Efficacy of procainamide and lidocaine in terminating sustained monomorphic ventricular tachycardia

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.

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.

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.