Left Atrial Volumetric/Mechanical Coupling Index in Heart Failure With Preserved Ejection Fraction

Area of Science:

• Cardiology
• Echocardiography
• Heart Failure Research

Background:

• Left atrial (LA) dysfunction is prevalent in heart failure with preserved ejection fraction (HFpEF).
• The LA volumetric/mechanical coupling index (LACI) assesses LA contractile function, but its clinical utility in HFpEF is not well-defined.
• An elevated LACI suggests impaired LA mechanical performance relative to its volume, indicating uncoupling.

Purpose of the Study:

• To investigate the associations between LACI and echocardiographic indices in HFpEF patients.
• To evaluate the prognostic significance of LACI in predicting cardiovascular outcomes in HFpEF.

Main Methods:

• Analysis of 562 patients from the prospective multicenter PURSUIT-HFpEF registry.
• Calculation of LACI and categorization into quartiles.
• Examination of associations with echocardiographic parameters and clinical outcomes over a median follow-up of 40 months.

Main Results:

• A negative correlation was observed between LA volume index and late diastolic mitral annular velocity (r=-0.26; P<0.001), indicating impaired atrial Frank-Starling mechanism.
• Patients with higher LACI quartiles exhibited unfavorable characteristics, including increased filling pressures and diastolic dysfunction.
• Elevated LACI was significantly associated with an increased incidence of cardiovascular death or heart failure rehospitalization (log-rank P=0.001).
• Multivariable analysis confirmed LACI as a significant predictor of adverse cardiovascular outcomes (HR, 1.18 per quartile increase; P=0.045).

Conclusions:

• LA mechanical activity declines with LA enlargement in HFpEF, signifying inherent volumetric/mechanical uncoupling.
• LACI emerges as a clinically valuable index for stratifying cardiovascular risk in patients with HFpEF.