Mechanisms of cardiac perforation leading to tamponade in balloon mitral valvuloplasty.

Mechanisms of cardiac perforation in 10 cases of cardiac tamponade encountered in a single-center series of 903 balloon mitral valvuloplasty procedures were elucidated by precise localization of the site of perforation at subsequent surgery. These mechanisms were perforation of the aortic root and adjacent right atrium by sliding up of the transseptal set (2), apical tears by straight-tip balloon catheters driven distally during mitral valve dilatation (3), apical perforations by guidewires introduced through catheters wedged in the apex (2), tear of the posterior right atrial wall by dilatation of the track produced by very low septal punctures (2), and right ventricular perforation by a pacing catheter (1). Multivariate analysis showed cardiac perforation to be significantly related to the total experience at the center (inversely) and to patient age (directly). Left ventricular perforation occurred exclusively in patients > 40 yr of age. Understanding these mechanisms has enabled formulation of effective strategies to prevent cardiac perforation.