The echocardiographic parameters total atrial conduction time, left atrial volume index and left atrial strain reflect adverse atrial remodelling and fibrosis in atrial fibrillation (AF) as well as occurrence/recurrence of AF. Reversal of left atrial (LA) remodelling and fibrosis after conversion of AF to sinus rhythm is difficult to monitor because tissue sampling is not possible, and methods of atrial imaging have marked limitations. However, reversal of LA remodelling may be an indicator of treatment success after restoration of sinus rhythm and an important predictor for AF recurrence.

 

To investigate echocardiographic parameters indicating reverse left atrial remodelling and potential associations with AF recurrence after pulmonary vein isolation (PVI).

 

Prospective, diagnostic and observational study. Sample size calculation for the primary endpoint (change in PA-TDI duration (s. below) after PVI) yielded 44 patients to be analyzed (power of 80%, two-sided significance level of 5%). We consecutively screened patients for eligibility, who underwent PVI for symptomatic paroxysmal AF between June 2018 and July 2019. Patients were only included, if they presented in sinus rhythm during echocardiography as most parameters indicating LA remodeling cannot be determined in the presence of AF. ECG and transthoracic echocardiography were performed the day before (baseline) and after PVI as well as 3 months thereafter. AF recurrence was determined by Holter-ECG at 3 month and telephone follow-up at 12 months after PVI. Echocardiographic parameters of LA remodelling (total atrial conduction time (time from the onset of the P-wave to the peak septal or lateral a'-wave by tissue Doppler imaging (PA-TDI duration)), LA volume index (LAVI) and LA strain-analysis (reserviour strain (LASr), conduit strain (LAScd), contraction strain (LASct)) were determined by transthoracic echocardiography as recommended by current guidelines.

 

58 of 110 screened patients admitted for PVI fulfilling the inclusion and exclusion criteria were included in the study (mean age: 60.7±12.1 years, male sex: 66%, hypertension: 69%, coronary artery disease: 24%). PA-TDI duration significantly decreased already the day after PVI compared to baseline (septal PA-TDI duration 105.6±15.1 vs. 80±14.9 ms, p≤0.001; lateral PA-TDI duration 123.1±16.5 vs 106.9±14.3 ms, p≤0.001). This decrease compared to baseline persists at the 3 month follow-up (septal PA-TDI duration: 105.6±15.1 vs. 78.6±14.2 ms, p≤0.001; lateral PA-TDI duration: 123.1±16.5 vs. 105.7±17.2 ms, p≤0.001). LAVI did not change the day after PVI (47.6±13.7 vs 44.3±11.3 ml/qm) but showed a significant reduction at the 3 month follow-up compared to baseline (47.6±13.7 vs. 40.8±9.9 ml/qm, p<0.05). Parameters of LA-strain (LASr, LAScd, LASct) did not change after PVI compared to baseline. AF recurred in 13 patients after PVI (22.4%) at 12 month follow-up. Septal tissue doppler a´, LAVI/a´ and septal PA-TDI duration, determined the day after PVI, were significantly different in patients with and without recurrence of AF (s. Fig.).

 

The change in echocardiographic parameters of left atrial remodelling and –function potentially indicates reversal of adverse left atrial remodelling after PVI in patients with paroxysmal AF. Of note, changes in parameters indicating an improvement of electro-mechanical remodelling proceed changes in parameters of structural remodelling.