P OLYMORPHIC VENTRICULAR tachycardia (PVT) is a variant of ventricular tachycardia, characterized by QRS complexes of changing amplitude, typically occurring at a rate of 200 to 250 depolarizations per minute. PVT in association with a prolonged QT interval comprise the torsades de pointes (TdP) syndrome.‘,* TdP may be caused by a variety of conditions (Table I), but is most commonly seen postoperatively in patients on antiarrhythmic medications, especially the class I-A agents such as quinidine and procainamide.3 Recognition of TdP syndrome is important because it may be resistant to. or worsened by, conventional treatment for the more common form of ventricular tachycardia. Unrecognized TdP that is inappropriately treated is potentially fatal.” A cast is reported of postoperative TdP, induced by procainamide and refractory to conventional therapy. that was successfully treated with isoproterenol.

Traditional autologous conduits are sometimes unavailable or unsuitable to permit total revascularization during coronary artery bypass grafting. In these patients the results of using nonautologous alternative conduits has been disappointing. Encouraged by the excellent longterm results seen with cryopreserved allograft valves, a clinical protocol was developed to evaluate the use of a commercially cryopreserved allograft saphenous vein (CPV). Our protocol consisted of using CPV when left internal mammary arteries and autologous saphenous vein grafts were unavailable or unsuitable for complete revascularization. Blood group (ABO) typed CPVs were thawed and implanted as required using standard surgical techniques. From December 1989 through June 1991, 19 of 1,602 patients who underwent coronary revascularization had CPVs implanted (1.2%). There were no operative deaths. An attempt was made to evaluate the patency of all grafts with coronary arteriography or ultrafast computed tomographic scans. Fourteen patients were available for patency evaluation. Patency rate in the 14 patients studied at a mean of 7 ± 2 months (range, 2 to 16 months) were: internal mammary artery, 93% (14/15); saphenous vein graft, 80% (4/5); and CPV, 41% (7/17). The patency of the CPV was significantly less than the patency rate for the saphenous vein and internal mammary artery (p = 0.004). We conclude that the short-term patency rate of CPVs is inferior to that of autologous vessels. Due to its poor patency, we recommend that CPV should only be used when no other autologous conduit is available.