14th International Congress
THE "NEW FRONTIERS"
OF ARRHYTHMIAS 2000

Jan. 29 - Feb. 5, 2000
Marilleva, Trento, Italy

RT-79

Pharmacological pump for treatment of vasovagal syncope: is phenylephrine the right drug?

Antonio Raviele, Franco Giada, Aldo Bonso, Gianni Gasparini, Sakis Themistoclakis, Andrea Corrado.
Division of Cardiology, Umberto I Hospital, Mestre-Venice, Italy

Abstract

BACKGROUND. Phenylephrine (PE) is a fast-acting alpha-agonist drug with short action duration and long stability at body temperature, which theoretically could be used in an implantable pharmacological pump for treatment of vasovagal syncope. To verify this hypotesis we studied the efficacy and safety of PE to abort syncope during head-up tilt testing (HUT) in patients with vasovagal syncope.

METHODS. We enrolled 10 consecutive patients (9 females and 1 male, mean age 44 years, range 21-73) with recurrent vasovagal syncope (median 18 episodes, range 6-100) and reproducible positive response during HUT. All 10 patients had no evidence of organic heart disease. Every subject underwent 2 consecutive HUT in a randomized, single-blind fashion in the same day: in one a bolus of PE (1 mg in 3 ml of saline solution) was delivered; in the other the same volume of placebo was injected. The drug or placebo were administered in the right atrium through a catheter introduced via jugular vein, at the time patient became symptomatic and blood pressure suddenly decreased more than 50% compared to basal values.

RESULTS. In 9 patients delivery of PE determined a significant raise of blood pressure able to prevent syncope or restore consciousness a few seconds after the injection, despite patients continued to be tilted-up. In only one patient with severe cardioinhibitory response during HUT, the drug was not succesfull. In all patients delivery of placebo did not prevent the development of syncope. The efficacy of PE in aborting syncope resulted statistically higher respect to placebo (90 vs 0%, p<0.001). PE was well tolerated in every case.

CONCLUSIONS. The delivery of PE is effective and safe in preventing or aborting the development of syncope during HUT; PE may be an appropriate agent to be used in an implantable pharmacological pump for treatment of vasovagal syncope.

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