Superior Vena Cava Isolation In Ablation Of Atrial Fibrillation

Usefulness of empiric superior vena cava isolation in paroxysmal atrial fibrillation ablation: a meta-analysis of randomized clinical trials

BACKGROUND

The long-term success rate of pulmonary vein isolation (PVI) is suboptimal due to the presence of non-pulmonary vein (PV) foci that can trigger atrial fibrillation (AF) in up to 11%. Among non-PV triggers, the superior vena cava (SVC) is a major site of origin of ectopic beats initiating AF.

OBJECTIVE

To compare data from randomized controlled trials (RCTs) assessing PVI + empiric SVC isolation (SVCI) versus PVI alone in terms of AF recurrence, procedure-related complications, and fluoroscopic and procedural times.

METHODS

A search of online scientific libraries (from inception to April 1, 2024) was performed. Four RCTs were considered eligible for the meta-analysis totaling 600 patients of whom 287 receiving PVI + SVCI and 313 receiving PVI alone.

RESULTS

In the overall population, SVCI + PVI was associated with a non-significant reduction of AF recurrence at follow-up (0.66 [0.43;1.00], p = 0.05, I2 0%). In patients with paroxysmal AF (PAF), a significant reduction of AF recurrence was related to SVCI + PVI (11.7%) as compared to PVI alone (19.9%) (0.54 [0.32;0.92], p = 0.02, I2 0%). No statistical differences were found among the groups in terms of fluoroscopic (3.31 [- 0.8;7.41], p = 0.11, I2 = 91%), procedural times (5.69 [- 9.78;21.16], p = 0.47, I2 = 81%), and complications (1.06 [0.33;3.44], p = 0.92, I2 = 0%).

CONCLUSION

The addition of SVCI to PVI in patients in PAF is associated with a significant lower rate of AF recurrence at follow-up, without increasing complication rates and procedural and fluoroscopy times.

An Uncommon Focus of a Common Phenomenon: Superior Vena Cava Triggering Atrial Fibrillation

Ablation of atrial fibrillation most commonly involves the pulmonary veins; however, the superior vena cava (SVC) is an important potentially arrhythmogenic structure that should not be overlooked. This case report demonstrates an excellent example of triggering activity localized to the SVC and the subsequent conversion to sinus rhythm with ablation of the SVC.

Epicardial adipose tissue around the superior vena cava: A single center study of factors related to atrial fibrillation

The superior vena cava (SVC) is the main component of non-pulmonary vein (PV) ectopy in patients with atrial fibrillation (AF). Researchers have found that epicardial adipose tissue (EAT) volume is related to the AF substrate, which can be defined by the low voltage area (LVA). This study aimed to investigate the relationship between SVC-EAT and SVC-AF. Twenty-six patients with SVC-AF triggers were identified as the SVC-AF group. Other three groups were defined and included as the LVA-AF group (LVA>5%), non-LVA-AF group (LVA<5%), and physical examination (PE) group. EAT around left atrium (LA-EAT) and SVC-EAT volumes were obtained using a cardiac risk assessment module. According to the SVC/LA-EAT ratio, there are significant differences between the SVC-AF group and the three control groups (the SVC-AF group 0.092±0.041 vs. the LVA-AF group 0.054±0.026, the non-LVA-AF group 0.052±0.022, and the PE group 0.052±0.019, all P<0.001). Receiver operating characteristic curve analysis suggests the optimal cut-off point of SVC/LA-EAT ratio is 6.8% for detecting SVC-AF patients, with 81.1% sensitivity, 73.1% specificity, and an area under the curve of 0.83 (95% confidence interval, 0.75-0.91). Those with SVC-AF have a higher SVC/LA-EAT ratio and empirical SVC isolation could be considered if the SVC/LA-EAT ratio was over 6.8%.

The Rogue P-wave: Atrial Dissociation Following Bicaval Heart Transplantation

We report the first case, to our knowledge, of atrial dissociation in a patient who underwent bicaval orthotopic heart transplantation. It was believed that atrioventricular dissociation prompting pacemaker implantation likely represented donor sinus bradycardia/arrest with intact atrioventricular conduction with surgically isolated recipient atrial activity.