ClinicalAblationTermination of macroreentrant atrial arrhythmias by pacing stimuli without global propagation
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.
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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.