PMC8292089_01
(a) Ventricular fibrillation detected by emergency medical services requiring defibrillation; (b) QTc measured in ECG obtained after correction of electrolyte abnormalities (measured by U-wave avoidance technique and calculated by the Bazett Formula: ); (c) measurement of QTc from baseline ECG done several years prior.
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fig1
The initial rhythm was VF (Figure 1(a)), and she was defibrillated with return of spontaneous circulation. ECG was obtained after correction of electrolyte abnormalities and showed prolonged QTc of 622 msec (Figure 1(b)). Notably, previous ECG on record from 5 years prior was normal with a QTc of 454 msec (Figure 1(c)).
(a) Telemetry strip showing bradycardia with prolonged QTc and R-on-T premature ventricular contraction initiating Torsades de pointes; (b) ECG after starting isoproterenol drip with QTc reduction to 465 msec. (c) ECG showing atrial pacing after placement of dual-chamber ICD, with QTc of 465 msec, prior to starting nadolol.
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fig2
Tdp, requiring cardioversion. Telemetry demonstrated persistently prolonged QTc intervals and bradycardia with a subsequent R-on-T premature ventricular complex initiating these episodes (Figure 2(a)). Amiodarone drip was thus discontinued, and the patient was started on an isoproterenol drip with a decrease in QTc to 465 msec and resolution of ventricular arrhythmias (Figure 2(b)), and the patient was extubated in three days. At the time of discharge, she was atrially paced at 90 BPM (Figure 2(c)) and started on nadolol 40 mg twice daily.