Early recurrence of atrial fibrillation as a predictor for 1-year efficacy after successful phased RF pulmonary vein isolation: evaluation of complaints and multiple Holter recordings

Item does not contain fulltextBACKGROUND: Early arrhythmia recurrences after pulmonary vein isolation (PVI) for atrial fibrillation (AF) are accepted as part of the blanking period. Their relevance for long-term efficacy is not well-known. We evaluated patients, who came to hospital with a documented recurrence of AF, or had a registered episode of AF on the 24-hour Holter 6 weeks after PVI and compared it with long-term outcome. METHODS: One hundred consecutive patients with paroxysmal AF were treated with the PVAC. In the 3-month blanking period patients who came to hospital with a documented recurrence of AF on ECG were recorded. 6 weeks after procedure a 24-hour Holter was performed. After 3 months patients were asked if they felt a relapse. Follow-up was performed at 3, 6, and 12 months with ECG, 7-day Holter at 6 and/or 12 months, and event recording if needed. RESULTS: Within the blanking period, 25/100 (25%) patients had a documented recurrence of AF while 46/100 (46%) patients felt a relapse. After the blanking period up to 12 months, 53/100 (53%) patients were free of AF without anti-arrhythmic drugs. Multivariate regression analyses revealed that absence of AF in the blanking period (OR 0.22 95%CI [0.05-0.98]) and absence of a relapse of symptoms suspect for AF during the blanking period (OR 0.21 95%CI [0.06-0.52]) were independent predictors of successful long-term outcome. CONCLUSIONS: Poor long-term outcome is strongly related to patients who experienced palpitations with ECG documented AF, AF on the 24-hour Holter at 6 weeks after PVI and a relapse in the blanking period

Freedom from paroxysmal atrial fibrillation after successful pulmonary vein isolation with pulmonary vein ablation catheter-phased radiofrequency energy: 2-year follow-up and predictors of failure

AIMS: In patients with paroxysmal atrial fibrillation (PAF) the pattern of atrial fibrillation (AF) episodes and the total AF burden, may be related to the efficacy of pulmonary vein isolation (PVI). We evaluated (pre)-procedural factors explaining the long-term outcome after PVI, using a ring-shaped multielectrode ablation catheter [pulmonary vein ablation catheter (PVAC)]. METHODS AND RESULTS: A total of 120 consecutive patients with PAF were treated with the PVAC. The patients' histories were obtained by a questionnaire and the clinical charts. Follow-up was performed at 3, 6, 12, 18, and 24 months with serial electrocardiogram, and multiple day Holter at 6, 12, and 24 months, as well as event recording in case of unexplained palpitations. At 1 year, 66 of 120 (55%, 95% confidence interval (CI) [46-63%]) patients were free of any left atrial (LA) arrhythmia without class I or III anti-arrhythmics after a single procedure. At 2 years, freedom from LA arrhythmia slightly declined further to 58 of 119 (49%, 95% CI [40-58%]). The only pre-procedural predictor of long-term success was a shorter duration of the longest episode of AF (hazard ratio (HR) 0.77 95% CI [0.64-0.92]). The only procedural predictor of long-term success was no need for direct current cardioversion (DCCV) for AF (HR 0.36 95% CI [0.21-0.61]). Since other characteristics in these PAF patients were very homogeneous, no further clinical predictors were observed. CONCLUSION: Freedom from LA arrhythmia after PVI for PAF with PVAC is 49% after 2-year follow-up, with little decline between year 1 and 2. Predictors of long-term failure were a longer duration of the longest episode of AF in the pre-procedural questionnaire, and a procedural DCCV for AF

Arrhythmia detection after atrial fibrillation ablation: value of incremental monitoring time

BACKGROUND: After pulmonary vein isolation (PVI), patients need to be followed to analyze the effect of the treatment. We evaluated the influence of the duration of Holter monitoring on the detection of arrhythmia recurrences after a single PVI at 12 months. METHODS: Consecutive patients with paroxysmal atrial fibrillation (AF) underwent successful PVI with phased radiofrequency and pulmonary vein ablation catheter. Follow-up was performed with electrocardiogram at 3, 6, and 12 months and 7-day Holter at 12 months. Symptomatic patients received additional event recording. The 7-day Holters at 12 months were evaluated for documented left atrial tachyarrhythmia recurrences, and each individual day with AF was categorized. RESULTS: At 12 months after the procedure, 21 of the 96 (22%) patients had AF on their 7-day Holter. In the patients with AF recurrence, there was an increase in sensitivity from 53% of a 1-day Holter up to 88% with 4-day Holter, and 100% of a 7-day Holter. Monitoring with duration of less than 4 days resulted in significantly less detection of patients with AF compared to 7-day Holter. CONCLUSIONS: A 4-day Holter at 12 months has an 88% sensitivity for arrhythmia detection, and appears to provide a sufficient monitoring time. Prolonging the monitoring time to 7 days does not significantly increase the yield

Safety of pulmonary vein isolation and left atrial complex fractionated atrial electrograms ablation for atrial fibrillation with phased radiofrequency energy and multi-electrode catheters

Item does not contain fulltextAIMS: Recently, a multi-electrode catheter system using phased radiofrequency (RF) energy was developed specifically for atrial fibrillation (AF) ablation: the pulmonary vein ablation catheter (PVAC), the multi-array septal catheter (MASC), and the multi-array ablation catheter (MAAC). Initial results of small trials have been promising: shorter procedure times and low adverse event rates. In a large single-centre registry, we evaluated the adverse events associated with multi-electrode ablation catheter procedures with PVAC alone, or combined with MASC and MAAC. METHODS AND RESULTS: In all, 634 consecutive patients with AF had 663 procedures with multi-electrode ablation catheters, 502 patients with the PVAC alone, 128 patients with PVAC/MASC/MAAC, 29 redo procedures with the PVAC or PVAC/MASC/MAAC, and 4 patients had a complicated transseptal puncture. Major and minor adverse events during 6 month follow-up were registered. In 15 cases (2.3%), major adverse events were seen within the first month after the procedure. These included complicated transseptal puncture (4), stroke (2), transient ischaemic attack (5), acute coronary syndrome (2), femoral pseudoaneurysm (1), and arteriovenous fistulae (1). Minor adverse events were seen in 10.7% at 6 months, mostly due to femoral haematoma (3.9%), and non-significant PV stenosis (5.2%). There was no difference in the occurrence of major adverse events between PVAC alone, or PVAC/MASC/MAAC ablation. CONCLUSION: Ablation with phased RF and multi-electrode catheters is accompanied by a major adverse event rate of 2.3% within 1 month and a minor event rate of 10.7% at 6 months

Safety of pulmonary vein isolation and left atrial complex fractionated atrial electrograms ablation for atrial fibrillation with phased radiofrequency energy and multi-electrode catheters

Item does not contain fulltextAIMS: Recently, a multi-electrode catheter system using phased radiofrequency (RF) energy was developed specifically for atrial fibrillation (AF) ablation: the pulmonary vein ablation catheter (PVAC), the multi-array septal catheter (MASC), and the multi-array ablation catheter (MAAC). Initial results of small trials have been promising: shorter procedure times and low adverse event rates. In a large single-centre registry, we evaluated the adverse events associated with multi-electrode ablation catheter procedures with PVAC alone, or combined with MASC and MAAC. METHODS AND RESULTS: In all, 634 consecutive patients with AF had 663 procedures with multi-electrode ablation catheters, 502 patients with the PVAC alone, 128 patients with PVAC/MASC/MAAC, 29 redo procedures with the PVAC or PVAC/MASC/MAAC, and 4 patients had a complicated transseptal puncture. Major and minor adverse events during 6 month follow-up were registered. In 15 cases (2.3%), major adverse events were seen within the first month after the procedure. These included complicated transseptal puncture (4), stroke (2), transient ischaemic attack (5), acute coronary syndrome (2), femoral pseudoaneurysm (1), and arteriovenous fistulae (1). Minor adverse events were seen in 10.7% at 6 months, mostly due to femoral haematoma (3.9%), and non-significant PV stenosis (5.2%). There was no difference in the occurrence of major adverse events between PVAC alone, or PVAC/MASC/MAAC ablation. CONCLUSION: Ablation with phased RF and multi-electrode catheters is accompanied by a major adverse event rate of 2.3% within 1 month and a minor event rate of 10.7% at 6 months

Online monitoring of the solvent and absorbed acid gas concentration in a CO2 capture process using monoethanolamine

method has been developed for online liquid analysis of the amine and absorbed CO2 concentrations in a postcombustion capture process using monoethanolamine (MEA) as a solvent. Online monitoring of the dynamic behavior of these parameters is important in process control and is currently achieved only using Fourier transform infrared spectroscopy. The developed method is based on cheap and easy measurable quantities. Inverse least-squares models were built at two temperature levels, based on a set of 29 calibration samples with different MEA and CO2 concentrations. Density, conductivity, refractive index, and sonic speed measurements were used as input data. The developed model has been validated during continuous operation of a CO2 capture pilot miniplant. Concentrations of MEA and CO2 in the liquid phase were predicted with an accuracy of 0.53 and 0.31 wt %, with MEA and CO2 concentrations ranging from 19.5 to 27.7 wt % and from 1.51 to 5.74 wt %, respectively. Process dynamics, like step changes in the CO2 flue gas concentration, were covered accurately, as well. The model showed good robustness to changes in temperature. Combining density, conductivity, refractive index, and sonic speed measurements with a multivariate chemometric method allows the real-time and accurate monitoring of the acid gas and MEA concentrations in CO2 absorption processes

Online monitoring of the solvent and absorbed acid gas concentration in a CO2 capture process using monoethanolamine

A method has been developed for online liquid analysis of the amine and absorbed CO2 concentrations in a postcombustion capture process using monoethanolamine (MEA) as a solvent. Online monitoring of the dynamic behavior of these parameters is important in process control and is currently achieved only using Fourier transform infrared spectroscopy. The developed method is based on cheap and easy measurable quantities. Inverse least-squares models were built at two temperature levels, based on a set of 29 calibration samples with different MEA and CO2 concentrations. Density, conductivity, refractive index, and sonic speed measurements were used as input data. The developed model has been validated during continuous operation of a CO2 capture pilot miniplant. Concentrations of MEA and CO2 in the liquid phase were predicted with an accuracy of 0.53 and 0.31 wt %, with MEA and CO2 concentrations ranging from 19.5 to 27.7 wt % and from 1.51 to 5.74 wt %, respectively. Process dynamics, like step changes in the CO2 flue gas concentration, were covered accurately, as well. The model showed good robustness to changes in temperature. Combining density, conductivity, refractive index, and sonic speed measurements with a multivariate chemometric method allows the real-time and accurate monitoring of the acid gas and MEA concentrations in CO2 absorption processes.Scopu

Development and characterization of the superconducting integrated receiver channel of the TELIS atmospheric sounder

The balloon-borne instrument TELIS (TErahertz and submillimetre LImb Sounder) is a three-channel superconducting heterodyne spectrometer for atmospheric research use. It detects spectral emission lines of stratospheric trace gases that have their rotational transitions at THz frequencies. One of the channels is based on the superconducting integrated receiver (SIR) technology. We demonstrate for the first time the capabilities of the SIR technology for heterodyne spectroscopy in general, and atmospheric limb sounding in particular. We also show that the application of SIR technology is not limited to laboratory environments, but that it is well suited for remote operation under harsh environmental conditions. Within a SIR the main components needed for a superconducting heterodyne receiver such as a superconductor�insulator�superconductor (SIS) mixer with a quasi-optical antenna, a flux-flow oscillator (FFO) as the local oscillator, and a harmonic mixer to phase lock the FFO are integrated on a single chip. Light weight and low power consumption combined with broadband operation and nearly quantum limited sensitivity make the SIR a perfect candidate for use in future airborne and space-borne missions. The noise temperature of the SIR was measured to be as low as 120 K, with an intermediate frequency band of 4�8 GHz in double-sideband operation. The spectral resolution is well below 1 MHz, confirmed by our measurements. Remote control of the SIR under flight conditions has been demonstrated in a successful balloon flight in Kiruna, Sweden. The sensor and instrument design are presented, as well as the preliminary science results from the first flight

Rationale and design of the PRAETORIAN trial: a Prospective, RAndomizEd comparison of subcuTaneOus and tRansvenous ImplANtable cardioverter-defibrillator therapy.

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