title: Effects of four antiarrhythmic drugs on the induction and termination of paroxysmal supraventricular tachycardia.
abstract: The electrophysiological effects of antiarrhythmic drugs were tested in 36 patients with recurrent paroxysmal supraventricular tachycardia (PSVT), 25 of whom had accessory pathway reentrant tachycardia (APRT) and 11 A-V nodal reentrant tachycardia (AVNRT; 10 of the slow-fast type one of the fast-slow type). The test drugs were procainamide (used in 19 patients), verapamil (in 27), disopyramide (in 31), and propranolol (in 15). The drugs were tested for their ability to terminate episodes of PSVT as well as to inhibit their induction. Procainamide had an inhibitory effect on APRT in nine of 12 patients (75%) and terminated episodes of APRT in seven of 11 patients (63.6%); in all of them V-A block was responsible for the termination. In four of six patients (66.7%) with slow-fast AVNRT and in one patient with fast-slow AVNRT, inhibition of the induction of tachycardia attacks was noted after procainamide. Termination of AVNRT was seen in the same number of patients. Verapamil inhibited the induction of APRT in 12 of 18 patients (66.7%) and terminated episodes of APRT in 10 of 16 patients (62.5%), all by A-V block. In six of eight patients (75%) with slow-fast AVNRT, inhibition of the induction as well as termination of tachycardia were noted after verapamil. Disopyramide had an inhibitory effect on APRT in seven of 23 patients (30.4%) and terminated APRT in five of 21 patients (23.8%) by V-A block, while AVNRT (all slow-fast type) was terminated in only one of eight patients (12.5%) by disopyramide. Disopyramide was less effective than previously reported. This could be attributed to a relatively low dosage and slow infusion speed. Propranolol inhibited the induction of APRT and terminated episodes of APRT in only one of 10 patients (10%). In two of four patients (50%) with slow-fast AVNRT, an inhibitory effect by propranolol was noted, but termination was seen in only one patients.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use*; D004206:Disopyramide / Q000627:therapeutic use; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011342:Procainamide / Q000627:therapeutic use; D011433:Propranolol / Q000627:therapeutic use; D013617:Tachycardia, Supraventricular / Q000188:drug therapy* / Q000517:prevention & control; D014700:Verapamil / Q000627:therapeutic use
chemical_list: D000889:Anti-Arrhythmia Agents; D011433:Propranolol; D014700:Verapamil; D004206:Disopyramide; D011342:Procainamide