Sun P; Cen H; 00, China.Chen S; Chen X; Jiang W; Zhu H; Liu Y; Liu H; Lu W;

BMC cardiovascular disorders [BMC Cardiovasc Disord] 2023 Mar 09; Vol. 23 (1), pp. 128.
Date of Electronic Publication: 2023 Mar 09.

Background: Beta-blockers are first-line clinical drugs for the treatment of chronic heart failure (CHF). In the guidelines for cardiac rehabilitation, patients with heart failure who do or do not receive beta-blocker therapy have different reference thresholds for maximal oxygen uptake (VO _2max ). It has been reported that left atrial (LA) strain can be used to predict VO _2max in patients with heart failure, which can be used to assess exercise capacity. However, most existing studies included patients who did not receive beta-blocker therapy, which could have a heterogeneous influence on the conclusions. For the vast majority of CHF patients receiving beta-blockers, the exact relationship between LA strain parameters and exercise capacity is unclear.
Methods: This cross-sectional study enrolled 73 patients with CHF who received beta-blockers. All patients underwent a thorough resting echocardiogram and a cardiopulmonary exercise test to obtain VO _2max , which was used to reflect exercise capacity.
Results: LA reservoir strain, LA maximum volume index (LAVI _max ), LA minimum volume index (LAVI _min ) (P < 0.0001) and LA booster strain (P < 0.01) were all significantly correlated with VO _2max , and LA conduit strain was significantly correlated with VO _2max (P < 0.05) after adjusting for sex, age, and body mass index. LA reservoir strain, LAVI _max , LAVI _min (P < 0.001), and LA booster strain (P < 0.05) were significantly correlated with VO _2max after adjusting for left ventricular ejection fraction, the ratio of transmitral E velocity to tissue Doppler mitral annulus e’ velocity (E/e’), and tricuspid annular plane systolic excursion. LA reservoir strain with a cutoff value of 24.9% had a sensitivity of 74% and specificity of 63% for the identification of patients with VO _2max  < 16 mL/kg/min.
Conclusion: Among CHF patients receiving beta-blocker therapy, resting LA strain is linearly correlated with exercise capacity. LA reservoir strain is a robust independent predictor of reduced exercise capacity among all resting echocardiography parameters.