P052: SYSTOLIC ANTERIOR MOTION CAUSING HEMODYNAMIC COLLAPSE DURING AF ABLATION IN A PATIENT WITHOUT STRUCTURAL HEART DISEASE
Anny Santana Beard, MD1; Taylor Rechter, MS2; Edward Parker, DO1
1Westside Regional Medical Center HCA FL; 2Dr. Kiran C. Patel College of Osteopathic Medicine
Systolic anterior motion (SAM) of the mitral valve has historically been associated with hypertrophic obstructive cardiomyopathy (HOCM). However, SAM is now recognized as a dynamic phenomenon that can occur in structurally normal hearts when alterations in ventricular loading conditions and contractility disrupt left ventricular geometry.
We present the case of a 68-year-old woman undergoing elective pulmonary vein isolation and left atrial appendage occluder placement for persistent atrial fibrillation under general anesthesia. Intraoperatively, she developed acute, profound hypotension. Transesophageal echocardiography revealed new-onset SAM of the mitral valve with dynamic LVOT obstruction. The patient had no prior history of hypertrophic cardiomyopathy or obstructive physiology.
Hemodynamic instability likely resulted from LVOT obstruction caused by the synergistic effects of a hyperdynamic, underfilled left ventricle, altered papillary muscle positioning, increased LVOT flow velocity, and augmented drag forces on the anterior mitral leaflet. Prompt management with preload augmentation and peripheral vasoconstriction resulted in hemodynamic stabilization.
This case illustrates how general anesthesia induced alterations in preload, afterload, and contractility can unmask dynamic LVOT obstruction even in patients without previously diagnosed structural heart disease. Furthermore, it highlights that mitral valve function depends not only on the structural integrity of the leaflet but also on the dynamic interplay between ventricular geometry and contractile state, both of which may predispose susceptible patients to SAM and cardiovascular collapse particularly under general anesthesia.