[Papillary muscle rupture during subaortic membrane balloon dilatation].

A 37 year-old female patient underwent catheter-balloon dilation for discrete subaortic stenosis. During the procedure severe mitral regurgitation was produced requiring emergency surgery. Transesophageal and intraoperative findings were posteriormedial papillary muscle rupture. Retrospective viewing of the cineangiogram during balloon inflation revealed distal balloon indentation, corresponding to the injured papillary muscle. This severe complication of the left ventricular outflow tract angioplasty should be avoided by careful positioning of the guidewire and balloon before inflation.