Diabetes mellitus is associated frequently with congestive heart failure in humans, even in the absence of associated coronary disease or hypertension. Nevertheless, the effects of the diabetic state on myocardial mechanics have not been studied. Accordingly, diabetes was induced in female Wistar rats by injection of streptozotocin (60 mg/kg). Left ventricular papillary muscles were studied 5, 10, and 30 weeks later and compared with controls. Relaxation was delayed significantly and velocity of shortening was depressed at all loads. However, the passive and active force-length curves, as well as the series elastic properties, were not altered. The changes in cardiac performance were found over a range of muscle lengths, stimulus frequencies, and bath concentrations of calcium, glucose, and norepinephrine. The duration of diabetes had no major effect on the mechanical changes observed. The possible influences of drug-induced cardiac toxicity, malnutrition, and altered thyroid hormone levels have been considered; the latter two factors could not be excluded completely from having some influence on the mechanical properties of diabetic cardiac muscle. Evidence is cited showing abnormalities in calcium uptake by sarcoplasmic reticulum and depressed actomyosin ATPase activity. Thus a cardiomyopathic state has been produced in the rat consequent to the induction of experimental diabetes mellitus. Various mechanisms for this entity have been suggested.

Six months of therapy with 60 mg of vesnarinone per day resulted in lower morbidity and mortality and improved the quality of life of patients with congestive heart failure. However, a higher dose of vesnarinone (120 mg per day) increased mortality, suggesting that this drug has a narrow therapeutic range; the long-term effects of vesnarinone are unknown.

These results suggest that when performed at regular intervals in stable patients with HF with a recent episode of clinical decompensation, ICG can identify patients at increased near-term risk of recurrent decompensation.

Perioperative complications do not increase with the use of BIMAs. Long-term survival is optimized with off-pump CABG and BIMA grafting. The low morbidity and mortality rates in this series are likely due to the continuous evolution of technology and the adoption of less invasive options for CABG patients. A more widespread use of BIMAs in CABG patients would continue to improve the overall excellent short- and long-term results of this operation.

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