ECG Case 023

Main Abnormalities

This ECG demonstrates the key features of sotalol toxicity:

• Sinus bradycardia (42 bpm)
• Very long QT interval (~600 ms)

Sotalol is a beta blocker with additional class III effects (potassium channel blockade), so it causes both bradycardia and QT prolongation in overdose.

Risk of Torsades

• In comparison to ECG Quiz 022, this patient is at significant risk of TdP
• The combination of bradycardia and significant QT prolongation means that this patient plots well above the “at risk” line on the QT nomogram
• Prophylaxis of TdP in this case would include correction of QT-dependent electrolytes (K, Mg, Ca) to the high-normal range and positive chronotropy (e.g. with isoprenaline) to move the patient below the at-risk line

Further Reading

• Wiesbauer F, Kühn P. ECG Mastery: Yellow Belt online course. Understand ECG basics. Medmastery
• Wiesbauer F, Kühn P. ECG Mastery: Blue Belt online course: Become an ECG expert. Medmastery
• Kühn P, Houghton A. ECG Mastery: Black Belt Workshop. Advanced ECG interpretation. Medmastery
• Rawshani A. Clinical ECG Interpretation ECG Waves
• Smith SW. Dr Smith’s ECG blog.
• Wiesbauer F. Little Black Book of ECG Secrets. Medmastery PDF