Really Wide Complex Tachycardia (RWCT = QRS > 200 ms)
Take home Points
DDx of ST-segment elevation
DDx of Short QTc Interval
Take-home points
ECG findings in Hypothermia
Onset of ECG findings can vary, but resolve with warming
Narrow-Complex & Regular Tachycardia Differential
To differentiate…always look at what the atrium is doing
(V1 typically best lead to look for atrial activity)
ECG findings in Hyperkalemia
ST-segment elevation in aVR with ST-segment depression in multiple other leads
STE in aVR (>1-1.5 mm) differential diagnosis
Post-seizure ECG’s
Always think of the following differentials when interpreting the ECG of patients with new onset or unexplained seizures:
ECG Findings in Severe Hypokalemia
Cardiac Risk Factors
Cardiovascular effects of marijuana
Take-home Points
References:
Differential Dx for Wide Complex Tachycardia
Take-home Points
ECG Potpourri Case Pearls
Case 1
Case 2
ECG findings in Pulmonary Embolism
Case 3 & 4
Co, et al. J Emerg Med 2017 (PMID: 27742402) – identified the most common ECG changes in patients with known PE when comparing their ECGs with previous ECGs
Case 5
Electrical alternans is a broad term that describes beat to beat variation in amplitude or axis of QRS complexes. It is an ECG sign suggestive of tamponade or large pericardial effusion but can be seen in other conditions such as SVT with an accessory pathway. Electrical alternans is distinct from the more gradual variation in QRS amplitude demonstrated in this case, which is due to respiratory variation in a tachypneic patient as the heart position and proximity to the ECG leads changes with inspiration and exhalation.
Case 6 & 7
Always think of the following differentials when interpreting the ECG of patients with syncope, when the history and physical exam are non-diagnostic:
Case 8
Sinus tachycardia has one P wave for every QRS. P waves in sinus rhythm should be upright in limb leads (I, II, III, aVF), inverted in aVR, and biphasic in V1. The rhythm in this case is atrial tachycardia with 2:1 conduction, with P waves buried in T waves.
Case 9
Low Voltage Definition
Low Voltage QRS Differential
ST-segment Elevation Differential Dx
ST-segment elevation in aVR with ST-segment depression in multiple other leads
STE in aVR (>1-1.5 mm) differential diagnosis
Differential diagnosis for wide QRS
Hyperkalemic Paralysis aka Impressive Syndrome
Take-home Points
References:
Differential Dx for long QT interval (greatest concern when QTc > 500ms)
Causes of prolonged QT-interval summary
Prolonged QT due to abnormal/prolonged T –waves
Prolonged QT due to prolonged ST-segment
Take-home points:
Take-home points:
The ECG in left ventricular hypertrophy (LVH)
ECG findings of LVH
LVH with strain pattern & cardiac ischemia
Diagnosing STEMI in patients with LVH with strain pattern
Take-home points
Reference:
Armstrong EJ, Kulkarni AR, Bhave PD, et al. Electrocardiographic criteria for ST-elevation myocardial infarction in patients with left ventricular hypertrophy. Am J Cardiol. 2012;110(7):977-983. PMID: 22738872
The ECG in left ventricular hypertrophy (LVH)
ECG findings of LVH
LVH with strain pattern & cardiac ischemia
Diagnosing STEMI in patients with LVH with strain pattern
Take-home points
Reference:
Armstrong EJ, Kulkarni AR, Bhave PD, et al. Electrocardiographic criteria for ST-elevation myocardial infarction in patients with left ventricular hypertrophy. Am J Cardiol. 2012;110(7):977-983. PMID: 22738872
Differential Dx for Regular Wide Complex Tachycardias
Take-home points
Reference:
Nikolić G. The Bix rule. Heart Lung 2008;37(4):321–2. PMID: 18620109.
Take-home points
Ashman Phenomenon
Ashman phenomenon is an intraventricular conduction abnormality caused by a change in the heart rate. Aberrantly conducted beats (usually seen in atrial fibrillation) are often mistaken for PVCs or ventricular tachycardia, causing diagnostic confusion. Ashman phenomenon is an ECG finding that is usually linked to benign conduction irregularity, but it is an important finding to be aware of to avoid misdiagnosis
Take home points
Ashman phenomenon
References:
Wolff-Parkinson-White (WPW) Syndrome
WPW Syndrome with SVT
WPW Syndrome with Atrial Fibrillation
Take Home Points:
WPW + Atrial Fibrillation
References:
Take Home Points:
References:
Left Bundle Branch Block Basics
Sgarbossa & Modified Sgarbossa Criteria
Sgarbossa & modified Sgarbossa criteria can be used to help diagnose acute coronary occlusion with good specificity in the setting of LBBB
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 occlusion MI in the presence of LBBB
References:
Last week we reviewed how to diagnose acute coronary occlusion in patients with LBBB, this week we will focus on how you can diagnose occlusion MI in patients with paced rhythms. To review last week’s video and written summary click here!
Ventricular Paced Rhythm Basics
Ventricular Paced Rhythm and Acute Coronary Occlusion MI
Sgarbossa and the more recently validated Modified Sgarbossa Criteria (MSC) can be used to help diagnose acute coronary occlusion with high specificity in the setting of paced rhythms. The modified criteria have been shown to be more sensitive than the original criteria (Dodd et al., PMID: 34172301):
Take home Points
Diagnosing occlusion MI in the presence ventricular paced rhythms
References:
Amiodarone
Wolff-Parkinson-White (WPW) Syndrome
WPW Syndrome with SVT
WPW Syndrome with Atrial Fibrillation
Take Home Points:
WPW + Atrial Fibrillation
References:
Treating dysrhythmias in pregnancy
Take Home Points:
Treating dysrhythmias in pregnancy
References:
Wolff-Parkinson-White (WPW) Syndrome
Take Home Points:
Artifact
Differential diagnosis for regular wide complex tachycardias (RWCT)
Take Home Points:
Take Home Points:
EMS Cases Week – Key Points
Case #1
Narrow complex regular tachycardia DDx
Max sinus heart rate = 220 – age
Case #2
Ventricular Rhythms
AIVR
Case #3
ECG findings of hypothermia:
Case #4
Right ventricular myocardial infarction
Case #5
ST-segment elevation in aVR with ST-segment depression in multiple other leads
STE in aVR (>1-1.5 mm) differential diagnosis
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:
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 conduction in atrial flutter:
Take-home points:
Take-home points:
Reference:
Mattu A, Zira D, Tabas JA, Brady WJ. An Adverse Outcome With Cardioversion of a Wide-Complex Tachycardia. Ann Emerg Med. 2022 Feb;79(2):113-115. PMID: 35065739
Hypercalcemia
Etiologies
ECG findings
Treatment
DDx 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
Atrial flutter and atrial tachycardia:
Take-home points:
Atrial flutter and atrial tachycardia:
Take-home points:
ECG Diagnosis of Ventricular Tachycardia (VT)
Mattu Algorithm for Wide Complex Tachycardias (WCTs)
What about an Adenosine diagnostic challenge?
Take-home points:
References:
Troponin testing in Supraventricular Tachycardia (SVT)
Take-home points:
References:
Take-home points:
References:
Take-home points:
Posterior Occlusion MI
Take-home point:
Reference:
Meyers HP, Bracey A, Lee D, et al. Ischemic ST-Segment Depression Maximal in V1-V4 (Versus V5-V6) of Any Amplitude Is Specific for Occlusion Myocardial Infarction (Versus Nonocclusive Ischemia). J Am Heart Assoc. 2021 Dec 7;10(23):e022866. Epub 2021 Nov 15. PMID: 34775811
Differential diagnosis for T-wave inversions
Differential diagnosis for T-wave inversions in V1-V3
Take home Points:
Persistent juvenile T-wave pattern
Take-home Points
References:
Differential diagnoses for T wave inversions
Differential diagnoses for long QTc interval
Brain-Heart Interaction (ECG abnormalities)
Take-home Points:
References:
Normal Right Bundle Branch Block (RBBB)
Take home points:
Differential diagnoses for T wave inversions
Wellens’ waves (T wave inversion patterns associated with ACS)
Wellens’ Syndrome
Take home Points
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
Take home points
What is the most accurate isoelectric baseline (PR segment vs. TP segment) to assess the magnitude of ST segment deviation?
Reference:
Left ventricular assist devices (LVADs)
Take home points
Reference:
Gopalsami Anand. Left Ventricular Assist Devices (LVAD). In: Mattu A and Swadron S, ed. CorePendium. Burbank, CA: CorePendium, LLC. https://www.emrap.org/corependium/chapter/recS6rSMCMOtqKNe9/Left-Ventricular-Assist-Devices-LVAD#h.2wv9a9z2n011. Updated October 7, 2021. Accessed May 13, 2022.
Subtle early signs of ischemia
ST-segment elevation in aVR with ST-segment depression in multiple other leads
STE in aVR (>1-1.5 mm) differential diagnosis
Bizarre Bradycardia
ECG findings in Hyperkalemia
Wellens Syndrome
Take home points
ECG findings in patients on digoxin
Bizarre Bradycardia
ECG findings in Hyperkalemia
Diagnosing occlusion MI in the presence of LBBB & RV paced rhythms
Take home points
Subtle early signs of ischemia
Recent stress testing and catheterizations are not predictive of new plaque rupture!
Take home points
References:
Subtle early signs of ischemia
Take home points
Differential diagnoses for T wave inversions
Differential diagnosis for T-wave inversions in V1-V3
Differential Dx for long QT interval (greatest concern when QTc > 500ms)
Causes of prolonged QT-interval summary
Prolonged QT due to abnormal/prolonged T –waves
Prolonged QT due to prolonged ST-segment
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
Differential diagnosis for narrow complex irregular tachycardia
Differential diagnosis for short QTc interval
ST-segment elevation in aVR with ST-segment depression in multiple other leads
STE in aVR (>1-1.5 mm) differential diagnosis
ECG findings in Hypothermia
Bifascicular & Trifascicular Blocks
Bifascicular Block
Trifascicular 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
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:
Differential diagnosis for narrow complex irregular tachycardia
Differential diagnosis for narrow complex regular tachycardia
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
Right ventricular myocardial infarction
Differential diagnosis for narrow complex irregular tachycardia
Differential diagnosis for narrow complex regular tachycardia
To differentiate…always look at what the atrium is doing
(V1 typically best lead to look for atrial activity)
What is the most accurate isoelectric baseline (PR segment vs. TP segment) to assess the magnitude of ST segment deviation?
Take home points
Differential diagnosis for narrow complex irregular tachycardia
Differential diagnosis for narrow complex regular tachycardia
To differentiate…always look at what the atrium is doing
(V1 typically best lead to look for atrial activity)
ECG findings in Hypothermia
Take home points
Polymorphic ventricular tachycardia (PVT)
Types of polymorphic ventricular tachycardia
Take home points
2 main types of polymorphic ventricular tachycardia
Further Reading:
Viskin S, Chorin E, Viskin D, et al. Polymorphic Ventricular Tachycardia: Terminology, Mechanism, Diagnosis, and Emergency Therapy. Circulation. 2021 Sep 7;144(10):823-839. PMID: 34491774
Differential diagnosis for T wave inversions in V1-V2
Normal ECG Lead Placement
Take home points
When the V1-V2 electrodes are placed too high on the chest…
Reference:
Walsh B. Misplacing V1 and V2 can have clinical consequences. Am J Emerg Med. 2018 May;36(5):865-870. PMID: 29472037