Acute and long-term beta-adrenergic blockade for patients with neurocardiogenic syncope.

Abstract

OBJECTIVES:

This study was designed to prospectively evaluate the long-term outcome of drug therapy guided by head-up tilt testing for the management of unexplained syncope and near syncope.

BACKGROUND:

Head-up tilt testing is used to evaluate patients with unexplained syncope. The validity of acute drug testing and the efficacy of long-term oral therapy for prevention of recurrent syncope have not been investigated in large patient groups.

METHODS:

We studied 296 consecutive patients with unexplained syncope or near syncope who underwent 80 degrees head-up tilt testing with and without isoproterenol challenge. The efficacy of intravenous and oral beta-blocker therapy was evaluated by repeat testing. Patients with both positive and negative responses to therapy were followed up for rates of recurrence of syncope.

RESULTS:

A total of 193 patients (65%) had a positive tilt test response; 89% of these 193 required isoproterenol challenge to elicit this response. Patients with a positive tilt test result had lower values for heart rate at rest (mean +/- SD 69 +/- 13 vs. 74 +/- 14 beats/min, p = 0.046) and systolic blood pressure (137 +/- 28 vs. 145 +/- 30 mm Hg, p = 0.0018) at baseline than did the patients with a negative tilt test result. Intravenous propranolol blocked the positive response in 163 (90%) of 181 patients retested. Oral beta-blockers were effective by tilt test criteria in 118 (94%) of 125 patients; 12 (10%) had recurrent clinical symptoms while taking beta-blockers. Eight (42%) of 19 patients who had a negative tilt test response during beta-blocker therapy had recurrent symptoms when they stopped therapy. Three (23%) of 13 patients receiving empiric beta-blocker therapy had recurrent symptoms. The follow-up period for the patients with a positive tilt test result was 28 +/- 11 months (range 5 to 48).

CONCLUSIONS:

Intravenous propranolol is effective in preventing neurocardiogenic syncope diagnosed during head-up tilt testing and predicts the response to oral beta-blocker therapy. Oral beta-blocker therapy prevents recurrent syncope in the majority of patients. Recurrence of syncope is lowest when efficacy of oral beta-blocker therapy is confirmed by repeat head-up tilt testing.

• Authors: M M Cox, B A Perlman, M R Mayor, T A Silberstein, E Levin, L Pringle, A Castellanos, R J Myerburg
• Journal: Journal of the American College of Cardiology (J Am Coll Cardiol) Vol. 26 Issue 5 Pg. 1293-8 (Nov 01 1995) ISSN: 0735-1097 [Print] United States
• PMID: 7594046 (Publication Type: Clinical Trial, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Adrenergic beta-Antagonists
• Propranolol
• Isoproterenol

Topics

• Administration, Oral
• Adrenergic beta-Antagonists (administration & dosage)
• Adult
• Aged
• Female
• Follow-Up Studies
• Humans
• Injections, Intravenous
• Isoproterenol (administration & dosage)
• Male
• Middle Aged
• Propranolol (administration & dosage)
• Prospective Studies
• Syncope (drug therapy)
• Tilt-Table Test