Pressure waveform analysis for occlusion assessment significantly reduces contrast medium use in cryoballoon pulmonary vein isolation.

BACKGROUND: Pulmonary vein (PV) occlusion is crucial for adequate lesion formation during cryoballoon-guided pulmonary vein isolation (CB-PVI). PV occlusion is usually confirmed by angiographies over the inflated balloon device. The aim of our study was to analyze the safety and efficacy of pressure waveform-based PV occlusion assessment during CB-PVI utilizing a novel fully integrated pressure analysis tool. METHODS: Consecutive patients with symptomatic atrial fibrillation (AF) scheduled for CB-PVI were prospectively enrolled for pressure waveform-based PV occlusion assessment. A patient cohort receiving conventional angiographies served as control group. Patients with common PV ostia were excluded. RESULTS: The study group consisted of 40 patients (16 females, mean age was 64.5 ± 9.7, 45% persistent AF). The control group consisted of 40 matched patients. All 160 PVs in the study group were successfully isolated without the use of additional venograms confirming PV occlusion. The mean procedure duration was 69 ± 12 min in the study group with a mean fluoroscopy duration of 11.5 ± 4.4 min. The mean contrast medium volume was 22 ± 9 ml in the study group and 36 ± 12 ml in the control group (p = 0.0001). Mean procedure duration, mean balloon temperatures, and mean ablation application durations did not differ significantly between the study and the control group. No periprocedural complications occurred. CONCLUSION: CB-PVI utilizing a fully integrated pressure waveform analysis tool to assess PV occlusion is feasible and safe and significantly reduces the amount of contrast medium without impact on procedural parameters and freedom from arrhythmia recurrence.

Magnetic resonance assessment of left atrial scar formation following a novel very high-power short-duration workflow for atrial fibrillation ablation.

AIMS: Atrial fibrillation (AF) ablation protocols using energy delivery with very high power and short duration (vHPSD) have been introduced to improve lesion formation. This study reports procedural data of vHPSD ablation in AF patients and analyses characteristics of ablation-induced left atrial (LA) scar formation from cardiac magnetic resonance imaging (MRI). METHODS AND RESULTS: Sixty consecutive patients undergoing index pulmonary vein isolation following our institutional Q4U-AF workflow were prospectively enrolled. Ablation was conducted using a contact force sensing catheter allowing for vHPSD ablation using a temperature-controlled ablation mode. Thirty patients underwent cardiac late gadolinium enhancement MRI of the LA 3 months after ablation to assess LA scar. Mean procedural duration was 66.5 ± 14.8 min. Mean ablation time was 4.7 ± 0.9 min with a mean number of 69.9 ± 14.2 applications. First-pass isolation was achieved in 51 patients (85%) for the right pulmonary veins (RPVs), in 37 patients (61.7%) for the left pulmonary veins (LPVs), and in 34 patients (56.7%) for both pulmonary veins (PVs). Magnetic resonance imaging at 3 months post-ablation demonstrated a mean scar width of 14.4 ± 2.6 mm around RPVs and 11.9 ± 1.9 mm at LPVs (P > 0.05). Complete PV encirclement was observed in 76.7% for RPVs, in 76.7% for LPVs, and in 66.7% for both PV pairs. During a mean follow-up of 4.7 ± 1.4 months, arrhythmia recurrence was observed in 3.3% of the patients. CONCLUSION: Pulmonary vein isolation following a novel vHPSD workflow resulted in short procedure duration and high acute and mid-term efficacy. Magnetic resonance imaging demonstrated durable and transmural PV lesions with homogeneous and contiguous scar formation.

Novel cryoballoon ablation system for pulmonary vein isolation: multicenter assessment of efficacy and safety-ANTARCTICA study.

AIMS: Pulmonary vein isolation (PVI) either by balloon devices or radiofrequency forms the cornerstone of invasive atrial fibrillation (AF) treatment. Although equally effective cryoballoon (CB)-based PVI offers shorter procedure duration and a better safety profile. Beside the worldwide established Arctic Front Advance system, a novel CB device, POLARx, was recently introduced. This CB incorporates unique features, which may translate into improved efficacy and safety. However, multicentre assessment of periprocedural efficacy and safety is lacking up to date. METHODS AND RESULTS: A total of 317 patients with paroxysmal or persistent AF were included and underwent POLARx CB-based PVI in 6 centres from Germany and Italy. Acute efficacy and safety were assessed in this prospective multicenter observational study. In 317 patients [mean age: 64 ± 12 years, 209 of 317 (66%) paroxysmal AF], a total of 1256 pulmonary veins (PVs) were identified and 1252 (99,7%) PVs were successfully isolated utilizing mainly the short tip POLARx CB (82%). The mean minimal CB temperature was -57.9 ± 7°C. Real-time PVI was registered in 72% of PVs. The rate of serious adverse events was 6.0% which was significantly reduced after a learning curve of 25 cases (9.3% vs. 3.0%, P = 0.018). The rate of recurrence-free survival after mean follow-up of 226 ± 115 days including a 90-day blanking period was 86.1%. CONCLUSION: In this large multicentre assessment, the novel POLARx CB shows a promising efficacy and safety profile after a short learning curve.

First in human validation of impedance-based catheter tip-to-tissue contact assessment in the left atrium.

BACKGROUND: In this study, a new method of contact assessment based on the measurement of the local electrical properties at the catheter tip-to-tissue interface was validated in a blinded fashion in vivo in the human left atrium. METHODS: Using a 3-terminal circuit model, local resistance and reactance between catheter tip and tissue surface were measured and combined in an electrical coupling index (ECI). Twelve patients undergoing atrial fibrillation (AF) catheter ablation were included in this study. The catheter was placed in the left atrium at various levels of contact. Blinded to the physician, measurements of electrogram amplitudes, pacing thresholds, and impedances at the catheter tip-to-tissue interface were performed. RESULTS: As the catheter went from noncontact to contact, ECI increased from 118 +/- 15 to 145 +/- 24 (P < 0.0001), electrogram amplitudes increased from 0.14 +/- 0.16 to 2.0 +/- 1.9 mV (P < 0.0001), and pacing thresholds decreased from 13.9 +/- 3.1 to 3.1 +/- 2.0 mA (P < 0.0001). ECI was significantly higher in vascular tissue as compared with trabeculated and smooth myocardium. Patch orientation, operator, body mass index, or clinical type of AF had no influence on ECI values. On a patient-by-patient analysis, true contact/noncontact locations showed a mean ECI difference of 32.7 +/- 11.6 units (95% CI 25.8-39.6). A cut-off value of 5 ECI units was able to separate contact from noncontact with 97% sensitivity and 95% specificity. CONCLUSION: Measurement of local impedances between catheter tip and tissue is feasible to reproducibly describe electrical catheter contact within the left atrium in a clinical setting of AF catheter ablation.