Cryoablation versus radiofrequency ablation for the treatment of atrioventricular nodal reentrant tachycardia: results of a prospective randomized study

Abstract

Catheter cryoablation of AVNRT is a clinically effective alternative to RF ablation, with excellent acute success rate. Despite a slightly higher rate of recurrence during long-term follow-up, these results suggest that cryoablation may be considered as first-line approach, especially in younger people, where the risk of permanent pacing because of inadvertent AV block may be relevant.

2015 ACC/AHA/HRS Guideline for the Management of Adult Patients With Supraventricular Tachycardia

“…191 The precise location of the focal AT is ultimately confirmed by mapping during EP studies when successful ablation is achieved. [123][124][125][126][127][192][193][194][195][196] Focal AT has been localized to the crista terminalis, right or left atrial free wall or appendage, tricuspid or mitral annulus, paraseptal or paranodal areas, pulmonary veins, coronary sinus, and coronary cusps, but it originates more frequently from the right atrium than from the left atrium. 197,198 The underlying mechanism of focal AT can be automatic, triggered activity, or microreentry, but methods to distinguish the mechanism through pharmacological testing or EP study are of modest value because of limited sensitivity and specificity.…”

“…197,198 The underlying mechanism of focal AT can be automatic, triggered activity, or microreentry, but methods to distinguish the mechanism through pharmacological testing or EP study are of modest value because of limited sensitivity and specificity. 123,199,200 An automatic AT can be transiently suppressed by adenosine or by overdrive pacing and may be terminated by beta blockers, diltiazem, or verapamil. Whereas a triggered AT can be terminated by adenosine or overdrive pacing, its response to beta blockers, diltiazem, or verapamil may be variable.…”

“…In many reports, the response to intravenous drug therapy was evaluated by EP study rather than in the clinical environment. 123,200,[204][205][206][207] In the clinical setting, if the diagnosis is uncertain, vagal maneuvers may be attempted to better identify the mechanism of SVT.…”

Maintaining Contact for Effective Mapping and Ablation

“…Although these features of cryoablation may be useful in areas of the heart where the targeted substrate is close to critical structures (eg, the His bundle) and where small degrees of translational motion of an unstuck catheter tip during energy application would increase the risk of complications, the risk of arrhythmia recurrence tends to be greater with cryo-than radiofrequency ablation. [5][6][7] Thus, in areas where there is no concern about collateral damage, the use of cryoablation would likely not be preferred.…”

“…However, ablation with cryo-energy does not have the same long-term success rates as radiofrequency. [5][6][7] If there was a way to maintain not just effective but also stable contact with the underlying myocardium during radiofrequency ablation, this would carry the benefit of minimizing complication risk attributable to inadvertent delivery of energy to close-by structures. This may be achieved either by limiting motion of the catheter or by limiting when energy is delivered.…”