Left atrial reservoir strain measurements derived from intracardiac echocardiography in patients with atrial fibrillation: comparison with transthoracic echocardiography.

BACKGROUND: Intracardiac echocardiography (ICE) provides accurate left atrial (LA) anatomical information in the procedure of atrial fibrillation (AF) ablation but lacks LA functional assessment. LA reservoir strain (LASr) is an excellent marker of LA reservoir function. This study aimed to assess the agreement between LASr derived from ICE and transthoracic echocardiography (TTE) in AF patients and analyze the reproducibility of LASr assessed by ICE combined with speckle tracking imaging. METHODS: This study prospectively enrolled 110 patients with a clinical diagnosis of AF who were ready for AF ablation, including 71 patients with paroxysmal AF and 39 with persistent AF. TTE and ICE examinations were performed on each individual before AF ablation. LASr measurements derived from ICE and TTE images were using dedicated LA-tracking software. Pearson correlation coefficients (r) and Bland-Altman plots were used to evaluate the agreement of LASr between the two modalities. Intraclass correlation coefficients (ICCs) were used to assess intra- and inter-observer reproducibility. RESULTS: The agreement between LASr obtained from ICE and TTE, especially between LASrLPV (LASr derived from LA left pulmonary vein view of ICE) and LASrTTE (LASr derived from TTE) were good in both paroxysmal and persistent AF patients [r = 0.890 (P < 0.001) for overall population; r = 0.815 (P < 0.001) and Bias ± LOA: -0.3 ± 9.9% for paroxysmal AF; r = 0.775 (P < 0.001) and Bias ± LOA: -2.6 ± 3.9% for persistent AF, respectively]. But the values of LASr derived from ICE were slightly lower than those of TTE, especially in patients with persistent AF. The ICCs for LASr derived from ICE were excellent (all ICCs > 0.90). CONCLUSIONS: In patients with AF, LASr derived from ICE demonstrated excellent reproducibility and showed good agreement with LASr obtained from TTE. Obtaining LASr from ICE images may be a supplementary method to evaluate LA reservoir function in AF patients and expands the potential of ICE in the field of cardiac function assessment.