The Journal of thoracic and cardiovascular surgery
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J. Thorac. Cardiovasc. Surg. · Nov 1988
Age-related changes in the ability of hypothermia and cardioplegia to protect ischemic rabbit myocardium.
Hypothermia combined with pharmacologic cardioplegia protects the globally ischemic adult heart, but this benefit may not extend to children; poor postischemic recovery of function and increased mortality may result when this method of myocardial protection is used in children. The relative susceptibilities to ischemia-induced injury modified by hypothermia alone and by hypothermia plus cardioplegia were assessed in isolated perfused immature (7- to 10-day-old) and mature (6- to 24-month-old) rabbit hearts. Hearts were perfused aerobically with Krebs-Henseleit buffer in the working mode for 30 minutes, and aortic flow was recorded. ⋯ Thomas' Hospital solution No. 2 caused a decremental loss of postischemic function in contrast to incremental protection with multidose cardioplegia in the mature heart. We conclude that immature rabbit hearts are significantly more tolerant of ischemic injury than mature rabbit hearts and that, unexpectedly, St. Thomas' Hospital solution No. 2 damages immature rabbit hearts.
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J. Thorac. Cardiovasc. Surg. · Nov 1988
Case ReportsA new technique for repair of mitral insufficiency caused by ruptured chordae of the anterior leaflet.
Prolapse of the anterior leaflet of the mitral valve is the result of ruptured chordae, elongated chordae, or elongated or ruptured papillary muscle. Several techniques have been described for the correction of mitral valve insufficiency. However, when there is severe rupture of the chordae, the most widely accepted solution is valve replacement. ⋯ Studies performed 3 and 4 months postoperatively showed competent and well-functioning valves. One patient required a valve replacement for acute mitral insufficiency 5 years later, but the other patient was doing well 3 years after the operation. Despite the limited experience, we believe this technique offers a reasonable alternative to valve replacement.
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J. Thorac. Cardiovasc. Surg. · Nov 1988
Optimal myocardial protection during crystalloid cardioplegia. Interrelationship between volume and duration of infusion.
There is often a large difference between volumes of crystalloid cardioplegic solution used clinically (2 to 4 ml/gm myocardium) and experimentally (in rat heart preparations, volumes of 30 ml/gm or more are used). In an attempt to reconcile these differences and define the minimum volume and/or duration of infusion of the St. Thomas' Hospital cardioplegic solution consistent with maximal myocardial protection, we have used the isolated working rat heart to characterize the relationships between myocardial protection and (1) the duration of cardioplegic infusion and (2) the volume of cardioplegic infusion. ⋯ Maximal protection was observed with 30, 60, and 120 seconds of infusion (recovery of cardiac output = 56.7% +/- 5.9%, 45.1% +/- 7.9%, and 56.2% +/- 6.8%, respectively). Our results suggest that, for maximum myocardial protection, the St. Thomas' Hospital solution should be infused at a rate of not less than 2.0 ml/gm wet weight of heart and that the duration of infusion should be not less than 30 seconds.