Background: The standard surgical approach to hypertrophic obstructive cardiomyopathy (HOCM) was modified in the present series with a combination of extended myectomy with partial excision and mobilization of the papillary muscles.
Methods and results: Between 1979 and 1992, 58 patients (38 men and 20 women; mean age, 49 +/- 24 years) with HOCM were operated on with the use of this different technique. Their intraventricular gradients were 79 +/- 33 (+/- SD) mm Hg at rest and increased to 147 +/- 48 mm Hg with provocative maneuvers. Mild-to-moderate mitral regurgitation was present in 60% of the patients, and severe regurgitation was present in 5%. Ten patients required additional aortocoronary bypass graft surgery. Follow-up (mean, 84 months) was complete (100%). Hemodynamic improvement was documented by a significant (P < .01) decrease in left ventricular end-diastolic pressure from 19 +/- 9 to 14 +/- 6 mm Hg and reduction of basal outflow tract gradients to 5 +/- 7 mm Hg at rest and 16 +/- 24 mm Hg after provocation. Late mortality was 1.4% per patient-year, and no sudden cardiac deaths occurred during follow-up. Functional status was excellent for 84% of the patients; 8 patients were in New York Heart Association functional class III, and none were in class IV. Echocardiography revealed no outflow tract obstruction.
Conclusions: Extended myectomy and reconstruction of the subvalvular mitral apparatus in HOCM result in excellent functional improvement with relief of outflow tract obstruction. The technique can be performed safely despite its more aggressive surgical nature and allows an individualized strategy depending on the patient's extent and distribution of left ventricular hypertrophy.