[Effect of the class IA anti-arrhythmic agents ajmaline on end-systolic pressure-volume relations (conductance technique)]

Abstract

To evaluate cardiodepressive risks of antiarrhythmic treatment with ajmaline, we monitored, in addition to conventional hemodynamic parameters, end systolic pressure-volume relations (ESPVR) to assess potential negative inotropic effects. Twelve patients (CAD without ischemia; EF = 60 +/- 3%) underwent hemodynamic analysis with and without the influence of ajmaline (1 mg/kg, i.v.) both 1) at rest (paced heart rate of 90 bpm) and 2) during tachycardia of 160 bpm. As a result, LV-pump function was found to have diminished moderately: EF by 23% vs 10%, respectively; stroke volume by 10% vs 0%; cardiac work by 5% vs 16%, and dP/dtmax by 14% vs 19%. While preload increased under the influence of ajmaline (LVEDP by 17% vs 30%), the LV-volumes increased (EDV by 18% vs 12%; ESV by 58% vs 21%), afterload remained unchanged. Ajmaline caused the loops of the ESPVR to move rightward and the slope k of the ESPVR to decrease, thus indicating loss of inotropy during the influence of the antiarrhythmic agent. Thus, ajmaline showed a tendency to generate cardiodepressive effects in patients with normal LV-function, and to depress contractility in single cases that clinically had no consequences. The conductance technique proved useful and safe in the assessment of inotropic drug effects by analyzing the ESPVR within the catheterization laboratory routine.