Effects of tocainide on left ventricular performance at rest and during acute alterations in heart rate and systemic arterial pressure. An echocardiographic study.

To determine if the new antiarrhytbmic agent tocainide depresses left ventricular function we performed a double-blind cross-over trial of tocainide and placebo in 10 patients with valvular heart disease and recorded echocardiograms (a) in the basal state, (b) during atropine-induced increases in heart rate, and (c) during acute pressure loading with phenylephrine. The drug doses were 400 mg every 8 hours for 3 days, and the mean tocainide plasma concentration in the tocainide group was 5-3 ,ug/ml.