Influence of post-surgery time after cardiac transplantation on exercise responses. Med. Sci. Sports Exerc., Vol. 28, No. 2, pp. 171-175, 1996. To test the hypothesis that exercise response changes with time after cardiac transplantation, we investigated the cardiorespiratory responses of nine orthotopic heart transplant patients (52.4 +/- 2 yr) during graded exercise tests (30 W.3 min-1) done at 1, 3, 6, 9 and 12 months post-surgery. At peak exercise, 1) oxygen uptake per kg of body weight (VO2), minute ventilation (VE) and oxygen pulse (O2 pulse) did not change significantly between 1 and 12 months postsurgery; 2) transplanted heart rate (HRt) and delta heart rate (peak exercise heart rate--resting heart rate) increased significantly over time (P < 0.01; P < 0.05) with a marked increase between 1 and 3 months (P < 0.05); and (3) a significant negative correlation existed between O2 pulse and HRt (r = -0.36, P < 0.05), whereas no correlation was found between delta heart rate and delta VO2 (peak exercise VO2- resting VO2, l.min-1). During submaximal exercise, HRt increased significantly over time (P < 0.001); VO2, VE, and O2 pulse showed no significant change; and the VO2-HRt relationship shifted toward higher values of HRt. We conclude that, in the absence of formal physical training, the exercise response of denervated transplanted heart increases in relation to post-surgery time but does not affect oxygen uptake at submaximal and peak levels of exercise.
Following cardiac transplantation bacterial mediastinitis is a severe early complication. Between March 1986 and September 1993, cardiac transplant operations were performed in 101 patients, of whom six developed purulent mediastinitis. Treatment consisted of surgical débridement, closed local irrigation, drainage and systemic antibiotics. No patient died as a result of bacterial mediastinitis. Low cardiac output and requirements for resternotomy for bleeding and prolonged artificial ventilation were significantly higher in the group with sternal infection. In contrast, since January 1991 the dose of corticosteroid was decreased from 5 mg/kg per day to 1.5 mg/kg per day beginning on the first day after operation. A total of 51 heart transplant operations have been subsequently performed without sign of mediastinal infection.
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