Patients with drug-refractory atrioventricular nodal reentrant tachycardia: Clinical features, electrophysiological characteristics, and predictors of medication failure

Assessment of atrial functional remodeling in patients with atrioventricular nodal reentrant tachycardia with and without drug-induced type 1 Brugada pattern: A case-control study

PURPOSE

The time interval between the onset of the P-wave on electrocardiogram (ECG) and peak A' velocity of the lateral left atrial wall assessed by tissue Doppler imaging (PA-TDI interval) determine total atrial conduction time (TACT) which reflects atrial remodeling and arrhythmic substrate. In this retrospective study, we aimed to assess TACT in patients with atrioventricular nodal reentrant tachycardia (AVNRT) with and without drug-induced type 1 Brugada electrocardiogram ECG pattern (DI-Type 1 BrP) and control subjects.

METHODS

Study population consisted of 62 consecutive patients (46 women; mean age 44 ± 12 years) undergoing electrophysiological study and ablation for symptomatic, drug-resistant AVNRT, and 42 age-matched and sex-matched control subjects. All patients and control subjects underwent ajmaline challenge test and tissue Doppler imaging.

RESULTS

A DI-Type 1 BrP was uncovered in 24 of 62 patients with AVNRT (38.7%). PA-TDI interval was similar among AVNRT patients with and without DI-Type 1 BrP (124 ± 12 ms vs 119 ± 14 ms, respectively, P = .32), but significantly longer in patients with AVNRT with as well as without DI-Type 1 BrP than in control subjects (124 ± 12 ms and 119 ± 14 ms vs 105 ± 11 ms, respectively, P < .001).

CONCLUSION

The TACT assessed by PA-TDI interval is longer in patients with AVNRT with and without DI-Type 1 BrP than in age-matched and sex-matched healthy control subjects.

Evaluation of the effect of radiofrequency catheter ablation on autonomic function in patients with atrioventricular nodal reentrant tachycardia by head-up tilt table test

Background:

One of the recommended treatments for atrioventricular nodal reentrant tachycardia (AVNRT), is radiofrequency catheter ablation (RFCA). However, RFCA may affect the autonomic system. This study aims to evaluate the effect of RFCA on autonomic system in patients with PSVT by head-up tilt table (HUTT) test.

Materials and Methods:

In a before–after study, 22 patients with PSVT were enrolled. Data were collected with a data collection form that included two parts. Electrocardiogram (ECG), echocardiogram, 24-h Holter monitoring, HUTT test, heart rate variability (HRV) indexes, and symptoms of all patients were recorded 24 h before and 1 month after the ablation. Wilcoxon, McNemar, Mann–Whitney U, and Chi-square tests were used to analyze the data.

Results:

Of the total 22 patients, 31.8% were male and 68.2% were female. There were significant differences in heart palpitation (P < 0.0001) and non-specific symptoms (P = 0.031) and no significant difference in head-up tilt test results and HRV indices before and after RFCA. The results showed that there were no significant differences in specific and non-specific symptoms in patients with AVNRT with positive and negative HUTT before and after RFCA.

Conclusions:

The observed difference in heart palpitation and non-specific symptoms emphasized the role of AVNRT in causing these symptoms. Autonomic dysfunction is more probably an accompanying condition of AVNRT than causing symptoms. We could not find any significance in the results of HUTT after RFCA. HUTT cannot determine or predict the symptoms after RFCA.

Clinical and electrophysiological characteristics of typical atrioventricular nodal reentrant tachycardia in the elderly - changing of slow pathway location with aging

BACKGROUND

The aim of this study was to retrospectively evaluate the clinical and electrophysiological characteristics of elderly patients with typical atrioventricular nodal reentrant tachycardia (AVNRT), and to assess the acute safety and efficacy of slow-pathway radiofrequency (RF) ablation in this specific group of patients.

METHODS AND RESULTS

The present study retrospectively included a total of 1,290 patients receiving successful slow-pathway RF ablation for typical slow-fast AVNRT. Patients were divided into 2 groups: group I included 1,148 patients aged <65 years and group II included 142 patients aged >65 years. The required total procedure duration and total fluoroscopy exposure time were significantly higher in group II vs. group I (P=0.005 and P=0.0001, respectively). The number of RF pulses needed for a successful procedural end-point was significantly higher in group II than in group I (4.4 vs. 7.2, P=0.005). While the ratio of the anterior location near to the His-bundle region was significantly higher in group II, the ratio of posterior and midseptal locations were significantly higher in group I (P=0.0001). The overall procedure success rates were similar. There was no significant difference between the 2 groups in respect of the complications rates.

CONCLUSIONS

This experience demonstrates that RF catheter ablation, targeting the slow pathway, could be considered as first-line therapy for typical AVNRT patients older than 65 years as well as younger patients, as it is very safe and effective in the acute period of treatment.

Atrial pacing during radiofrequency deliveries for catheter ablation of para-Hisian arrhythmias

BACKGROUND

Atrial pacing during radiofrequency (RF) deliveries is a technique to facilitate rapid recognition of impaired atrioventricular (AV) conduction during slow pathway ablation of AV nodal reentrant tachycardia. The objective of our study was to report this technique in the catheter ablation of para-Hisian arrhythmias.

METHODS

The study included a total of 48 patients who underwent ablation of para-Hisian arrhythmias including accessory pathways (APs), atrial tachycardias (ATs), and ventricular arrhythmias (VAs) in 6, 9, and 33 patients, respectively.

RESULTS

AT was successfully eliminated in all cases without any accelerated junctional rhythm (JR) occurring. JR appeared during RF deliveries in 20 patients (3 with APs, 17 with VAs). In 11 of 20 patients, RF deliveries were terminated when JR appeared and restarted during atrial pacing at a faster rate than the JR. No transient complete AV block was observed in the 11 patients, however it occurred in 1 of the remaining 9 without atrial pacing (p=0.25). Small His bundle potentials were recorded at the effective ablation site before the RF delivery in 11 (55%) patients. No patients had any AV conduction disturbances at the end of and after the procedure. APs were successfully eliminated in 2 of 3 patients. VAs were completely and partially eliminated in 10 and 4 of 17 patients, respectively.

CONCLUSIONS

Atrial pacing during RF applications might be helpful to avoid AV conduction disturbances during catheter ablation of APs close to the His bundle and idiopathic VAs originating in the vicinity of the His bundle.