Thioridazine Overdose

Report:

Junctional/sinus rhythm

VEB, dimorphic couplet

Non-sustained ventricular tachycardia (torsade de pointes)

Comment:

The torsades were very frequent, but the 12-lead ECG did not catch the best of them. Nevertheless, the one shown here is reasonably convincing. It is unfortunate that it straddles the lead transition in the middle of the recording.

The QT interval is approximately 0.56”, best seen here in V5; the computer got it at only 0.28”! It is interesting that the torsade is preceded by a dimorphic couplet. This may be an additional insult to the homogeneity of ventricular repolarisation, observed to precede uniform VT or VF as well113.

Below (Fig 126a) is her sinus rhythm ECG a day later, with temporary pacemaker turned off in CCU. The QT is 0.53”, giving a QTc 0.58” for the rate of 72/min. It also shows an exception to the rule that lead V1 is superior to L2 for rhythm strips & monitoring: this one is next to useless!

126a. Long QT interval. 127. 78 year old lady on sotalol therapy for recurrent atrial fibrillation.

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