Cardiac amyloidosis (CA) is an infiltrative cardiomyopathy caused by the extracellular deposition of amyloid fibrils in the myocardium. Although cardiac amyloidosis patients primarily present with heart failure symptoms, arrhythmias and conduction system disease are frequently encountered. Atrial fibrillation (AF) is observed in up to 70% of patients at the time of diagnosis, and patients typically have controlled ventricular rates caused by concomitant conduction system disease. Thromboembolic risk is particularly high in patients with CA and AF, and left atrial thrombi have been observed even in the absence of clinically diagnosed AF. Atrioventricular nodal and infra-Hisian disease are common, and permanent pacemakers are frequently required. The use of implantable cardioverter-defibrillators in this population is controversial. This review summarizes the published data and therapeutic strategies surrounding arrhythmias and conduction system disease with the goal of aiding clinicians managing the clinical complexities of CA.

Aims: Obesity decreases arrhythmia-free survival after atrial fibrillation (AF) ablation by mechanisms that are not fully understood. We investigated the impact of pre-ablation bariatric surgery (BS) on AF recurrence after ablation. Methods and results: In this retrospective observational cohort study, 239 consecutive morbidly obese patients (body mass index ≥40 kg/m2 or ≥35 kg/m2 with obesity-related complications) were followed for a mean of 22 months prior to ablation. Of these patients, 51 had BS prior to ablation, and our primary outcome was whether BS was associated with a lower rate of AF recurrence during follow-up. Adjustment for confounding was performed with multivariable Cox proportional hazard models and propensity-score based analyses. During a mean follow-up of 36 months after ablation, 10/51 patients (20%) in the BS group had recurrent AF compared with 114/188 (61%) in the non-BS group (P < 0.0001). In the BS group, 6 patients (12%) underwent repeat ablation compared with 77 patients (41%) in the non-BS group, (P < 0.0001). On multivariable analysis, the association between BS and lower AF recurrence remained significant. Similarly, after weighting and adjusting for the inverse probability of the propensity score, BS was still associated with a lower hazard of AF recurrence (hazard ratio 0.14, 95% confidence interval 0.05–0.39; P = 0.002). Conclusion: Bariatric surgery is associated with a lower AF recurrence after ablation. Morbidly obese patients should be considered for BS prior to AF ablation, though prospective multicentre studies should be performed to confirm our novel finding.

The amount of fibrosis in the left atrium (LA) predicts atrial fibrillation (AF) recurrence after catheter ablation (CA). We aim to identify whether regional variations in LA fibrosis affect AF recurrence. This post hoc analysis of the DECAAF II trial includes 734 patients with persistent AF undergoing first-time CA who underwent late gadolinium enhancement magnetic resonance imaging (LGE-MRI) within 1 month prior to ablation and were randomized to MRI-guided fibrosis ablation in addition to standard pulmonary vein isolation (PVI) or standard PVI only. The LA wall was divided into seven regions: anterior, posterior, septal, lateral, right pulmonary vein (PV) antrum, left PV antrum, and left atrial appendage (LAA) ostium. Regional fibrosis percentage was defined as a region’s fibrosis prior to ablation divided by total LA fibrosis. Regional surface area percentage was defined as an area’s surface area divided by the total LA wall surface area before ablation. Patients were followed up for a year with single-lead electrocardiogram (ECG) devices. The left PV had the highest regional fibrosis percentage (29.30 ± 14.04%), followed by the lateral wall (23.23 ± 13.56%), and the posterior wall (19.80 ± 10.85%). The regional fibrosis percentage of the LAA was a significant predictor of AF recurrence post-ablation (odds ratio = 1.017, P = 0.021), and this finding was only preserved in patients receiving MRI-guided fibrosis ablation. Regional surface area percentages did not significantly affect the primary outcome. We have confirmed that atrial cardiomyopathy and remodelling are not a homogenous process, with variations in different regions of the LA. Atrial fibrosis does not uniformly affect the LA, and the left PV antral region has more fibrosis than the rest of the wall. Furthermore, we identified regional fibrosis of the LAA as a significant predictor of AF recurrence post-ablation in patients receiving MRI-guided fibrosis ablation in addition to standard PVI.