Elderly patient with accidental overdose of sotalol. Describe the ECG.
Describe and interpret this ECG
ECG ANSWER and INTERPRETATION
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.