Transcatheter Cryoablation Part I: Preclinical Experience

T he papillary muscles (PMs) from the left ventricle (LV) have been shown to be a potential site of origin of ventricular arrhythmias (VAs) in patients with and without structural heart disease.1 Catheter ablation has been described as an effective treatment for these arrhythmias, although radiofrequency delivery at these regions has been associated with poor manipulation and catheter stability compared with other VAs. 2 See Editorial by Latchamsetty and BogunPrevious data on catheter cryoablation of PMs VAs showed high-success and low complication rates. 3 There is yet no data available comparing results of both cryoenergy and radiofrequency for catheter cryoablation of PM-related arrhythmias.This study compares procedural outcomes and recurrence rate after catheter cryoablation or radiofrequency ablation for the treatment of ventricular tachycardia (VT) and premature ventricular complexes (PVCs) localized at the PMs of the LV, with the aid of intracardiac echocardiography (ICE) and image integration. MethodsA total of 21 patients with recurrent VAs originating at the PMs of the LV were identified from retrospective review of 189 consecutive patients (men 52%, age 44 years, range 28-54 years) with symptomatic sustained VT (n=58), nonsustained VT (n=40), or PVC (n=91) referred for catheter ablation to the Buenos Aires Cardiovascular Institute (Buenos Aires, Argentina) between January 2014 and January 2016. Scar-related VT was observed in 45 patients (24%). The sites of origin of idiopathic VAs included the right ventricular (RV) outflow tract in 82 (43%), aortomitral continuity in 24 (13%), posteromedial PM (PMPM) in 19 (10%), anterolateral PM (ALPM) in 3 (1.5%), aortic root in 3 (1.5%), fascicles of the left bundle branch in 2 (1%), mitral annulus in 1 (0.5%), and other sites in 11 (6%). This study retrospectively included 21 patients with symptomatic, drug refractory, and single morphology VAs originated at the PMs of the LV. The institutional review committee approved the study and © 2016 American Heart Association, Inc. Circ Arrhythm Electrophysiol Original ArticleBackground-Catheter radiofrequency ablation of ventricular arrhythmias (VAs) arising from the left ventricle's papillary muscles has been associated with inconsistent results. The use of cryoenergy versus radiofrequency has not been compared yet. This study compares outcomes and complications of catheter ablation of VA from the papillary muscles of the left ventricle with either cryoenergy or radiofrequency. Methods and Results-Twenty-one patients (40±12 years old; 47% males; median ejection fraction 59±7.3%) with drug refractory premature ventricular contractions or ventricular tachycardia underwent catheter cryoablation or radiofrequency ablation. VAs were localized using 3-dimensional mapping, multidetector computed tomography, and intracardiac echocardiography, with arrhythmia foci being mapped at either the anterolateral papillary muscle or posteromedial papillary muscles of the left ventricle. Focal ablation was performed using an 8-mm cryoa...

Section: Discussionmentioning

confidence: 99%

Results of Cryoenergy and Radiofrequency-Based Catheter Ablation for Treating Ventricular Arrhythmias Arising From the Papillary Muscles of the Left Ventricle, Guided by Intracardiac Echocardiography and Image Integration

Rivera

Ricapito

Linkevičius

et al. 2016

“…Progressive cooling below −40°C results in the formation of intracellular ice crystals, which is the first step in ensuring adherence of the catheter to the tissue during the cryolesion. 16 In addition, fullflow cryorefrigerant is usually achieved within 1 minute, and at that time the slope of the curve starts to plateau. Therefore, during hypothermia the catheter adheres to the tissue affording greater stability, therefore, eliminating the brushing effect that occurs during beat-to-beat rocking heart motions and with respiratory variations.…”

Section: Predictors Of Late Pv Reconnectionsmentioning

confidence: 99%

On the Quest for the Best Freeze

Ciconte

Mugnai

Sieira

et al. 2015

118

Background— The second-generation cryoballoon is effective in achieving acute pulmonary vein isolation (PVI) and favorable clinical outcome. To date, no data are available on factors affecting late PV reconnection after second-generation cryoballoon ablation. Methods and Results— A total of 29 consecutive patients (25 male, 86.2%; mean age 57.8±13.8 years) underwent a repeat procedure, after a mean 11.6±4.5 months (range, 3.5–19.7 months), after index ablation using the 28-mm second-generation cryoballoon. All repeat ablations were performed using a 3-dimensional electroanatomical mapping system. Among all 115 PVs, including 1 left common ostiums (LCOs), 25 (21.7%) showed a PV reconnection in 20 patients (1.25 per patient). Persistent PVI could be documented in 90 of 115 PVs (78.2%). In 9 of 29 patients (31%), all PVs were electrically isolated. In the multivariable analysis, time to PVI ( P =0.03) and failure to achieve −40°C within 60 s ( P =0.05) independently predicted late PV reconnection. At receiver-operator curve analysis, time to PVI <60 s identified the absence of PV reconduction (sensitivity, 86.7%; specificity, 86.2%; positive predictive value, 59.1%; and negative predictive value, 96.4%; area under the curve, 0.85; confidence interval, 0.73–0.97; P <0.001). Conclusions— The rate of late PV reconnection after second-generation cryoballoon ablation is low (1.25 PVs/patient). Faster time to isolation and achievement of −40°C within 60 s independently predict durable PVI. In addition, 60-s cut-off for time to PVI indicates persistent isolation with 96.4% negative predictive value. These parameters might guide the operator whether to perform further applications to ensure a long-lasting PVI.

“…Our aim was to accelerate rewarming by allowing immediate return of convective blood flow that has been shown to limit the extent of cryolesions. 7,8 Indeed, balloon inflation during cryoapplication results in complete occlusion of the vein and stops blood flow. Normally, when cryoapplication is stopped, deflation does not occur until balloon temperature rises to +20°.…”

Section: Forced Deflation Emergency Maneuvermentioning

confidence: 99%

Novel Electromyographic Monitoring Technique for Prevention of Right Phrenic Nerve Palsy During Cryoballoon Ablation

Franceschi

Koutbi

Mancini

et al. 2013

Background-Right phrenic nerve palsy (PNP) is the most frequent complication of cryoballoon ablation. Diaphragmatic electromyography can predict PNP with a comfortable safety margin. Our goal was to evaluate the feasibility, efficacy, and safety of electromyography-guided PN monitoring using a novel hepatic vein approach for prevention of PNP. Methods and Results-This study includes 57 patients (47 males) indicated for cryoballoon ablation for treatment of atrial fibrillation. During right superior pulmonary vein ablation, the PN was paced at 60 beats per minute and diaphragmatic compound motor action potential (CMAP) amplitude was recorded via a quadripolar catheter positioned in a subdiaphragmatic hepatic vein. If a 30% drop in CMAP amplitude was observed, ablation was discontinued with forced deflation. Reliable recording of CMAP before ablation was feasible in 50 of 57 patients (88%). In 7 patients (12%), stable PN pacing could not be achieved. In 44 of 50 patients, CMAP amplitude remained constant during cryoapplication. The mean value of CMAP amplitude was 639.7±240.5 µV; mean variation was 13±4.3%. In 6 of 50 patients (12%) including 5 treated with a 23-mm cryoballoon and 1 with a 28-mm cryoballoon, the 30% reduction cutoff was reached and cryoablation was discontinued. Recovery of CMAP amplitude after discontinuing cryoablation took <60 seconds in all cases. No PNP or complication related to PN monitoring occurred. Conclusions-Recording of diaphragmatic CMAP using a catheter positioned in a subdiaphragmatic hepatic vein seems feasible during cryoballoon ablation. Electromyography-guided PN monitoring seems safe and potentially helpful for prevention of PNP. (Circ Arrhythm Electrophysiol. 2013;6:1109-1114.)