Association of Reduced Left Atrial Reserve With Exercise Intolerance and Outcome in Hypertension

Area of Science:

• Cardiology
• Cardiovascular Physiology
• Echocardiography

Background:

• Hypertensive heart disease (HHD) is a major cause of heart failure with preserved ejection fraction (HFpEF).
• Mechanisms linking HHD to symptomatic heart failure remain unclear.
• Left atrial (LA) mechanical function during exercise may offer insights into HFpEF progression.

Purpose of the Study:

• To investigate the association between exercise response of LA mechanical function and functional capacity, symptoms, and outcomes in hypertensive patients across the heart failure spectrum.
• To identify predictors of HF progression and adverse events in HHD.

Main Methods:

• Echocardiography assessed LA reservoir peak atrial longitudinal strain (PALS), peak atrial contractile strain (PACS), and LA stiffness index at rest and post-exercise in 139 patients with HHD (stages A, B, and C HFpEF).
• Patients were followed for development of HF and/or atrial fibrillation.
• Statistical analysis identified associations between LA function parameters, exercise capacity, and clinical outcomes.

Main Results:

• Exercise capacity declined progressively from stage A to C HFpEF.
• Impaired exercise-induced changes in PALS and PACS were observed with increasing HF severity.
• LA strain reserves (PALS and PACS) were independently associated with exercise capacity.
• LA stiffness reserve and E/e' were strongly associated with symptomatic HF.
• Reduced PALS and PACS reserves predicted adverse outcomes (HF and/or atrial fibrillation) over 25 months.

Conclusions:

• Impaired exercise reserve of LA strain and stiffness are linked to reduced functional capacity in hypertensive patients.
• LA strain reserve is an independent predictor of adverse outcomes in HHD.
• These LA mechanical parameters may be key determinants of progression to overt heart failure in HHD, with varying contributions based on HF stage.