Ventricular Fibrillation Induced by Conducted Sinus or Supraventricular Beat

Abstract

We report a case of a 35-year-old housewife who had a repetitive ventricular fibrillation following cardiac surgery. This arrhythmia was induced by sinus or supraventricular ectopic beats conducted to the ventricles and interrupting the preceding T or T+U wave during incomplete A-V dissociation. The cycle length (Q-Q) and the Q-Q/Q-T ratio of the beats preceding fibrillation were significantly shorter than the Q-Q and Q-Q/Q-T ratio of the beats not preceding fibrillation. These findings suggest that ventricular fibrillation is more likely to occur when the supraventricular impulse is conducted to the ventricles early in the cycle and interrupts the T or T+U wave.