Is surgery the gold standard in the treatment of obstructive hypertrophic cardiomyopathy?

Objectives: Hypertrophic cardiomyopathy is a complex and relatively common genetic cardiac disease and has been the subject of intensive scrutiny and investigation for over 40 years. The aim of this non-randomized cohort study was to compare subjective and objective outcomes in hypertrophic cardiomyopathy patients undergoing drug therapy, surgical myotomy-myectomy, dual-chamber pacing and alcohol septal ablation.

Methods: We examined 194 patients: 103 with non-obstructive hypertrophic cardiomyopathy and 91 with obstructive hypertrophic cardiomyopathy. All the patients with a non-obstructive form were on drug therapy. Ninety-one consecutive patients with drug-refractory obstructive hypertrophic cardiomyopathy were treated invasively. Dual-chamber pacemaker implantation was performed for 49 patients with previous positive temporary pacing test (Group 1). In 28 patients with massive left ventricle hypertrophy and obliteration of its cavities, extensive myotomy-myectomy was performed (Group 2). In 14 patients with midventricular obstruction and appropriate coronary anatomy, alcohol septal ablation was performed (Group 3).

Results: The peak left ventricle outflow tract gradient was 84.1 ± 15.2 mmHg in Group 1, 113.3 ± 14.9 mmHg in Group 2 and 97.5 ± 8.9 mmHg in Group 3. Dual-chamber pacing in Group 1 with optimal atrio-ventricular delay (85-180 ms for atrium pacing and 45-120 ms for atrial sensing) leads to dramatic decreases in left ventricle outflow tract gradient to 17.6 ± 11.8 mmHg and degree of mitral regurgitation. After extensive myectomy in Group 2, we observed a reduction of left ventricle outflow tract gradient to 17.3 ± 10.2 mmHg. Septal alcohol ablation in Group 3 leads to a left ventricle outflow tract gradient decrease from 97.5 ± 8.9 to 25.3 ± 5.8 mmHg.

Conclusions: Surgical myectomy, dual-chamber pacing and alcohol septal ablation are equally effective in reducing obstruction in case of correct indications. Dual-chamber pacing is indicated in functional reversible states characterized by excitation delay. Alcohol septal ablation is preferable in cases with midventricular obstruction and appropriate coronary anatomy. Surgical methods are indicated in anatomical irreversible changes and remain the gold standard for obstructive hypertrophic cardiomyopathy treatment.