Puzzle 2004 2 73, A fainting lady with some extrasystoles - Answer: Difference between revisions

#the arrhythmia is not preceded by a pause; TdP is a polymorphic ventricular arrhythmia almost exclusively encountered in the setting of prolongation of the QT interval and preceded by a pause.

#The rate is very high (up to 300 beats/min); typically, TdP has a rate of 220 beats/min.  

#The coupling interval of the initiating beat is extremely short; TdP in the setting of a prolonged QT interval is always initiated by a premature beat with a long coupling interval, originating from the descending part of the prolonged T wave or from a pronounced U wave; the preceding pause further prolongs the QT interval and the usual initiating sequence is a long-short-long sequence. The extremely short coupling interval of the initiating beats (± 240 ms in this case) is the hallmark of this arrhythmia, which is known as short-coupled torsades de pointes.1 Males and females are equally affected and the mean age is 35 years of age. The family history is often positive for sudden cardiac death. The prognosis is poor when left untreated. The arrhythmias in the setting of this syndrome do not respond reliably to any antiarrhythmic drug. Hence, ICD treatment is mandatory. It is important to state that the occurrence of just one such short-coupled extrasystole (≤300 ms) in a fainting patient (e.g. at 24-hour monitoring) should raise the suspicion of this malignant arrhythmia syndrome. Such short coupling intervals are otherwise only ever seen in acute