1008-10 Electrocardiographic Configuration Criteria Distinguishing “Endocardial” from “Epicardial” Accessory Pathways in the Left Posteroseptal Space

To assess whether the surface ECG allows distinction of manifest accessory pathways (APs) located at the subendocardial from those at the subepicardial aspect of the left postero-septal (PS) space, 12-lead surface ECGs were compared between 17 pts with an “endocardial” (ENDO) AP and 24 pts with an “epicardial” (EPI) manifest AP. Location of the AP was defined by the site of successful pulse delivery: EPI PS APs were ablated from within the coronary sinus (CS); ENDO PS APs were ablated from the left ventricle. PR interval and QRS duration did not differ between the 2 groups at baseline ECG (ENDO, 102±20ms and 145±22ms; EPI. 99±18ms and 149±27). Delta wave polarity in lead V1 was positive or isoelectric in all patients. A negative delta wave simultaneously recorded in leads II, III and aVF was found in 15/24 EPI APs and in 3/17 ENDO APs (p<0.001). Among EPI APs, wide and deep Q waves in the inferior leads were found in 3/12 ablated from the middle cardiac vein, and in 0/5 EPI APs ablated from within the CS, representing a highly specific but poorly sensitive marker. Delta wave in ENDO APs was simultaneously positive in leads II, III and aVF in 11/17. QRS patterns associated with endo APs showed typical fragmented rsr1s1 in inferior leads in 12/24 cases.ConclusionsDelta wave and QRS activation allow distinction of ENDO vs EPI APs located in the PS space in the majority of cases

Contemporary Patients with Congenital Heart Disease: Uniform Atrial Tachycardia Substrates Allow for Clear Ablation Endpoints with Improved Long-Term Outcome

Background: Poor outcome after atrial tachycardia (AT) radiofrequency catheter ablation (RFCA) in repaired congenital heart disease (CHD) has been attributed to CHD complexity. This may not apply to contemporary patients. The objective of our study was to assess outcome after RFCA for AT in contemporary patients with CHD according to prior atrial surgery and predefined procedural endpoints. Methods: Patients with CHD referred for AT RFCA to 3 European centers were classified as no atrial surgery/cannulation only, limited or extensive prior atrial surgery. Procedural success was predefined as termination and nonreinducibility for focal AT and bidirectional block across ablation lines for intra-atrial reentrant tachycardia and after empirical substrate ablation for noninducible patients. Patients were followed for AT recurrence and mortality. Results: Ablation was performed in 290 patients (41±17 years, 59% male; 3-dimensional mapping 89%, irrigated tip catheters 90%, transbaffle access 15%). In 197, 233 AT were targeted (196 intra-atrial reentrant tachycardia [64% cavotricuspid (mitral) isthmus-dependent, 33% systemic-venous incision-dependent] and 37 focal AT). In 93 noninducible patients, empirical substrate ablation was performed. Procedural success was achieved in 209 (84%) patients. AT recurred in 148 (54%) 10 (interquartile range, 0-25) months after RFCA. AT-free survival was significantly better in patients with no atrial repair/cannulation only and in patients with complete procedural success independently of CHD complexity. From 94 patients undergoing reablation, the initially targeted substrate had recovered in 64%. Conclusions: In contemporary patients with CHD, outcome after AT ablation is associated with presence of prior atrial surgery and achievement of predefined procedural endpoints rather than CHD complexity. Techniques to improve lesion durability are likely to further improve long-term outcome

Management of paediatric arrhythmias in Europe

WOS: 000368445700024PubMed ID: 25995398We read with great interest the EP wire report entitled ‘How are arrhythmias managed in the paediatric population in Europe? Results of the European Heart Rhythm Survey’ by HernandezMadrid et al. 1 On behalf of the Arrhythmias and Electrophysiology Working Group of the Association for European Pediatric and Congenital Cardiology (AEPC), we would like to comment on the methodology and content of the article. The EHRA Research Network Centers do not include any of the dedicated paediatric centresproviding interventional electrophysiological therapy. This creates a major sampling errorand negatesthe validityof the conclusions of the survey. By including the paediatric centres, we would expect the results to be markedly different. The conclusion that paediatric catheter ablations in Europe are mainly performed by adult electrophysiology teams is not justified