In six normal subjects and 6 patients with primary cardiomyopathy, left ventricular performance was evaluated at rest and during isometric handgrip exercise after 4 days of oral N-acetylprocainamide (NAPA) at each of three dosage levels (3, 4.5, and 6 gm/day). Changes in heart rate, blood pressure, and echocardiographic performance indices were noted during isometric exercise, but no effect of NAPA could be demonstrated. In five additional patients with ventricular dysrhythmias due to cardiac diseases, NAPA was given by vein until dysrhythmias were controlled and then a maintenance infusion was continued for 48 hr. Continuous ECG recordings showed excellent dysrhythmia control in four of the five patients, but no effect of NAPA on heart rate, blood pressure, mean pulmonary artery pressure, mean pulmonary artery wedge pressure, or cardiac output was demonstrated, either at the peak of initial infusion (serum NAPA 27 ± 6.7 μgmlml) or at steady state during the maintenance infusion (16 ± 4.5 μgm/ml). We conclude that NAPA by vein and mouth in clinically appropriate doses should be safe in patients with reduced left ventricular performance due to cardiac disease.
ASJC Scopus subject areas
- Pharmacology (medical)