Left ventricular dysfunction in normotensive Type 1 diabetic patients: the impact of autonomic neuropathy

The pathophysiological mechanisms responsible for increased cardiovascular mortality in diabetic autonomic neuropathy (AN) are largely unknown. The aim was to determine the relative role of AN in the pathogenesis of cardiac diastolic dysfunction and left ventricular hypertrophy in Type 1 diabetes.

Ten Type 1 diabetic patients with AN, defined by cardiovascular tests (AN+) and 10 age- and sex-matched patients without neuropathy (AN-) as well as 10 healthy subjects (C) participated in the study. Left ventricular diastolic function was assessed by Doppler echocardiography, whilst systolic function was evaluated by cine magnetic resonance (MR) imaging.

Doppler echocardiography showed a significant decrease in E/A ratio, i.e. the ratio between peak Early transmitral filling velocity during early diastole (E-wave) and peak transmitral Atrial filling velocity during late diastole (A-wave), in AN+ compared with C (P < 0.01) [0.95 +/- 0.08 (mean +/- sem) (AN+); 1.19 +/- 0.09 (AN-); 1.33 +/- 0.10 (C)]. The E-wave deceleration time was significantly shorter in AN+ compared with AN- and C (P < 0.02) [178 +/- 7 ms (AN+); 203 +/- 9 ms (AN-); 205 +/- 9 ms (C)]. Cine MR imaging showed a significantly greater left ventricular mass index in AN+ compared with C [103 +/- 4 g/m(2) (AN+) vs. 98 +/- 7 (AN-) and 92 +/- 4 g/m(2) (C), P < 0.05].

Autonomic neuropathy is associated with left ventricular hypertrophy and diastolic dysfunction in Type 1 diabetic patients.