Single freeze per vein strategy with the second-generation cryoballoon for atrial fibrillation: a propensity score-matched study between 180- and 240-s application time in a large cohort of patients

Aims: The single-freeze strategy using the second-generation cryoballoon (CB-A, Arctic Front Advance, Medtronic, Minneapolis, MN, USA) has been reported to be as effective as the recommended double-freeze approach in several single-centre studies. In this retrospective, international, multicentre study, we compare the 3-min single-freeze strategy with the 4-min single-freeze strategy. Methods and results: Four hundred and thirty-two patients having undergone pulmonary vein isolation (PVI) by means of CB-A using a single-freeze strategy were considered for this analysis. A cohort of patients who were treated with a 3-min strategy (Group 1) was compared with a propensity score-matched cohort of patients who underwent a 4-min strategy (Group 2). Pulmonary vein isolation was successfully achieved in all the veins using the 28-mm CB-A. The procedural and fluoroscopy times were lower in Group 1 (67.8 ± 17 vs. 73.8 ± 26.3, P < 0.05; 14.9 ± 7.8 vs. 24.2 ± 10.6 min, P < 0.05). The most frequent complication was PNP, with no difference between the two groups (P = 0.67). After a mean follow-up of 13 ± 8 months, taking into consideration a blanking period of 3 months, 85.6% of patients in Group 1 and 87% of patients in Group 2 were free from arrhythmia recurrence at final follow-up (P = 0.67). Conclusion: There is no difference in acute success, rate of complications, and freedom from atrial fibrillation recurrences during the follow-up between 3-min and 4-min per vein freeze strategies. The procedural and fluoroscopy times were significantly shorter in 3-min per vein strategy

Single freeze strategy with the second-generation cryballoon for atrial fibrillation: a multicenter international retrospective analysis in a large cohort of patients

PURPOSE: The second-generation cryoballoon (CB-A, Arctic Front Advance, Medtronic, Minneapolis, MN, USA) has proven to be highly effective in achieving freedom from atrial fibrillation; nonetheless, the ideal number and duration of freezing cycles is still a matter of debate. We investigated the acute success, procedural complications, and clinical outcome of a single freeze strategy using the CB-A in a large, retrospective, international multicenter study. METHODS: Between January 2013 and September 2015, 818 consecutive patients (58 ± 12 years, 68% males) with drug-resistant atrial fibrillation (AF) who underwent a CB-A using a single freeze strategy were taken into consideration for our analysis. RESULTS: Paroxysmal AF was documented in 74.1% of the patients, while 25.9% presented with persistent AF. Additional freezes were needed in a mean 1.4 veins per patient. 0.2% of the patients experienced persistent PNP that was still documented at the last follow-up. After a median follow-up of 14 ± 8 months, taking into consideration a blanking period (BP) of 3 months, 692 patients (84.6%) were free from arrhythmia recurrence. After a single procedure, AF recurrence during BP and persistent AF were identified as predictors of clinical recurrence after BP. CONCLUSIONS: Single freeze CB-A ablation is effective in treating drug-resistant AF and affords freedom from arrhythmia recurrences in 84.6% of patients during a 14-month follow-up. Persistent AF and recurrence during BP are predictors of arrhythmia recurrences

Single freeze strategy with the second- generation cryballoon for atrial fibrillation: a multicenter international retrospective analysis in a large cohort of patients

PURPOSE: The second-generation cryoballoon (CB-A, Arctic Front Advance, Medtronic, Minneapolis, MN, USA) has proven to be highly effective in achieving freedom from atrial fibrillation; nonetheless, the ideal number and duration of freezing cycles is still a matter of debate. We investigated the acute success, procedural complications, and clinical outcome of a single freeze strategy using the CB-A in a large, retrospective, international multicenter study. METHODS: Between January 2013 and September 2015, 818 consecutive patients (58 ± 12 years, 68% males) with drug-resistant atrial fibrillation (AF) who underwent a CB-A using a single freeze strategy were taken into consideration for our analysis. RESULTS: Paroxysmal AF was documented in 74.1% of the patients, while 25.9% presented with persistent AF. Additional freezes were needed in a mean 1.4 veins per patient. 0.2% of the patients experienced persistent PNP that was still documented at the last follow-up. After a median follow-up of 14 ± 8 months, taking into consideration a blanking period (BP) of 3 months, 692 patients (84.6%) were free from arrhythmia recurrence. After a single procedure, AF recurrence during BP and persistent AF were identified as predictors of clinical recurrence after BP. CONCLUSIONS: Single freeze CB-A ablation is effective in treating drug-resistant AF and affords freedom from arrhythmia recurrences in 84.6% of patients during a 14-month follow-up. Persistent AF and recurrence during BP are predictors of arrhythmia recurrences

The High-Altitude water cherenkov (HAWC) observatory in México: The primary detector

The High-Altitude Water Cherenkov (HAWC) observatory is a second-generation continuously operated, wide field-of-view, TeV gamma-ray observatory. The HAWC observatory and its analysis techniques build on experience of the Milagro experiment in using ground-based water Cherenkov detectors for gamma-ray astronomy. HAWC is located on the Sierra Negra volcano in México at an elevation of 4100 meters above sea level. The completed HAWC observatory principal detector (HAWC) consists of 300 closely spaced water Cherenkov detectors, each equipped with four photomultiplier tubes to provide timing and charge information to reconstruct the extensive air shower energy and arrival direction. The HAWC observatory has been optimized to observe transient and steady emission from sources of gamma rays within an energy range from several hundred GeV to several hundred TeV. However, most of the air showers detected are initiated by cosmic rays, allowing studies of cosmic rays also to be performed. This paper describes the characteristics of the HAWC main array and its hardware.UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Físic