Quantifying left atrial mechanical work in patients with atrial fibrillation with or without heart failure and preserved ejection fraction undergoing pulmonary vein isolation

Background Atrial cardiomyopathy is a hallmark feature of heart failure with preserved ejection fraction and associated with atrial fibrillation. Progressive loss of atrial mechanical function and hence ventricular filling has been proposed to underly HFpEF progression. However, comprehensive invasive hemodynamic data in this population remain scarce. We have developed a technique to integrate echocardiography and invasive pressure measurements in patients undergoing pulmonary vein isolation to estimate atrial mechanical function. Methods We retrospectively analysed patients with symptomatic, paroxysmal atrial fibrillation and preserved ejection fraction who underwent pulmonary vein isolation (PVI) at a single center in Berlin between March and July 2023. Inclusion criteria included sinus rhythm at admission, simultaneous left atrial pressure measurements and echocardiographic left atrial strain measurements acquired within 24 hours of the procedure. From these data, we derived left atrial pressure-strain loops to estimate atrial stiffness and atrial mechanical work. Subgroup comparisons were performed between patients with and without heart failure with preserved ejection fraction (HFpEF), defined as the presence of heart failure signs and symptoms along with an elevated NT-proBNP (>220 pg/mL). Results Among 33 patients, left atrial pressure-strain loops were successfully reconstructed in 25 (13 without and 12 with HFpEF). Patients with HFpEF had higher NT-proBNP levels (686.58 vs. 91.4 pg/ml) and were older (68.5 vs. 58.9 years), while ejection fraction (61.9% vs. 62.5%), BMI (26.7 vs. 28.3 kg/m²) and left atrial volume index (37.09 vs. 41.8 ml/m²) were similar. In line with previous reports, atrial stiffness—assessed by the ratio of atrial reservoir strain to v-wave height - was elevated in HFpEF patients (3.27 vs 7.09; %/mmHg, p< 0.05). Patients with HFpEF had a numerically lower contractile strain (-8.0 vs -11.6; %; ns) while active mechanical pressure (a-wave height: 5.1 vs 2.8; mmHg, p < 0.05) was increased. Accordingly, estimated atrial mechanical work (estimated area of the atrial "a loop") was unaltered (40.42 vs 35.35; %*mmHg, ns). Conclusion The combination of echocardiography and invasive pressure measurements in patients undergoing PVI provides detailed insights into left atrial mechanical function. Our preliminary data in patients with atrial fibrillation suggests that the presence of HFpEF is associated with increased atrial stiffness but suprisingly active atrial mechanical work remained unchanged.