Hemodynamic long-term results after medical and surgical therapy of hypertrophic cardiomyopathies.

The therapeutic effectiveness of propranolol, verapamil and surgery (transaortal subvalvular myectomy) in hypertrophic cardiomyopathy was assessed in 100 patients with hypertrophic obstructive cardiomyopathy (HOCM) and 12 patients with hypertrophic non-obstructive cardiomyopathy (HNCM) by means of exercise tests with hemodynamic measurements. The effects of propranolol were assessed in 13 HOCM patients, of verapamil in 68 HOCM patients and 12 HNCM patients, and of surgery in 31 HOCM patients after a mean of 3 to 9 months. Of the 68 verapamil-treated patients, 23 were reexamined once more after a mean of 38 months. Ten of the 31 surgically treated patients were reexamined after a mean of 52 months. In the studies performed within the first year of medical treatment or after surgery, verapamil was clinically and hemodynamically superior to propranolol, but not as effective as surgical treatment. Functional limitation according to the NYHA classification improved after propranolol in 31% of the patients, after verapamil in 41%, and after surgery in 94% of the cases. Improvements by more than one NYHA class were observed exclusively after surgical treatment. Maximal exercise capacity was, on average, not changed after propranolol, but increased after verapamil and, more substantially, after surgery. These different responses to treatment could be attributed to hemodynamic changes, especially concerning heart rate, stroke volume, cardiac output, arterio-venous oxygen difference and pulmonary artery pressure. In the case of verapamil, the beneficial hemodynamic effects occurred independently of the site of intraventricular obstruction in HOCM (subvalvular or midventricular), but seemed to be superior in HOCM as compared to HNCM. The late reexaminations, an average of 38 months after beginning verapamil treatment and 52 months after surgery, demonstrated that the initial salutary clinical and hemodynamic effects of verapamil were not maintained during long-term follow-up in the majority of patients, whereas they persisted or even intensified during long-term observation after surgery.