To establish the clinical efficacy of a single oral dose of
pirmenol, we evaluated electrophysiologic and hemodynamic effects simultaneously after
drug administration, performing electrophysiologic testing in 20 patients with ECG-documented
paroxysmal supraventricular tachycardia (PSVT) before and after a single oral 200-mg dose of
pirmenol. Hemodynamic measurements were made with a Swan-Ganz
catheter in the first 10 consecutive patients. In a different series of patients, we administered a single 200-mg oral dose of
pirmenol to evaluate its acute termination effect in 7 patients with PSVT and 9 with
paroxysmal atrial fibrillation.
Pirmenol prolonged the refractory period of the retrograde conduction system in patients with or without an accessory pathway, and
supraventricular tachycardia was no longer inducible at 60 min in 11 patients [8 of 11 with atrioventricular (AV) reentrant
tachycardia and 3 of 5 with
AV nodal reentrant tachycardia].
Pirmenol increased the heart rate (p < 0.01) and total systemic resistance (p < 0.05), and reduced the stroke volume index (p < 0.01), all significantly. The plasma concentration of
pirmenol at 1 h after administration was 0.75 +/- 0.48 microgram/ml. A single oral dose of
pirmenol during
tachyarrhythmia successfully restored sinus rhythm in 4 of 7 (57%) patients with PSVT and 4 of 9 (44%) patients with
paroxysmal atrial fibrillation. A single oral dose of
pirmenol was well tolerated as episodic treatment in patients with supraventricular
tachyarrhythmias.