Myocardial protection during cardioplegia in open-heart surgery: a review.

The use of cardioplegia (pharmacologically induced electromechanical arrest) to achieve the ideal conditions for cardiac surgical operations was introduced over 20 years ago in clinical practice. Since then a number of ingredients have been added in various proportions to different cardioplegic solutions and their evaluation in experimental laboratories and clinical practice has continued. Any additive to a cardioplegic solution should be investigated in experimental laboratories and asanguinous cardioplegic solutions should be carefully formulated to avoid extremes of ionic concentrations, pH and osmolarity. Cold blood cardioplegia has not been found advantageous when compared with conventional asanguinous solutions. A combination of pharmacologically induced arrest with cold asanguinous cardioplegic solution and topical hypothermia protects the myocardium better than topical hypothermia alone or normothermic cardioplegia, and continuous infusion of cardioplegic solutions has proved no better than multidose administration. Multidose administration of cold cardioplegic solutions with moderate hypothermia and surface cooling has been found most satisfactory for prolonged aortic cross clamping (up to two hours). Use of cardioplegia in recent years has undoubtedly improved the prognosis of a number of patients undergoing surgical correction of complex cardiac lesions.