Feasibility and safety of laser balloon pulmonary vein isolation in patients with prior left atrial appendage occlusion device implantation.

INTRODUCTION: With the increasing adoption of left atrial appendage occlusion (LAAO) procedures and the eligibility of patients for pulmonary vein isolation (PVI) post device placement, we examined the feasibility and safety of laser balloon (LB) for PVI in patients with prior LAAO. METHODS: We retrospectively examined consecutive patients with paroxysmal or persistent, drug-resistant atrial fibrillation (AF) who underwent LB PVI, after Watchman FLX device implantation at Rush University Medical Center between January 2020 and December 2021. RESULTS: Seven patients (four persistent and three paroxysmal) with a mean age of 64 ± 11 years, predominantly male sex (86%), were included in the study. Two (29%) patients had prior cryoablation PVI with recurrence of AF. The mean CHA2 DS2 VASc is 2.6 ± 0.5 and the mean HAS-BLED score is 3.4 ± 0.8. The mean follow-up duration was 10 ± 7 months. The mean duration between Watchman FLX device implantation and LB PVI was 592 days. Acute first pass left pulmonary vein (PV) isolation was achieved in 100% of the procedures. There were no periprocedural complications such as death, pericardial tamponade or effusion, phrenic nerve injury, PV stenosis, device perforation or embolization, or worsening peri-device leak in any of the patients. None of the patients had AF recurrence after the blanking period. CONCLUSION: LB PVI was safe and effective with 100% acute isolation of left-sided veins in patients with prior LAAO device.

Mechanisms of Undersensing by a Noise Detection Algorithm That Utilizes Far-Field Electrograms With Near-Field Bandpass Filtering.

BACKGROUND: Implantable cardioverter defibrillators (ICDs) must establish a balance between delivering appropriate shocks for ventricular tachyarrhythmias and withholding inappropriate shocks for lead-related oversensing ("noise"). To improve the specificity of ICD therapy, manufacturers have developed proprietary algorithms that detect lead noise. The SecureSenseTM RV Lead Noise discrimination (St. Jude Medical, St. Paul, MN, USA) algorithm is designed to differentiate oversensing due to lead failure from ventricular tachyarrhythmias and withhold therapies in the presence of sustained lead-related oversensing. METHODS AND RESULTS: We report 5 patients in whom appropriate ICD therapy was withheld due to the operation of the SecureSense algorithm and explain the mechanism for inhibition of therapy in each case. Limitations of algorithms designed to increase ICD therapy specificity, especially for the SecureSense algorithm, are analyzed. CONCLUSION: The SecureSense algorithm can withhold appropriate therapies for ventricular arrhythmias due to design and programming limitations. Electrophysiologists should have a thorough understanding of the SecureSense algorithm before routinely programming it and understand the implications for ventricular arrhythmia misclassification.

Prospective study of zero-fluoroscopy laser balloon pulmonary vein isolation for the management of atrial fibrillation.

BACKGROUND: In recent years, there has been increased focus on the development of safe and effective strategies to minimize and ultimately eliminate fluoroscopy use in the electrophysiology lab due to the inherent risks to patients and staff associated with this imaging source. However, studies examining these innovative fluoroless strategies for pulmonary vein isolation (PVI) using catheters without direct 3D mapping system integration are lacking. We sought to develop a method to perform zero-fluoroscopy laser balloon PVI for patients with atrial fibrillation (AF), and to test the safety and efficacy of this approach. METHODS: We developed a standardized method for performing PVI using the X3 laser balloon (LB) system, 3-dimensional electroanatomic mapping (3D-EAM) and intracardiac echocardiography (ICE) in a cohort of patients with symptomatic AF. The primary endpoint of the study was the ability to perform PVI without the use of fluoroscopy. Secondary outcomes were rate of successful transseptal puncture on first attempt, first pass isolation of target PVs, mean procedural time, active laser time to achieve PVI, need for use of supplemental energy sources, and procedural complication rates. RESULTS: Two hundred consecutive patients undergoing PVI were recruited in the study. In the zero-fluoroscopy group, LB PVI was successfully performed in 100% of participants (n = 100) without the need for fluoroscopy. Transseptal access was achieved in 100% of cases on the first attempt. Successful first pass PVI was achieved in 360 of the 387 pulmonary veins attempted (93%). Mean procedural time was 68.2 ± 16.2 min in the zero-fluoroscopy group versus 67.5 ± 17.0 min in the conventional fluoroscopy group. PVI was able to be achieved in 100% of cases in both groups without need for use of supplemental energy sources. In the zero-fluoroscopy group there were minimal complications, with 3% of all cases having groin complications and 1 patient with a pericardial effusion noted post-procedure which was managed conservatively. CONCLUSIONS: We demonstrated that successful zero-fluoroscopy LB PVI could be performed at a single high-volume center by experienced operators in an effective manner, without significant complications.

Wide area circumferential ablation for pulmonary vein isolation using radiofrequency versus laser balloon ablation.

Background: Persistent atrial fibrillation (AF) is associated with high recurrence rates of AF and atypical atrial flutters or tachycardia (AFT) postablation. Laser balloon (LB) ablation of the pulmonary vein (PV) ostia has similar efficacy as radiofrequency wide area circumferential ablation (RF-WACA); however, an approach of LB wide area circumferential ablation (LB-WACA) may further improve success rates. Objective: To evaluate freedom from atrial tachyarrhythmia (AFT/AF) recurrence postablation using RF-WACA versus LB-WACA in persistent AF patients. Methods: This was a retrospective multicenter study. Patients were followed for up to 24 months via office visits, Holter, and/or device monitoring. The primary endpoint was freedom from AFT/AF after a single ablation procedure. Secondary endpoints included freedom from AF, freedom from AFT, first-pass isolation of all PVs, and procedural complications. Results: Two hundred and four patients were studied (LB-WACA: n = 103; RF-WACA: n = 101). Patients' baseline characteristics were similar except patients in the RF-WACA group were older (64 vs. 68, p = .03). First-pass isolation was achieved more often during LBA (LB-WACA: 88% vs. RF-WACA 75%; p = .04). Procedure (p = .36), LA dwell (p = .41), and fluoroscopy (p = .44) time were similar. The mean follow-up was 506 ± 279 days. Sixty-six patients had arrhythmic events including 24 AFT and 59 AF recurrences. LB-WACA group had higher arrhythmia-free survival (p = .009) after single ablation procedures. In the multivariate Cox regression model, RF-WACA was associated with a higher recurrence of AFT compared with LB-WACA (Adjusted HR 3.16 [95% CI: 1.13-8.83]; p = .03). Conclusions: LB-WACA was associated with higher freedom from atrial arrhythmias mostly driven by the lower occurrence of AFT compared with RF-WACA.

Clinical Applications of Laser Technology: Laser Balloon Ablation in the Management of Atrial Fibrillation.

Catheter-based ablation techniques have a well-established role in atrial fibrillation (AF) management. The prevalence and impact of AF is increasing globally, thus mandating an emphasis on improving ablation techniques through innovation. One key area of ongoing evolution in this field is the use of laser energy to perform pulmonary vein isolation during AF catheter ablation. While laser use is not as widespread as other ablation techniques, such as radiofrequency ablation and cryoballoon ablation, advancements in product design and procedural protocols have demonstrated laser balloon ablation to be equally safe and effective compared to these other modalities. Additionally, strategies to improve procedural efficiency and decrease radiation exposure through low fluoroscopy protocols make this technology an increasingly promising and exciting option.

Sensing failure associated with the Medtronic Sprint Fidelis defibrillator lead.

INTRODUCTION: The diameter of implantable cardioverter-defibrillator (ICD) leads has become progressively smaller over time. However, the long-term performance characteristics of these smaller ICD leads are unknown. METHODS: We retrospectively evaluated 357 patients who underwent implantation of a Medtronic Sprint Fidelis defibrillating lead at two separate centers between September 2004 and October 2006. Lead characteristics were measured at implant, at early follow-up (1-4 days post implant), and every 3-6 months thereafter. RESULTS: During the study period, 357 patients underwent implantation of the Medtronic Sprint Fidelis lead. The mean R-wave measured at implant through the device was not different (P = NS) when compared with that measured at first follow-up (10.5 +/- 5.0 mV vs 10.7 +/- 5.1 mV). Forty-one patients (13%) had an R-wave amplitude

R-wave amplitude changes measured by electrocardiography during early transmural ischemia.

BACKGROUND: Changes in the amplitude of the R wave (RWA) on the electrocardiogram (ECG) have been described during acute myocardial ischemia and infarction. However, this has not been well studied in a controlled setting. We hypothesized that significant increase in RWA occurs during early transmural myocardial ischemia. METHODS: We prospectively evaluated changes in RWA in 50 patients during brief episodes of transmural ischemia induced by first balloon occlusion (mean, 38 seconds at 6-10 atmospheric pressures) during elective percutaneous coronary intervention. We recorded 12-lead ECGs at 20-second intervals before and during balloon inflation in 16 right coronary arteries, 14 left circumflex arteries, and 20 left anterior descending arteries. R wave amplitude was digitally measured in each of the 12 leads in every ECG using the ECG interval editor (General Electric HC, Menomonee Falls, WI). Intracoronary (IC) ECGs were also recorded in 4 patients. The mean of the RWA in each lead before balloon inflation was compared to the mean RWA during balloon inflation. RESULTS: R wave amplitude significantly increased during balloon inflation from baseline in limb leads I, II, aVL, and all the precordial leads with the exception of lead V(1). The RWA increase did not reach statistical significance in leads III, aVF, and V(1). Mean RWA increase was consistent in all leads except aVR during the brief episodes of ischemia during initial balloon inflation because of the inverse polarity of this lead. The increase in RWA was seen in most patients (mean, 75%) in whom transmural ischemia was induced by first balloon inflation. Besides, the RWA showed an increase from baseline in 3 patients who had IC-lead recordings. CONCLUSION: R wave amplitude increases significantly in precordial leads (V(2)-V(6)) and limb leads (I, II, aVL) of the surface ECG during brief episodes of transmural ischemia. The increase in RWA might be consistent with the expansion of the left ventricular cavity during ischemia and/or alterations in conduction that are intrinsic to the myocardium.

Retrospective review of Arctic Front Advance Cryoballoon Ablation: a multicenter examination of second-generation cryoballoon (RADICOOL trial).

BACKGROUND: Pulmonary vein isolation (PVI) via catheter ablation is an approved therapy for patients with drug-refractory and symptomatic atrial fibrillation (AF). Furthermore, cryoballoon is now considered to be as effective as focal radiofrequency catheter ablation. This study examines the second-generation cryoballoon performance in a US multicenter review of real-world practices. METHODS: By retrospective chart collections, the long-term efficacy and safety of the cryoballoon procedure were assessed in 15 US centers. All patients had a history of drug-refractory symptomatic paroxysmal AF and were treated with a cryoballoon PVI strategy at the index ablation. RESULTS: Four hundred fifty-two patients were evaluated, and acute PVI was achieved in 99% of patients by cryoballoon catheter ablation. In 0.88% of patients (4/452), an additional focal ablation catheter was used to achieve acute PVI during the ablation procedure. Average procedure time was 128 (range 82 to 260) min, using an average of 17 (range 1 to 19) min of fluoroscopy. The most frequent adverse event was transient phrenic nerve injury (1.5%; 7/452 patients) which all resolved by the end of the procedure with no diaphragmatic dysfunction at discharge. There were no strokes, transient ischemic attacks, cardiac tamponade, atrioesophageal fistulas, or deaths during the study. At the 12-month efficacy endpoint, single-procedure success of freedom from atrial arrhythmia was 87% (393/452 patients). CONCLUSIONS: This real-world examination of the US practice demonstrates that second-generation cryoballoon ablation by PVI strategy is safe and effective among patients with paroxysmal AF.

Accuracy of intracardiac echocardiography for assessing the esophageal course along the posterior left atrium: a comparison to magnetic resonance imaging.

BACKGROUND: Atrioesophageal fistula is a potentially fatal complication of ablation in the left atrium (LA) to treat atrial fibrillation. OBJECTIVE: The objective of our study was to systematically evaluate the diagnostic potential of intracardiac echocardiography (ICE) for accurately assessing the esophageal course along the posterior LA. METHODS: Thirty-five patients underwent magnetic resonance imaging (MRI) before and ICE during pulmonary vein (PV) isolation to visualize the esophagus. The location of the esophagus was determined in relation to the PVs and anatomic regions of the LA by both ICE and MRI. Using the MRI images as a reference, the accuracy of ICE localization was assessed. RESULTS: The most common location for the esophagus to appear was the mid-posterior wall (80% of patients by ICE, 71% of patients by MRI), followed by the left posterior wall (71% of patients by ICE, 63% of patients by MRI) and the right posterior wall (60% of patients by ICE, 51% of patients by MRI). The esophagus was seen to course near the left PV antrums (left superior PV antrum 34% of patients by ICE and MRI; left inferior PV antrum 34% of patients by ICE, 37% of patients by MRI), left superior PV (17% of patients by ICE, 20% of patients by MRI), left inferior PV (17% of patients by ICE and MRI), right inferior PV antrum (29% of patients by ICE, 37% of patients by MRI) and the right inferior PV (3% of patients by ICE, 17% of patients by MRI). The sensitivity for esophageal location by ICE compared to that by MRI ranged between 33% (right inferior PV) and 92% (left superior PV antrum, left inferior PV antrum, and mid-posterior wall). The specificity for esophageal location by ICE compared to that by MRI ranged between 60% (mid-posterior wall) and 100% (right inferior PV). The positive predictive value ranged between 80% (left inferior PV) and 100% (right inferior PV). The negative predictive value ranged between 84% (right inferior PV antrum) and 96% (left superior PV antrum). CONCLUSION: Phased array ICE provides rapid, real-time localization of the esophagus during LA ablation that is comparable to MRI.

Cryoablation inside the pulmonary vein after failure of radiofrequency antral isolation.

BACKGROUND: Antral pulmonary vein (PV) ablation with radiofrequency (RF) energy has become widely used as a curative approach for the treatment of atrial fibrillation. In some patients, despite antral ablation, PV entry and exit conduction block (BDB) cannot be achieved with RF energy. Cryoablation inside the PV may be an effective method to achieve BDB. OBJECTIVE: This study sought to describe a strategy of cryoablation within the PV to produce BDB in patients in whom antral RF ablation has failed. METHODS: In 15 of 148 consecutive patients (57 +/- 8.9 years old, 80% male) with atrial fibrillation (14 paroxysmal, 1 chronic) undergoing PV isolation cryoablation (CryoCath Technologies, Inc., Montreal, Canada) was performed 12 +/- 2 mm inside the PV after RF antral isolation failed. Nine patients were undergoing a repeat PV isolation procedure. Procedural and follow-up data were recorded and collected. RESULTS: In these 15 patients, BDB could not be achieved in 23 veins (12 left superior PV) with antral or ostial ablation alone. After cryoablation inside the vein, all patients had documented PV BDB and were in normal sinus rhythm at the end of the procedure. The average PV diameter before and after the procedure was unchanged (1.77 +/- 0.18 vs 1.74 +/- 0.19, P = .641). The average fluoroscopic and procedure times were 57 +/- 16 min and 5.3 + 1.2 hours, respectively. At 1-year follow-up, 75% of patients remained in sinus rhythm off antiarrhythmic medication; 7 of 9 patients undergoing a repeat procedure were in sinus rhythm at 1 year off antiarrhythmics. None of the patients had clinical evidence of PV stenosis after cryoablation. CONCLUSION: Cryoablation inside the PV after failed antral isolation with RF is a safe and effective method to achieve acute BDB.

Initial Clinical Experience With a New Automated Antitachycardia Pacing Algorithm: Feasibility and Safety in an Ambulatory Patient Cohort.

BACKGROUND: Antitachycardia pacing (ATP) in implantable cardioverter-defibrillators (ICD) decreases patient shock burden but has recognized limitations. A new automated ATP (AATP) based on electrophysiological first principles was designed. The study objective was to assess the feasibility and safety of AATP in ambulatory ICD patients. METHODS AND RESULTS: Enrolled patients had dual chamber or cardiac resynchronization therapy ICDs, history of ≥1 ICD-treated ventricular tachycardias (VT)/ventricular fibrillation episode, or a recorded, sustained monomorphic VT. Detection was set to ventricular fibrillation number of intervals to detect=24/32, VT number of intervals to detect≥16, and a fast VT zone of 240 to 320 ms. AATP prescribed the components and delivery of successive ATP sequences in real time, using the same settings for all patients. ICD datalogs were uploaded every ≈3 months, at unscheduled visits, exit, and death. Episodes and adverse events were adjudicated by separate committees. Results were adjusted (generalized estimating equations) for multiple episodes. AATP was downloaded into the ICDs of 144 patients (121 men), aged 67.4±11.9 years, left ventricular ejection fraction 33.1±13.6% (n=137), and treated 1626 episodes in 49 patients during 14.5±5.1 months of follow-up. Datalogs permitted adjudication of 702 episodes, including 669 sustained monomorphic VT, 20 polymorphic VT, 10 supraventricular tachycardia, and 3 malsensing episodes. AATP terminated 39 of 69 (59% adjusted) sustained monomorphic VT in the fast VT zone, 509 of 590 (85% adjusted) in the VT zone, and 6 of 10 in the ventricular fibrillation zone. No supraventricular tachycardias converted to VT or ventricular fibrillation. No anomalous AATP behavior was observed. CONCLUSIONS: The new AATP algorithm safely generated ATP sequences and controlled therapy progression in all zones without need for individualized programing.

Verification of a novel atrial fibrillation cryoablation dosing algorithm guided by time-to-pulmonary vein isolation: Results from the Cryo-DOSING Study (Cryoballoon-ablation DOSING Based on the Assessment of Time-to-Effect and Pulmonary Vein Isolation Guidance).

BACKGROUND: There are no recommendations on the optimal dosing for cryoablation of atrial fibrillation (Cryo-AF). OBJECTIVE: 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. METHODS: In this multicenter study, we examined the acute/long-term safety/efficacy of Cryo-AF using the proposed dosing algorithm (Cryo-AFDosing; n = 355) against a conventional, nonstandardized approach (Cryo-AFConventional; n = 400) in a nonrandomized fashion. RESULTS: Acute PV isolation was achieved in 98.9% of patients in Cryo-AFDosing (TT-PVI = 48 ± 16 seconds) vs 97.2% in Cryo-AFConventional (P = .18). Cryo-AFDosing 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-AFConventional. 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-AFDosing and Cryo-AFConventional. However, Cryo-AFDosing 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). CONCLUSION: 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.

Paradoxical undersensing during atrial flutter: what is the mechanism?

A patient with congenital complete heart block underwent implantation of a dual-chamber pacemaker. He presented to the emergency room with fatigue and was found to be in atrial flutter. Device interrogation revealed undersensing of 5 mV flutter waves at a programmed sensitivity of 0.5 mV. Due to undersensing, mode switch did not occur. This case illustrates apparently paradoxical undersensing of atrial flutter waves by a dual-chamber pacemaker and can be explained by a phenomenon known as "quiet timer blanking."

Anti-arrhythmic medications increase non-cardiac mortality - A meta-analysis of randomized control trials.

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 I (2). 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, I (2) index=24%) and all-cause mortality (OR=1.09, [95% CI: 1.01, 1.18], p=0.04, I (2)=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, I (2)=53%) or arrhythmic mortality (OR=1.00, [95% CI: 0.89, 1.13], p=0.94, I (2)=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.

Catheter ablation using the third-generation cryoballoon provides an enhanced ability to assess time to pulmonary vein isolation facilitating the ablation strategy: Short- and long-term results of a multicenter study.

BACKGROUND: Limited data exist on cryoablation of atrial fibrillation (Cryo-AF) using the newly available third-generation (Arctic Front Advance-Short Tip [AFA-ST]) cryoballoon. OBJECTIVE: 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. METHODS: 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. RESULTS: 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). CONCLUSION: 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.

Quantification of the cryoablation zone demarcated by pre- and postprocedural electroanatomic mapping in patients with atrial fibrillation using the 28-mm second-generation cryoballoon.

BACKGROUND: 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. OBJECTIVE: The purpose of this study was to determine the area of ablation during cryoballoon PV isolation. METHODS: 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. RESULTS: The posterior LA wall had a mean surface area of 31.1 (±1.6 SEM) cm(2). 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) cm(2), 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. CONCLUSION: 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.