QT dispersion in microalbuminuric Type 1 diabetic patients without myocardial ischemia

Microalbuminuria is associated with an increased risk of cardiac death. We assessed whether urinary albumin excretion is related to abnormalities of the QT interval independently of myocardial ischemia. Thirty-four patients with type 1 diabetes who were free from ischemic heart disease on the basis of normal stress electrocardiography and echocardiography were studied. Maximal QT interval and dispersion were significantly greater in the group with microalbuminuria (n=17) compared to controls (n=17) with normal urinary albumin excretion (394 [26.1] vs. 373.8 [27.8] ms; P=.044 and 62.4 [21.8] vs. 42.7[11.6] arbitrary units; P=.009). Autonomic function was similar between the groups. Urinary albumin excretion correlated positively with QT dispersion (P=.023). These data suggest that in type 1 diabetic patients, QT abnormalities can occur independently of autonomic dysfunction or myocardial ischemia and may be related to the processes which increase urinary albumin leakage.