Left atrial function and maximal exercise capacity in heart failure with preserved and mid-range ejection fraction

Area of Science:

• Cardiology
• Cardiovascular Physiology
• Echocardiography

Background:

• Exercise intolerance is a primary symptom in heart failure with preserved or mid-range ejection fraction (HFpEF/HFmrEF).
• Left atrial (LA) function plays a role in regulating left ventricular filling and pulmonary venous pressures, potentially influencing exercise capacity.

Purpose of the Study:

• To investigate the association between left atrial (LA) function and maximal exercise capacity in patients diagnosed with HFpEF or HFmrEF.
• To determine if LA strain parameters can predict reduced peak exercise capacity in this patient population.

Main Methods:

• Analysis of 65 patients from the German HFpEF Registry meeting specific inclusion criteria (NYHA class ≥II, LVEF >40%, structural heart disease/diastolic dysfunction, elevated NT-proBNP).
• Evaluation of LA function using speckle-tracking echocardiography.
• Maximal cardiopulmonary exercise testing to determine peak VO2, with patients classified using a 14 mL/kg/min cut-off.
• Statistical analysis including linear regression and receiver operating characteristic (ROC) curve analysis.

Main Results:

• Patients with lower peak VO2 (<14 mL/kg/min) exhibited significantly impaired LA reservoir strain (14±5% vs. 21±9%, P=0.002), conduit strain (9±2% vs. 13±4%, P=0.001), and contractile strain (7±4% vs. 11±6%, P=0.02) compared to those with higher peak VO2.
• Lower LA reservoir strain values were independently associated with impaired peak VO2 after adjusting for clinical covariates (β=0.29, P=0.02).
• LA reservoir strain <22% demonstrated 93% sensitivity and 49% specificity in predicting peak VO2 <14 mL/kg/min.

Conclusions:

• Reduced left atrial (LA) reservoir strain is a significant marker of decreased maximal exercise capacity in patients with HFpEF or HFmrEF.
• LA reservoir strain may serve as a valuable clinical tool for predicting exercise capacity in patients with HFpEF/HFmrEF.
• Echocardiographic assessment of LA strain provides incremental predictive value for exercise capacity beyond traditional clinical factors.