Isolation of Canine Coronary Sinus Musculature From the Atria by Radiofrequency Catheter Ablation Prevents Induction of Atrial Fibrillation

Abstract

Background-The junction between the coronary sinus (CS) musculature and both atria contributes to initiation of atrial tachyarrhythmias. The current study investigated the effects of CS isolation from the atria by radiofrequency catheter ablation on the induction and maintenance of atrial fibrillation (AF). Methods and Results-Using an optical mapping system, we mapped action potentials at 256 surface sites in 17 isolated and arterially perfused canine atrial tissues containing the entire musculature of the CS, right atrial septum, posterior left atrium, left inferior pulmonary vein, and vein of Marshal. Rapid pacing from each site before and after addition of acetylcholine (0.5 μmol/L) was applied to induce AF. Epicardial radiofrequency catheter ablation at CS-atrial junctions isolated the CS from the atria. Rapid pacing induced sustained AF in all tissues after acetylcholine. Microreentry within the CS drove AF in 88% of preparations. Reentries associated with the vein of Marshall (29%), CS-atrial junctions (53%), right atrium (65%), and pulmonary vein (76%) (frequently with 2-4 simultaneous circuits) were additional drivers of AF. Radiofrequency catheter ablation eliminated AF in 13 tissues before acetylcholine (P<0.01) and in 5 tissues after acetylcholine. Radiofrequency catheter ablation also abbreviated the duration of AF in 12 tissues (P<0.01). Conclusions-CS and its musculature developed unstable reentry and AF, which were prevented by isolation of CS musculature from atrial tissue. The results suggest that CS can be a substrate of recurrent AF in patients after pulmonary vein isolation and that CS isolation might help prevent recurrent AF. (Circ Arrhythm Electrophysiol. 2014;7:1181-1188.)

Frequency Gradient Within Coronary Sinus Predicts the Long‐Term Outcome of Persistent Atrial Fibrillation Catheter Ablation

“…Oral et al demonstrated that in a small population with AF ablation, electrical disconnection of the CS from the LA lowered the inducibility of AF after PVI. Further study on a canine AF model also confirmed that isolating the CS from the atria eliminated AF induction . Our present study shows that an increased gradient between CSd and CSp, as in the CSd/CSp ratio, might be an independent predictor for AF termination and long‐term outcome.…”

“…Further catheter ablation at CS-atrial junctions by isolating the CS from the atria eliminated the sustained AF. 21 In the current context we hypothesized whether the characteristics of CS activities would help us to identify a subset of patients in whom the electrical activities of CS might play an important role in maintenance of AF and predict the outcome of AF ablation.…”

Association of Rate-Dependent Conduction Block Between Eccentric Coronary Sinus to Left Atrial Connections With Inducible Atrial Fibrillation and Flutter

“…1 Canine studies have pointed to the participation of CS musculature to left atrial (LA) connections in unstable macro-reentrant atrial tachycardia (AT) and atrial flutter (AFL) with degeneration to atrial fibrillation (AF). 2–5 Additionally, the CS is a source of focal triggered activity in 15% of patients with AF recurrence despite pulmonary vein isolation (PVI). 6 Ablation of endocardial and epicardial aspects of the CS has been shown to prolong the fibrillatory cycle length and terminate AF in selected patients.…”

Double trouble within the coronary sinus: What is the mechanism?

“…Of note, while the patient was in SR, constant pacing at the inferior aspect of the ridge reproduced the same windshield wipers pattern seen during LAT within the CS ( Figure 3A The variability of the conduction through the CS-LA connections, related to their intrinsic conductive properties (conduction-delay), [2][3][4] explains the variable relationship between the endocardial and the epicardial activation.…”

“…1 Subsequently, elegant studies have described the electrophysiological properties of these connections as well as their potential supporting role for re-entrant tachycardias and AF. [2][3][4] Despite all these robust publications, during several years the clinical implications of these connections have been relatively neglected by the electrophysiological community. However, besides their importance in the understanding of LATs as highlighted by our observation, a recent publication has pointed out the interest of these CS-LA connections (in particular the Marshall's bundle) as potential targets for the treatment of persistent AF in humans.…”