Systolic anterior motion of mitral valve after valve surgery
Systolic anterior motion of mitral valve after valve surgery: Systolic anterior motion (SAM) of anterior mitral leaflet (AML) is a classical finding in hypertrophic obstructive cardiomyopathy and it is a factor causing the obstruction as well as associated mitral regurgitation. But systolic anterior motion of the anterior mitral leaflet can also occur without hypertrophic cardiomyopathy, after repair of mitral valve. If the leaflet is very redundant an myxomatous, there can be SAM when the left ventricular size decreases after valve repair and if the ventricle is hyperdynamic. This is more likely when the distance between the valve coaptation point and the interventricular septum. Undersized annuloplasty ring also contributes to the development of post mitral valve repair SAM. A non dilated, hyperdynamic left ventricle is another contributory factor .
Methods to prevent SAM and left ventricular outflow tract obstruction (LVOTO) after mitral valve repair has been described . Triangular or quadrangular resection of the mid portion of the posterior leaflet and posterior band annuloplasty were performed. Posteriorly directed mid posterior leaflet secondary chordae which would otherwise have been resected, were transferred to the underside of the middle of the mid anterior leaflet with a small piece of associated valve as anchoring pledget. This was to prevent SAM and LVOTO. The redundant anterior leaflet edge was thus kept away from the left ventricular outflow tract. No post operative SAM or LVOTO were observed in these cases after mitral valve repair. Authors suggest the use of extra chordae tendinae whenever available, to tether the redundant anterior leaflet from flipping to the left ventricular outflow tract.