Effects of left atrial function on pulmonary arterial pressure in acute myocardial infarction, hypertrophic and dilated cardiomyopathy.

BACKGROUND: To investigate the differential contribution of the left atrial (LA) function and left ventricular (LV) fibrosis to pulmonary arterial systolic pressure (PASP) in hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM) and reperfused acute myocardial infarction (AMI). METHODS: Data of 370 patients with HCM (n = 133), DCM (n = 114) and reperfused AMI (n = 123) who underwent both echocardiography and cardiovascular magnetic resonance (CMR) were comprehensively reviewed. Phasic LA volumes, LA-global longitudinal strain (GLS), LA stiffness index, defined as E/e'/LA-GLS and extracellular volume fraction (ECV) of LV were measured using CMR. RESULTS: E/e' was correlated with PASP in all groups; however, the predicted value was significantly attenuated after adjusting for LA volume and LA strain in HCM and DCM, but remained significant in AMI. The LA stiffness index was related to PASP in HCM (p = 0.01) and DCM (p = 0.03) independent of LA volume index and E/e', but not in AMI. In DCM, ECV was significantly related to PASP (p < 0.001) independent of LA volume index and E/e'. When subdivided according to the linear regression between PASP and E/e', patients in the discrepantly high PASP group had lower total emptying fraction and reservoir fraction of left atrium in HCM and DCM but not in AMI. CONCLUSIONS: The LA function in HCM and DCM and LV fibrosis in DCM correlated with PASP independent of E/e' and LA size, contrary to that in AMI. These results suggest the presence of LA dysfunction in non-ischemic cardiomyopathies and usefulness of ECV measurement in DCM for the comprehensive evaluation of LV diastolic function.