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

Abstract

Hypertensive heart disease (HHD) is a leading contributor to heart failure with preserved ejection fraction (HFpEF). However the mechanisms behind the transition to the symptomatic phase remain unclear. We sought the association of the exercise response of LA mechanical function with functional capacity, symptoms and outcome across the HF spectrum in hypertension. Echocardiography (including LA reservoir [PALS] and contractile strain [PACS], and LA stiffness index) were performed at rest and immediately post-exercise in 139 patients with HHD- 35 with stage A, 48 with stage B and 56 with stage C HFpEF. Patients were followed for HF and atrial fibrillation (AF). Exercise capacity was progressively worse from stage A through stage B to stage C, and accompanied by a gradual impairment of changes in PALS and PACS from rest to exercise, whereas LA stiffness reserve remained unchanged until stage C. PALS and PACS reserves were independently associated with exercise capacity(p=0.017 and 0.008, respectively). LA stiffness reserve and E/e' were the strongest associations of symptomatic HF. Over a median of 25 months, 35 patients developed HF and/or AF. PALS and PACS reserves were associated with the study endpoints after adjusting for age, diabetes, NT-proBNP, LA volume index, resting E/e' and resting PALS/PACS. Impaired exercise reserve of LA strain and stiffness are associated with reduced functional capacity in hypertension, and LA strain reserve is independently associated with outcome. These parameters appear to be determinants of progression to overt HF in HHD, however their contribution may differ depending on HF stage.