Comparison of Electrophysiologic Profiles in Pediatric Patients with Incidentally Identified Pre-Excitation Compared with Wolff-Parkinson-White Syndrome.

The rising utilization of screening electrocardiograms has resulted in increased incidental identification of ventricular pre-excitation in pediatric patients. We compared accessory pathways of incidentally identified pre-excitation to Wolff-Parkinson-White Syndrome (WPW) with the aim to identify factors important in preprocedural counseling and planning. This single-center, retrospective study of patients ≤18 years without congenital heart disease identified 227 patients diagnosed with pre-excitation and referred for invasive electrophysiology study between 2008 and 2017. WPW Syndrome was diagnosed in 178 patients, while 49 patients had incidental identification of pre-excitation. Anterograde conduction of incidentally identified accessory pathways was not clinically different between the two cohorts at baseline or upon isoproterenol infusion. However, the proportion of accessory pathways meeting high-risk criteria was significantly lower than in patients diagnosed with WPW, 12% versus 28% (p < 0.05). Retrograde conduction at baseline of incidentally diagnosed accessory pathways was slower with a median block cycle length 365 milliseconds (IQR 260 to 450) versus 290 milliseconds (IQR 260 to 330, p < 0.01). In the incidentally identified cohort, right-sided, paraHisian, and fascicular pathways were more common with fewer attempted ablations (71% vs 94%, p < 0.001) and lower success rate (91% vs 97%, p < 0.001). A binomial logistic regression analysis further indicated patients incidentally identified with pre-excitation were associated with having lower rates of inducible supraventricular tachycardia, atrial fibrillation, and ablations performed, in addition, to having right-sided pathways. In conclusion, as patients with incidentally identified pre-excitation present more frequently for consideration of invasive electrophysiology study, these results impact procedural approaches, technical considerations, patient counseling, and outcome expectations.

2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias.

Ventricular arrhythmias are an important cause of morbidity and mortality and come in a variety of forms, from single premature ventricular complexes to sustained ventricular tachycardia and fibrillation. Rapid developments have taken place over the past decade in our understanding of these arrhythmias and in our ability to diagnose and treat them. The field of catheter ablation has progressed with the development of new methods and tools, and with the publication of large clinical trials. Therefore, global cardiac electrophysiology professional societies undertook to outline recommendations and best practices for these procedures in a document that will update and replace the 2009 EHRA/HRS Expert Consensus on Catheter Ablation of Ventricular Arrhythmias. An expert writing group, after reviewing and discussing the literature, including a systematic review and meta-analysis published in conjunction with this document, and drawing on their own experience, drafted and voted on recommendations and summarized current knowledge and practice in the field. Each recommendation is presented in knowledge byte format and is accompanied by supportive text and references. Further sections provide a practical synopsis of the various techniques and of the specific ventricular arrhythmia sites and substrates encountered in the electrophysiology lab. The purpose of this document is to help electrophysiologists around the world to appropriately select patients for catheter ablation, to perform procedures in a safe and efficacious manner, and to provide follow-up and adjunctive care in order to obtain the best possible outcomes for patients with ventricular arrhythmias.

Use of Programmed Ventricular Extrastimulus During Supraventricular Tachycardia to Differentiate Atrioventricular Nodal Re-Entrant Tachycardia From Atrioventricular Re-Entrant Tachycardia.

OBJECTIVES: This study hypothesized that early coupled ventricular extrastimuli (V2) stimulation might yield a more robust differentiation between atrioventricular nodal re-entrant tachycardia (AVNRT) and atrioventricular re-entrant tachycardia (AVRT). BACKGROUND: Programmed V2 during supraventricular tachycardia are useful to differentiate AVNRT from AVRT by subtracting the ventriculoatrial (VA) interval from the stimulus to atrial depolarization (stimulus atrial [SA]) interval, but all such maneuvers have limitations. METHODS: Patients with either AVNRT or AVRT were investigated. The entire tachycardia cycle length (TCL) was scanned with V2 delivered from the right ventricular apex. The SA-VA difference was calculated with V2 clearly resetting the tachycardia. The prematurity of V2 was calculated by dividing the coupling interval (CI) by the TCL. RESULTS: A total of 210 patients (102 with AVNRT) were included. The SA-VA difference was >70 ms in all AVNRT patients and was <70 ms in all AVRT patients with right and septal accessory pathways (APs), except for those with decremental APs, in whom there was an overlap between AVNRT and AVRT with left APs. However, a SA-VA difference >110 ms with a CI/TCL of <65% distinguished AVNRT from AVRT using the left AP, with sensitivity and specificity of 87% and 100%, respectively. Ventricular overdrive pacing resulted in tachycardia termination or AV dissociation in 28% of patients compared with 15% of patients using the V2 technique (p = 0.008). CONCLUSIONS: A SA-VA of >70 ms using the V2 technique differentiated AVNRT from AVRT using septal and right APs. Use of the V2 technique with a short CI differentiated AVNRT from AVRT using left APs. The V2 technique less frequently resulted in tachycardia termination compared with ventricular entrainment.

Radiation safety protocol using real-time dose reporting reduces patient exposure in pediatric electrophysiology procedures.

Radiation exposure during pediatric catheterization is significant. We sought to describe radiation exposure and the effectiveness of radiation safety protocols in reducing exposure during catheter ablations with electrophysiology studies in children and patients with congenital heart disease. We additionally sought to identify at-risk patients. We retrospectively reviewed all interventional electrophysiology procedures performed from April 2009 to September 2011 (6 months preceding intervention, 12 months following implementation of initial radiation safety protocol, and 8 months following implementation of modified protocol). The protocols consisted of low pulse rate fluoroscopy settings, operator notification of skin entrance dose every 1,000 mGy, adjusting cameras by >5 at every 1,000 mGy, and appropriate collimation. The cohort consisted of 291 patients (70 pre-intervention, 137 after initial protocol implementation, 84 after modified protocol implementation) at a median age of 14.9 years with congenital heart disease present in 11 %. Diagnoses included atrioventricular nodal reentrant tachycardia (25 %), atrioventricular reentrant tachycardia (61 %), atrial tachycardias (12 %), and ventricular tachycardia (2 %). There were no differences between groups based on patient, arrhythmia, and procedural characteristics. Following implementation of the protocols, there were significant reductions in all measures of radiation exposure: fluoroscopy time (17.8 %), dose area product (80.2 %), skin entry dose (81.0 %), and effective dose (76.9 %), p = 0.0001. Independent predictors of increased radiation exposure included larger patient weight, longer fluoroscopy time, and lack of radiation safety protocol. Implementation of a radiation safety protocol for pediatric and congenital catheter ablations can drastically reduce radiation exposure to patients without affecting procedural success.