Electrocardiographic Left Ventricular Hypertrophy in Type 1 Diabetes

Abstract

In the general population, left ventricular hypertrophy (LVH), either defined by echocardiographic or electrocardiogram (ECG) criteria, is strongly predictive of cardiovascular events, independent of conventional risk factors (1–3). Normotensive type 1 diabetic patients with nephropathy have an increase in left ventricular mass independent of blood pressure (4) and a decrease in diastolic function (5). In the general population, LVH causes electrical heterogeneity in the heart (6) and is associated with sudden cardiac death secondary to ventricular arrhythmias. Both QT interval duration (QTc) and dispersion (QTd) are affected by electrical heterogeneity and associated with sudden death (7). The EURODIAB IDDM Complications Study is a cross-sectional clinic-based study of diabetes complications recruiting 3,250 type 1 European diabetic subjects (8) using standardized methods of data collection. We aimed to assess ECG-LVH prevalence and association with coronary heart disease (CHD), microvascular complications, QTc, and QTd in this large cohort. Details of the subjects and the procedures of the EURODIAB study have been published elsewhere (8–13). To assess the role of insulin resistance, an estimated glucose disposal rate (GDR) was calculated as previously described (14). Metabolic syndrome was defined according to World Health Organization guidelines (15). LVH was defined by ECG Cornell voltage-duration product [(RaVL + SV3) × QRS complex duration] >2,623 mm × ms in …