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Atrial Remodeling After Catheter Ablation for Atrial Fibrillation
Study Questions:
What is the long-term effect on atrial electrical and structural function after catheter ablation (CA) for atrial fibrillation (AF)?
Methods:
The investigators assessed if recovery of left ventricular (LV) function with the restoration of sinus rhythm was associated with changes in atrial electrical and structural characteristics in a subgroup of patients who underwent CA as part of the CAMERA-MRI study. Detailed electroanatomical (EA) mapping of the right atrium (RA) using CARTO3 and a force sensing catheter was performed at initial CA and electively at least 12 months after CA in patients with >90% reduction in AF burden following ablation. Bipolar voltage, fractionation, and conduction velocity were collected in four segments together with echocardiography and cardiac magnetic resonance imaging. Paired Student’s t-test was used to compare means from baseline to follow-up.
Results:
Fifteen patients (mean age 59.1 ± 6.8 years) underwent repeat RA EA mapping. At a mean follow-up of 23.4 ± 11.9 months, LV ejection fraction improved from 33.6 ± 3.2% to 54.1 ± 3.2% (p = 0.001), RA area decreased from 28.4 ± 2.0 to 20.8 ± 1.2 cm2 (p < 0.001), and LA area decreased from 32.9 ± 2.3 to 26.8 ± 1.4 cm2 (p = 0.007). On EA mapping, RA bipolar voltage increased from 1.6 ± 0.1 to 1.9 ± 0.1 mV (p = 0.04). Tissue voltage increased across all regions, which achieved statistical significance at the posterior (p = 0.002) and septal (p = 0.01) segments. There was a significant decrease in complex fractionated electrograms from 21.7 ± 3.5% to 8.3 ± 1.8% (p = 0.002); however, no significant change occurred in global or regional conduction velocities (p = 0.5).
Conclusions:
The authors concluded that recovery of atrial electrical and structural changes was observed following restoration of sinus rhythm and recovery of LV function in patients who underwent CA for persistent AF and LV systolic dysfunction.
Perspective:
This study reports that post-CA, RA tissue voltage improved significantly, particularly in the posterior and septal regions, and the proportion of complex fractionated electrograms was reduced significantly with no significant differences in atrial conduction velocities. Furthermore, there were significant improvements in atrial dimensions and function at a mean follow-up of approximately 2 years. These changes may explain the long-term success of CA in patients with AF and otherwise unexplained cardiomyopathy, but needs validation in larger prospective studies.
Clinical Topics: Arrhythmias and Clinical EP, Cardiovascular Care Team, Heart Failure and Cardiomyopathies, Noninvasive Imaging, Prevention, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Acute Heart Failure, Echocardiography/Ultrasound, Magnetic Resonance Imaging
Keywords: Arrhythmias, Cardiac, Atrial Fibrillation, Atrial Remodeling, Catheter Ablation, Cardiomyopathies, Catheter Ablation, Echocardiography, Heart Failure, Magnetic Resonance Imaging, Secondary Prevention, Stroke Volume, Ventricular Function, Left
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