The Journal of thoracic and cardiovascular surgery
-
J. Thorac. Cardiovasc. Surg. · Oct 1983
Experimental mitral regurgitation. Physiological effects of correction on left ventricular dynamics.
It has been suggested that mitral valve replacement for mitral regurgitation can precipitate acute myocardial failure by increasing left ventricular afterload. However, most studies of this problem have involved anesthesia, acute surgical trauma, or ischemic cardioplegia, each of which can influence myocardial function. The pure hemodynamic consequences of mitral valve replacement were investigated by surgically instrumenting eight dogs with ultrasonic transducers to measure left ventricular diameter, electromagnetic flow probes to measure ascending aortic blood flow, and micromanometers to measure left ventricular and pleural pressures. ⋯ However, forward cardiac output increased in all studies, implying improved pump efficiency and overall cardiac performance. Thus the improvement in pump efficiency associated with restoration of mitral valve competence uniformly increases forward cardiac output despite an increased ventricular afterload and a decreased total stroke volume. Although there may be differences between this relatively acute model and chronic forms of mitral regurgitation encountered clinically, these data suggest that forward cardiac output should increase with correction of mitral regurgitation and that the associated augmentation in afterload is probably not a major factor causing low cardiac output after correction.
-
J. Thorac. Cardiovasc. Surg. · Oct 1983
Case ReportsComplications of intercostal nerve blocks performed under direct vision during thoracotomy: a report of two cases.
Intrathoracic intercostal nerve block is a well-described procedure used to provide postoperative pain relief following thoracotomy. The two cases described present possible complications secondary to such blocks and suggest that the routine use of intrathoracic intercostal nerve blocks should be discouraged.