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In patients with hypertrophic cardiomyopathy myocardial fibrosis is an independent predictor of adverse outcome. A new technique of HOCM surgical correction in patients with extreme hypertrophy and septal myocardial fibrosis has been proposed.
The excision of the asymmetrical hypertrophied area of the interventricular septum (IVS) causing obstruction was performed from the conal part of the right ventricle corresponding to the zone of obstruction of the left ventricle (LV). This excision was carried out on the right side of the IVS and not trough the whole IVS thickness. The areas of septal myocardial fibrosis were removed corresponding to the zone of delayed enhancement (DE) imaging. Myocardial fibrosis was detected by cardiovascular magnetic resonance (with DE imaging). Eleven HOCM patients with extreme hypertrophy (NYHA Class 3.1), myocardial fibrosis and episodes of ventricular tachycardia (VT) underwent this procedure. Five patients had biventricular obstruction. The follow-up period was 38.9 ± 15.6 months.
Ten patients were free of symptoms (NYHA class 1) and one patient had only mild limitations. The mean echocardiographic gradient in LV decreased from 88.9 ± 10.0 to 9.7 ± 1.3 mmHg, the mean value of gradient in right ventricular outflow tract was reduced from 45.2 ± 4.7 to 3.8 ± 1.3 mmHg. Echocardiographically determined septal thickness was reduced from 34.5 ± 3.8 to 15.5 ± 1.6 mm. Sinus rhythm without block of His bundle right branch was noted in all patients after surgery. VT was not registered. None of the patients needed implantation of cardioverter-defibrillator after surgery.
This novel technique of HOCM surgical correction provides the precise removal of the areas of septal fibrosis and effective elimination of biventricular obstruction in patients with extreme hypertrophy who can not be treated with the current surgical techniques. The approach avoids mechanical damage to the heart conduction system.