Ablation within the coronary venous system in young patients: A focus on safety

Despite decades of experience, catheter ablation of an accessory atrioventricular pathway (AP) in the posteroseptal region can still be challenging owing to complex anatomy and the proximity to coronary arteries. This is especially true for APs involving the musculature around the proximal coronary sinus (CS), the middle cardiac vein, or a diverticulum off the CS. 1 Sun Y. Arruda M. Otomo K. et al. Coronary sinus-ventricular accessory connections producing posteroseptal and left posterior accessory pathways: incidence and electrophysiological identification. Circulation. 2002; 106: 1362-1367 Crossref PubMed Scopus (202) Google Scholar The coronary venous system (CVS) can be navigated with high precision guided by a contrast injection in the CS, and the mapping data tend to be relatively unambiguous within these structures, usually displaying a clear AP potential. But even when AP localization is firm, the delivery of safe and effective ablation energy is not straightforward. Two obstacles can frustrate ablation efforts. The first is altered thermodynamics for conventional radiofrequency (RF) energy in a semi-enclosed space with reduced blood flow, causing high temperatures and low power delivery. The second relates to the risk of injury to adjacent coronary arterial branches. Unfortunately, efforts to overcome the former with irrigated RF ablation only increases the risk of the latter. The operator is often forced to accept cautious low power RF applications or else resort to cryoablation with a higher-than-average likelihood of AP recurrence. 2 Aoyama H. Nakagawa H. Pitha J.V. et al. Comparison of cryothermia and radiofrequency current in safety and efficacy of catheter ablation within the canine coronary sinus close to the left circumflex coronary artery. J Cardiovasc Electrophysiol. 2005; 16: 1218-1226 Crossref PubMed Scopus (105) Google Scholar ,3 Bar-Cohen Y. Cecchin F. Alexander M.E. Berul C.I. Triedman J.K. Walsh E.P. Cryoablation for accessory pathways located near normal conduction tissues or within the coronary venous system in children and young adults. Heart Rhythm. 2006; 3: 253-258 Abstract Full Text Full Text PDF PubMed Scopus (90) Google Scholar Another option may be to consider pericardial access for epicardial ablation, 4 Upadhyay S. Walsh E.P. Cecchin F. Triedman J.K. Villafane J. Saul J.P. Epicardial ablation of tachyarrhythmias in children: experience at two academic centers. Heart Rhythm. 2017; 40: 1017-1026 Google Scholar but there is no advance guarantee that an epicardial target will be any safer than a CVS target with respect to coronary vessels and, on occasion, may actually be more hazardous. Catheter ablation of coronary sinus accessory pathways in the youngHeart RhythmVol. 20Issue 6PreviewAccessory atrioventricular pathways (APs) are the most common tachycardia substrate for supraventricular tachycardia (SVT) in the young. Endocardial catheter ablation of AP may be unsuccessful in up to 5% of patients because of a coronary sinus location. Full-Text PDF