Our findings indicate that myocardial damage in patients with diabetes affects diastolic function before systolic function. The intentional assessment of diastolic function is advisable for early detection of LV dysfunction before clinical symptoms appear, with follow-up to detect further deterioration of cardiac status.

One hundred and fifty-seven young cardiac asymptomatic type 1 diabetics and 54 control subjects were examined with M-mode echocardiography to elucidate the early changes in left ventricular systolic function (LVSF) in diabetes mellitus. Out of 157 diabetics a group of 40 newly diagnosed diabetics without diabetic complications was formed (retinopathy, nephropathy, autonomic neuropathy). They had ejection fraction (71.3 ± 3.3%), fractional shortening (FS = 40.5 ± 2.3%) and corrected mean velocity of circumferential fiber shortening (1.23 ± 0.11 circ/s) significantly higher than those of the control subjects (65.7 ± 3.0, 36.3 ± 2.3, 1.08 ± 0.09), but end-diastolic volume index (as preload, 72.9 ± 11.7 ml/m2), end-systolic meridional wall stress (MWSs, as afterload, 65.7 ± 12.4kdyn/cm2) and heart rate (HR = 72.8 ± 10.0 bpm) were unchanged significantly compared to the control values (68.6 ± 10.8, 70.9 ± 15.0, 74.4 ± 11.0). In 90% of the newly diagnosed diabetics the FS was above the 95% confidence limits of the control FS/MWSs relation, on the background of a significant difference (p < 0.001) in the frequency distribution between diabetics and control group (37%). These changes were probably due to increased myocardial contractility, rather than the changes in the loading condition since the other determinants of LVSF, such as preload, afterload and HR, were unchanged. In conclusion, our data impose the hypothesis that one of the early manifestations of the noncoronary diabetic cardiopathy is the increased myocardial contractility.

The present study was designed as an attempt to elucidate some reasons for the contradictory findings concerning the relationship between the duration of diabetes and left ventricular (LV) function. 157 young (age 26.2 years) cardiacasymptomatic type 1 diabetics were divided into the following five groups: (1) without complications (n = 86); (2) with mild complications (n = 39); (3) with severe complications (n = 32); (4) with microangiopathy (MIC) - retinopathy and/or nephropathy only (n = 39), and (5) with cardiac autonomic neuropathy (CAN) only (n = 22). LV function was studied by M-mode echocardiography. Fractional shortening (FS), isovolumic relaxation time (IRT) and interval from minimal LV dimension to mitral valve opening (MD-MO) correlated with the duration of disease in the entire group (r = -0.62, r = 0.71, r = 0.72, p < 0.0001, n = 157), and in the complications free group (r = -0.54, r = 0.49, r = 0.49, p < 0.001, n = 86). These relations were weaker (r < 0.05) in the milder group (FS: r = -0.34, p < 0.03; IRT: r = 0.41, p < 0.04) and were statistically not significant (p > 0.05) in the severe group (FS: r = 0.06; IRT: r = -0.10), MIC group (FS: r = -0.25; MD-MO: r = 0.40) and CAN group (FS: r = -0.18; MD-MO: r = 0.22). Based on the lines of best fit for the groups, we found that in early years of diabetes even for similar duration, the patients with complications (mild, severe, MIC or CAN) had more (p < 0.05) prolonged IRT and lower FS than those without complications. The findings presented show that the specific diabetic complications (MIC and CAN) affect the relationship between the duration of diabetes and LV function, and accelerate the appearance of LV dysfunction. This fact may explain the contradictory findings concerning the influence of the duration of disease on LV function.