Objective: To compare survival and outcome in patients receiving a mechanical or bioprosthetic heart valve prosthesis. Design: Randomised prospective trial. Setting: Tertiary cardiac centre. Patients: Between 1975 and 1979, patients were randomised to receive either a Bjork-Shiley or a porcine prostheses. The mitral valve was replaced in 261 patients, the aortic in 211, and both valves in 61 patients. Follow up now averages 20 years. Main outcome measures: Death, reoperation, bleeding, embolism, and endocarditis. Results: After 20 years there was no difference in survival (Bjork-Shiley v porcine prosthesis (mean (SEM)): 25.0 (2.7)% v 22.6 (2.7)%, log rank test p = 0.39). Reoperation for valve failure was undertaken in 91 patients with porcine prostheses and in 22 with Bjork-Shiley prostheses. An analysis combining death and reoperation as end points confirmed that Bjork-Shiley patients had improved survival with the original prosthesis intact (23.5 (2.6)% v 6.7 (1.6)%, log rank test p < 0.0001); this difference became apparent after 8-10 years in patients undergoing mitral valve replacement, and after 12-14 years in those undergoing aortic valve replacement. Major bleeding was more common in Bjork-Shiley patients (40.7 (5.4)% v 27.9 (8.4)% after 20 years, p = 0.008), but there was no significant difference in major embolism or endocarditis. Conclusions: Survival with an intact valve is better among patients with the Bjork-Shiley spherical tilting disc prosthesis than with a porcine prosthesis but there is an attendant increased risk of bleeding.

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The resting membrane potential difference (Em) of skeletal muscle was measured in 26 normal human subjects, 7 patients with mild illness, and 21 patients with severe, debilitating medical disorders. A closed transcutaneous approach to the muscle was made by needle puncture and the Em was measured utilizing standard Ling electrodes. Measurements revealed an Em of -88 ±-3.8 mv in healthy subjects and -89 ± 2.1 mv in patients hospitalized for minor medical problems. The mean Em in 21 in-hospital patients, judged to be severely ill clinically from a variety of causes, was -66.3 ±9.0 mv. Open deltoid muscle biopsies were performed in 7 of the healthy subjects and in 13 of the severely ill group. Estimation of the intraextracellular water partition was made by calculating the chloride space from the previously measured Em. Analysis of the muscle samples revealed no significant difference in the intra-extracellular potassium ratios of the two groups biopsied. Intracellular Nat concentrations were uniformly increased in the muscle samples of the severely ill subjects and averaged 42.3% higher than those of the normal subjects. The mechanisms which might account for the elevation of intracellular Nat and a depression of Em independent of changes in intraextracellular Ki' ratios are discussed and it is suggested that this defect may be a generalized cellular abnormality which is a common quality of serious illnesses.

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Aims: The purpose of this study was to determine that the administration of an angiotensin converting enzyme (ACE) inhibitor enalapril would confer protection against doxorubicin-induced experimental heart failure, and attenuate the development of left ventricular dysfunction. Methods: Seventeen dogs were chronically instrumented with an intracoronary catheter and received doxorubicin weekly for 4 weeks. Animals were assigned to two groups: group 1: untreated heart failure; and group 2: simultaneous enalapril administration (5 mg twice a week). Hemodynamic data were obtained at week 0 and 12. Echocardiography was performed weekly. Results: Survival improved with simultaneous enalapril administration (36% in group 1 vs. 100% in group 2, Ps0.04). The increase in the left ventricular end-diastolic pressure was significantly reduced at week 12 (17"1 mmHg in group 1 vs. 9"1 mmHg in group 2, Ps0.0042). The fall in left ventricular stroke work index was significantly prevented (52% in group 1 vs. 21% in group 2, Ps0.006). The increase in right ventricular end-diastolic diameter was significantly reduced by enalapril prophylaxis. Conclusion: Simultaneous treatment with enalapril was beneficial in the prevention of doxorubicin-induced cardiomyopathy.