A Case Series of Very Slow Atrioventricular Nodal Reentrant Tachycardia Resembling Junctional Tachycardia

Introduction: The surface EKG of typical atrioventricular nodal reentrant tachycardia (AVNRT) shows simultaneous ventricular-atrial (RP) activation with pseudo R’ in V1 and typical heart rates ranging from 150-220/min. Slower rates are suspicious for junctional tachycardia (JT). However, occasionally we encounter typical AVNRT with slow ventricular rates. We describe a series of typical AVNRT cases with heart rates under 110/min. Methods: A total of 1972 patients with AVNRT who underwent slow pathway ablation were analyzed. Typical AVNRT was diagnosed when; 1) evidence of dual atrioventricular nodal conduction, 2) tachycardia initiation by atrial drive train with A-H-A response, 3) septal ventriculoatrial (VA) time < 70 ms, and 4) ventricular-atrial-ventricular (V-A-V) response to ventricular overdrive (VOD) pacing with post pacing interval-tachycardia cycle length (PPI-TCL) > 115ms. JT was excluded by either termination or advancement of tachycardia by atrial extrastimuli (AES) or atrial overdrive (AOD) pacing. Results: We found 11 patients (Age 20-78 years old, 6 female) who met the above-mentioned criteria. The TCL ranged from 560ms to 782ms. Except for one patient showing tachycardia termination, all patients demonstrated a V-A-V response and PPI-TCL over 115ms with VOD. AES or AOD pacing successfully excluded JT by either advancing the tachycardia in 10 patients or by tachycardia termination in one patient. Slow pathway was successfully ablated, and tachycardia was not inducible in all patients. Conclusions: This case series describes patients with typical AVNRT with slow ventricular rate (less than 110/min) who may mimic JT. We emphasize the importance of using pacing maneuvers to exclude JT.

Clinical recurrence of palpitations following slow pathway ablation in patients with suspected paroxysmal supraventricular tachycardias but non-documented, non-inducible tachycardias

Funding Acknowledgements Type of funding sources: None. Introduction Catheter ablation is recommended as first-line treatment in patients with atrioventricular nodal reentry tachycardias (AVNRT). However, the best therapeutic modality in patients with dual AV nodal physiology but non-inducible tachycardias in electrophysiological study (EPS) remains controversial, especially when no tachycardias have been documented. Our objective was to evaluate the results of empirical slow pathway ablation in patients showing dual AV nodal physiology but non-inducible AVNRT. Methods Multicenter, retrospective, observational registry of consecutive patients undergoing EPS due to clinical suspicion of paroxysmal supraventricular tachycardias (PSVT), but with no prior ECG documentation. Clinical, EPS and ablation (when performed) data were collected and andalyzed. Results 427 patients of 12 centers were included. Mean age was 46.3 ±16.1 and 297 (69.6%) were females. AVNRT was induced in 188 patients (typical in 181 cases, atypical in 7). Dual AV nodal physiology with or without single nodal echo beats, but with no sustained tachycardia and without evidence of accessory pathway was present in 68 patients. Ablation of the slow pathway was performed in 187/188 patients with AVNRT and in 30/68 patients with dual physiology. Among subjects with non-inducible tachycardia, ablation reduced significantly recurrences (39.5% in non-ablated vs. 16.7%; p = 0.04), with a level equivalent to those with ablated AVNRT(14.4% vs. 16.7%; p = 0.75). Procedure-related complications were similar in both groups: empirical ablation n = 1; 3.3% vs. induced tachycardia n = 6; 3.2% (p = 0.98). Conclusions In patients with high clinical suspicion of PSVT but non-documented and non-inducible arrhythmias, the presence of dual AV nodal physiology makes AVNRT a likely mechanism of the clinical tachycardia. Catheter ablation of slow pathway reduces the risk of recurrence to a level equivalent to those with inducible and ablated AVNRT. AVNRT (n = 188) Dual nodal physiology (n = 68) p value Age (years) 48.6 ± 16.3 41.9 ± 14.0 &lt;0.01 Female 71.8% 67.7% 0.52 Years symptomatic 9.3 ± 11.3 3.6 ± 8.1 &lt;0.01 Sudden onset 83.9% 88.0% 0.54 Abrupt end 73.4% 74.6% 0.96 Previous rate-slowing drugs 30.9% 25.0% 0.36 Previous antiarrhythmic drugs 5.9% 2.9% 0.35 Isoproterenol in EPS 70.0% 89.7% &lt;0.01

Comparison of conventionally performed and electroanatomic mapping system guided catheter ablation for AV nodal reentrant tachycardia - prospective single-centre study

Funding Acknowledgements Type of funding sources: None. Introduction Radiofrequency (RF) catheter ablation in atrioventricular nodal reentry tachycardia (AVNRT) is highly effective. Three-dimensional electroanatomic mapping system (EAMS)-guided procedures are becoming more widespread. Purpose We aimed to compare EAMS-guided procedures to conventionally, only-fluoroscopy approach for slow pathway ablation. Methods 152 patients undergoing electrophysiological study and slow pathway ablation due to documented AV nodal reentrant tachycardia were included in our prospective single-centre study. In 102 patients the procedure was performed conventionally (Group 1) and 50 patients underwent an electroanatomic mapping system (EAMS) -guided approach (Group 2). Results In Group 2, 80% of the procedures were performed without the use of radiation. The procedure time (median (interquartile range): 65 (50-84) min vs. 75 (60-96.3) min, p =0.005) was significantly shorter in Group 1, with longer fluoroscopy time (4.2 (2.4-7.9) min vs. 0 (0-0) min, p &lt; 0.001). There was no difference either in the number of RF applications (mean ± standard deviation 10.8 ± 8.5 vs. 10.2 ± 7.7, p = 0.66) or in the ablation time (297 ± 237 s vs. 294 ± 196 s, p = 0.74). All patients were treated successfully. One recurrence occurred in each groups during the follow-up. Conclusions In our series, EAMS-guided approach for slow pathway ablation was associated with reduced fluoroscopy and longer procedure time compared to conventional, only-fluoroscopy approach. No difference was found in ablation time, success rate or recurrence.

Colchicine is an effective treatment for late onset AV-block caused by radiofrequency catheter ablation

We present a case of complete atrioventricular (AV) block following slow pathway ablation for atrioventricular nodal reentrant tachycardia (AVNRT) treated only by colchicine administration. The patient’s electrocardiogram showed complete AV-block at two weeks after catheter ablation. Colchicine is effective for late-onset AV-block caused by catheter ablation for AVNRT.