VENTRICULAR FUNCTION DURING CARDIAC SURGERY

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These studies will examine the effect of surgical correction of acquired and congenital heart disease on the systolic and diastolic properties of the left and right ventricles in human adults, children, and infants. State of the art measuring devices and algorithms will be employed for intraoperative measurements and long-term follow-up. Improved pump function during corrective surgery will be correlated with changes in myocardial properties, since impaired contractility and compliance can be hidden by improved hemodynamics. For specific operations in which the pathophysiology of surgical correction is not well understood, specific mechanisms that promote a successful long term result will be defined. Outpatient studies will examine chronic changes in ventricular size and function, which will be related to intraoperative events. Laboratory studies will develop advanced methods for intraoperative study and reduce the cost of such studies, making the technology widely available. Intraoperative measurements will include pressure by micromanometer, flow by electromagnetic or ultrasonic flowmeter, and dimensions by sonomicrometry, two-dimensional echocardiography, and ventricular impedance. End-diastolic volume will be correlated with end-diastolic pressure to measure compliance, and with pressure-volume stroke work to measure contractile function (preload recruitable stroke work). Contractility will also be measured from pressure-volume loops (end- systolic pressure-volume relation). End-diastolic pressure-ventricular performance relations will also be measured, since these directly influences patient symptoms. These goals will be accomplished by a dedicated faculty with the right combination of clinical experience and laboratory background to conduct these studies effectively and safely. Results will improve care of patients undergoing cardiac surgery, will clarify deficiencies of current management, will expand understanding of the pathophysiology of heart surgery, and will make low cost methods for the study of systolic and diastolic properties generally available to cardiac surgeons and laboratory scientists.