The association between the spatial QRS-T angle with cardiac autonomic neuropathy in subjects with Type 2 diabetes mellitus.

AIMS

To examine differences in the spatial QRS-T angle in patients with Type 2 diabetes mellitus with and without cardiac autonomic neuropathy.

METHODS

Two hundred and thirty-two patients with diabetes mellitus (105 with cardiac autonomic neuropathy and 127 without cardiac autonomic neuropathy) and 232 control subjects, matched by gender and age, were studied. Diagnosis of cardiac autonomic neuropathy was based on the classic autonomic function tests. All subjects underwent a digital electrocardiographic recording. Electrocardiographic parameters were measured using the Modular Electrocardiographic Analysis (MEANS) program. Left ventricular mass index (LVMi) and global myocardial performance index (Tei index) of the left ventricle were assessed by ultrasonography.

RESULTS

The spatial QRS-T angle was higher in the patients with diabetes in comparison with the control subjects (24.5 ± 10.7 vs. 9.7 ± 4.5°, P < 0.001) and in the patients with diabetes and cardiac autonomic neuropathy than in those without cardiac autonomic neuropathy (30.1 ± 11.3 vs. 19.5 ± 7.1, P < 0.001). No differences were found in the QT interval between the studied groups. Multivariate linear regression analysis in subjects with diabetes after controlling for age, gender, BMI, blood pressure, diabetes duration, HbA(1c) , lipids, microalbuminuria and insulin resistance, demonstrated significant and independent associations between the spatial QRS-T angle with presence and severity of cardiac autonomic neuropathy, all parameters of heart rate variability, LVMi and Tei index.

CONCLUSIONS

The spatial QRS-T angle is increased in patients with Type 2 diabetes who have cardiac autonomic neuropathy, suggesting increased ventricular arrhythmogenicity, and is associated with the structural and functional properties of the myocardium. Further research is warranted to evaluate its role in cardiovascular risk stratification of patients with diabetes.