Left Atrial Strain in Evaluation of Heart Failure with Preserved Ejection Fraction

Background: Patients with heart failure with preserved ejection fraction (HFpEF) may have elevated left ventricular filling pressure with exercise (LVFP-ex), despite normal LVFP at rest. The aim of this study was to assess the diagnostic value of resting left atrial strain (LAS) in detecting elevated LVFP-ex in patients with dyspnea evaluated on exercise stress echocardiography. Methods: Two-dimensional speckle-tracking analysis for LAS was performed in 669 consecutive patients (mean age, 64 ± 14 years; 53% men) who underwent treadmill echocardiographic evaluation and had left ventricular ejection fractions ≥ 50%. Assessment of LVFP at rest LVFP-ex was based on the 2016 American Society of Echocardiography guidelines for diastolic function assessment. An E/e′ ratio ≥ 15 after exercise is considered to indicate elevated LVFP-ex. A continuous diagnostic score of HFpEF was calculated on the basis of the European Society of Cardiology HFA-PEFF diagnostic algorithm. Results: LAS_reservoir was lowest in patients with elevated LVFP at rest (n = 81) and lower in those with normal resting filling pressure who developed elevated LVFP-ex (n = 108) compared with those who maintained normal LVFP-ex (29.0 ± 5.2% vs 33.1 ± 5.0% vs 39.3 ± 4.8%, P < .001). Lower LAS_reservoir was associated with worse exercise capacity as assessed by metabolic equivalents, exercise time, and functional aerobic capacity (multivariate-adjusted P values all < .05). In patients with normal or indeterminate LVFP at rest (n = 587), LAS_reservoir and preexercise HFA-PEFF score demonstrated areas under the curve of 0.82 and 0.7, respectively, for elevated LVFP-ex. There were 28% higher odds of developing elevated LVFP-ex per 1% decrease in LAS_reservoir (odds ratio, 0.78; 95% CI, 0.74–0.82). Among patients with intermediate scores (n = 461), 123 developed elevations in LVFP-ex and were classified as having HFpEF per the diagnostic algorithm. The addition of LAS_reservoir improved the diagnostic value of HFA-PEFF score for HFpEF (area under the curve increased from 0.71 to 0.80, P = .01). Conclusions: LAS_reservoir has potential to identify patients with intermediate scores for HFpEF who may develop elevated LVFP-ex only and is therefore a promising alternative to aid in diagnosis when exercise testing is not feasible.