Clinical and ultramicroscopic myocardial randomized study of beating versus arrested heart for mitral surgery Estudo randomizado clínico e ultramicroscópico na cirurgia valvar mitral com o coração com atividade elétrica versus sem atividade elétrica

AbstractIntroduction: Beating heart surgery on normothermic by-pass simulates physiologic cardiac status. Objectives: This study compared clinical and transmission electron microscopic aspects of myocardial protection during mitral valve replacement using warm retrograde perfusion in empty beating versus arrested heart with cold blood antero-grade cardioplegia. Methods: Randomized study to evaluate myocardial cellular ischemia-reperfusion of both techniques to replace the mitral valve. Thirty-four patients were randomly assigned into group A (beating heart) and group B (arrested heart). The following parameters were assessed: echocardiography, blood chemistry, hemoglobin, lactate. During the surgical procedure a total of 102 myocardial biopsies were performed for ultrastructural analysis from anterior left ventricular wall: before cardiopulmonary by-pass, before aortic desclamping and 10 minutes after reperfusion. Results: Elevation of lactate at 3 hours during the proce-dure was higher in group A, but similar at the end of surgery (