Ventricular arrhythmias from the coronary venous system: Prevalence, mapping, and ablation.

BACKGROUND:The coronary venous system (CVS) is linked to the origin of idiopathic epicardial ventricular arrhythmias (VAs). OBJECTIVE:The purpose of this study was to identify the prevalence and effective mapping/ablation strategies for idiopathic VAs mapped to the CVS. METHODS:Detailed activation and pace-mapping of the right ventricle (RV), left ventricle (LV), CVS, and aortic cusps was performed, followed by attempted catheter ablation. RESULTS:Forty-seven of 511 patients with non-scar-related VAs (21 males, age 55 ± 15) had earliest activation in the CVS, 39 ± 18 ms before QRS. Twenty-five (53%) were in the great cardiac vein, 19 (40%) in the anterior interventricular vein, and 3 (7%) in the middle cardiac vein. We ablated inside CVS in 32 patients (68%) at the earliest activation site, in 18 patients at an adjacent CVS site, and in 14 patients because of an inability to advance the catheter in 4, inadequate power delivery in 2, and for safer distance from the coronary artery in 8. Proximity to coronaries precluded ablation inside the CVS in the remaining 15 patients (32%), who underwent ablation from adjacent left sinus of Valsalva, RV or LV endocardium, or LV epicardium. Success was achieved in 17 of 18 (94%) ablated at the earliest CVS site and in 16 of 29 (55%) ablated at adjacent CVS or non-CVS sites. CONCLUSION:Idiopathic VAs are occasionally (9%) linked to CVS. Although ablation at the earliest CVS site is effective, it is often (62%) precluded, mainly because of proximity to coronary arteries. Ablation at adjacent CVS and non-CVS sites can be successful in 55% of these anatomically challenging cases, for an overall ablation success rate of 70%.