Electrophysiologic Effects of Diltiazem,a Calcium Antagonist,in Patients With Impaired Sinus or Atrioventricular Node Function

Abstract

The electrophysiologic effects of diltiazem, a calcium antagonistic agent, were studied in 30 subjects with various degrees of sinus or AV node dysfunc tion. After diltiazem was administered, sinus activity was not depressed in con trol subjects, whereas marked inhibition was observed in some of the patients with sick sinus syndrome. Ventricular automaticity was little affected by this drug. The AV conduction system was significantly depressed, and there was no difference in degree between controls and AV block patients. The depression of the AV conduction system became more marked as the basic atrial cycle length was shortened. The drug had no apparent effects on atrial refractoriness, atrial echo zone, or the accessory pathway system.

Conclusively, diltiazem affects mainly sinus and AV conduction systems. Its effect on the sinus node may provide a hazardous problem in patients with the sick sinus sysdrome patients, while its effect on the AV node will have thera peutic value in patients with AV nodal re-entrant arrhythmias.

Get full access to this article

View all access options for this article.

References

Sato, M. , Nagao, T. , Yamaguchi, I. , et al.: Pharmacological studies on a new 1, 5-benzothiazepine derivative (CRD-401). Arzneim. Forsch., 21: 1338, 1971 .

Zipes, D.P. , Fischer, J.C. : Effects of agents which inhibit the slow channel on sinus node automaticity and atrioventricular conduction in the dog. Circ., Res., 34: 184, 1974.

Husaini, M.H. , Kvasnicka, J. , Rydén , L. , et al.: Action of verapamil on sinus node, atrioventricular, and intraventricular conduction . Br. Heart J., 35: 734, 1973.

Spurrell, R.A.J. , Krikler, D.M. , Sowton , E. : Effects of verapamil on electrophysiological properties of anomalous atrioventricular connexion in Wolff-Parkinson-White syndrome. Br. Heart J., 36: 256, 1974.

Rosen, M.R. , Wit, A.L. , Hoffman, B.F. : Electrophysiology and pharmacology of cardiac arrhythmias. VI. Cardiac effects of verapamil. Am. Heart J., 89: 665, 1973.

Wellens, H.J.J. , Tan, S.L. , Bär, F.W.H. , et al.: Effect of verpamil studied by programmed electrical stimulation of the heart in patients with paroxysmal re-entrant supraventricular tachycardia. Br. Heart J., 39: 1058, 1977.

Carrasco, H.A. , Fuenmayor, A. , Barboza , J.S. , et al.: Effect of verapamil on normal sinoatrial node function and on sinus syndrome. Am. Heart J., 96: 760, 1978.

Takagi, M. , Tsuruha, Y. , Shiozu, H. , et al.: Effect of diltiazem hydrochloride on the atrioventricular conduction . Shinzo, 10: 298, 1978 (in Japanese).