Left Atrial Morphology and Function: A Strong Cardiovascular Predictor of Outcome.

Dear Sir,

The original article entitled “Left atrial size and heart failure hospitalization in patients with diastolic dysfunction and preserved ejection fraction” has been recently published in a previous issue of the Journal of Cardiovascular Echography.[1]

In this manuscript, the authors aim to understand which echocardiographic factors can predict the transition from asymptomatic diastolic dysfunction to an overt symptomatic heart failure with preserved ejection fraction (HFpEF). For this purpose, patients hospitalized with suspected heart failure between January 2012 and November 2014 with a transthoracic echocardiogram demonstrating preserved systolic function were screened. Echocardiographic analysis demonstrated higher right ventricular systolic pressures, left ventricular (LV) mass index, E/A, and E/e’ in patients with HFpEF compared to a group of hypertensive patients. Similarly, differences were observed in most left atrial (LA) parameters including larger LA maximum and minimum volume indices, as well as smaller LA-emptying fractions in the heart failure group. Multivariate logistic regression analysis revealed LA minimum volume index to have the strongest association with heart failure hospitalization after adjustment for creatinine and body mass index. The authors conclude that minimum volume index best correlates with HFpEF in this patient cohort with diastolic dysfunction.

LA size is an established marker of risk for adverse outcomes in HFpEF.

Baseline LA volume index was found to be an important independent predictor of all-cause mortality in patients with heart failure and should be reported routinely in these patients undergoing echocardiography.[2]

Data available in literature confirm that LA volume index on resting echocardiography, specifically in patients with suspected heart failure and normal LV systolic function is a powerful independent predictor of LV diastolic dysfunction as predicted by serum NTproBNP.[3]

However, LA enlargement is most of the time preceded by silent LA dysfunction and fibrosis, which can be both considered even earlier markers of increased LV filling pressure and diastolic dysfunction. Speckle tracking echocardiography allows to evaluate LA deformation during all the phases of cardiac cycle: reservoir, conduit, and booster pump function. Due to increased LA stiffness and reduced LA compliance, LA function is impaired, especially during reservoir phase, proportionally with LV longitudinal strain, despite preserved LV ejection fraction.[4] LA stiffness derived from the ratio between LA reservoir and E/e’ is a noninvasive dimensionless parameter that was demonstrated to be correlated with invasive LA pressure.[5]

By adding to LA volumetric assessment, the evaluation of LA deformation parameters and LA stiffness index, authors might have increased the power of echocardiographic LA parameters in predicting the development of HFpEF.

In conclusion, LA anatomical remodeling as expressed by LA enlargement, associated with earlier LA functional impairment as expressed by reduced LA strain, and increased stiffness allows to perform not only a reliable hemodynamic assessment of LV end-diastolic pressure but also to obtain a prognostic stratification of patients that would eventually develop overt HFpEF and who may benefit from closer surveillance and tighter control of risk factors.

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Conflicts of interest

There are no conflicts of interest.