Relationship between early diastolic dysfunction and abnormal microvolt T-wave alternans in patients with type 2 diabetes.

Background-Abnormal microvolt T-wave alternans (MTWA), a marker of ventricular arrhythmic risk, is a highly prevalent condition in patients with type 2 diabetes mellitus (T2DM) and is correlated with glycemic control. However, there is uncertainty as to whether central or peripheral hemodynamic factors are associated with abnormal MTWA in T2DM individuals. Methods and Results-We studied 50 consecutive, well-controlled T2DM outpatients without a history of ischemic heart disease and with normal systolic function. All patients underwent a complete echocardiographic Doppler evaluation with spectral tissue Doppler analysis. MTWA analysis was performed noninvasively during submaximal exercise. Effective arterial elastance, arterial compliance, and heart rate variability were also measured. Compared with patients with MTWA negativity (n=38), those with MTWA abnormality (n=12, 24%) had significantly lower e' (7.6+/-1.3 versus 9.1+/-1.7 cm/s; P<0.01), a' (10.2+/-1.6 versus 12.7+/-1.9 cm/s; P<0.001) and s' velocities (8.7+/-1.1 versus 10.2+/-1.5 cm/s; P=0.001) and higher indexed left ventricular mass (121.3+/-16.4 versus 107.5+/-16.5 g/m(2); P=0.016), indexed left atrial volume (33.5+/-11.9 versus 23.6+/-5.6 mL/m(2); P<0.001), and E/e' ratio (8.8+/-1.4 versus 6.5+/-1.3; P<0.001). Multivariable logistic regression analysis revealed that higher E/e' ratio was the only independent correlate of abnormal MTWA (adjusted odds ratio, 3.52; 95% confidence interval, 1.19 to 10.6; P=0.02) after controlling for glycemic control and other potential confounders. Conclusions-In this pilot study, we found that early diastolic dysfunction, as measured by tissue Doppler imaging, is independently associated with MTWA abnormality in T2DM individuals with normal systolic function. Further larger studies are needed to examine the reproducibility of these results.