The primary goal of this research is to measure systolic performance of the human left ventricle before, during and after cardiac surgery. This information will be used to analyze the efficacy of surgical procedures, the efficacy of myocardial preservation, and the probability of long-term survival and clinical improvement based on observations in the perioperative period and in long-term follow-up. The primary source of this information will be two-dimensional echocardiographic images of the human left ventricle obtained both in the open chest and in closed chest patients. Additional information will be provided by intraoperative recordings of left ventricular pressure, stroke volume, and dP/dt. These recordings will be combined with echocardiographic determination of mass and end-diastolic volume to derive mechanical indices of left ventricular performance including peak contractile element velocity, peak wall stress, and more conventional parameters such as pressure-volume stroke work, tension-time index, and ejection fraction. An additional goal is to define alterations in left ventricular compliance during open heart surgery, by combining end-diastolic pressure and dimension measurements over a wide range of filling pressures provided by the heart-lung machine. In postoperative patients, the mass of the left ventricle will be studied by echocardiography to determine the extent to which increased mass can be utilized as an index of injury following cardiac surgery, cardiac transplantation, and trauma with hemorrhagic shock and hemodilution. Laboratory studies will examine the functional importance of alterations in left ventricular mass due to hemodilution, global ischemia, and arterial pressure with and without global ischemia. The extent to which edema can be reversed by mechanical and pharmacologic interventions, and the hemodynamic significance of that reversal, will also be explored.
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