Pericardial Fat and the Risk of Atrial Tachy-arrhythmia Recurrence Post Pulmonary Vein Isolation: A Computed Tomography Study

Background: Obesity is increasingly recognized as a novel risk factor that contributes significantly to the frequency of atrial fibrillation (AF). There has been a growing interest in assessing the impact of local fat deposits and the appearance of AF. Pericardial fat and epicardial fat have been hypothesized to exert local and systemic pathogenic effects nearby cardiac structures.

Objectives: The aim of this study was to evaluate the impact of pericardial and epicardial fat volume on the outcome of patients who underwent a first pulmonary vein isolation (PVI) using cryoablation.

Methods: One hundred and thirty consecutive patients (61 ± 2, 88 male) with AF (88 paroxysmal, 42 persistent) who underwent contrast enhanced ECG-gated computed tomography (CT) before PVI were included. Fifty patients in normal sinus rhythm who underwent ECG-gated CT to rule out coronary artery disease served as a control group. Epicardial, pericardial and peri-atrial fat volumes were quantified by CT.

Results: Patients with persistent AF had significantly higher total fat volume (244 ± 100.3 ml) compared to paroxysmal AF (199 ± 71.2ml) and normal subjects (81.5 ± 23.1 ml); P < 0.0001. Recurrence of AF occurred in 26/130 patients (20%) at a mean follow-up time of 20.5 ± 8.48 months. As compared with those whom had successful AF ablation, patients with post ablation recurrence of AF or redo procedures had increased epicardial (115.6 ± 49.5 ml vs. 81.6 ± 40.3 ml; respectively, P < 0.0008), pericardial (166.2 ± 60.6 ml vs. 73.5 ± 47.2 ml; respectively, P<0.0001), peri-atrial (65.6 ± 21.6 ml vs. 44.3 ± 19.6 ml; respectively, P<0.0001), and total fat volume (281.8 ± 87.5 ml vs. 198,7 ± 76.1 ml; respectively, P<0.0001).

Conclusions: Pericardial and epicardial fat, as assessed by contrast enhanced CT, was associated with the severity of AF and procedural outcomes after PVI. Assessment of pericardial and epicardial fat tissue may be useful to stratify the risk of recurrence after PVI.