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

Highlights•LA reservoir strain and stiffness reserves determine functional capacity in HHD.•Impaired LA strain response to stress predicts HF progression and atrial fibrillation.•LA strain and stiffness reserves may improve clinical risk stratification in HHD.AbstractBackgroundHypertensive 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.ObjectivesWe sought to find the association of the exercise response of left atrial (LA) mechanical function with functional capacity, symptoms, and outcome across the heart failure (HF) spectrum in hypertension.MethodsEchocardiography (including LA reservoir peak atrial longitudinal strain [PALS] and peak atrial contractile strain [PACS] and LA stiffness index) was performed at rest and immediately postexercise 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.ResultsExercise capacity was progressively worse from stage A through stage B to stage C and was accompanied by a gradual impairment of changes in PALS and PACS from rest to exercise, whereas LA stiffness reserve remained unchanged until stage C. Peak atrial longitudinal strain and PACS reserves were independently associated with exercise capacity (P = .017 and .008, respectively). Left atrial stiffness reserve and E/e' were the strongest associations of symptomatic HF. Over a median of 25 months, 35 patients developed HF and/or atrial fibrillation. Peak atrial longitudinal strain and PACS reserves were associated with the study end points after adjusting for age, diabetes, N-terminal pro-B type natriuretic peptide, LA volume index, resting E/e', and resting PALS/PACS.ConclusionsImpaired 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.Graphical abstractCentral Illustration. Left atrial strain and stiffness responses to exercise in HHD. Top frame: Examples of LA strain curves from representative patients from each HF category with hypertension. Trajectories of changes of exercise capacity, symptomatic status and LA strain, and stiffness reserve across the HF stages of HHD: LA reservoir strain reserve (ΔPALS), calculated by subtracting the resting value from the exercise value, and exercise capacity gradually deteriorated from HF stage A through HF stage B to HF stage C. Left atrial stiffness index reserve (ΔLA Stiffness), calculated in the same way as ΔPALS, was similar in preclinical stage A and stage B, and increased only in symptomatic stage C. Bottom frame: Increased risk of HF worsening and atrial fibrillation development as ΔPALS decreases.Central Illustration