INTRAVENOUS CALCIUM-CHLORIDE IN THE CONVERSION OF PAROXYSMAL SUPRAVENTRICULAR TACHYCARDIA TO NORMAL SINUS RHYTHM

This brief report describes several cases of paroxysmal supraventricul ar tachycardia that converted promptly to normal sinus rhythm within 1 to 2 minutes of receiving intravenous calcium salts as pretreatment i n anticipation of verapamil therapy. A review of calcium's hemodynamic and dromotropic effects suggests that this probably was due to electr ophysiological effects rather than mere coincidence. Calcium raises bl ood pressure, which may reflexively increase cardiac parasympathetic t one, and also has a direct slowing effect on atrioventricular conducti on, Adenosine remains the drug of choice in the treatment of paroxysma l supraventricular tachycardia. However, in addition to preventing hyp otension when used as pretreatment to verapamil, intravenous calcium i tself may terminate supraventricular tachycardia. (C) 1996 by W.B. Sau nders Company