Adverse hemodynamic and clinical effects of encainide in severe chronic heart failure
Gottlieb, S.S.; Kukin, M.L.; Yushak, M.; Medina, N.; Packer, M.
Annals of Internal Medicine 110(7): 505-509
1989
ISSN/ISBN: 0003-4819 PMID: 2493762 Document Number: 342182
Study Objective: To evaluate the hemodyanmic effects of the antiarrhythmic drug, encainide, in patients with severe chronic heart failure. Design: Unblinded, before-after study. Setting: Referral center for patients with heart failure. Patients: Thirty patients with severe chronic heart failure and a left ventricular ejection fraction less than 40%. Interventions: Invasive hemodynamic measurements were done (using a balloon-tipped thermodilution catheter) before and for 3 hours after a single oral dose of 50 mg of encainide. Measurements and Main Results: Ninety to one hundred and twenty minutes after its administration, encainide produced a signficant deterioration in cardiac peformance, as reflected by a fall in cardiac index from 2.3 to 1.8 L/min .cntdot. m2 body surface (mean change 0.5 .+-. 0.1; P < 0.001), a fall in stroke work index from 26 to 18 g-m/m2 (mean change 8 .+-. 2; P < 0.001), and an increase in left ventricular filling pressure from 19 to 22 mm Hg (mean change 3 .+-. 2; P < 0.05). These deleterious hemodyanimc effects were accompained by worsening symptoms of heart failure in 8 of the 30 patients. Serum levels of encainide and its metabolites, O-desmethylencainide and 3-methoxy-O-desmethylencainide, were within the therapeutic range in most patients. Conclusions: Encainide can cause adverse hemodynamic and clinical effects in patients with severe chronic heart failure.