Papillary muscle scarring is encountered frequently during operations for sustained ventricular tachycardia (VT). Indications for excision of the papillary muscle scar and mitral valve replacement (MVR) are controversial. The findings in 46 consecutive patients undergoing operative electrophysiologic map-directed endocardial resections for VT were reviewed. There was papillary muscle scarring in 15 patients (average age: 59 years; sex: 11 male, 4 female; average ejection fraction: 31 +/- 14%). Eleven patients had a VT with the site of origin on a scarred papillary muscle; four had another VT site of origin. Six patients underwent papillary muscle scar resection (5 with MVR); six underwent papillary muscle cryotherapy (-60 C X 2 min); and three had neither papillary muscle resection nor MVR. All six patients with papillary muscle resection +/- MVR are alive and free of arrhythmia after 14.3 +/- 7.6 months of follow-up. Five of six patients treated by papillary muscle cryotherapy alone manifested spontaneous (4 patients) or inducible (1 patient) VT during early postoperative evaluation. Two of the three patients with untreated papillary muscle scarring developed late complications requiring reoperation. One patient developed mitral regurgitation requiring MVR 5 months later. The other developed a previously undocumented VT 2 years after operation. Significant papillary muscle scarring visualized at the time of operation for arrhythmia is an indication for resection of the scar and the papillary muscle, even if this necessitates MVR. In this series, attempts to preserve the papillary muscle, by incomplete resection of the scar or by cryotherapy, resulted in a high failure rate owing to recurrent VT or mitral regurgitation.