TREATMENT OF PAROXYSMAL SUPRAVENTRICULAR TACHYCARDIA WITH A UNIQUE ORAL DOSIS OF DILTIAZEM AND PROPRANOLOL

Chronic antiarrhythmic therapy for the prevention of episodes of paroxysmal supraventricular tachycardia is limited by its elevated cost, the development of side effects and lack of patients' collaboration. In this study the efficacy and safety of a single oral dose of diltiazem (180 mg) and propranolol (80 mg) were assessed. Eighteen episodes of supraventricular tachycardia were treated in 17 patients, 9 female and 8 male, aged between 19 and 60 years old (mean 45,3 +/- 11,4). The episodes had begun 3 months to 40 years before. They were divided in 3 groups: group 1 (placebo), 6 episodes; group II (diltiazem-propranolol), 12 episodes; and group III (patients from the placebo group without spontaneous recovery of sinus rhythm who were given active drug), 6 episodes. There were no spontaneous conversions in group I (placebo) within 80 minutes. In group II, ten out of 12 episodes responded to the combination after 38,8 +/- 20,8 minutes (seven episodes were converted to sinus rhythm within the first 45 minutes). In group III (non-responders to placebo who were subsequently given active drugs), four out of 6 episodes were suppressed after 50,7 +/- 16,7 minutes. The cycle of the tachycardia lengthened before conversion to sinus rhythm both in groups II and III. Neither sistolic nor diastolic blood pressure changed significantly in any group. Seven out of 14 patients who successfully converted to sinus rhythm in groups II and III, suffered mild to moderate sweat between 3 and 5 minutes before the end of the episodes. Two patients had arterial hypotension not requiring specific therapy. In one case a 2-second pause followed by A-V junctional rhythm was observed at the end of the arrhythmia. Prolonged PR interval (0,24 sec) was seen in two patients but it was transient. In conclusion, 14 out of 18 episodes recovered sinus rhythm with the oral combination of diltiazem and propranolol. The addition of the beta-blocker precludes the reflex sympathetic drive secondary to the peripheral vasodilatation produced by diltiazem. The episodic oral treatment is of practical usefulness in patients without severe organic heart disease and with good hemodynamic tolerance during the tachyarrhythmia.