Since the release of the second-generation cryoballoon (CB2; Arctic Front AdvanceTM, Medtronic Inc) and its design modifications with improved cooling characteristics, the technique, dosing, and ...complication profile is significantly different from that of the first-generation cryoballoon. A comprehensive report of CB2 procedural recommendations has not been reported.
The purpose of this study was to review the current best practices from a group of experienced centers to create a user’s consensus guide for CB2 ablation.
High-volume operators with a combined experience of more than 3000 CB2 cases were interviewed, and consensus for technical and procedural best practice was established.
Comprehensive review of the CB2 ablation best practice guide will provide a detailed technique for achieving safer and more effective outcomes for CB2 atrial fibrillation ablation.
There are no recommendations on the optimal dosing for cryoablation of atrial fibrillation (Cryo-AF).
The purpose of this study was to develop and prospectively test a Cryo-AF dosing protocol guided ...exclusively by time-to-pulmonary vein (PV) isolation (TT-PVI) in patients undergoing a first-time Cryo-AF.
In this multicenter study, we examined the acute/long-term safety/efficacy of Cryo-AF using the proposed dosing algorithm (Cryo-AF
; n = 355) against a conventional, nonstandardized approach (Cryo-AF
; n = 400) in a nonrandomized fashion.
Acute PV isolation was achieved in 98.9% of patients in Cryo-AF
(TT-PVI = 48 ± 16 seconds) vs 97.2% in Cryo-AF
(P = .18). Cryo-AF
was associated with shorter (149 ± 34 seconds vs 226 ± 46 seconds; P <.001) and fewer (1.7 ± 0.8 vs 2.9 ± 0.8; P <.001) cryoapplications, reduced overall ablation (16 ± 5 minutes vs 40 ± 14 minutes; P <.001), fluoroscopy time (13 ± 6 minutes vs 29 ± 13 minutes; P <.001), left atrial dwell time (51 ± 14 minutes vs 118 ± 25 minutes; P <.001), and total procedure time (84 ± 23 minutes vs 145 ± 49 minutes; P <.001) but similar nadir balloon temperature (-47°C ± 8°C vs -48°C ± 6°C; P = .41) and total thaw time (43 ± 27 seconds vs 45 ± 19 seconds; P = .09) as compared to Cryo-AF
. Adverse events (2.0% vs 2.7%; P = .48), including persistent phrenic nerve palsy (0.6% vs 1.2%; P = .33) and 12-month freedom from all atrial arrhythmias (82.5% vs 78.3%; P = .14), were similar between Cryo-AF
and Cryo-AF
. However, Cryo-AF
was specifically associated with fewer atypical atrial flutters/tachycardias during long-term follow-up (8.5% vs 13.5%; P = .02) as well as fewer late PV reconnections at redo procedures (5.0% vs 18.5%; P <.001).
A novel Cryo-AF dosing algorithm guided by TT-PVI can help individualize the ablation strategy and yield improved procedural endpoints and efficiency as compared to a conventional, nonstandardized approach.
Catheter ablation for atrial fibrillation (AF) has emerged as a popular procedure. The purpose of this study was to examine whether there exist differences or disparities in ablation utilization ...across gender, socioeconomic class, insurance, or race. Using the Nationwide Inpatient Sample (2000 to 2012), we identified adults hospitalized with a principal diagnosis of AF by ICD 9 code 427.31 who had catheter ablation (ICD 9 code–37.34). We stratified patients by race, insurance status, age, gender, and hospital characteristics. A hierarchical multivariate mixed-effect model was created to identify the independent predictors of AF ablation. Among an estimated total of 3,508,122 patients (extrapolated from 20% Nationwide Inpatient Sample) hospitalized with a diagnosis of AF in the United States from the year 2000 to 2012, 102,469 patients (2.9%) underwent catheter ablations. The number of ablations was increased by 940%, from 1,439 in 2000 to 15,090 in 2012. There were significant differences according to gender, race, and health insurance status, which persisted even after adjustment for other risk factors. Female gender (0.83 95% CI 0.79 to 0.87; p <0.001), black (0.49 95% CI 0.44 to 0.55; p <0.001), and Hispanic race (0.64 95% CI 0.56 to 0.72; p <0.001) were associated with lower likelihoods of undergoing an AF ablation. Medicare (0.93, 0.88 to 0.98, <0.001) or Medicaid (0.67, 0.59 to 0.76, <0.001) coverage and uninsured patients (0.55, 0.49 to 0.62, <0.001) also had lower rates of AF ablation compared to patients with private insurance. In conclusion we found differences in utilization of catheter ablation for AF based on gender, race, and insurance status that persisted over time.
Objectives This study describes the histopathologic and electrophysiological findings in patients with recurrence of atrial fibrillation (AF) after pulmonary vein (PV) isolation who underwent a ...subsequent surgical maze procedure. Background The recovery of PV conduction is commonly responsible for recurrence of AF after catheter-based PV isolation. Methods Twelve patients with recurrent AF after acutely successful catheter-based antral PV isolation underwent a surgical maze procedure. Full-thickness surgical biopsy specimens were obtained from the PV antrum in areas of visible endocardial scar. Before biopsy, intraoperative epicardial electrophysiological recordings were taken from each PV using a circular mapping catheter. Results Twenty-two PVs were biopsied from the 12 patients 8 ± 11 months after ablation. Eleven of the 22 specimens (50%) revealed transmural scar, and 11 (50%) showed viable myocardium with or without scar. Each biopsy specimen demonstrated evidence of injury, most commonly endocardial thickening (n = 21 95%) and fibrous scar (n = 18 82%). Seven of the 22 specimens (32%) showed conduction block at surgery. Transmural scar was more likely to be seen in the biopsy specimens from the PVs with conduction block than in specimens from the PVs showing reconnection. However, viable myocardium alone or mixed with scar was seen in 2 specimens from PVs with conduction block. Conclusions PVs showing electrical reconnection after catheter-based antral ablation frequently reveal anatomic gaps or nontransmural lesions at the sites of catheter ablation. Nontransmural lesions are noted in some PVs with persistent conduction block, suggesting that lesion geometry may influence PV conduction. The histological findings show that nontransmural ablation can produce a dynamic cellular substrate with features of reversible injury. Delayed recovery from injury may explain late recurrences of AF after PV isolation.
There are 2 Food and Drug Administration–approved catheters (ThermoCool RF and Arctic Front Advance cryoballoon) for the treatment of drug refractory and symptomatic paroxysmal atrial fibrillation. ...Each tool is used to ablate the area surrounding the pulmonary veins (PVs). However, no study has described and quantified the ablated surface area after the application of cryoablation lesions with the second-generation cryoballoon.
The purpose of this study was to determine the area of ablation during cryoballoon PV isolation.
Preprocedural computed tomography angiography of the left atrium (LA) was conducted in 43 patients to accurately determine spatial chamber dimensions. Before and after the ablation procedure, a detailed 3-dimensional electroanatomic map of the LA was created and merged onto the computed tomography angiogram to improve the accuracy of the data recordings.
The posterior LA wall had a mean surface area of 31.1 (±1.6 SEM) cm2. Left- and right-sided antral PV surface areas of cryoballoon ablation were not statistically different (P = .935), which were 11.4 (±0.8 SEM) and 11.3 (±0.8 SEM) cm2, respectively. In total, 27% of the posterior LA wall remained unablated, electrically functional, and homogeneous with regard to voltage conductivity. This ablation strategy resulted in 95.3% freedom from atrial fibrillation at 6 months.
The area of the posterior LA wall ablation with the cryoballoon catheter is wide and antral, and the resulting posterior LA wall debulking could be a part of the cryoballoon efficacy beyond discrete PV isolation.
Cryoballoon ablation has been associated with a significant incidence of phrenic nerve injury (PNI).
The purpose of this study was to evaluate whether recordings of diaphragmatic compound motor ...action potentials (CMAP) on a modified lead I during cryoballoon ablation can predict PNI.
Cryoballoon ablation was performed in 109 patients with atrial fibrillation (AF). During ablation of the right-sided pulmonary veins, the phrenic nerve was paced from the superior vena cava. The right and left arm electrodes from a 12-lead ECG were positioned 5 cm above the xiphoid process and 16 cm along the right costal margin. The amplitude of CMAP was recorded on lead I during ablation.
Cryoballoon was applied 424 times in 211 right-sided veins. PNI occurred in 7 (6.4%) patients. The average CMAP amplitude did not significantly change in patients without PNI from the initial average CMAP amplitude of 0.34 ± 0.18 mV to 0.32 ± 0.17 mV (P = .58). In patients who developed PNI, there was a significant decrease in the initial average CMAP amplitude during the ablation from 0.33 ± 0.14 mV to 0.09 ± 0.05 mV (P <.001). The maximal percent change in the average CMAP amplitude in patients with PNI was higher (70% ± 10%) than in patients without PNI (7.6% ± 7%; P <.001). In any patient without PNI, the CMAP amplitude did not decrease more than 35% from baseline.
Recording of CMAP amplitude on a modified lead I is reliable and could be early and sensitive method for predicting PNI in patients undergoing cryoballoon ablation for AF.
Limited data exist on cryoablation of atrial fibrillation (Cryo-AF) using the newly available third-generation (Arctic Front Advance-Short Tip AFA-ST) cryoballoon.
In this multicenter study, we ...evaluated the safety and efficacy of Cryo-AF using the AFA-ST vs the second-generation (Arctic Front Advance AFA) cryoballoon.
We examined the procedural safety and efficacy and the short- and long-term clinical outcomes associated with a first-time Cryo-AF performed in 355 consecutive patients (254/355 72% with paroxysmal AF), using either the AFA-ST (n = 102) or the AFA (n = 253) cryoballoon catheters.
Acute isolation was achieved in 99.6% of all pulmonary veins (PVs) (AFA-ST: 100% vs AFA: 99.4%; P = .920). Time to pulmonary vein isolation was recorded in 89.2% of PVs using AFA-ST vs 60.2% using AFA (P < .001). PVs targeted using AFA-ST required fewer applications (1.6 ± 0.8 vs 1.7 ± 0.8; P = .023), whereas there were no differences in the balloon nadir temperature (AFA-ST: −47.0°C ± 7.3°C vs AFA: −47.5°C ± 7.8°C; P = .120) or thaw time (AFA-ST: 41 ± 24 seconds vs AFA: 44 ± 28 seconds; P = .056). However, AFA-ST was associated with shorter left atrial dwell time (43 ± 5 minutes vs 53 ± 16 minutes; P < .001) and procedure time (71 ± 11 minutes vs 89 ± 25 minutes; P < .001). Furthermore, Cryo-AF using AFA-ST was completed more frequently by “single-shot” PV ablation (27.4% vs 20.2%; P = .031). Persistent phrenic nerve palsy (AFA-ST: 0% vs AFA: 0.8%; P = .507) and procedure-related adverse events (AFA-ST: 1.0% vs AFA: 1.6%; P = .554) were similar, as was the freedom from recurrent atrial arrhythmias at 10 months of follow-up (AFA-ST: 81.8% vs AFA: 79.9%; P = .658).
Cryo-AF using the AFA-ST cryoballoon offers an enhanced ability to assess time to pulmonary vein isolation, allowing for fewer cryoapplications and shorter left atrial dwell time and procedure time. Consequently, this allowed for procedural completion more frequently using a “single-shot” PV ablation with equivalent safety and efficacy.
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Abstract Introduction Anti-arrhythmic medications (AAMs) are known to increase cardiac mortality significantly due to their pro-arrhythmic effects. However, the effect of AAMs on non-cardiac ...mortality has not been evaluated. Methods Trials published in English language journals from 1990 to 2015 were thoroughly retrieved by searching websites such as PubMed, Medline, Cochrane Library, and Google Scholar. Randomized controlled trials reporting non-cardiac deaths as primary or secondary outcomes were used to compare AAMs to non-arrhythmic therapy (AV nodal blocking agents, implantable cardiovascular defibrillation (ICD), or placebo). Information regarding the sample size, treatment type, baseline characteristics, and outcomes was obtained by using a standardized protocol. The fixed effect model was used to perform meta-analysis, and results were expressed in terms of odds ratio (OR) with confidence interval (CI) of 95%, inter study heterogeneity was assessed using I2 . Intention to treat principle was applied to extract data. Results Total of 18,728 patients were enrolled in 15 trials; 9359 patients received AAMs and 9369 received non-arrhythmic therapy. AAMs were associated with an increased risk of non-cardiac mortality (OR=1.30, 95% CI: 1.12, 1.50, p =0.0005, I2 index=24%) and all-cause mortality (OR=1.09, 95% CI: 1.01, 1.18, p =0.04, I2 =54%) as compared to non-arrhythmic therapy. There was no difference in the cardiac mortality (OR=1.01, 95% CI: 0.92, 1.11, p =0.82, I2 =53%) or arrhythmic mortality (OR=1.00, 95% CI: 0.89, 1.13, p =0.94, I2 =64%) between the two groups. Conclusion AAMs are associated with an increased risk of non-cardiac and all-cause mortality. The effect of AAMs, especially amiodarone, on non-cardiac mortality requires further evaluation.
Prolongation of the QTc Interval Is Seen Uniformly During Early Transmural Ischemia David N. Kenigsberg, Sanjaya Khanal, Marcin Kowalski, and Subramaniam C. Krishnan Methods: To understand ...electrocardiographic changes accompanying early ischemia, ECGs recorded at 20-s intervals during angioplasty were analyzed with 2 automated systems: MUSE (n-74) and Interval Editor (IE) (n-50). Results: Ischemia prolonged Bazett’s QTc interval uniformly (100%). With MUSE, QTc interval prolonged from 423 ± 25 to 455 ± 34 ms (p < 0.001). With IE, QTc interval prolonged from 424.0 ± 27 to 458 ± 33 ms (p < 0.001). Time to maximal QTc interval prolongation, change in T-wave polarity, ST-segment elevation, and ST-segment depression were 22, 24, 29 and 35 s, occurring in 100%, 7%, 15%, and 7% respectively. Conclusion: QTc interval prolongs uniformly in ischemia. Compared with other ECG indexes, it is also the earliest.
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