Amal Mattu’s ECG Case of the Week – June 22, 2015

Case 1: LBBB and AMI

Which patients with LBBB need emergent reperfusion therapy?

• 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)

 

For more on this, review the case from June 1^st, 2015

Case 2: Atrial Fibrillation with WPW

• Very rapid, irregularly irregular tachycardia
• Rates may approach 250-300 bpm or higher
• Variable QRS-complex shape and width
• Often misdiagnosed as SVT, VT, or A.fib with aberrancy
• AV nodal blockers (BB/CCB’s, Digoxin, Amiodarone, etc.) can cause V.fib & death

​Avoid all AV nodal blockers in Atrial fibrillation with WPW!

Case 3: Septal STEMI vs Hyperkalemia?

ECG findings in Hyperkalemia

• Peaked T-waves
• Widening of the QRS (often marked)
• Prolonged PR-interval
• Flattening and eventual loss of P-waves
• Tachydysrrhythmias
• Advanced AV Blocks and sinus pauses
• Fascicular & Bundle Branch Blocks
• Pseudo ACS with ST-segment changes (can mimic STEMI with focal STE!)
• Pseudo Brugada syndrome pattern
• Sine wave morphology

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

• Accelerated idioventricular rhythm (AIVR) is a relatively benign reperfusion arrhythmia
• It often occurs during reperfusion with thrombolytics after MI
• True ventricular tachycardia typically has a rate > 120 bpm

Case 5: Syncope & Anteroseptal ST-segment Depression

 Differential for ST-depression in anteroseptal leads

• Anteroseptal ischemia
• Posterior STEMI
  • Mirror image of septal STEMI in leads V1-V3
  • Look for tall R waves, ST-depression, and upright T waves in V1-V3 on conventional 12 lead ECGs
  • Even 0.5 mm of STE on posterior lead ECGs is diagnostic
• Miscellaneous
  • RBBB
  • Hypokalemia

 ST-depression in the anteroseptal leads might represent posterior STEMI. Get posterior leads!

 

Case 6: Really Wide Complex Tachycardia

• When the QRS complex is really wide (> 1 big box or 200 ms) think of tox. and metabolic etiologies (ex. hyperkalemia and severe acidosis)
• Consider empiric treatment with Calcium & Sodium Bicarbonate!

 For more about Na²⁺ channel blocker toxicity, review the case from Feb 23rd, 2015

 

Case 7: Bizarre Bradycardia

• Remember that hyperkalemia can also cause bizzare bradycardias and AV blocks
• When dealing with a bizarre rhythm that is not responding to ACLS therapy, consider empiric treatment for hyperkalemia!

 

Case 8: Low Voltage

Low Voltage Definition

• Specific Definition
  • QRS amplitudes in limb leads all < 5 mm OR in all chest leads < 10mm
• Sensitive Definition
  • QRS amplitudes in I+II+III < 15 mm OR V1+V2+V3 < 30 mm

Low Voltage QRS Differential

• “Low Power”
  • Myxedema (severe hypothyroidism)
  • Infiltrative diseases (Amyloid, Sarcoid, etc.)
  • End stage cardiomyopathy​
• Conduction blockage
  • Fluid/Effusion (pericardial or pleural)
  • Fat (obesity)
  • Air (COPD)

 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