Assessment of left ventricular function
In planning a cardiac operation, the key objective should be to accomplish the best possible benefit for the myocardium with the least possible stress. The ultimate objective for most cardiac operations is to preserve and protect myocardial function through correction of the mechanical burden, such as a septal defect, malfunctioning valve, or obstructed coronary artery. In the preoperative evaluation of the cardiac patient, the anesthesiologist wishes to know the basis for the existing burden on the myocardium, its current state of compensation and, if possible, its margin of functional reserve. This information will influence all phases of surgical management: preoperative, intraoperative, and postoperative. There is no single examination or parameter that will provide the anesthesiologist with all that he needs to know.
The simplest and most cost-effective means of evaluating the cardiac patient is a careful review of the history and physical examination by the anesthesiologist who will be responsible for his management. Much can be learned about the state of the myocardium by observing such simple signs as the persistent, nonproductive cough, cold clammy skin, pulsus alternans, among many others. The chest roentgenogram and electrocardiogram should be systematically evaluated rather than the mere acceptance of the officially recorded interpretations.
A number of “noninvasive methods” are available, which may help supplement the simple clinical observations. The echocardiogram may demonstrate abnormal dilatation of one or more chambers, diminished wall motion, or paradoxical motion of the interventricular septum. The interpretation should be made with caution, however, for the M-mode echocardiogram provides only . . .