INFLUENCE OF THE CLASS 1B ANTIARRHYTHMIC AGENT MEXITIL ON HEMODYNAMICS AND CONTRACTILITY (SLOPE EMAX) IN PATIENTS WITH ISCHEMIC CORONARY-ARTERY DISEASE [CONDUCTANCE (VOLUME) CATHETER TECHNIQUE]

To evaluate cardiodepressive risks of antiarrhythmic treatment, we ana lyzed endsystolic pressure-volume relationships (ESPVR) and pump funct ion, under Mexitil (class 1B) 3 mg/kg i.v., in 13 patients with corona ry artery disease (CAD), both 1. at rest and 2. under tachycardia. DP/ dtmax fell by 4 and 1%, slope Emax by 4 and 9%, and loops of the ESPVR moved rightward by 27 and 19% (p > 0.05), all indicating lack of sign ificant inotropy loss with Mexitil. Unloading proved irrelevant, param eters of left ventricular (LV) pump function decreased by 3-18%, while LV volumes increased (end diastolic by 14 and 14%, endsystolic by 29 and 38%; p < 0.05). Conclusion: The antiarrhythmic effects of Mexitil are generated without impairing either LV pump function or contractili ty in a clinically relevant fashion, while LV volumes tend to increase , probably indicating changes in LV compliance. Thus, the drug can be used safely in ischemic CAD.