Antiarrhythmic and hemodynamic evaluation of indecainide and procainamide in nonsustained ventricular tachycardia.
The present trial was a placebo-controlled, randomized, parallel study comparing indecainide to procainamide. A 24-hour intravenous phase measured and compared invasive hemodynamics, followed by oral administration for assessment of arrhythmia suppression. Thirty-two patients (mean age 61 years) with asymptomatic or mildly symptomatic nonsustained ventricular tachycardia (VT) were evaluated, 15 while receiving indecainide and 17 while receiving procainamide. A total of 8 patients had serious toxicity during the intravenous phase; 6 receiving indecainide experienced increased left ventricular dysfunction or worsening arrhythmia (sustained VT, arrhythmic death) while 2 receiving procainamide developed serious hypotension. Proarrhythmia developed in 3 of 15 (20%) of the indecainide patients, but in no procainamide patient. In those tolerating indecainide, long-term suppression of ventricular premature complexes (VPCs) and of runs of VT was more consistent than with procainamide. While indecainide was a potent suppressor of spontaneous VPCs and VT, patients with significant left ventricular dysfunction could not tolerate it. The indecainide patients developing serious toxicity had a common hemodynamic profile: ejection fraction less than 25%, elevated left ventricular filling pressures, low cardiac and stroke volume index and minimal cardiac reserve. Indecainide has a poor risk-benefit ratio in patients similar to the current population, who have potentially lethal ventricular arrhythmias and severe left ventricular dysfunction.
Cardiac Arrhythmia Study Unit, Baylor College of Medicine, Methodist Hospital, Houston, Texas 77030.
C M
CM
Pratt
M J
MJ
Francis
A A
AA
Seals
W
W
Zoghbi
J B
JB
Young
D000284:Administration, Oral; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D015716:Electrocardiography, Ambulatory; D005260:Female; D005449:Fluorenes / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D011342:Procainamide / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D016032:Randomized Controlled Trials as Topic; D013318:Stroke Volume; D013610:Tachycardia / Q000188:drug therapy* / Q000503:physiopathology
D000889:Anti-Arrhythmia Agents; D005449:Fluorenes; C042398:indecainide; D011342:Procainamide