Two versus one repeat freeze-thaw cycle(s) after cryoballoon pulmonary vein isolation: the alster extra pilot study.

BACKGROUND: Repeated freezing (bonus applications) during cryoballoon pulmonary vein isolation (PVI) has been suggested to improve lesion durability. However, the long-term clinical effects of repeated freezing have not been investigated. METHODS AND RESULTS: A total of 51 patients (pts) with paroxysmal atrial fibrillation (AF) underwent PVI using the single big (28 mm) cryoballoon technique. One (27 pts, group I) or 2 bonus applications (24 pts, group II) were performed at all PVs subsequent to PVI. Clinical follow-up consisted of continuous rhythm monitoring by an implantable cardiac monitor (ICM, 24 pts) and serial 7-day Holter-ECG recording (7DH, 27 pts). The primary endpoint was defined as recurrent AF or atrial tachycardia. Acute PVI of all PVs was obtained in 50/51 pts (98%). The median (Q1;Q3) follow-up duration in this study was 384 (213;638) days. The primary endpoint occurred in 48% (group I, 15 pts ICM, 12 pts 7DH) and 46% (group II, 9 pts ICM, 15 pts 7DH), P = 0.84. Procedure- and fluoroscopy-time for group I versus group II was 193 ± 56 minutes versus 207 ± 27 and 33 ± 13 minutes versus 34 ± 11 minutes, respectively. Right phrenic nerve palsy (PNP) occurred in 3 pts (all group II, time to resolution: 128 ± 112 days). In 2 of these pts, PNP occurred during the second bonus application. CONCLUSION: Application of 2 when compared to 1 freeze-thaw cycle(s) following cryoballoon PVI did not result in improved clinical success but was associated with a higher complication rate.

Cryoballoon temperature predicts acute pulmonary vein isolation.

BACKGROUND: Cryoballoon pulmonary vein isolation (PVI) currently requires a long cryoballoon application (CBA) time of 240 to 300 seconds, thus repeated ineffective CBA prolongs procedure duration. We hypothesized that cryoballoon temperature (CBT) may be used to discriminate between effective and ineffective CBA during freezing. OBJECTIVE: This study sought to evaluate CBT as a predictor of CBA efficiency. METHODS: Sixty-six patients with atrial fibrillation underwent PVI using the single big (28 mm) cryoballoon technique. CBT was continuously recorded. After each CBA (300 seconds), a Lasso catheter (Biosense Webster, Inc., Diamond Bar, California) was placed into the target pulmonary vein (PV) to determine whether electrical PV disconnection was present. Only the first CBA at each PV was analyzed to avoid cumulative effects. RESULTS: The CBT was lower during CBA at superior compared with inferior PVs. When individual CBAs were grouped according to successful/failed PVI, CBT was lower for those CBAs that resulted in successful PVI at all time points analyzed. To test the performance of CBT to predict failed CBA, receiver-operator curves were constructed. A minimal CBT of ≥ -42°C/ -39°C (superior/inferior PVs) predicted failed PVI with 73%/92% specificity (area under the curve 0.82/0.81); positive predictive value (PPV) 74%/74%. A minimal CBT of < -51°C was invariably associated with PVI. After 120 seconds of freezing, a CBT of ≥ -36°C/ -33°C (superior/inferior PVs) predicted failed PVI with 97%/95% specificity (area under the curve 0.82/0.76); PPV 82%/80%. CONCLUSION: Balloon temperature predicts successful target PVI during cryoablation and may serve in the early identification of noneffective balloon applications.

Characterization of conduction recovery after pulmonary vein isolation using the "single big cryoballoon" technique.

BACKGROUND: Pulmonary vein isolation using the cryoballoon technique (CB-PVI) has evolved into a simple and safe alternative for point-by-point radiofrequency ablation. Systematic analysis of conduction recovery occurring after CB-PVI and causing recurrent atrial fibrillation has not yet been performed. OBJECTIVE: The purpose of this study was to analyze conduction recovery after PVI using the single big (28-mm) cryoballoon technique. METHODS: Twenty-six patients with recurrent atrial tachyarrhythmia after previous CB-PVI underwent repeat ablation. Pulmonary vein (PV) reisolation was performed by antral irrigated radiofrequency ablation using electroanatomic mapping. For analysis of the location of conduction gaps, the ipsilateral LA-PV junction was divided into six equally distributed segments. RESULTS: PV reconduction frequently occurred into multiple (>2) PVs (54% patients). Conduction gaps could be abolished by single point ablation in 63% (lateral) and 41% (septal) of patients or by incomplete circular lesions in the remaining patients. A significantly higher number of patients exhibited conduction recovery at inferior segments (85% lateral, 77% septal) compared with superior segments (42% lateral, 31% septal). Furthermore, the ridge between PV ostia and left atrial appendage (LAA) was highly associated with reconduction into lateral PVs (81% of patients). Retrospective analysis of the initial CB-PVI-procedure revealed lower freezing temperatures at superior than inferior PVs as well as sharp catheter angulations with loss of central cryoballoon alignment to reach inferior PVs. CONCLUSION: Conduction recovery after CB-PVI occurs at a high incidence at inferior sites around ipsilateral PV ostia and the LAA-PV ridge. Modifications of the technique to ensure optimal balloon-tissue contact at predilection sites may improve long-term success rates.

Cryoballoon pulmonary vein isolation with real-time recordings from the pulmonary veins.

INTRODUCTION: Cryoballoon (CB) ablation represents a novel technology for pulmonary vein isolation (PVI). We investigated feasibility and safety of CB-PVI, utilizing a novel spiral catheter (SC), thereby obtaining real-time PV potential registration. METHODS: Following double transseptal puncture, a Lasso catheter (Biosense Webster, Diamond Bar, CA, USA) and the 28 mm CB were positioned within the left atrium. A novel SC (Promap, ProRhythm Inc., Ronkonkoma, NY, USA) was inserted through the lumen of the CB allowing PV signal registration during treatment. Time to PV conduction block was analyzed. If no stable balloon position was obtained, the SC was exchanged for a regular guide wire and PV conduction was assessed after treatment by Lasso catheter. RESULTS: In 18 patients, 39 of 72 PVs (54%) were successfully isolated using the SC. The remaining 33 PVs were isolated switching to the regular guide wire. Time to PV conduction block was significantly shorter in PVs in which sustained PVI was achieved as compared to PVs in which PV conduction recovered within 30 minutes (33 +/- 21 seconds vs 99 +/- 65 seconds). In 40 PVs, time to PV conduction block was not obtained because of: (1) PVI not being achieved during initial treatment; (2) a distal position of the SC; or (3) isolation with regular guide wire. No procedural complications occurred. CONCLUSION: Visualization of real-time PV conduction during CB PVI is safe, feasible, and allows accurate timing of PVI onset in a subset of PVs. Time to PV conduction block predicts sustained PVI. However, mechanical properties of the SC need to be improved to further simplify CB PVI.

Right ventricular rapid pacing in catheter ablation of atrial fibrillation: a novel application for cryoballoon pulmonary vein isolation.

BACKGROUND: Cryoballoon ablation (Arctic Front, Cryocath) represents a novel technology for pulmonary vein isolation (PVI). The initial phase of a freeze is crucial for cryolesion formation which is determined by local temperature depending on blood flow. We investigated the impact of right ventricular rapid pacing (RVRP) on temperature kinetics in patients (pts) with paroxysmal atrial fibrillation (PAF). METHODS AND RESULTS: Right ventricular rapid pacing was performed from the RV apex. Absolute minimal temperature (MT, degrees C), temperature slopes [time (s) to 80% MT; dT/dt), area under the curve (AUC) and arterial blood pressure (ABP, mmHg) were compared (group I: with RVRP vs. group II: without RVRP). RVRP (mean duration 55 +/- 7 s) was performed in 11 consecutive PAF pts (41 PVs, age 58 +/- 9 years, LA size 44 +/- 6 mm, normal ejection fraction). Only freezes with identical balloon positions were analyzed (11/41 PVs). RVRP (cycle length 333 +/- 3 ms) induced a significant drop in ABP (group I: 45 +/- 3 mmHg vs. group II: 100 +/- 18 mmHg, p < 0.001). MT was not different between group I and group II (-45.0 +/- 4.4 vs. -44.3 +/- 3.4 degrees C, p = 0.46), whereas slope (38.0 +/- 4.6 s vs. 51.6 +/- 14.4 s, p = 0.0034) and AUC (1090 +/- 4.6 vs. 1181 +/- 111.2, p = 0.02) was significantly changed. In one pt, a ventricular tachycardia was induced. PVI was achieved in 41/41 PVs. CONCLUSION: Right ventricular rapid pacing significantly accelerates cryoballoon cooling during the initial phase of a freeze possibly suggesting improved cryolesions.

The 'single big cryoballoon' technique for acute pulmonary vein isolation in patients with paroxysmal atrial fibrillation: a prospective observational single centre study.

AIMS: Cryothermal energy (CTE) ablation via a balloon catheter (Arctic Front, Cryocath) represents a novel technology for pulmonary vein isolation (PVI). However, balloon-based PVI approaches are associated with phrenic nerve palsy (PNP). We investigated whether 'single big cryoballoon'-deployed CTE lesions can (i) achieve acute electrical PVI without left atrium (LA) imaging and (ii) avoid PNP in patients with paroxysmal atrial fibrillation (PAF). METHODS AND RESULTS: After double transseptal punctures, one Lasso catheter and a big 28 mm cryoballoon catheter using a steerable sheath were inserted into the LA. PV angiography and ostial Lasso recordings from all PVs were obtained. Selective PV angiography was used to evaluate balloon to LA-PV junction contact. CTE ablation lasted 300 s, and the PN was paced during freezing at right-sided PVs. Twenty-seven patients (19 males, mean age: 56 +/- 9 years, LA size: 42 +/- 5 mm) with PAF (mean duration: 6.6 +/- 5.7 years) were included. PVI was achieved in 97/99 PVs (98%). Median (Q(1); Q(3)) procedural, balloon, and fluoroscopy times were 220 min (190; 245), 130 min (90; 170), and 50 min (42; 69), respectively. Three transient PNP occurred after distal PV ablations. No PV stenosis occurred. Total median (Q(1); Q(3)) follow-up time was 271 days (147; 356), and 19 of 27 patients (70%) remained in sinus rhythm (3-month blanking period). CONCLUSION: Using the single big cryoballoon technique, almost all PVs (98%) could be electrically isolated without LA imaging and may reduce the incidence of PNP as long as distal ablation inside the septal PVs is avoided.

The German Competence Network on Atrial Fibrillation (AFNET).

The German Competence Network on Atrial Fibrillation (AFNET) is an interdisciplinary national research network funded by the Federal Ministry of Education and Research (BMBF) since 2003. The AFNET aims at improving treatment of atrial fibrillation (AF), the most frequent sustained arrhythmia of the heart. The AFNET has established a nationwide patient registry on manifestation, diagnostics, and therapy of AF in Germany. The data analyzed to date demonstrate that patients with AF are likely to have multiple comorbidities (hypertension, valvular heart disease, coronary artery disease, diabetes mellitus) and an advanced age. Regarding oral anticoagulation, guideline adherence is very high. Basic research has identified specific changes in atrial tissue during AF-induced remodeling providing the rationale for novel therapeutic interventions. Clinical trials are being carried out to optimize pharmacological and nonpharmacological treatments. The ANTIPAF trial is designed to prove that angiotensin II receptor blockers reduce the incidence of paroxysmal AF. The Flec-SL trial tests the efficacy of a short-term treatment with antiarrhythmic drugs after cardioversion. The Gap-AF trial investigates the impact of complete pulmonary vein (PV) isolation versus incomplete circumferential PV ablation on AF recurrences. The effect of preventive pacing on the recurrence of paroxysmal AF is studied in the BACE-PACE trial.