Chronic verapamil therapy in pediatric and young adult patients with hypertrophic cardiomyopathy.
Oral verapamil, 5.2 +/- 1.1 mg/kg/day (range 2.8 to 7), was administered to 13 pediatric patients with hypertrophic cardiomyopathy for 13 +/- 6 months (range 2 to 20). The patients had significant symptomatic improvement on verapamil therapy. Murmur intensity diminished in 6 patients during therapy and left ventricular (LV) electromotive forces on the electrocardiogram diminished in 4, increased in 5 and did not change in 4. Exercise endurance increased from 8.4 +/- 3.9 to 10.9 +/- 2.8 minutes (p less than 0.01). Seven patients had ST-segment depression (0.38 +/- 0.28 mV) before verapamil therapy, which improved after verapamil therapy in 5 (0.24 +/- 0.17 mV, p less than 0.02). Of 4 patients with exercise-induced ventricular ectopic activity, 3 had diminution or abolishment of ectopy following verapamil. By echocardiography, the patients had an increase in LV end-diastolic dimension from 3.4 +/- 0.7 to 3.9 +/- 0.8 cm (p less than 0.01), with no significant change in shortening fraction (46.1 +/- 8.0% vs 44.6 +/- 8.0%). When adjusted for body size and age there was a significant decrease in LV septal thickness (from 106 +/- 70 to 45 +/- 52% of predicted normal values, p less than 0.05) and LV posterior wall thickness (from 40 +/- 45 to 5 +/- 26% of predicted normal values p = 0.05) after verapamil. Isovolumic relaxation time decreased from 69 +/- 26 to 42 +/- 19 ms after verapamil (p less than 0.01). Systolic anterior motion of the anterior mitral leaflet disappeared in 5 of 8 patients and midsystolic closure of the aortic valve was no longer present in 4 of 8.(ABSTRACT TRUNCATED AT 250 WORDS)
D000293:Adolescent; D000328:Adult; D002312:Cardiomyopathy, Hypertrophic / Q000188:drug therapy* / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D004452:Echocardiography; D004562:Electrocardiography; D005080:Exercise Test; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009200:Myocardial Contraction; D014700:Verapamil / Q000627:therapeutic use*
D014700:Verapamil