Left atrial dysfunction in type 2 diabetes mellitus: insights from cardiac MRI

The left atrium (LA) modulates left ventricular filling through reservoir, conduit and booster pump functions. Only limited data exist on LA involvement in type 2 diabetes mellitus (DM2). This study sought to assess LA function in asymptomatic DM2 with cardiac MRI. We hypothesized that cardiac MRI can detect LA dysfunction in asymptomatic DM2. Forty-five patients with asymptomatic DM2 and 24 normoglycaemic controls were studied. MRI cine imaging was performed to measure LA maximal and minimal volumes. A flow-sensitive phase-contrast gradient-echo sequence was used for flow measurements perpendicular to the orifice of the mitral valve, to quantify active LA stroke volume. LA total, passive and active emptying volumes and fractions were calculated. LA reservoir function, namely LA total ejection fraction, was significantly greater in controls compared to patients with DM2 (62.2 ± 5.2 vs 57.0 ± 7.6 %, P = 0.004). LA passive ejection fraction was also greater in the controls (26.2 ± 9.5 vs 16.1 ± 11.0 %, P < 0.001). Regarding parameters of LA booster pump function, LA active ejection fraction was not significantly different between groups. DM2 was demonstrated to be an independent determinant of LA function. Cardiac MRI enables the detection of LA dysfunction in asymptomatic DM2, characterized by a reduction in LA reservoir and conduit functions. (orig.)