Non-invasive assessment of left ventricular function in diabetics without clinical heart disease

Vectorcardiographic evaluation of diabetic cardiomyopathy and of its contributing factors

In order to investigate the prevalence of vectorcardiographic bites, expression of small areas of fibrosis, atrophy or degeneration of the myocardium, we studied, using the vectorcardiograms (VCG) of 101 diabetic patients (35 with insulin-dependent and 66 with non-insulin-dependent diabetes mellitus, aged from 25 to 60 years, without hypertension, coronary artery disease, or intraventricular conduction defects) and 228 normal control subjects, matched for age and sex. The prevalence of bites was 38.6% in diabetic patients and 10.0% in the control group (p less than 0.001). Diabetic patients were also subdivided into groups according to age, sex, metabolic control, risk factors for coronary heart disease, type of diabetes, duration of diabetes and diabetic microangiopathy. No correlation was found between any of the variables investigated nor of a combination of these, and the presence of bites. We conclude that VCG is a sensitive test for cardiac involvement in diabetic patients but that it cannot be used to identify any specific factor able to influence the onset and evolution of this involvement.

Myocardial function and hemoglobin oxygen affinity during hyperglycemia in the fetal lamb

To determine the effects of maternal hyperglycemia on fetal hemodynamic and cardiac function, a study was carried out on nine chronically catheterized fetal sheep. In six fetuses, glucose was infused intravenously with an initial dose of 5 mg/kg per min. Data were compared with controls. This dose was gradually increased to 16 mg/kg per min by the fifth day. The initial blood glucose was 14.7 +/- 3.0 mg/dl and increased to 54.6 +/- 16.4 mg/dl by the last day of the infusion period (P less than 0.001). The PO2 decreased from a baseline of 20.25 +/- 3.40 to 15.88 +/- 5.24 mmHg (P less than 0.01). Similarly significant decreases were also observed for the blood O2 content and O2 hemoglobin saturation: 8.5 +/- 1.7 to 6.4 +/- 2.2 ml/dl and 62.3 +/- 13.6 to 46.1 +/- 17.6%, respectively, during hyperglycemia (P less than 0.01). The duration of the preejection period (PEP) before the start of the experiment was 45 +/- 4 ms; a final value of 57 +/- 10 ms was obtained (P less than 0.01). However, the electromechanical delay and ejection time (ET) showed no significant variation. The ratio of the PEP/ET increased from 0.31 +/- 0.04 to 0.38 +/- 0.07 (P less than 0.01) during hyperglycemia. The reticulocytes increased from 1.4 +/- 1.8 to 3.1 +/- 2.9% (P less than 0.05) and the 2,3-diphosphoglycerate decreased from 4.4 +/- 1.1 to 2.8 +/- 1.2 mumol/g hemoglobin (P less than 0.005). This study demonstrated that fetal hyperglycemia depresses myocardial function in the fetal lamb. The changes in cardiac function could not be explained by the small drop in O2 saturation.