Prospective study of heart disease in untreated maturity onset diabetics

Abstract

Frequent abnormalities of left ventricular function were demonstrated by systolic time intervals and M-mode echocardiography in 69 maturity onset diabetics without clinical heart disease before and during standard hypoglycaemic treatment. The response of the ratio of pre-ejection period (PE) to left ventricular ejection time (LVET) during the first two months of treatment identified two groups of patients. Group A had a normal or slightly raised ratio which fell with treatment. In group B the ratio was significantly higher and did not change even after four months treatment. The change in group A was thought to be a result of the improvement in blood glucose, as the correlation between the random blood glucose before treatment and PEP/LVET ratio was lost with reduction of hyperglycaemia. The persistently raised PEP/LVET in group B suggested significant left ventricular dysfunction. Abnormalities of the diastolic closure rate and isovolumic relaxation time were frequently detected and in only nine of 69 patients were both within 2 SD from normal. They were more pronounced in group B and were significantly different from group A and normal subjects. Group B could be subdivided into six patients (group B1) with outward wall motion in isovolumic relaxation and delayed aortic valve closure caused by incoordination and nine (group B2) who did not show these changes. An exercise electrocardiogram was positive in two of five group B1 patients and negative in the seven tested in group B2. Three patients in group B2 and one in group A had clinically apparent diabetic microvascular disease. Coronary artery disease was common and seven patients (six in group B1 and one in group A) demonstrated left ventricular wall dyskinesis in the absence of symptoms; 11 of the original group of 110 were excluded because of symptomatic disease. A smaller group had slow ejection and relaxation, probably a result of increased left ventricular stiffness from myocardial involvement by diabetic microvascular disease.