Objective:
Hypertrophic cardiomyopathy (HCM) is a congenital condition with a broad spectrum of phenotypic variability. A small group of patients may develop symptomatic midventricular obstruction which can be difficult to eliminate through a transaortic approach alone. Our objective was to evaluate the early outcomes of a transapical approach for relief of midventricular obstructive HCM.
Methods:
Between 1985 and 2007, 13 symptomatic patients with obstructive midventricular HCM underwent transapical midventricular myectomy. Information from a prospective database was reviewed.
Results:
The median age was 40 years (range 11-65); 58% were female. Twelve patients(92%) had fatigue and shortness of breath, 9(69%) had presyncope or syncope, 7(54%) had palpitations, and 5(46%) had angina. The mean preoperative EF was 74±7%. All patients were on medical therapy: calcium channel blockers(n=9), beta-blockers(n=8), and disopyramide(n=2). Atrial arrhythmias were present in 2 patients, ventricular arrhythmias in 3, and 5 patients had an AICD. The median preoperative resting midcavitary gradient was 36mmHg; provoked gradient was 52mmHg. All patients had a transapical midventricular myectomy and 8 patients had concomitant transaortic septal myectomy; 9.9±3.7g of muscle was removed. There were no iatrogenic injuries to the aortic or mitral valve and there were no early ventricular arrhythmias. All patients had a successful reduction in midcavitary gradients (postoperative 7±11mmHg) with a mean EF of 67±11%.
Conclusions:
Midventricular myectomy through an apical incision effectively eliminates midventricular obstruction in symptomatic patients without significant change in left ventricular function. Further follow up is needed to determine if this approach impacts late left ventricular function or arrhythmogenic potential.