Suppression of the repetitive ventricular response: an index of long-term antiarrhythmic effectiveness of aprindine for ventricular tachycardia in man.

The repetitive ventricular response, defined as the production of two or more ventricular premature complexes in response to a single ventricular pacing stimulus, is common in patients with serious ventricular arrhythmias. Twenty-seven patients with refractory ventricular tachycardia were studied to determine whether acute suppression of the repetitive ventricular response by aprindine predicts long-term effectiveness of this agent. Twenty-three of the 27 patients had the repetitive ventricular response before intravenous administration of aprindine, whereas only 6 had the response after aprindine. All patients were maintained on a regimen of oral aprindine and evaluated repeatedly for a mean of 12 months. Twenty of the 21 patients who had no repetitive ventricular response after intravenous aprindine manifested clinical improvement compared with only 1 of the 6 in whom the repetitive response was present after aprindine (P less than 0.0005). Aprindine is a useful agent in refractory ventricular tachycardia, and the absence of the repetitive ventricular response after its intravenous administration predicts long-term clinical responsiveness to the oral form.