Surgery for hypertrophic cardiomyopathy

Abstract

Hypertrophic cardiomyopathy (HCM) is a genetically determined cardiac disease characterised by otherwise unexplained myocardial hypertrophy of the left ventricle, and may result in left ventricular outflow tract obstruction. It is the most common cause of sudden cardiac death in young adults due to arrhythmias. Septal myectomy is a surgical treatment for HCM with moderate to severe outflow tract obstruction, and is indicated for patients with severe symptoms refractory to medical therapy. The surgical approach involves obtaining access to the interventricular septum via transaortic, transapical or transmitral approaches, and excising a portion of the hypertrophied myocardium to relieve the outflow tract obstruction. Large, contemporary series from centres experienced in septal myectomy patients have demonstrated a low early mortality of <2 %, excellent long-term survival that matches the general population, and durable relief of symptoms.

Keywords: Alcohol septal ablation; Hypertrophic cardiomyopathy; Left ventricular outflow tract obstruction; Septal myectomy.

Fig. 1

Intraoperative transesophageal echocardiography (TEE) monitoring. a Pre-myectomy image demonstrating basal septal hypertrophy (* white arrow) and systolic anterior motion of the anterior mitral valve (white arrow) causing dynamic outflow tract obstruction. Right atrium (RA), right ventricle (RV), left atrium (LA), left ventricle (LV), aortic valve (** white arrow). b Post-myectomy image demonstrating basal septum resection and relief of outflow tract obstruction

Fig. 2

Transaortic myectomy for basal HCM. a View of the interventricular septum and outflow tract obstruction (labelled white arrow); right coronary leaflet (RC), left coronary leaflet (LC), and non-coronary leaflet (NC) of the aortic valve. b Scalpel shown incising the basal septum, beginning to the right of the nadir of the right coronary leaflet and extending leftwards to avoid the atrioventricular conduction bundle. c Resected portion of the myocardium (RM) being removed. d View of the septum post-myectomy showing relief of the obstruction; the nadir of the right coronary leaflet (* white arrow); anterior mitral valve leaflet (** white arrow) retracted by cardiotomy sucker

Fig. 3

Transapical myectomy for midventricular HCM. a Site of apical incision, made in a bare area parallel and lateral to the left anterior descending artery (white arrows), and cranial to the true left ventricular apex (black arrow). b Resection of midventricular portion of hypertrophied myocardium

Fig. 4

Transapical myectomy for apical HCM. a View through the apical incision prior to myectomy demonstrating thickened myocardium; left anterior descending artery (white arrow). b Post-myectomy demonstrating reduced myocardial thickness and increased cavity size