Prevention of SAM phenomenon after reconstructive mitral valve surgery

Abstract

Systolic anterior motion (SAM) of the mitral valve (MV) can be a life-threatening condition. The SAM can result in severe left ventricular outflow tract obstruction and/or mitral regurgitation and is associated with up to 20% risk of sudden death (which is substantially lower in hypertrophic cardiomyopathy (HCM)).The mechanisms of SAM are complex and depend on the functional status of the ventricle. The SAM can occur in all cases, but is typically observed in patients with HCM or following MV repair.Echocardiography (2D, 3D and stress) has a central diagnostic role as the application of echocardiographic SAM predictors allows the incorporation of prevention techniques during surgery and post-operative SAM assessment.MRI (magnetic resonance imaging) has a special role in understanding the dynamic nature of SAM, especially in anatomically atypical hearts (including HCM).This article describes what the clinician needs to know about SAM ranging from pathophysiological mechanisms and imaging modalities to conservative (medical) and surgical approaches and their respective outcomes.A stepwise approach consisting of medical therapy, followed by aggressive volume loading and beta-adrenoreceptor blockers. Surgery is the final option. The correct choice of surgical technique requires an understanding of the anatomical substrate of SAM.