Background: Recent studies showed that left atrial strain (LAS) demonstrated a linear relationship to peak VO₂. Reduced skeletal muscle endurance (RME) is associated with peak VO₂ as well. Less is known about the relationship between central (LAS) and peripheral (muscle endurance) limitations of exercise capacity in HF. A novel cardiac marker (LAS) was not investigated in this regard yet.

Methods: We recruited 55 participants: 17 HFpEF, 18 HFrEF outpatients and 20 healthy controls (HC) prospectively at the University Hospital Jena, Germany. All participants underwent echocardiography, cardiopulmonary exercise testing, and isokinetic muscle function. 

Results: Patients with HFpEF and HFrEF showed reduced LAS and left atrial ejection fraction (LAEF) compared to HC (p≤0.001). Patients with reduced LAEF (< mean value) showed reduced peak VO₂: 14.3±3.5 vs. 18.5±3.5 ml/min/kg, p=0.003 and RME: 64.3±23.9 vs. 88.5±32.3 Nm/kg, p=0.028. Similar results were found in patients with reduced LAS. Reduced left ventricular global strain (LVGLS) was not associated with RME. The area under the curve of LAS and LAEF in patients with HF in association with RME were (0.76 vs.0.80) with 95% confidence interval (CI) (0.59-0.96, p=0.012 vs. 0.63-0.98, p=0.006, respectively). Logistic regression analysis showed that LAEF adjusted to LVGLS, LAS, and left atrial fractional area change was the only independent factor in predicting muscle endurance (OR=0.82, 95% CI: 0.11-1.54, p=0.026).

Conclusion: LAS/LAEF are suitable cardiac markers in demonstrating the link between cardiac and peripheral limitations of exercise capacity and could play an important role in evaluating exercise intolerance in patients with HF.