Cardiac asystole: a manifestation of neurally mediated hypotension-bradycardia

Department of Medicine, University of Minnesota Medical School, Minneapolis.

It has been proposed that prolonged cardiac asystole mimicking an episode of sudden cardiac death may occur as a manifestation of neurally mediated hypotension-bradycardia syndrome. To assess this possibility, electrocardiographic and hemodynamic findings during upright tilt testing were evaluated in six survivors of suspected asystolic sudden cardiac arrest with normal conventional electrophysiologic evaluation (Group I). These observations were compared with findings in two control groups: six patients with syncope but without evident asystole and with normal conventional electrophysiologic evaluation but demonstrable neurally mediated hypotension-bradycardia (Group II), and six patients with syncope in whom conventional electrophysiologic evaluation provided a presumptive diagnosis (Group III). Patients in all three groups ranged in age from 16 to 59 years. During head-up tilt testing (either alone or with isoproterenol infusion), patients in both Groups I and II developed syncope in less than or equal to 5 min, whereas patients in Group III remained asymptomatic. Patients in Groups I and II exhibited a similar tilt-induced decrease in mean arterial pressure (-46 +/- 9 and -40 +/- 9 mm Hg, respectively, p = NS) and heart rate (-44 +/- 28 and -49 +/- 12 beats/min, respectively, p = NS). In contrast, patients in Group III manifested only a moderate decrease in mean arterial pressure (-14 +/- 5 mm Hg) and had an increase in heart rate (+14 +/- 8 beats/min). Both mean arterial pressure and heart rate changes in Group I and Group II patients differed significantly (p less than 0.001) from values in Group III patients.(ABSTRACT TRUNCATED AT 250 WORDS)

This article has been cited by other articles:

				A. Raviele Tilt-induced asystole: a useful prognostic marker or clinically unrelevant finding? Eur. Heart J., March 2, 2002; 23(6): 433 - 437. [Full Text] [PDF]

				G Baron-Esquivias, A Pedrote, A Cayuela, J.I Valle, J.M Fernandez, E Arana, M Fernandez, F Morales, J Burgos, and A Martinez-Rubio Long-term outcome of patients with asystole induced by head-up tilt test Eur. Heart J., March 2, 2002; 23(6): 483 - 489. [Abstract] [Full Text] [PDF]

				A. M Dart, X.-J. Du, and B. A Kingwell Gender, sex hormones and autonomic nervous control of the cardiovascular system Cardiovasc Res, February 15, 2002; 53(3): 678 - 687. [Full Text] [PDF]

				A. Zaidi, P. Clough, P. Cooper, B. Scheepers, and A. P. Fitzpatrick Misdiagnosis of epilepsy: many seizure-like attacks have a cardiovascular cause J. Am. Coll. Cardiol., July 1, 2000; 36(1): 181 - 184. [Abstract] [Full Text] [PDF]

				T. Koga, S. Kaseda, N. Miyazaki, N. Kawazoe, I. Abe, S. Sadoshima, K. Onoyama, and T. Koga Neurally-Mediated Syncope Induced by Lung Cancer: A Case Report Angiology, March 1, 2000; 51(3): 263 - 267. [Abstract] [PDF]

				F. Duru, U. Bauersfeld, and R. Candinas Autonomic effects of radiofrequency catheter ablation Europace, January 1, 2000; 2(2): 181 - 185. [Abstract] [PDF]

				M. E. Vloka, J. E. Tamis, and J. S. Steinberg Neurally Mediated Syncope in 2 Patients With Extracardiac Disease Arch Intern Med, March 22, 1999; 159(6): 625 - 627. [Abstract] [Full Text] [PDF]

				D. L. Jardine, H. Ikram, C. M. Frampton, R. Frethey, S. I. Bennett, and I. G. Crozier Autonomic control of vasovagal syncope Am J Physiol Heart Circ Physiol, June 1, 1998; 274(6): H2110 - H2115. [Abstract] [Full Text] [PDF]

				F. J. DiMario Jr Breath-Holding Spells in Childhood Arch Pediatr Adolesc Med, January 1, 1992; 146(1): 125 - 131. [Abstract] [PDF]

				B. P. Grubb, G. Gerard, K. Roush, P. Temesy-Armos, L. Elliott, H. Hahn, and C. Spann Differentiation of Convulsive Syncope and Epilepsy with Head-Up Tilt Testing Ann Intern Med, December 1, 1991; 115(11): 871 - 876. [Abstract] [PDF]

				A. S. Manolis, M. Linzer, D. Salem, and N. A. M. Estes III Syncope: Current Diagnostic Evaluation and Management Ann Intern Med, June 1, 1990; 112(11): 850 - 863. [Abstract] [PDF]