SUPRAVENTRICULAR TACHYARRHYTHMIAS AND RATE-RELATED HYPOTENSION - CARDIOVASCULAR EFFECTS AND EFFICACY OF INTRAVENOUS VERAPAMIL

IV verapamil is the preferred drug for the acute management of supraventricular tachyarrhythmias (SVTs) in the absence of contraindications to its use. SVT complicated by hypotension has been considered a relative contraindication for the use of IV verapamil. However, the efficacy of IV verapamil in the management of "rate-related" hypotension has not been specifically addressed. The purpose of this study was to assess the effects of IV verapamil in patients with SVTs and arterial hypotension. A retrospective and prospective study design was used. Inclusion criteria were SVT (QRS duration, less than 120 ms; R-R interval, regular or irregular), QRS rate of 140 or more, systolic blood pressure of 90 mm Hg or less, and normal mental status. We identified 21 episodes of SVT meeting inclusion criteria in 19 patients. SVT was due to atrioventricular node re-entry in 17, atrial fibrillation in three, and atrial flutter in one. There were seven men and 12 women, with a mean age (± SD) of 52 ± 17 years. Systolic blood pressure before verapamil was 70 ± 28 mm Hg, and QRS rate was 192 ± 19. IV calcium was not administered before IV verapamil. After IV verapamil administration (mean dose, 6.5 ± 4.3 mg), a positive response (conversion to sinus rhythm or ventricular rate of less than 120) was noted in 17 of 21 episodes (80%). Post-treatment systolic blood pressure increased to 98 ± 16 mm Hg (P < .005 vs pretreatment), and ventricular response rate decreased to 112 ± 39 (P < .001 by two-tailed paired t test). In one case of atrial fibrillation, verapamil therapy was followed by a decrease in systolic blood pressure despite a 20-beats/min decrease in ventricular response rate. We conclude that IV verapamil is a safe and effective drug for the management of SVT complicated by rate-related arterial hypotension. © 1990 American College of Emergency Physicians.