Elsevier

Heart Rhythm

Volume 19, Issue 7, July 2022, Pages 1084-1096
Heart Rhythm

Clinical
Ablation
Termination of macroreentrant atrial arrhythmias by pacing stimuli without global propagation

https://doi.org/10.1016/j.hrthm.2022.03.1220Get rights and content

Background

Electrical stimulation during ventricular tachycardia resulting in tachycardia termination without global propagation (TWGP) is a well-recognized phenomenon. However, there is a paucity of literature showing a similar phenomenon in atrial arrhythmias.

Objective

The purpose of the study was to evaluate the significance of TWGP in atrial arrhythmias.

Methods

Electrophysiological studies performed from 2000 to 2019 at Methodist Hospital, Indiana University were reviewed retrospectively. Thirty-four patients were identified in whom stimulation during atrial tachycardia/flutter resulted in TWGP.

Results

Of the 34 patients, 12 (29%) had cavotricuspid isthmus (CTI)–dependent atrial flutter and 22 (71%) had other atrial arrhythmias during which TWGP was seen. Mean age of the population was 53 ± 13 years; and 68% were male. Previous catheter ablation for atrial fibrillation, atrial flutter, or other atrial tachyarrhythmias had been performed in 70.5%, and 44% previously had undergone cardiac surgery involving the atria. Congenital heart disease was present in 20.5%; 3 patients were status post lung transplant. Mean cycle length of atrial arrhythmia in which TWGP was seen was 317 ± 76 ms. The sites at which TWGP was seen reproducibly were highly specific for successful termination of the arrhythmias with radiofrequency energy. The arrhythmia circuits were 12 CTI-dependent atrial flutter, 11 left atrial macroreentrant atrial tachycardia (MRAT), 1 involving both left and right atria, and 8 were other right atrial MRAT.

Conclusion

Termination of macroreentrant atrial arrhythmias by pacing stimuli without global propagation identifies a narrow diastolic isthmus at which catheter ablation is highly effective.

Introduction

In early 1980s, termination of ventricular tachycardia (VT) during the ventricular refractory period by low-energy DC shocks was demonstrated in experimental animals1 and clinical studies.2 Ruffy et al3 obtained similar results with low-energy stimulation using standard catheter electrodes. This observation led to the hypothesis that the electrode was fortuitously placed on, or very near, a critical anatomic site responsible for sustaining VT. This was later shown to suggest reentry as the mechanism of arrhythmia4 and termed as VT termination with “nonglobal capture” by a pacing stimulus. Termination of VT with nonglobal capture/nonpropagated stimulus is well described in the literature and has been helpful in guiding radiofrequency (RF) ablation of scar-based macroreentrant VT, in conjunction with concealed entrainment. However, this phenomenon is not well known in atrial arrhythmias. The purpose of this retrospective study was to assess the prevalence and implications of the phenomenon of atrial arrhythmia termination without global propagation (TWGP) of pacing stimuli.

Section snippets

Methods

We retrospectively reviewed electrophysiological (EP) studies performed from 2000 to 2019 at Methodist Hospital, Indiana University on patients with organized atrial tachyarrhythmias (n = 1423). The research reported in this study adhered to the Declaration of Helsinki as revised in 2013. The human investigation review committee of Indiana University approved this study.

Results

The phenomenon of TWGP was seen during EP study in 34 patients (2%) (mean age 53 ± 13 years; 68% male) (Table 1). Mean age of those with typical atrial flutter vs other atrial arrhythmias was 52 ± 17 years vs 53 ± 11 years, respectively (P = .74). Of these 34 patients, 12 (29%) had cavotricuspid isthmus (CTI)–dependent atrial flutter and 22 (71%) had other atrial arrhythmias. Of the 22 non–isthmus-dependent atrial flutters, 11 were left atrial macroreentrant atrial tachycardia (MRAT), 1

Discussion

The results of this study demonstrate that the phenomenon of TWGP occurs in atrial as well as ventricular arrhythmias and indicates a site for successful ablation. As with other diagnostic maneuvers, TWGP ideally should be reproducible. One should suspect TWGP has occurred when there is a sudden pause in the middle of the tachycardia, a change to a different tachycardia (eg, clockwise to counterclockwise flutter, implying reversal of the circuit) (Figure 4), or termination of tachycardia after

Conclusion

Termination of macroreentrant atrial arrhythmias by stimulation without global propagation identifies a relatively narrow diastolic isthmus and site of effective catheter ablation.

References (14)

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Funding Sources: The authors have no funding sources to disclose. Disclosures: Dr Miller has served as a consultant with Biosense Webster; received honoraria for lectures; and receives fellowship funding support. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.

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