Abstract
Atrial fibrillation (AF) is known to cause adverse remodeling of left atrium (LA). Radiofrequency catheter ablation (RFCA) of AF is associated with decrease in LA volume. However, the impact of RFCA on left atrial appendage (LAA) volume and hemodynamic function is not fully understood. We analyzed 123 patients who underwent cardiac magnetic resonance imaging (MRI) evaluation before and after RFCA in Korea University Anam Hospital. LA and LAA volume were measured before and after RFCA based on cardiac MRI. Baseline LA volume was 99.5 ± 38.4 cm3 and decreased to 74.6 ± 28.5 cm3 after RFCA (p < 0.001). LA diameter measured with transthoracic echocardiography was also decreased after RFCA (43.3 ± 6.2 mm at baseline and 39.9 ± 5.9 mm at follow up; p < 0.001). However, LAA volume was significantly increased after RFCA (19.4 ± 8.5 cm3 at baseline and 23.7 ± 13.3 cm3 at follow up; p < 0.001). Total ablation time and additional substrate modification was associated with change in LA volume. After RFCA, average LAA velocity measured by transesophageal echocardiography was increased to 51.0 cm/sec from 41.1 cm/sec (p < 0.001). In conclusion, LAA volume was increased after RFCA in contrast to LA volume. Our data raise a concern about worsening hemodynamics of LA and LAA following RFCA and long term clinical significance of enlarged LAA after RFCA needs further evaluation.
Highlights
Radiofrequency catheter ablation (RFCA) has emerged as a treatment of choice for antiarrhythmic drug (AAD) refractory symptomatic atrial fibrillation (AF) patients[1]
Recent study performed by Wylie et al.[25] showed that RFCA is associated with reduced atrial systolic function despite decreased left atrium (LA) volume which suggests that LA scar formation and consequent stiff LA are the principal mechanism for decreased LA volume following RFCA
Among 546 patients who performed cardiac magnetic resonance imaging (MRI) before RFCA, 312 patients who completed 1 year follow up after first-time RFCA were indicated for follow up MRI and 123 patients who underwent follow up MRI were included in the final analysis (Fig. 1)
Summary
Radiofrequency catheter ablation (RFCA) has emerged as a treatment of choice for antiarrhythmic drug (AAD) refractory symptomatic atrial fibrillation (AF) patients[1]. Thrombus and spontaneous echocontrast (SEC) in LAA and reduced LAA flow velocity are all associated with ischemic stroke in AF patients[13,14,15]. Flow stasis in LAA and its consequences, which is SEC and thrombus formation, are important risk factors for developing clinical ischemic stroke. Recent study performed by Wylie et al.[25] showed that RFCA is associated with reduced atrial systolic function despite decreased LA volume which suggests that LA scar formation and consequent stiff LA are the principal mechanism for decreased LA volume following RFCA. Understanding the hemodynamic and mechanical impact of RFCA on LAA would be important to anticipate future risk of ischemic stroke and to determine anticoagulation strategy in AF patients. We performed this study to evaluate the influence of RFCA on both LA and LAA in AF patients
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