Orthotopic canine heart transplantation: left ventricular contractility during chronic rejection

Myocardial left ventricular contractility is assessed in 8 orthotopic heart-transplanted dogs during chronic rejection by a noninvasive method. The mean circumferential velocity of shortening (Vcf) is calculated from endocardial marker motion on cinefilms. A model for chronic rejection after cardiac transplantation was obtained by histocompatibility matching in DLA identical Beagle littermates. No immunosuppressive treatment was used. All dogs eventually died of chronic rejection; mean survival time was 112.5 days. LV contractility shows the following pattern: Chronic rejection causes an important contractility decrease (P less than 0.001) with two significant drops: (1) from the week preoperative to the first week after transplantation (P less than 0.02) and (2) from week terminal minus one to the terminal week (P less than 0.01). This study describes the technique and the changes in Vcf observed over a period of time in a predictable model.