Effects of Intravenous Disopyramide on Myocardial Function in Patients with Different Degrees of Cardiac Failure

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Abstract
The effects of i.v. disopyramide phosphate on myocardial function were evaluated by non-invasive indices of cardiac performance (systolic time intervals, STI) in 15 patients with atherosclerotic heart disease and different degrees of cardiac failure. Disopyramide (1.5 mg/kg) was given i.v. over a period of 5 min. This drug induced in patients in I-II classes of NYHA [New York Heart Association] a significant decrease of LVETc [left ventricular ejection time], while PEP [pre-ejection period], ICT [isometric contraction time] and PEP/LVET ratio rose significantly. STI were affected more markedly in patients in III-IV classes of NYHA. Particularly affected were contractility indices (PEP, ICT, PEP/LVET) which were reduced significantly more in patients in III-IV classes compared to patient in I-II classes. LVETc, which correlates to stroke volume and cardiac output, was similarly worsened by the drug in the 2 groups of patients. Disopyramide has relevant depressant effects on myocardial performance, simultaneously reducing stroke volume and contractility; the effect on contractility is more marked in patients with severe left ventricular impairment.