Abstract
Left ventricular ejection time (LVET) and pre-ejectoin period (PEP) can be derived from the simultaneous recordings of arterial pressure form, phonocardiogram and electrocardiogram. Using the PEP/LVET and 1/PEP2 as the indices of cardiac contraction. We studied the effect of a new antiarrhythmic agent, mexiletine, on left ventricular function during halothane anesthesia in 15 subjects.
Intravenous mexiletine 2mg/kg showed no significant depressive action on cardiac contraction. The dosages of 2.5 and 3mg/kg, however, decreased mean arterial pressure and 1/PEP2 and increased PEP/LVET significantly. This means that mexiletine exerted a depressive action on myocardium in 2.5 and 3mg/kg doses, but there were no significant changes in cardiac contraction among three groups. We conclude that mexiletine shows no dose-dependent cardiac depression during halothane anesthesia at the dose of 2 to 3mg/kg.
