Objective: To investigate the relation between diabetic autonomic neuropathy (DAN) and left ventricular (LV) function in type 1 diabetic patients.
Research design and methods: A total of 57 type 1 diabetic patients free of coronary artery disease and arterial hypertension were studied. Diagnosis of DAN was established by autonomic nervous function (ANF) tests, and LV systolic and diastolic functions were assessed by radionuclide ventriculography at rest.
Results: There were 24 patients who had definite DAN, established by the presence of two or more abnormal ANF tests, and 33 subjects were without DAN. DAN patients had impaired LV filling pattern, obvious by a reduced peak filling rate (3.1 +/- 1.1 vs. 3.7 +/- 0.7 end-diastolic volume [EDV]/s, P = 0.011) and first third filling fraction (35.3 +/- 19.5 vs. 50.8 +/- 16%, P = 0.002) as well as an increased time to peak filling (159.4 +/- 45.1 vs. 134.2 +/- 33.4 ms, P = 0.02) after correction for age and heart rate. There were no differences between the two groups with regard to ejection fraction, cardiac output, and cardiac index, whereas the peak emptying rate was greater in DAN patients (4.1 +/- 0.8 vs. 3.6 +/- 0.8 EDV/s, P = 0.019), suggesting LV hypercontractility. DAN patients had an increased heart rate (83.4 +/- 11.9 vs. 72.7 +/- 9.3 bpm, P = 0.001) and slightly higher systolic blood pressure. As a result, LV working load at rest was higher in DAN patients (11,109 vs. 9,096 bpm x mmHg, P < 0.001). Moreover, a correlation was found between abnormal LV systolic and diastolic indexes and the number of abnormal ANF tests.
Conclusions: At rest, DAN patients have impaired LV filling pattern, slightly increased LV systolic function, and a higher LV working load, in comparison to non-DAN type 1 diabetic patients.