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The Frank-Starling relationship generally has been examined with filling pressure as the index of preload, resulting in a curvilinear function that plateaus at higher filling pressures. To investigate this relationship further in the intact heart, 32 dogs were chronically instrumented with left ventricular and pleural micromanometers and with regional (10(More)
In nine conscious, chronically instrumented dogs, ultrasonic dimension transducers measured left ventricular anterior-posterior and septal-free wall minor axis and major axis diameters. Matched micromanometers measured right and left ventricular transmural and transeptal pressures. Ventricular pressures and volumes were varied by inflation of implanted vena(More)
Ventilation with positive end-expiratory pressure (PEEP) is associated with reduced cardiac output, but the mechanisms involved are controversial. Possible explanations include increased intrathoracic pressure, reflex changes in myocardial inotropism, pulmonary vascular obstruction and abnormal ventricular interaction. Three types of conscious canine(More)
Adequate coronary blood flow is a major determinant for successful resuscitation from cardiopulmonary arrest. To develop compression techniques that optimize coronary blood flow, we implanted in eight dogs electromagnetic flow probes that measured circumflex coronary blood flow and ascending aortic blood flow. Micromanometers measured left ventricular and(More)
Considerable effort has been expended in recent years by a number of laboratories to improve methods of cardiopulmonary resuscitation. This article briefly summarizes 5 years of investigation by our group on hemodynamic support during external cardiac massage. In most studies, long-term canine preparations were used, and implanted transducers allowed(More)
During coronary artery bypass grafting, 20 patients underwent epicardial placement of miniature ultrasonic dimension transducers across the minor-axis diameter of the left ventricle to monitor cardiac function postoperatively. Left atrial or left ventricular pressure was measured in all patients, and thermodilution cardiac outputs were obtained routinely.(More)
Pulse transit sonomicrometry is a well-accepted method for assessing cardiac dimensions and function in research animals. Unfortunately, this technique has been hampered in chronic applications by a significant incidence of transducer failure secondary to leakage of corrosive biological fluids into the piezoelectric material. The fluid leakage generally(More)
Displacement of the left ventricular diastolic pressure-dimension relationship (change in compliance) has been observed with alterations in coronary perfusion pressure. The relative contribution of coronary (myocardial) blood flow, as compared with the perfusion pressure at which flow occurs, was studied in 10 dogs during diastolic relaxation by potassium(More)