Augmented Fragmentation of Atrial Activity Upon Premature Electrical Stimuli by Verapamil

Abstract

The significance of fragmented activity obtained from the atrium during electrophysiologic study (EP study) was confirmed since it was al ways observed just at the onset of fi brillation. It was preceded by extra stimuli or atrial flutter, and the initial site of fragmentation varied from case to case. The premature-stimu lus-induced widening of the atrial wave was observed in some cases who had normal size of atrium and no heart failure. The widening was aug mented by administration of vera pamil but not by procainamide, suggesting that for such widening or fragmented activity, slow-fiber-medi ated conduction seems to be responsi ble. One case with intraatrial reen trant tachycardia developed fragmentation lasting for 1.0 second after verapamil.

Therefore, some apparently nor mal atria may have a subclinical elec trophysiologic abnormality that can be disclosed by premature stimula tions or verapamil.

Get full access to this article

View all access options for this article.

References

Ohe T. , Namamatzu S. , et al: Relation between the widening of the fragmented atrial activity-zone and atrial fibrillation. Am J Cardiol 52:1219-1223, 1983.

Niwano S. , Aizawa Y. , et al: Prediction of atrial fibrillation from the electrophysiological data. Jpn Electrocardiol (in press), 1988.

Ishiguro J. , Aizawa Y. , et al: Marked fragmentation and atrial fibrillation after use of verapamil . Jpn Electro-cardiol 6:59, 1986 (abstract).

Wellens Hjj , Schuilenburg RM , Durrer D. : Electrical stimulation of the heart in patients with ventricular tachycardia . Circulation 56:216-226, 1972.

Josephson ME , Horwitz LN , Farshidi A. , et al: Recurrent sustained ventricular tachycardia. I. Mechanism. Circulation 57:431-440, 1978.

Aizawa Y. , Satoh M. , et al: Early experience of endocardial mapping of the left ventricle . Jpn Circ J 51:1283-1288, 1987 .

Killip T. , Gault JM : Mode of onset of atrial fibrillation in man. Am Heart J 70:172-179, 1965.

Bennett MA , Pentecost BL : The pattern of onset and spontaneous cessation of atrial fibrillation in man . Circulation 56:981-988, 1970.

Scherf D. , Terranova R. : Mechanism of auricular flutter and fibrillation. Am J Physiol 159:137-143, 1949.

10.

Moe GK , Abildskov JA : Atrial fibrillation as a self-sustaining arrhythmia independent of focal discharge . Am Heart J 58:59-70, 1959.

11.

Moore FM , Fischer G. , Detweiler DC : The initiation and maintenance of auricular fibrillation in normal young and adult cattle. Physiologist 3:116-123, 1960.

12.

Allessie MA , Bonke Fim , Shoopman Fjg : Circus movement in rabbit atrial muscle as a mechanism of tachycardia. II. The role of nonuniform recovery in the occurrence of undirectional block as studied with multiple electrodes. Circ Res 39:168-177, 1976.

13.

Hordof AJ , Edie R. , et al: Electrophysiologic properties and response to pharmacologic agents of fibers from diseased human atrium. Circulation 54:774-779, 1976.

14.

Ten Eick RE , Singer DH : Electrophysiological properties of diseased human atrium. 1. Low diastolic potential and altered cellular response to potassium. Circ Res 44:545-577, 1979.

15.

Dreifus LS , Hajat K. , Watanabe Y. , et al: Ventricular fibrillation: A possible mechanism of sudden death in patients with Wolff-Parkinson-White syndrome. Circulation 58:986-997, 1978.

16.

Horowitz LN , Josephson ME , Farshidi R. , et al: Recurrent sustained ventricular tachycardia. Role of the electrophysiologic study in selection of antiarrhythmic regimens . Circulation 58:986-997, 1978.