Diastolic abnormalities might precede systolic abnormalities of left ventricular function in Type 1 (insulin-dependent) diabetes mellitus

✍ Scribed by C. Punzengruber

• Publisher: Springer
• Year: 1986
• Tongue: English
• Weight: 122 KB
• Volume: 29
• Category: Article
• ISSN: 0012-186X
• DOI: 10.1007/bf00452074

✦ Synopsis

Letters to the Editor

Diastolic abnormalities might precede systolic abnormalities of left ventricular function in Type I (insulin-dependent) diabetes mellitus

Dear Sir, Thuesen et al. [1] recently reported on an increased myocardial contractility in Type I diabetic patients which was related to the state of metabolic control. They used echocardiography to measure left ventricular fractional shortening and mean circumferential shortening velocity to assess myocardial function. Left ventricular performance depends on intrinsic myocardial contractility, preload and afterload. Both echocardiographic parameters are affected by loading conditions. No differences in left ventricular diastolic diameters compared with controls were noted by the authors. Therefore, no differences in preload might be assumed. On the other hand, an increase in cardiac output was observed in diabetic patients, despite a similar mean arterial pressure. Therefore, peripheral vascular resistance has to be lower in the diabetic study group. This might account for the increase in fractional shortening and mean circumferential shortening velocity. We therefore suggest that poor metabolic control in diabetic patients alters loading conditions by decreasing afterload. Whether intrinsic myocardial contractility is enhanced remains to be established.

In addition, we performed an echocardiographic study on well controlled Type 1 diabetic patients with a similar mean duration of disease (8 + 6 years) without evidence of significant diabetic microangiopathy [2]. Our study group consisted of 50 Type I diabetic patients (26 + 8 years), educated and treated as previously described [3]. Longterm metabolic control was assessed throughout 12 months by multiple HbA1 measurements; one-third had HbA1 values in the range of nondiabetic subjects. No significant difference in left ventricular systolic performance could be observed when well-controlled Type I diabetic patients were compared with age-and sex-matched nondiabetic controls [2]. A significant prolongation of the isovolumetric relaxation period, reflecting an early diastolic event, could be demonstrated even in diabetic patients with HbA1 concentrations in the physiologic range. Therefore, systolic performance of the left ventricle in shortterm Type 1 diabetic patients with near normoglycemia might be normal, although subtle alterations of diastolic function might already be present.