Recurrent A V block following ablation for AVNRT

Automatic algorithmic driven monitoring of atrioventricular nodal re-entrant tachycardia ablation to improve procedural safety

Background

During slow pathway modification for atrioventricular nodal reentrant tachycardia, heart block may occur if ablation cannot be stopped in time in response to high risk electrogram features (HREF).

Objectives

To develop an automatic algorithm to monitor HREF and terminate ablation earlier than human reaction.

Methods

Digital electrogram data from 332 ablation runs from February 2020 to June 2022 were included. They were divided into training and validation sets which contained 126 and 206 ablation runs respectively. HREF in training set was measured. Then a program was developed with cutoff values decided from training set to capture all these HREF. Simulation ablation videos were rendered using validation set electrogram data. The videos were played to three independent electrophysiologists who each determined when to stop ablation. Timing of ablation termination, sensitivity, and specificity were compared between human and program.

Results

Reasons for ablation termination in the training set include short AA time, short VV time, AV block and VA block. Cutoffs for the program were set to maximize program sensitivity. Sensitivity and specificity for the program in the validation set were 95.2% and 91.1% respectively, which were comparable to that of human performance at 93.5% and 95.4%. If HREF were recognized by both human and program, ablations were terminated earlier by the program 90.2% of times, by a median of 574 ms (interquartile range 412-807 ms, p < 0.001).

Conclusion

Algorithmic-driven monitoring of slow pathway modification can supplement human judgement to improve ablation safety.

Radiofrequency catheter ablation of atrioventricular nodal reentry tachycardia in children and adolescents: a single center experience

Purpose

Atrioventricular nodal reentry tachycardia (AVNRT) is less common in pediatric patients than in adult patients. Thus, data for pediatric AVNRT patients are insufficient. Hence, we aimed to analyze the patient characteristics, treatment, and any recurrences in pediatric AVNRT patients.

Methods

We reviewed the records of 50 pediatric AVNRT patients who had undergone radiofrequency catheter ablation (RFCA) between January 1998 and December 2016 at a single regional center. The patients were aged ≤18 years.

Results

Among 190 pediatric patients who underwent RFCA for tachyarrhythmia, 50 (26.3%; mean age, 13.4±2.6 years) were diagnosed as having AVNRT by electrophysiological study. Twenty-five patients (25 of 50, 50%) were male. Twenty patients (20 of 50, 40%) used beta-blockers before RFCA. All patients had no structural heart disease except 1 patient with valvular aortic stenosis and coarctation of the aorta. RFCA was performed using the anatomic approach under fluoroscopic guidance. The most common successfully ablated region was the midseptal region (25 of 50, 50%). Slow pathway (SP) ablation and SP modulation were performed in 43 and 6 patients, respectively. Complication occurred in 1 patient with complete atrioventricular block. During follow-up, 6 patients had recurrence of supraventricular tachycardia, as confirmed by electrocardiography. Among them, 5 underwent successful ablation at the first procedure. In 1 patient, induction failed during the first procedure.

Conclusion

RFCA is safe and effective in pediatric AVNRT patients. However, further research is needed for establishing the endpoints of ablation in pediatric AVNRT patients and for identifying risk factors by evaluating data on AVNRT recurrence after RFCA.

Practice makes perfect: relationship between hospital procedure volume and permanent pacemaker implantation after paroxysmal supraventricular tachycardia ablation

PURPOSE

Paroxysmal supraventricular tachycardia (PSVT) ablation can result in injury to the atrioventricular (AV) node causing complete heart block requiring permanent pacemaker (PPM) implantation. Few studies have examined the impact of hospital PSVT ablation volume and PPM implantation rates post ablation.

METHODS

We included adult patients from the Nationwide Inpatient Sample (NIS) database, from 1998 to 2011, using ICD-9 diagnoses codes 427.0 and 427.89 for PSVT and ICD-9 procedure code 37.34 for ablation. Patients with concomitant arrhythmias, prior pacemaker/defibrillator implants, or pre-existing sinus node dysfunction were excluded. Multivariate logistic regression analysis was performed to identify predictors of PPM implantation.

RESULTS

There were 119,938 PSVT ablations from 1998 to 2011 with a mean age of 54.6 ± 17.5 years and 64.1% females. The overall PPM implantation rate was 3.2%. PPM implantation rates in the first (1-14 ablations/year), second (15-32 ablations/year), and third (> 32/ablations/year) tertiles of annual PSVT ablation volume were respectively 4.4, 3.3, and 1.9% (p < 0.001). Increasing age, female gender, bifascicular, or trifascicular block and teaching hospital status were independent predictors of PPM implantation. The adjusted odds ratio for PPM implantation in hospitals performing > 32 PSVT ablations/year compared to hospitals performing ≤ 14 PSVT ablations/year was 0.54 (95% confidence interval 0.3-0.9, p = 0.026).

CONCLUSIONS

PPM implantation rates are significantly lower in hospitals performing > 32 PSVT ablations/year, indicating that hospital experience is an important determinant of outcomes after PSVT ablation.