Central role of left atrial dynamics in limiting exercise cardiac output increase and oxygen uptake in heart failure: insights by cardiopulmonary imaging

Abstract

In heart failure (HF), the haemodynamic response to exercise in relation to left atrial (LA) dynamics is unexplored. We sought to define whether abnormal LA dynamics during exercise may play a role in cardiac output (CO) limitation and tested its ability to predict outcome.

New insights into the role of left atrial function during exercise in heart failure

“…Regardless of the precise mechanism, it is clear from this study 9 and others 6,11 that abnormal LA strain serves as a robust echocardiographic biomarker of abnormal central haemodynamic reserve, whether assessed during rest or with exercise. Since LA and LV function are intricately intertwined through atrio‐ventricular coupling, LA strain may better reflect the cumulative impact of LV and LA pressure elevation on the lungs and right ventricle, 6 as opposed to traditional echocardiographic markers focused primarily on the left ventricle 10 .…”

“…These important findings add to the growing literature from the Guazzi group demonstrating the feasibility and potential value of adding submaximal LA strain to exercise testing, now in the largest HF cohort studied to date 7–9 . However, as with any study, certain caveats bear consideration.…”

“…To address this gap, Sugimoto and colleagues performed cardiopulmonary exercise testing to peak exhaustion with Doppler‐derived CO and echocardiographic LA strain in 195 HF patients and 46 controls reported in this issue of the Journal 9 . The majority of their HF cohort included HF with reduced EF (HFrEF) ( n = 153; 105 with EF <40% and 48 with EF 40–50%), while 42 had HF with preserved EF (HFpEF).…”

“…Since LA and LV function are intricately intertwined through atrio‐ventricular coupling, LA strain may better reflect the cumulative impact of LV and LA pressure elevation on the lungs and right ventricle, 6 as opposed to traditional echocardiographic markers focused primarily on the left ventricle 10 . The authors have now substantially advanced this literature by demonstrating the feasibility of dynamic LA strain response during submaximal exercise 7–9 . With further multicentre validation, LA strain may emerge as one of the most useful non‐invasive indices of deranged central haemodynamics, which remain challenging to identify, especially in suspected HFpEF 10 .…”

July 2020 at a glance: focus on imaging and cardiomyopathies

“…Impaired LA strain may contribute to reduced exercise capacity 18 . Sugimoto et al 19 . showed that a blunted LA strain is associated with lower stroke volume and cardiac output response to exercise and worse outcomes in HF patients.…”