Hemodynamic effects of pirmenol, a new antiarrhythmic agent, assessed noninvasively

The cardiovascular effects of a new antiarrhythmic Class I agent, pirmenol, were assessed noninvasively in 10 patients without heart failure. Infusion of 100 mg pirmenol was given over 30 min following baseline M-mode echocardiography, cuff blood pressure and systolic time interval measurements. The measurements were repeated after the infusion, and 15 and 60 min later. Heart rate increased by 14.7% (P less than 0.01). Significant increases were also noted in afterload parameters, mean arterial pressure (+10.1%; P less than 0.001) and mid-systolic left ventricular wall stress (+8.0%; P less than 0.05). Concomitantly a slight increase was observed in preload, reflected in lengthening of left ventricular end-diastolic diameter (+4.8%; P less than 0.05). A decrease in fractional shortening (-6.5%; P less than 0.05) and an increase in pre-ejection period/left ventricular ejection time ratio (+16.2%; P less than 0.01) suggested a negative inotropic effect. The increased afterload and heart rate may have contributed to changes in these indices, and therefore myocardial depression may appear more pronounced than it actually was. The main effects of intravenous administration of pirmenol are elevations in heart rate and blood pressure. The induced decrease in myocardial contractility is slight.