No abstract

SUMMARYAlthough catecholaminergic polymorphic ventricular tachycardia (CPVT) is associated with fatal ventricular arrhythmias and sudden death, the ECG findings are not fully understood. In this paper, we report on alterations in the U-wave.Seven patients from 6 families with CPVT in which bidirectional tachycardia and polymorphic VT were induced by exercise or isoproterenol infusion visited our hospitals. VT was not inducible by programmed electrical stimulation. A novel gene mutation of the ryanodine receptor 2 (RyR2) was confirmed in 2 families.In one of these patients, U-wave alternans was observed following ventricular pacing at 160 beats/min. In the other patient, U-wave alternans was observed during the recovery phase after the exercise stress test, which was terminated because of polymorphic VT. In both cases, leads V 3 -V 5 were the leads showing alternans most clearly. In the third patient, a negative U-wave became positive following a pause from sinus arrest and a change in T-wave was also noted.Since such findings were not found in the other subjects who underwent electrophysiologic study, isoproterenol infusion or exercise stress testing, the phenomenon seems to be relevant to the underlying pathogenesis of CPVT. The genesis and significance of Uwave alteration need to be determined. (Int Heart J 2006; 47: 381-389)

The dominant prolongation of the filtered QRS duration in the right precordial leads may be related to the risk of arrhythmic event in Brugada syndrome.

Background:The efficacy of antiarrhythmic drugs in terminating sustained monomorphic ventricular tachycardia (SMVT) was assessed in a retrospective manner to provide a basis for recommending their use. Methods and Results:The 90 patients were included in this study to evaluate the efficacy to terminate SMVT using procainamide or lidocaine. All patients were alert and responsive. The mean systolic blood pressure was 91±25 mmHg (range, 40-150 mmHg). SMVT was diagnosed from ECG recordings and later in an electrophysiologic study. VTs with a cycle length of 329±55 and 324±61 ms were treated with the mean doses of 358±50 mg and 81±30 mg of procainamide and lidocaine and were terminated in 53/70 (75.7%) and in 7/20 (35.0%) respectively. The drugs were discontinued if there was no rise in blood pressure after slowing of the tachycardia rate or if there were signs of impending deterioration in consciousness. Though procainamide was effective, blood pressure was often low and DC shock should be available at all times during administration of the drug. Conclusions:Procainamide, the relatively older drug, was more effective than lidocaine in terminating SMVT associated with structural heart diseases. This is a retrospective analysis but can form the basis for formulating guidelines for initial management of SMVT. (Circ J 2010; 74: 864 - 869)

Patients with Brugada syndrome have a high prevalence of high defibrillation energy requirement, and short ventricular ERP and VFCL.