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Systolic and diastolic function were assessed at preoperative cardiac catheterization in 6 patients with classic tricuspid atresia and were compared with those in control subjects. All patients had systemic-to-pulmonary shunts. Left ventricular end-systolic and end-diastolic volumes and masses were significantly larger in the patient group; stroke volume and the ratio of volume to mass were also higher, but not significantly. Mean end-diastolic, peak systolic and end-systolic pressures were similar. Mean stress and end-systole and peak systole were significantly higher in the patient group. Operant chamber stiffness tended to be lower than normal, but was not statistically significant, and myocardial stiffness was normal for the patient group also. Indexes of systolic function were compared. The rate-corrected mean velocity of fiber shortening in the patient group was lower and its relation with stress at end-systole was variable with 4 abnormal patients. The ratio of stress and end-systole/end-systolic volume was significantly lower in patients. The duration of hospital stay did not correlate with end-diastolic volume or any parameter. Thus, this study found abnormalities of load-dependent and independent indexes of systolic function with normal diastolic function in young preoperative patients with tricuspid atresia. (Am J Cardiol 1994;73:292-297)

This study assessed the effect of pressure load, volume load and surgery on left ventricular chamber stiffness (b) and myocardial stiffness (k). A normal range for chamber stiffness and myocardial stiffness was also established. A total of 44 patients were studied: 8 were control subjects, 12 had volume load and 24 had pressure load. At cardiac catheterization simultaneous high fidelity pressures (P) and left ventricular volumes (V) were obtained in one diastolic cycle. From the relation P = aVb, operant chamber stiffness (b) was estimated for each patient. Similarly, the relation between stress (σ) and radius (B) was approximated by σ = cBfand the myocardial stiffness (k) derived for each patient. Mean values for chamber or myocardial stiffness for the diagnostic groups were not significantly different but differed within the operative groups. Mean values for b and k were greater in the post-open heart surgery group than in the post-closed heart surgery or nonsurgical group.