Effect of hyperglycaemia-induced hyperosmolality on heart function in the dog.

Changes in myocardial water content, left ventricular diastolic stiffness, cardiac performance, coronary blood flow, myocardial contractile force, rate of change of myocardial force, and peak acceleration of the aortic volume flow were examined in twenty-five dogs during glucose-induced hyperosmolality before and after pancreatectomy, the latter with and without insulin treatment. Glucose-induced hyperosmolality accounted for myocardial dehydration, increased diastolic stiffness and consequent decrease of left ventricular performance only in the absence of insulin, while coronary blood flow, myocardial contractile force, rate of change of myocardial force and peak acceleration of the aortic volume flow increased independently from the presence or absence of insulin during the glucose-induced hyperosmolality. These findings suggest that the frequent development of heart failure in hyperosmolar diabetic coma could partly be explained by myocardial dehydration and by the consequent decrease in left ventricular compliance and performance.