lead
DDx for ST-segment elevation in aVR (with multilead ST-depression) “global cardiac ischemia”
Take-home points:
Reference:
aVR – The forgotten 12th lead
DDx for ST-segment elevation in aVR (with multilead ST-depression) “global cardiac ischemia”
Take-home points:
Reference:
Riley, et al. Am Heart J 2013. PMID: 23237133
Take-home points:
Get serial ECG’s in suspected ACS!
Subtle early signs of ischemia
When you seen any of these…one ECG begets another!
Reference:
Schläpfer, et al. J Am Coll Cardiol 2017. PMID: 28838369
Take-home points:
Reference:
Poor R-wave Progression Differential
Defined as a < 3 mm R-wave by lead V3
Clues to RV Infarction on the 12-lead ECG
Narrow-Complex & Regular Tachycardia Differential
1. Sinus Tachycardia
2. Supraventricular Tachycardia (SVT)
3. Atrial flutter with 2:1 Conduction
To differentiate…always look at what the atrium is doing (V1 typically best lead to look for atrial activity)
Narrow Complex & Irregular Tachycardia Differential
ECG findings in Hyperkalemia
Regular Really Wide Complex Tachycardia (RRWCT)
Post-syncope ECG
When the history and physical exam do not suggest a diagnosis, always think of the following differentials when interpreting the ECG of patients with syncope or new-onset seizures:
Differential Diagnosis for T-wave inversions
Arrhythmogenic Right Ventricular Cardiomyopathy
Take home Points
References:
Hyperkalemia
Durfey N, et al. Severe Hyperkalemia: Can the Electrocardiogram Risk Stratify for Short-term Adverse Events? WJEM 2017. PMID: 28874951
ECG findings in Hyperkalemia
Reference:
Durfey N, Lehnhof B, Bergeson A, et al. Severe Hyperkalemia: Can the Electrocardiogram Risk Stratify for Short-term Adverse Events? West J Emerg Med 2017;18(5):963–71. PMID: 28874951
Always think of the following differentials when interpreting the ECG of patients with syncope:
Hypertrophic Cardiomyopathy
Take-home point:
Hypertrophic cardiomyopathy is a common cause of sudden cardiac death in young males. Look for high voltage and deep narrow Q-waves. Diagnostic test is a dopple echocardiogram!
Can’t miss differential diagnosis for chest pain
Can’t miss differential diagnosis for dyspnea (with clear lungs)
Differential diagnosis for right axis deviation
Differential diagnosis for low voltage QRS
Take-home point:
ECG findings in Hypothermia
Is this Reflux???
Take home points
ECG findings in Pulmonary Embolism
ECG findings in PE associated with hemodynamic instability and increased morbidity and mortality (not necessarily specific for PE):
Take home Points
References:
Shopp JD, Stewart LK, Emmett TW, Kline JA. Findings From 12-lead Electrocardiography That Predict Circulatory Shock From Pulmonary Embolism: Systematic Review and Meta-analysis. Acad Emerg Med 2015;22(10):1127–37. PMID: 26394330
Dibgy,GC, Kulka P, Zhan ZQ, et al. The value of electrocardiographic abnormalities in the prognosis of pulmonary embolism: a consensus paper. Ann Noninvasive Electrocardiol 2015. May;20(3):207-23. PMID: 25994548
Kukla P, McIntyre WF, Fijorek K, et al. Electrocardiographic abnormalities in patients with acute pulmonary embolism complicated by cardiogenic shock. Am J Emerg Med 2014;32(6):507–10. PMID: 24602894
Zhan Z-Q, Wang C-Q, Nikus KC, et al. Electrocardiogram patterns during hemodynamic instability in patients with acute pulmonary embolism. Ann Noninvasive Electrocardiol 2014;19(6):543–51.PMID: 24750207
Abarca E, Baddi A, Manrique R. ECG manifestations in submassive and massive pulmonary embolism. Report of 4 cases and review of literature. Journal of Electrocardiology 2014;47(1):75–9. PMID: 23890684
ECG findings in Hypothermia
Take home points
Narrow-Complex & Regular Tachycardia Differential
To differentiate…always look at what the atrium is doing.
Take home points:
SVT’s
Wolff-Parkinson-White Syndrome
WPW with SVT
Check out last week’s case that covers WPW with orthodromic and antidromic SVT here: February 22, 2016 Case of the Week
Wolff-Parkinson-White Syndrome with Atrial Fibrillation
Pitfall: Treatment with Amiodarone results in patient decompensation (see references)
Take Home Points:
WPW + Atrial Fibrillation
References:
Take Home Points:
Hyperacute T-waves
When in doubt get serial ECGs to evaluate for dynamic changes that could help you diagnose an early STEMI!
Take Home Points:
Don’t jump to conclusions! Be systematic.
Systematic approach to ECGs
Differential for Rightward Axis Deviation
Differential for QRS Prolongation
Differential for Prolonged QTc Interval
Na+ channel blocker toxicity
Take Home Points:
Ventricular Tachycardia (VT)
References:
1. Katritsis DG, Zareba W, Camm AJ. Nonsustained ventricular tachycardia. J Am Coll Cardiol 2012;60(20):1993–2004. PMID: 23983773
2. Foley P, Kalra P, Andrews N. Amiodardone—avoid the danger of torsade de pointes. Resuscitation. 2008;76(1):137-41. PMID: 17716804
Differential for Prolonged QTc Interval
Himalayan T-waves
Take Home Points:
Atrial Septal Defect (ASD)
Take Home Points:
Reference
Heller J, Hagège AA, Besse B, et al. “Crochetage” (notch) on R wave in inferior limb leads: a new independent electrocardiographic sign of atrial septal defect. JAC 1996;27(4):877–82. PMID: 8613618
Want to learn about low risk chest pain?
Check out the recent lectures from the University of Maryland Emergency Cardiology Symposium here: Livestream Lectures & check out the #UMESC16 tweets.
Uncomplicated Right Bundle Branch Block
Take Home Points:
Want to learn about low risk chest pain?
Check out the recent lectures from the University of Maryland Emergency Cardiology Symposium here: Livestream Lectures & check out the #UMESC16 tweets.
ECG findings in Hyperkalemia
Take Home Points:
Differential diagnosis for regular wide complex tachycardia
Take Home Points:
ECG 1 Answer
Multifocal atrial tachycardia with voltage criteria for LVH. Treat the underlying condition!
Differential Diagnosis for Narrow Complex Irregular Tachycardia
ECG 2 Answer
Sinus tachycardia with complete heart block and a junctional escape rhythm. There is evidence of inferior STEMI with probable posterior extension.
Pearl: Remember that sinus rhythm should have upright p-waves in the limb leads (inverted in aVR)
ECG 3 Answer
Atrial fibrillation with complete heart block and a junctional escape rhythm. The ECG suggests digoxin toxicity. There are also biphasic T-waves that deflect down before going up “reverse Wellens’ waves” a.k.a. “NikEleKam T waves” caused by U-waves and a prolonged QT interval that is consistent with severe hypokalemia
ECG 4 Answer
Calcium & Bicarb!
This is a regular really wide complex tachycardia that is too slow to be ventricular tachycardia. You should think of toxicological and metabolic causes. Treat empirically with Calcium & Bicarb when in doubt!
Case 5 Answer
Early inferior wall STEMI
New T-wave inversion in aVL may be an early reciprocal change
Case 6 Answer
Artifact. There are intrinsic beats that can be mapped out. Correlate clinically!
ECG 7 Answer
Hypertrophic obstructive cardiomyopathy (HOCM)
For more on HOCM, review the case from November 16, 2015.
ECG 8 Answer
Impressive Syndrome, treat for hyperkalemia!
Hyperkalemic Periodic Paralysis (HYPP) a.k.a Impressive Syndrome
Take-home point:
For more on this topic, review the case from December 28, 2015.
ECG 9 Answer
Sinus rhythm with junctional trigemeny, left axis deviation, and WPW
Differential Diagnosis for Short PR interval
Differential diagnosis of leftward axis
For more on WPW, review the case from February 22, 2016 & February 29, 2016.
ECG 10 Answer
TCA/ Na+ channel blocker toxicity. Treat with Sodium Bicarbonate.
Na+ channel blocker toxicity ECG
To learn more about Na+ channel blocker toxicity review the case from March 14, 2016.
ECG 11 Answer
Calcium for Hyperkalemia
ECG findings in Hyperkalemia
Causes of Rightward Axis Deviation
Pearl: When you see a wide QRS rhythm with a rightward axis, think of HYPERKALEMIA or other sodium channel blocker toxicities.
For more practice on this topic, review the case from Jan 12, 2015.
ECG 12 Answer
Hypokalemia causing Himalayan T-waves and a prolonged QT interval. Watch out for Torsades!
Himalayan T-waves
Differential for Prolonged QTc Interval
For more practice on this topic, review the case from March 28, 2016.
Left anterior fascicular block (LAFB)
Differential diagnosis for leftward axis
Left posterior fascicular block (LPFB)
Differential diagnosis for rightward axis
| Type of Fascicular Block | LAFB | LPFB |
| Axis | Left Axis Deviation | Right Axis Deviation |
| Leads I & aVL |  |
 |
| Lead III |  |
 |
Bonus Pearls:
Bifascicular Block
Trifascicular Block
References:
Diagnostic criteria for Acute Pericarditis
ECG findings in Pericarditis vs. STEMI
Step 1. Factors that strongly favor STEMI:
Look for the factors that rule in STEMI before thinking pericarditis!
Step 2. Factors that suggest pericarditis (only after step 1):
When in doubt…do serial ECGs and consider CATH!
Take home points:
References:
Imazio M, Gaita F, LeWinter M. Evaluation and Treatment of Pericarditis: A Systematic Review. JAMA 2015;314(14):1498–506. PMID: 26461998
Normal Right Bundle Branch Block (RBBB)
Take home points:
Look at all the leads and trace out where the QRS ends and where the J-point begins to evaluate for ST-segment deviations.
Age as a cardiac risk factor
ECG Pearls: Pericarditis vs. STEMI
Final take-home points:
CAD, ACS, & STEMI DOES occur in young patients!
References
Marsan RJ, Shaver KJ, Sease KL, et al. Evaluation of a clinical decision rule for young adult patients with chest pain. Academic Emergency Medicine 2005;12(1):26–31. PMID: 15635134.
Lumen stenosis doesn’t matter…It’s all about plaque vulnerability!
Plaque vulnerability based on 3 major factors
Recent stress testing and catheterizations are not predictive of new plaque rupture!
Final take-home points:
References:
Libby P. Mechanisms of acute coronary syndromes and their implications for therapy. N Engl J Med 2013;368(21):2004–13. PMID: 23697515
Arbab-Zadeh A, Nakano M, Virmani R, et al. Acute coronary events. Circulation 2012;125(9):1147–56. PMID: 22392862
Fanaroff AC, Rymer JA, Goldstein SA, et al. Does This Patient With Chest Pain Have Acute Coronary Syndrome?: The Rational Clinical Examination Systematic Review. JAMA 2015;314(18):1955–65. PMID: 26547467
Virmani R, Burke AP, Farb A, et al. Pathology of the vulnerable plaque. J Am Coll Cardiol 2006;47(8 Suppl):C13–8. PMID: 16631505
Caussin C, Ohanessian A, Lancelin B, et al. Coronary plaque burden detected by multislice computed tomography after acute myocardial infarction with near-normal coronary arteries by angiography. AJC 2003;92(7):849–52. PMID: 14516892
ECG Diagnosis of Ventricular Tachycardia (VT)
Mattu Algorithm for Wide Complex Tachycardias (WCTs)
Final take-home points:
References:
Jastrzebski M, Kulka P, Czarnecka D, et al. Comparison of five electrocardiographic methods for differentiation of wide QRS-complex tachycardias. Europace 2012;14(8):1165-71. PMID:22333239
Szelényi Z, Duray G, Katona G, et al. Comparison of the “real-life” diagnostic value of two recently published electrocardiogram methods for the differential diagnosis of wide QRS complex tachycardias. Acad Emerg Med 2013;20(11):1121–30. PMID: 24238314
ECG Diagnosis of Ventricular Tachycardia (VT)
Mattu Algorithm for Wide Complex Tachycardias (WCTs)
What about an Adenosine diagnostic challenge?
Final take-home points:
References:
Marill KA, Wolfram S, Desouza IS, et al. Adenosine for wide-complex tachycardia: efficacy and safety. Crit Care Med 2009;37(9):2512-8. PMID:19623049
Jastrzebski M, Kulka P, Czarnecka D, et al. Comparison of five electrocardiographic methods for differentiation of wide QRS-complex tachycardias. Europace 2012;14(8):1165-71. PMID:22333239
Szelényi Z, Duray G, Katona G, et al. Comparison of the “real-life” diagnostic value of two recently published electrocardiogram methods for the differential diagnosis of wide QRS complex tachycardias. Acad Emerg Med 2013;20(11):1121–30. PMID: 24238314
ECG findings in Pulmonary Embolism
Differential diagnosis for tall R-wave in V1
Differential diagnosis for rightward axis
ECG findings in PE associated with hemodynamic instability and increased morbidity and mortality (not specific for PE):
Final take-home points:
References:
Shopp JD, Stewart LK, Emmett TW, Kline JA. Findings From 12-lead Electrocardiography That Predict Circulatory Shock From Pulmonary Embolism: Systematic Review and Meta-analysis. Acad Emerg Med 2015;22(10):1127–37. PMID:26394330
Dibgy,GC, Kulka P, Zhan ZQ, et al. The value of electrocardiographic abnormalities in the prognosis of pulmonary embolism: a consensus paper. Ann Noninvasive Electrocardiol 2015. May;20(3):207-23. PMID:25994548
Kukla P, McIntyre WF, Fijorek K, et al. Electrocardiographic abnormalities in patients with acute pulmonary embolism complicated by cardiogenic shock. Am J Emerg Med 2014;32(6):507–10. PMID:24602894
Zhan Z-Q, Wang C-Q, Nikus KC, et al. Electrocardiogram patterns during hemodynamic instability in patients with acute pulmonary embolism. Ann Noninvasive Electrocardiol 2014;19(6):543–51.PMID:24750207
Abarca E, Baddi A, Manrique R. ECG manifestations in submassive and massive pulmonary embolism. Report of 4 cases and review of literature. Journal of Electrocardiology 2014;47(1):75–9. PMID:23890684
Prehospital ECG Pearls
Final take-home points:
YOU must be the experts in electrocardiography!
Systematic approach to ECGs
Causes of ST-segment Elevation
Take home points:
References
Littmann L, Taylor L, Brearley WD. ST-segment elevation: a common finding in severe hypercalcemia. Journal of Electrocardiology 2007;40(1):60–2. PMID: 17027838
Nishi SPE, Barbagelata NA, Atar S, et al. Hypercalcemia-induced ST-segment elevation mimicking acute myocardial infarction. Journal of Electrocardiology 2006;39(3):298–300. PMID: 16777515
Systematic approach to ECGs
Causes of ST-segment Elevation
Take home points:
References
Littmann L, Taylor L, Brearley WD. ST-segment elevation: a common finding in severe hypercalcemia. Journal of Electrocardiology 2007;40(1):60–2. PMID: 17027838
Nishi SPE, Barbagelata NA, Atar S, et al. Hypercalcemia-induced ST-segment elevation mimicking acute myocardial infarction. Journal of Electrocardiology 2006;39(3):298–300. PMID: 16777515
Review Key Teaching Points (Red Box)
Quick Evaluation of the QT-interval
T-waves should end before the midpoint of the R-R interval.
Beware of a prolonged QT when the T-waves end after ½ the R-R wave distance.
Differential for Prolonged QTc Interval
Bonus Pearl
Prolongation of the ST-segment contributing to a prolonged QT interval is the hallmark ECG change in hypocalcemia. Only hypocalcemia and hypothermia produce these ECG changes, so when the temperature is normal…consider hypocalcemia!
Left Bundle Branch Block
Sgarbossa Criteria
Take-home Points:
References:
Pacemakers and AMI
Sgarbossa Criteria
A. Concordant STE ≥ 1mm (in any lead)
B. Concordant STD ≥ 1mm in V1, V2, or V3
C. Discordant STE ≥ 5mm (most specific)
Take-home Points:
References:
Polymorphic Ventricular Tachycardia & Torsade de pointes vs. Artifact
Take home points
Clues to RV Infarction on the 12-lead ECG
Take home points
Differential for ST-depression in anteroseptal leads
Posterior STEMI (“inferolateral”) – the most common type of missed STEMI!
Take-home Points:
References:
ECG findings in TCA/Na+ channel blocker toxicity
Causes of Rightward Axis Deviation
Causes of QRS Prolongation
Differential for Prolonged QTc Interval
Take-home Points:
Non-STE ACS (Class IA in national guidelines)
Reference:
Amsterdam EA, Wenger NK, Brindis RG, et al. 2014 AHA/ACC Guideline for the Management of Patients with Non-ST-Elevation Acute Coronary Syndromes: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol. 2014;64(24):e139–228. PMID: 25260718.
Take-home Points:
de Winter T-waves
References:
Differential for ST-depression in anteroseptal leads
Posterior STEMI (“inferolateral”) – the most common type of missed STEMI!
Take-home Points:
References:
Poor R-wave Progression Differential
New T-wave inversion in aVL may be a reciprocal change
Take-home Points:
Differential Diagnosis for Diffuse ST-Elevation (STE)
Large Acute STEMI
Benign Early repolarization
Pericarditis/Myocarditis
Ventricular aneurysm
Vasospasm
Acute Pericarditis vs. Benign Early Repolarization (BER)
Take-home Points:
References:
Wolff-Parkinson-White Syndrome with Atrial Fibrillation
Pitfall: Treatment with Amiodarone results in patient decompensation (see references)
Take Home Points:
WPW + Atrial Fibrillation
References:
Ventricular Tachycardia (VT)
Take Home Points:
ECG findings in Hyperkalemia
Regular Really Wide Complex Tachycardia (RRWCT)
Take Home Points:
When ACLS isn’t working, think of toxicological and metabolic causes and consider empiric treatment with calcium and bicarb
Quick Evaluation of the QT-interval
T-waves should end before the midpoint of the R-R interval.
Beware of a prolonged QT when the T-waves end after ½ the R-R wave distance.
Differential for Prolonged QTc Interval
Take Home Points:
Quick Evaluation of the QT-interval
T-waves should end before the midpoint of the R-R interval.
Beware of a prolonged QT when the T-waves end after ½ the R-R wave distance.
Differential for Prolonged QTc Interval
Take Home Points:
Differential for Fever & Altered Mental Status
Differential for Widened QRS
Differential for Rightward Axis Deviation
Differential for Brugada pattern in V1
Differential for Non-conducted P-waves (P:QRS > 1, a.k.a “electrocardiographic polyuria”)
Differential for Left Axis Deviation
Left anterior fascicular block (LAFB)
| Type of Block | Left Anterior Fascicular Block | Left Posterior Fascicular Block |
| Axis | Left Axis Deviation | Right Axis Deviation |
| Leads I & aVL | |
|
| Lead III | |
|
Take Home Points:
When you see electrocardiographic polyuria…map out the P-waves and look closely at the PR-interval
Beware Hyperkalemia!
ECG findings in Hyperkalemia
Pearl: When you see a wide QRS rhythm with a rightward axis, think HYPERKALEMIA or other sodium channel blocker toxicities.
Bonus Pearl: Massive STE can mimic wide QRS complexes (usually only in a few leads, but usually not with a rightward axis).
Age as a cardiac risk factor
ECG Pearls: Pericarditis vs. STEMI
Final take-home points:
CAD, ACS, & STEMI DOES occur in young patients
References
Joseph A, Ackerman D, Talley JD, et al. Manifestations of coronary atherosclerosis in young trauma victims–an autopsy study. JAC 1993;22(2):459–67. PMID: 8335815
Marsan RJ, Shaver KJ, Sease KL, et al. Evaluation of a clinical decision rule for young adult patients with chest pain. Academic Emergency Medicine 2005;12(1):26–31. PMID: 15635134
ECG Pearls: Acute Pericarditis vs. STEMI
Look for the factors that rule in STEMI before thinking pericarditis!
Step 1. Factors that strongly favor STEMI:
Step 2. Factors that suggest acute pericarditis:
Nothing is 100%
When in doubt…do serial ECGs, ECHO, and consider CATH!
Acute Pericarditis
Final take-home points:
References
LeWinter MM. Clinical practice. Acute pericarditis. N Engl J Med 2014;371(25):2410–6.. PMID: 25517707
Imazio M, Brucato A, Cemin R, et al. A randomized trial of colchicine for acute pericarditis. N Engl J Med 2013;369(16):1522–8. PMID: 23992557
Alabed S, Cabello JB, Irving GJ, Qintar M, Burls A. Colchicine for pericarditis. Cochrane Database Syst Rev 2014;8:CD010652. PMID: 25164988
Hypercalcemia
Etiologies
Signs and symptoms
ECG findings
Treatment
Final take-home points:
References
Nishi SPE, Barbagelata NA, Atar S, et al. Hypercalcemia-induced ST-segment elevation mimicking acute myocardial infarction. Journal of Electrocardiology 2006;39(3):298–300. PMID: 16777515
Littmann L, Taylor L, Brearley WD. ST-segment elevation: a common finding in severe hypercalcemia. Journal of Electrocardiology 2007;40(1):60–2. PMID: 17027838
ECG Bonus Pearls:
References:
de Champlain F, Boothroyd LJ, Vadeboncoeur A, et al. Computerized interpretation of the prehospital electrocardiogram: predictive value of ST segment elevation myocardial infarction and impact on on-scene time. CJEM 2014. Mar;16(2):94-105. PMID: 24626114
Min MK, Ryu JH, Kim YI, et al. Does cardiac catheterization laboratory activation by electrocardiography machine auto-interpretation reduce door-to-balloon time? Am J Emerg Med 2014;32(11):1305–10. PMID: 25249338
Thygesen K, Alpert JS, Jaffe AS, et al. Third Universal Definition of Myocardial Infarction. J Am Coll Cardiol 2012;60(16):1581–98. PMID: 22958960
Causes of QRS Prolongation
Na2+ channel blocker toxicity
“The biggest reason we miss a diagnosis is that we make a diagnosis (and then stop looking)”
References:
Bebarta VS, Phillips S, Eberhardt A, et al. Incidence of Brugada electrocardiographic pattern and outcomes of these patients after intentional tricyclic antidepressant ingestion. AJC 2007;100(4):656–60. PMID: 17697824
Chan HY, Chan YC, Lau FL. Reversal of Brugada electrocardiographic pattern with sodium bicarbonate solution after amitriptyline overdose. Clin Toxicol (Phila) 2008;46(9):892–6. PMID: 18788005
Dysrhythmias can produce syncope or seizure-like activity so make sure to get an ECG!
Always think of the following differential when interpreting the ECG of patients with syncope or “new onset seizures”:
Differential for Prolonged QT
Remember to check electrolytes and medications!
Inverted U-waves
References:
Marriott HJL. Emergency Electrocardiography. 1997. Amazon Link.
Sovari AA, Farokhi F, Kocheril AG. Inverted U wave, a specific electrocardiographic sign of cardiac ischemia. American Journal of Emergency Medicine 2007;25(2):235–7. PMID: 17276833
Gerson MC, McHenry PL. Resting U wave inversion as a marker of stenosis of the left anterior descending coronary artery. The American Journal of Medicine 1980;69(4):545–50. PMID: 7424944
Pericardial Effusion
Low Voltage Definition
Low Voltage QRS Differential
New Low Voltage ECG + Tachycardia = Pericardial effusion until proven otherwise!
Avoid anticoagulants until pericardial effusion is ruled out.
Causes of Rightward Axis Deviation
ECG findings in Pulmonary Embolism
References:
Kosuge M, Kimura K, Ishikawa T, et al. Electrocardiographic differentiation between acute pulmonary embolism and acute coronary syndromes on the basis of negative T waves. AJC 2007;99(6):817–21. PMID: 17350373
Witting MD, Mattu A, Rogers R, Halvorson C. Simultaneous T-wave inversions in anterior and inferior leads: an uncommon sign of pulmonary embolism. Journal of Emergency Medicine 2012;43(2):228–35. PMID: 22142671
Further Reading:
Kukla P, McIntyre WF, Fijorek K, et al. Electrocardiographic abnormalities in patients with acute pulmonary embolism complicated by cardiogenic shock. Am J Emerg Med 2014;32(6):507–10. PMID: 24602894
Pre-hospital ECG Case Pearls
Patients with ventricular tachycardia can be stable, careful calling it anything else and treat with procainamide or electrical cardioversion.
Rhythm – Sinus bradycardia at a rate of ~ 57 bpm. Short PR interval.
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Differential Diagnosis for Short PR interval
LGL syndrome
Ablation procedures do not appear to be necessary, and there does not seen to be any clinical relevance.
Large pericardial effusion or tamponade, suggested by tachycardia, low voltage QRS and electrical alternans
Low Voltage Definition
Low Voltage QRS Differential
Pearls:
New low voltage ECG + Tachycardia = Pericardial effusion until proven otherwise! New low voltage ECG + Bradycardia = Myxedema until proven otherwise!
For more information about low voltage, review the case from April 6, 2015.
Posterior MI’s are the most common type of missed STEMI!
Differential for ST-depression in anteroseptal leads
Take home Point:
ST-depression in the anteroseptal leads might represent posterior STEMI. Get posterior leads!
References:
Waldo SW, Brenner DA, Li S, et al. Reperfusion times and in-hospital outcomes among patients with an isolated posterior myocardial infarction: insights from the National Cardiovascular Data Registry (NCDR). American Heart Journal 2014;167(3):350–4. PMID: 24576519
Ayer A, Terkelsen CJ. Difficult ECGs in STEMI: lessons learned from serial sampling of pre- and in-hospital ECGs. Journal of Electrocardiology 2014;47(4):448–58. PMID: 24792903.
Wei EY, Hira RS, Huang HD, et al. Pitfalls in diagnosing ST elevation among patients with acute myocardial infarction. Journal of Electrocardiology 2013;46(6):653–9. PMID: 23890685.
Waldo SW, Armstrong EJ, Kulkarni A, et al. Clinical characteristics and reperfusion times among patients with an isolated posterior myocardial infarction. J Invasive Cardiol 2013;25(8):371-5. PMID: 23913600.
LBBB and AMI
A new or presumed new LBBB used to be a STEMI equivalent. In the past few years, increasing literature has suggested that a new LBBB does NOT predict a high likelihood of AMI/acute thrombosis.
References:
Kontos MC, Aziz HA, Chau VQ, et al. Outcomes in patients with chronicity of left bundle-branch block with possible acute myocardial infarction. American Heart Journal 2011;161(4):698–704. PMID: 21473968.
Jain S, Ting HT, Bell M, et al. Utility of left bundle branch block as a diagnostic criterion for acute myocardial infarction. Am J Cardiol 2011;107(8):1111–6. PMID: 21296327.
Chang AM, Shofer FS, Tabas JA, et al. Lack of association between left bundle-branch block and acute myocardial infarction in symptomatic ED patients. Am J Emerg Med 2009;27(8):916–21. PMID: 19857407.
The most recent STEMI Guidelines state that new or presumed new LBBB is no longer an indication for emergent CLA/lytics!
Reference:
O’Gara PT, Kushner FG, Ascheim DD, et al. 2013 ACCF/AHA Guideline for the Management of ST-Elevation Myocardial Infarction. JAC 2013;61(4):e78–e140. PMID: 23256914.
Left Bundle Branch Block
Sgarbossa Criteria
Reference
Smith SW, Dodd KW, Henry TD, et al. Diagnosis of ST-Elevation Myocardial Infarction in the Presence of Left Bundle Branch Block With the ST-Elevation to S-Wave Ratio in a Modified Sgarbossa Rule. Ann Emerg Med. 2012;60(6):766–776. PMID: 22939607.
Neeland IJ, Kontos MC, de Lemos JA. Evolving considerations in the management of patients with left bundle branch block and suspected myocardial infarction. J Am Coll Cardiol 2012;60(2):96–105. PMID: 22766335.
Cai Q, Mehta N, Sgarbossa EB, et al. The left bundle-branch block puzzle in the 2013 ST-elevation myocardial infarction guideline: From falsely declaring emergency to denying reperfusion in a high-risk population. Are the Sgarbossa Criteria ready for prime time? American Heart Journal. 2013;166(3):409–413. PMID: 24016487.
Take-home Points:
Sgarbossa A –> concordant STE = AMI
Sgarbossa B –> concordant STD in V1, V2, or V3 = AMI
Revised Sgarbossa C –> discordant ST segment > 25% size of R or S wave = AMI (pending validation study)
Pacemakers and AMI
Sgarbossa Criteria
The criteria are reviewed below
Maloy, et al. WJEM 2010
Take-home Points:
Sgarbossa criteria appear to predict acute MI in patients with pacemakers. Criteria C (excessively discordant ST-segment elevation) may be most specific.
Reference
Sgarbossa EB. Recent advances in the electrocardiographic diagnosis of myocardial infarction: left bundle branch block and pacing. Pacing Clin Electrophysiol. 1996;19(9):1370–1379. PMID: 8880802.
Sgarbossa EB, Pinski SL, Gates KB, Wagner GS. Early electrocardiographic diagnosis of acute myocardial infarction in the presence of ventricular paced rhythm. GUSTO-I investigators. Am J Cardiol. 1996;77(5):423–424. PMID: 8602576.
Maloy KR, Bhat R, Davis J, Reed K, et al. Sgarbossa Criteria are Highly Specific for Acute Myocardial Infarction with Pacemakers. West J Emerg Med. 2010;11(4):354–357. PMID: 21079708.
Case 1: LBBB and AMI
Which patients with LBBB need emergent reperfusion therapy?
For more on this, review the case from June 1st, 2015
Case 2: Atrial Fibrillation with WPW
Avoid all AV nodal blockers in Atrial fibrillation with WPW!
Case 3: Septal STEMI vs Hyperkalemia?
ECG findings in Hyperkalemia
Beware…Hyperkalemia does whatever it wants to the ECG!
For more on hyperkalemia, review the case from Jan 12th, 2015
Case 4: Ventricular Tachycardia vs. AIVR
Case 5: Syncope & Anteroseptal ST-segment Depression
Differential for ST-depression in anteroseptal leads
ST-depression in the anteroseptal leads might represent posterior STEMI. Get posterior leads!
Case 6: Really Wide Complex Tachycardia
For more about Na2+ channel blocker toxicity, review the case from Feb 23rd, 2015
Case 7: Bizarre Bradycardia
Case 8: Low Voltage
Low Voltage Definition
Low Voltage QRS Differential
New low voltage ECG + Tachycardia = Pericardial effusion until proven otherwise!
Avoid anticoagulants until pericardial effusion is ruled out.
For more, review the case from April 6th, 2015
de Winter T-waves
References:
de Winter RJ, Verouden NJ, Wellens HJ, et al. A new ECG sign of proximal LAD occlusion. N Engl J Med. 2008 Nov 6;359(19):2071-3. PMID:18987380
Verouden NJ, Koch KT, Peters RJ, et al. Persistent precordial “hyperacute” T-waves signify proximal left anterior descending artery occlusion. Heart 2009;95(20):1701–6. PMID: 19620137
Rokos IC, French WJ, Mattu A, et al. Appropriate cardiac cath lab activation: optimizing electrocardiogram interpretation and clinical decision-making for acute ST-elevation myocardial infarction. Am Heart J. 2010 Dec;160(6):995-1003. PMID: 21146650
Stankovic I, Ilic I, Panic M, et al. The absence of the ST-segment elevation in acute coronary artery thrombosis: what does not fit, the patient or the explanation? J Electrocardiol 2011;44(1):7–10. PMID: 20591442
Goebel M, Bledsoe J, Orford JL, Mattu A, Brady WJ. A new ST-segment elevation myocardial infarction equivalent pattern? Prominent T wave and J-point depression in the precordial leads associated with ST-segment elevation in lead aVr. Am J Emerg Med 2014;32(3):287.e5–8. PMID: 24176590
Birnbaum I, Birnbaum Y. High-risk ECG patterns in ACS—need for guideline revision. J Electrocardiol 2013;46(6):535–9. PMID: 23863685
Chest Pain History: Associated symptoms
Clinical factors that INCREASE the likelihood of ACS:
Clinical factors that DECREASE the likelihood of ACS:
Pericarditis vs. STEMI
Step 1. Factors that rule-in STEMI:
Look for the factors that rule in STEMI before thinking pericarditis!
Step 2. Factors that suggest pericarditis:
When in doubt…do serial ECGs and consider CATH!
Bonus Pearl: Expect to see ST-segment changes in the first 10-15 minutes in cardiac arrest patients that have received epinephrine or were defibrillated.
Most Important Pearl:
Always look at all 12 leads & be systematic. When in doubt do serial ECG’s!
More Pearls:
Artifact is not uncommon!
Look at the patient:
New T-wave inversion in aVL may be a reciprocal change
Poor R-wave Progression
Differential Diagnosis for Diffuse ST-Elevation
Large Acute STEMI
Pericarditis/Myocarditis
Ventricular aneurysm
Early repolarization
Vasospasm
Pericarditis vs. STEMI
Step 1. Factors that strongly favor STEMI:
Look for the factors that rule in STEMI before thinking pericarditis!
Step 2. Factors that suggest pericarditis:
When in doubt…do serial ECGs and consider CATH!
Low Voltage Definition
Low Voltage QRS Differential
Pericardial Effusion
New low voltage ECG + Tachycardia = Pericardial effusion until proven otherwise!
Avoid anticoagulants until pericardial effusion is ruled out.
Ventricular Rhythms
AIVR
Take home points:
Ventricular tachycardia: HR > 120
Ventricular antiarrhythmics can kill!
Regular Really Wide Complex Tachycardia (RRWCT)
ECG findings in Hyperkalemia
Pearl:
Patients with hyperkalemia may present with significant bradycardia (without peaked T-waves or widening of the QRS). The bradycardia may not respond to conventional ACLS therapies. Having a high degree of suspicion for hyperkalemia when faced with a bizzare rhythm will save lives!
Take home points:
When in doubt, treat empirically for hyperkalemia with calcium & bicarb!
Typical ECG findings on the Pediatric ECG
Persistent juvenile T-wave pattern
Pearl: A prolonged QT interval in pediatric patients is ABNORMAL! The QTc for all patients under 16 years of age should be < 450 ms
Differential for Prolonged QT-interval caused by Prolonged T-wave’s
What are the only 2 things that prolong the QT-interval specifically by stretching the ST-segment?
Take home points:
Bonus:
For those who want more information about the normal interval limits for the pediatric ECG (and more), check out the following references with links to their free text articles:
Typical ECG findings on the Pediatric ECG
Persistent juvenile T-wave pattern
DDx: Ischemic, PE, ARVD
Bonus:
For those who want more information about the normal interval limits for the pediatric ECG (and more), check out the following references with links to their free text articles:
Take home points:
Most Important Pearl:
Always look at all 12 leads & be systematic. When in doubt do serial ECG’s!
True VT/Polymorphic VT/Torsade de pointes vs. Artifact
Artifact is not uncommon!
Look at the patient:
Diagnostic considerations in syncope should always include:
Causes of Rightward Axis Deviation
ECG findings in Pulmonary Embolism
Take home Points
PE can mimic ACS! Make sure to consider PE in cases of syncope and pay close attention to the axis and look for new TWI’s.
Wellens’ Syndrome:
Take home Points
Beware Wellens’ syndrome & Wellens’ waves
References:
de Zwaan C, Bär FW, Wellens HJ. Characteristic electrocardiographic pattern indicating a critical stenosis high in left anterior descending coronary artery in patients admitted because of impending myocardial infarction. Am Heart J, 1892 Apr;103(4 Pt 2):730-6. PMID: 6121481
Take home Points
Beware Wellens’ syndrome & Wellens’ waves, but also watch out for normal variants!
Make sure to check out last week’s case for a thorough review of true Wellens’ here. The following is a summary of last week’s content:
Wellens’ Syndrome:
References:
Wang K, Asinger RW, Marriott HJL. ST-segment elevation in conditions other than acute myocardial infarction. N Engl J Med 2003;349(22):2128–35. PMID: 14645641
Corrado D, Pelliccia A, Heidbuchel H, et al. Recommendations for interpretation of 12-lead electrocardiogram in the athlete. Eur. Heart J. 2010;31(2):243–59. PMID: 19933514
de Zwaan C, Bär FW, Wellens HJ. Characteristic electrocardiographic pattern indicating a critical stenosis high in left anterior descending coronary artery in patients admitted because of impending myocardial infarction. Am Heart J, 1892 Apr;103(4 Pt 2):730-6. PMID: 6121481
Post-Arrest and Syncope ECG Differential
Arrhythmogenic Right Ventricular Dysplasia (ARVD)
Take home Points
ARVD: Heightened Concern if
References:
Basso C., et al. Arrhythmogenic right ventricular cardiomyopathy. Lancet 2009;373(9671):1289–1300. PMID: 19362677
Diez D, Brugada J. Diagnosis and Management of Arrhythmogenic Right Ventricular Dysplasia: An article from the E-Journal of the ESC Council for Cardiology Practice, European Society of Cardiology 2008 [Full text].
ECG findings in Pulmonary Embolism
Take home Points
ECG findings in Hyperkalemia
Take home points:
Who Should Go To The Cath Lab Emergently?
Symptoms concerning for acute cardiac ischemia (CP or anginal equivalent)
+ STEMI ECG findings, or… “Sick” NSTE-ACS (unstable, acute heart failure, intractable ischemia)
Mattu Class I Indications
Reference:
Thygesen K, Alpert JS, Jaffe AS, et al. Third Universal Definition of Myocardial Infarction. J Am Coll Cardiol 2012;60(16):1581–98. PMID: 22958960
Differential for ST-depression in anteroseptal leads
References:
References:
4. Non-STE ACS (Class IA in national guidelines)
Reference:
Amsterdam EA, Wenger NK, Brindis RG, et al. 2014 AHA/ACC Guideline for the Management of Patients with Non-ST-Elevation Acute Coronary Syndromes: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol 2014;64(24):e139–228. PMID: 25260718.
Who Should Go To The Cath Lab Emergently?
Symptoms concerning for acute cardiac ischemia (CP or anginal equivalent)
+
STEMI ECG findings, or… “Sick” NSTE-ACS (unstable, acute heart failure, intractable ischemia)
Who Should Go To The Cath Lab Emergently?
Symptoms concerning for acute cardiac ischemia (CP or anginal equivalent)
+ STEMI ECG findings, or… “Sick” NSTE-ACS (unstable, acute heart failure, intractable ischemia)
Always think of the following differentials when interpreting the ECG of patients with syncope:
Hypertrophic Cardiomyopathy
Take-home points:
Hypertrophic cardiomyopathy is a common cause of sudden cardiac death in young males. Look for high voltage and deep narrow Q-waves.
Always think of the following differentials when interpreting the ECG of patients with syncope:
Take-home points:
Reciprocal changes can precede ST-segment elevation in STEMI. New TWI or ST-segment depression in aVL may predict an evolving inferior STEMI. Remember to always obtain serial ECGs in patients with ongoing or changing ischemic symptoms.
Differential for Prolonged QT Interval
Take-home points:
In patients with first time “seizures”, make sure to get an ECG and look for potential signs of dysrhythmia. Torsade de pointes may mimic seizure activity.
Concordant STE ≥ 1mm (in any lead) = Most specific for MI
Concordant STD ≥ 1mm in V1, V2, or V3 = Specific for MI
Discordant STE ≥ 5mm = Less specific for MI
Reference
Cai Q, Mehta N, Sgarbossa EB, et al. The left bundle-branch block puzzle in the 2013 ST-elevation myocardial infarction guideline: From falsely declaring emergency to denying reperfusion in a high-risk population. Are the Sgarbossa Criteria ready for prime time? American Heart Journal. 2013;166(3):409–413. PMID: 24016487.
Neeland IJ, Kontos MC, de Lemos JA. Evolving considerations in the management of patients with left bundle branch block and suspected myocardial infarction. J Am Coll Cardiol 2012;60(2):96–105. PMID: 22766335.
Mayers H, Limakakeng AT, Jaffa EJ, et al. Validation of the modified Sgarbossa criteria for acute coronary occlusion in the setting of left bundle branch block: A retrospective case-control study. American Heart Journal. 2015;170:1255-1264. DOI: http://dx.doi.org/10.1016/j.ahj.2015.09.005
Smith SW, Dodd KW, Henry TD, et al. Diagnosis of ST-Elevation Myocardial Infarction in the Presence of Left Bundle Branch Block With the ST-Elevation to S-Wave Ratio in a Modified Sgarbossa Rule. Ann Emerg Med. 2012;60(6):766–776. PMID: 22939607.
Sgarbossa EB. Recent advances in the electrocardiographic diagnosis of myocardial infarction: left bundle branch block and pacing. Pacing Clin Electrophysiol. 1996;19(9):1370–1379. PMID: 8880802.
The spiked helmet sign
References:
Hyperkalemic Periodic Paralysis (HYPP) a.k.a Impressive Syndrome
Take-home points:
EMS Cases Week 2 of 2 – Key Points
Case #6
Subtle early signs of ischemia
Case #7
Narrow complex regular tachycardia DDx
Case #8
Rate related ST-segment abnormalities
Case #9
Hyperkalemia:
Case #10
Differential for Non-conducted P-waves (P: QRS > 1, a.k.a “electrocardiographic polyuria”)
Blocked Premature Atrial Complexes
2nd degree AV Block: Mobitz I (Wenckebach)
2nd degree AV Block: Mobitz II
2nd degree AV Block: 2:1 conduction
2nd degree AV Block: Advanced AV Block or “High-grade AV Block”
3rd degree AV Block (Complete Heart Block) + AV dissociation
3rd degree AV Block (Complete Heart Block) + Isorhythmic AV dissociation
Differential diagnosis for T-wave inversions
Differential diagnosis for T-wave inversions in V1-V3
Always think of the following differentials when interpreting the ECG of patients with syncope when the history and physical exam are non-diagnostic:
Arrhythmogenic Right Ventricular Cardiomyopathy
Take home Points
References:
Take Home Points:
Reference:
Differential diagnosis for diffuse ST segment elevation without reciprocal ST segment depression
Take Home Points:
Differential for Non-conducted P-waves (P: QRS > 1)
Blocked Premature Atrial Complexes
2nd degree AV Block: Mobitz I (Wenckebach)
2nd degree AV Block: Mobitz II
2nd degree AV Block: 2:1 conduction
2nd degree AV Block: Advanced AV Block or “High-grade AV Block”
3rd degree AV Block (Complete Heart Block) + AV dissociation
3rd degree AV Block (Complete Heart Block) + Isorhythmic AV dissociation
Take Home Points:
Atrioventricular (AV) Block Review Summary
1st Degree AV Block
Differential for Non-conducted P-waves (P: QRS > 1, “electrocardiographic polyuria”)
Blocked Premature Atrial Complexes
2nd degree AV Block: Mobitz I (Wenckebach)
2nd degree AV Block: Mobitz II
2nd degree AV Block: 2:1 conduction
2nd degree AV Block: Advanced AV Block or “High-grade AV Block”
3rd degree AV Block (Complete Heart Block) + AV dissociation
3rd degree AV Block (Complete Heart Block) + Isorhythmic AV dissociation
Take Home Points:
Atrioventricular (AV) Block Review Summary
1st Degree AV Block
Differential for Non-conducted P-waves (P: QRS > 1, “electrocardiographic polyuria”)
Blocked Premature Atrial Complexes
2nd degree AV Block: Mobitz I (Wenckebach)
2nd degree AV Block: Mobitz II
2nd degree AV Block: 2:1 conduction
2nd degree AV Block: Advanced AV Block or “High-grade AV Block”
3rd degree AV Block (Complete Heart Block) + AV dissociation
3rd degree AV Block (Complete Heart Block) + Isorhythmic AV dissociation
Take Home Points:
Atrioventricular (AV) Block Review Summary
1st Degree AV Block
Differential for Non-conducted P-waves (P: QRS > 1, “electrocardiographic polyuria”)
Blocked Premature Atrial Complexes
2nd degree AV Block: Mobitz I (Wenckebach)
2nd degree AV Block: Mobitz II
2nd degree AV Block: 2:1 conduction
2nd degree AV Block: Advanced AV Block or “High-grade AV Block”
3rd degree AV Block (Complete Heart Block) + AV dissociation
3rd degree AV Block (Complete Heart Block) + Isorhythmic AV dissociation
Take Home Points:
Ventricular Rhythms
AIVR
Take-home Points:
References:
New T-wave inversion in aVL may be an early reciprocal change
Take-home Points:
Pacemakers and AMI
Take home Points
QRS fragmentation (fQRS)
Take home Points
References:
QRS fragmentation (fQRS)
Pseudonormalization of T waves
Take home Points
QRS fragmentation
Pseudonormalization of T waves
Key Pearl: When the symptoms are concerning but the ECG is non-diagnostic, look at old ECGs and get a repeat ECG!
References:
ECG findings in Hyperkalemia
ECG findings in patients on digoxin
Take home Points
References:
Levine M, Nikkanen H, Pallin DJ, et al. The effects of intravenous calcium in patients with digoxin toxicity. J Emerg Med 2011; 40:41-46. PMID:19201134
Diffuse ST segment elevation DDx
Large Acute MI
Acute Pericarditis
Early repolarization
Vasospasm
Ventricular aneurysm
STEMI or Acute Pericarditis?
ECG findings in STEMI vs. Acute Pericarditis
Know the differences in ECG findings & use a stepwise approach
Step 1. Factors that strongly suggest STEMI:
Look for the factors that rule in STEMI before thinking pericarditis!
Step 2. Factors that suggest pericarditis (look for these only after looking for STEMI in step 1):
When in doubt…do serial ECGs and consider CATH!
Highlights of new study on this topic: Evaluation of Spodick’s sign and other electrocardiographic findings as indicators of STEMI and pericarditis. J Emerg Med 2020. PMID: 32222321
Take home Points
References:
Left Bundle Branch Block Basics
Sgarbossa Criteria, Modified Sgarbossa Criteria, and the BARCELONA Criteria
A. Concordant ST elevation ≥ 1 mm (in any lead) = Most specific for MI in LBBB
B. Concordant ST depression ≥ 1 mm in V1, V2, or V3 = Specific for MI
C. Discordant ST elevation ≥ 5 mm = Less specific for MI in LBBB
Take home Points
Diagnosing OMI (STEMI equivalent) in the presence of LBBB
References:
ECG Diagnosis of Ventricular Tachycardia (VT)
Mattu Algorithm for Wide Complex Tachycardias (WCTs)
What about an Adenosine diagnostic challenge?
Take-home points:
References:
ECG findings in Hyperkalemia
Hyperkalemia
Durfey N, Lehnhof B, Bergeson A, et al. Severe hyperkalemia: Can the electrocardiogram risk stratify for short-term adverse events? West J Emerg Med. 2017;18(5):963-971. PMID: 28874951
Take-home Points:
Hyperkalemia does it all, and you’ve got to know what to look for!
Reference:
Subtle early signs of ischemia
Take-home Points:
Reference:
Surawicz B, Knilans T. Chou’s Electrocardiography in Clinical Practice: Adult and Pediatric. 6th Edition. Amazon link.
Subtle early signs of ischemia
Take-home Points:
Reference:
Surawicz B, Knilans T. Chou’s Electrocardiography in Clinical Practice: Adult and Pediatric. 6th Edition. Amazon link.
Differential for Non-conducted P-waves (P: QRS > 1, “electrocardiographic polyuria”)
Blocked Premature Atrial Complexes
2nd degree AV Block: Mobitz I (Wenckebach)
2nd degree AV Block: Mobitz II
2nd degree AV Block: 2:1 conduction
2nd degree AV Block: Advanced AV Block or “High-grade AV Block”
3rd degree AV Block (Complete Heart Block) + AV dissociation
3rd degree AV Block (Complete Heart Block) + Isorhythmic AV dissociation
Bifascicular & Trifascicular Blocks
Bifascicular Block
Trifascicular Block
ECG findings in Hyperkalemia
Differential for Non-conducted P-waves (P: QRS > 1, “electrocardiographic polyuria”)
Blocked Premature Atrial Complexes
2nd degree AV Block: Mobitz I (Wenckebach)
2nd degree AV Block: Mobitz II
2nd degree AV Block: 2:1 conduction
2nd degree AV Block: Advanced AV Block or “High-grade AV Block”
3rd degree AV Block (Complete Heart Block) + AV dissociation
3rd degree AV Block (Complete Heart Block) + Isorhythmic AV dissociation
ECG findings in Pulmonary Embolism
ECG findings in Hyperkalemia
BRASH syndrome
Bradycardia, Renal failure, AV nodal blocker, Shock, Hyperkalemia
LAFB vs. RAFB
|
Type of Fascicular Block |
Left Anterior FB |
Left Posterior FB |
|
Axis |
Left Axis Deviation |
Right Axis Deviation |
|
Leads I & aVL |
|
|
|
Lead III |
|
|
References:
Abarca E, Baddi A, Manrique R. ECG manifestations in submassive and massive pulmonary embolism. Report of 4 cases and review of literature. Journal of Electrocardiology 2014;47(1):75–9. PMID: 23890684
ECG findings in Hyperkalemia
Take-home Points
ECG findings in Hyperkalemia
BRASH syndrome
Bradycardia, Renal failure, AV nodal blocker, Shock, Hyperkalemia
ECG findings in patients on digoxin
ECG findings in STEMI vs. Acute Pericarditis
Know the differences in ECG findings & use a stepwise approach
Step 1. Factors that strongly suggest STEMI:
Look for the factors that rule in STEMI before thinking pericarditis!
Step 2. Factors that suggest pericarditis (look for these only after looking for STEMI in step 1):
When in doubt…do serial ECGs and consider CATH!
Pediatric Electrocardiography
Persistent juvenile T-wave pattern
Take-home points
Pediatric ECGs
References:
Subtle early signs of ischemia
Riley, et al. Am Heart J 2013. PMID: 23237133
Millard, et al. Ann Noninvasive Electrocardiol 2017. PMID: 28044391
Take-home points
Reference:
Subtle early signs of ischemia
Riley, et al. Am Heart J 2013. PMID: 23237133
Millard, et al. Ann Noninvasive Electrocardiol 2017. PMID: 28044391
Take-home points
Reference:
Electrical Storm
Take-home points
Electrical Storm
References:
Left Bundle Branch Block Basics
Sgarbossa Criteria, Modified Sgarbossa Criteria, & BARCELONA Criteria
Take home Points
Diagnosing occlusion MI in the presence of LBBB
References:
Take home Points
Artifact
Summary of the mechanisms of ACS and their implications for therapy (PMID: 23697515 & 30605419)
All plaques are not alike
Plaque vulnerability and likelihood of rupture is based on 3 major factors:
Recent stress testing and angiography does not rule out new plaque rupture!
Final take-home points: