High-field magnetoresistance of La0.67Sr0.33MnO3 thin films deposited on LiNbO3 substrates

Colossal magnetoresistive manganites have been widely studied due to their potential use in sensor and device applications. In this work, La0.67Sr0.33MnO3 thin films were deposited by pulsed laser ablation on LiNbO3 substrates and magnetoresistance measurements were performed using pulsed magnetic fields up to 25 T. The corresponding magnetoconductance of the films was fitted in order to obtain the grain boundary (GB) contribution to the transport properties. The observed temperature dependence of the fitting parameters was indicative of antiferromagnetism across GB spins and reflected the progressive reduction of magnetic ordering with increasing temperature.This work was supported in part by Project No. FEDER/POCTI 155/94 from Fundação para a Ciência e Tecnologia (FCT). I.T. Gomes, A. Pereira and J. Barbosa gratefully acknowledge Ph.D. grants (SFRH/BD/36348/2007, SFRH/BD/22373/2005 and SFRH/BD/41913/2007, respectively) from FCT

Utility of pace-matching mapping in the ablation of idiopathic ventricular tachyarrhythmias

Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017.Introduction: The electroanatomical mapping of idiopathic ventricular tachyarrhythmias (iVT) - premature ventricular contractions (PVC) and idiopathic ventricular tachycardia (VT) - is dependent on the recording of spontaneous PVC or induction of the clinical VT during the procedure to obtain the iVT activation map. The presence of infrequent and non-inducible iVT may preclude ablation. Pace-matching (PM) mapping of the anatomical region on interest, using the PaSo™ algorithm, may allow to circumvent this limitation. Purpose: Determination of the utility of the PaSo™pace-matching mapping for iVT ablation Methods: A single-center retrospective study was made, with inclusion of consecutive patients undergoing iVT ablation between October 2013 and October 2016. It was collected electroanatomical data, including the highest correlation obtained by PM (PaSo™). Success of the procedure was assessed (defined as the elimination of spontaneous PVC during the electrophysiological study and non-inducible iVT at the end) and the ability of the PaSo™ pace-matching mapping to guide effective ablation was determined. Results: 29 patients were studied (62.1% women, mean age 52.8±14.7 years). 65.5% presented symptomatic frequent PVC and 34.5% VT. The most frequent anatomic origin was the right ventricular outflow tract (58.6%), followed by the left coronary cusp (20.7%), mitro-aortic continuity (13.8%) and papillary muscles (6.9%). The ablation was successful (PVC elimination during the procedure) in 75.9% of the cases. In 79.3% of the cases it was possible to obtain an activation map; in 20.7% (6 cases) it was only possible to obtain a pace-matching map, because ocurred suppression of PVC during the procedure, and success was achieved in 5 of these cases. There was no relationship between success and anatomical region of origin of the iVT. The mean value of the better pace-matching correlation was 94.45% ± 3.95%, being significantly higher when the zone of interest was located in the right ventricle (95.71±3.23 vs. 92.68±4.3, p=0.04). There was a positive and significant association between the PaSo™ correlation value and success (r=0.554; p=0.007). Significantly higher correlations were observed in successful ablations [95.9% vs 92%; p=0.006), and the PaSo™ correlation value was a good predictor of success (AUC: 0.874, 95% CI 0.74–1.0, p=0.003). The pace-matching threshold of 93.55% predicted ablation success with 86.4% sensitivity and 85.7% specificity. Conclusion: In patients with iVT, pace-matching mapping provides a suitable method for performing ablation procedure, and it is essential in patients where spontaneous suppression of PVC occurs during the procedure. The achievement of a pace-matching correlation>93.55% conveniently identifies the dysrhythmic focus, allowing increasing of ablation success.info:eu-repo/semantics/publishedVersio

Implantation of ICD and CRT-D in the elderly population : will it be a limiting factor?

Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017Introduction: Implantable cardioverter defibrillator (ICD) and cardiac resynchronization (CRT-D) implantation in elderly patients is effective in preventing sudden death, although limited by the natural shorter life expectancy. The different device brands present very variable survival estimates and it has been discussed the availability of less expensive, less longevity generators for the elderly population. Purpose: To determine if the expected survival rate in the elderly patient population (≥75 years) should influence the selection of the desired longevity of the devices. Methods: A retrospective single-center study of consecutive patients who underwent implantation of ICD or CRT-D after November 1995. The mean survival of patients undergoing 1st implant or generator replacement at an advanced age (≥75 years) was evaluated and compared to the effective longevity of the generators. Cumulative survival analyzes using the Kaplan Meier method were used. Results: A total of 1312 cardiac devices were implanted, of which 163 generators in elderly patients (53% CDI and 47% CRT-D). Of these, 77% corresponded to the 1st implant. The median survival after implantation of the elderly patients was 6.8 years, not differing according to the type of device (Log-rank P = NS). The median longevity of CDI generators was 6.9 years, in line with the expected survival of elderly patients. Conversely, the median CRT-D longevity was 5.8 years, lower than the average survival of the elderly. For this reason, 21% of these CRT-D carriers were subsequently subjected to generator replacement, due to battery exhaustion. Conclusion: The effective longevity of ICDs is in agreement with an expected survival of elderly patients, for which it will not make sense to provide generators of shortened longevity for this population. The effective longevity of the CRTs is lower than the survival expectancy of the treatments, so that, paradoxically, generators with increased longevity should be favored.info:eu-repo/semantics/publishedVersio

Atrial fibrillation ablation : the added value of adenosine test in confirming pulmonary vein isolation

© The European Society of Cardiology 2018. All rights reserved.Introduction: Adenosine test has been increasingly used to confirm pulmonary vein isolation (PVI) in patients undergoing ablation of atrial fibrillation (AF). However, its impact on the success of ablation remains unknown. Purposes: To evaluate the results of the adenosine triphosphate (ATP) test in patients undergoing PVI and assess the success of ablation related to the use of this test (adenosine-guided PVI versus conventional PVI). Methods: Single-center prospective study of consecutive patients undergoing first AF ablation procedure, started at January 2013. After ablation, the persistence of PVI was tested with adenosine triphosphate administration (15–30mg by intravenous route). When adenosine triphosphate-induced pulmonary vein conduction (termed as reconduction) was observed, additional energy applications of radiofrequency were applied to obtain persistent isolation on retesting. Cardiac event recorder was performed at 7 days, 3, 6 and 12 months after ablation and annually from the 2nd year. The adenosine triphosphate-induced reconduction rate was evaluated depending on the pulmonary vein involved. The impact of adenosine test implementation in the success of the ablation at 365 days (recurrence of AF or supraventricular tachycardia) was determined by analysis of overall survival using Kaplan-Meier method. Results: Adenosine test was performed on 151 patients, with reconduction detected on at least one of the pulmonary veins in 11 patients (33.8%) and in 17.6% of the 641 pulmonary veins evaluated, with no statistically significant difference between the different veins. The overall success rate of AF ablation at 365 days was 72% and did not differ significantly between adenosine-guided PVI versus conventional PVI (74.3% versus 70.8%, P = NS), although the duration of follow-up had been shorter in the first group (median of 13.0 vs. 38.3 months; p<0.001). Conclusion: The adenosine-induced reconduction occurs in about one third of the patients. However, the additional adenosine-guided energy applications do not seem to increase the overall success of ablation. We found no significant reduction in the 1 year incidence of recurrent atrial tachyarrhythmias by ATP-guided PVI compared with conventional PVI.info:eu-repo/semantics/publishedVersio

A large outbreak of Legionnaires’ Disease in an industrial town in Portugal

Background We describe the investigation and control of an outbreak of Legionnaires’ disease in Portugal in October, November and December 2014. Methods Confirmed cases were individuals with pneumonia, laboratory evidence of Legionella pneumophila serogroup 1 and exposure, by residence, occupational or leisure to the affected municipalities. 49 possible sources were reduced to four potential sources, all industries with wet cooling system, following risk assessment. We geo-referenced cases’ residences and the location of cooling towers defining four study areas 10 km buffer centered on each cooling tower system. We compared the number of cases with expected numbers, calculated from the outbreak's attack rates applied to 2011 census population. Using Stones’ Test, we tested observed to expected ratios for decline in risk, with distance up to 10 km four directions. Isolates of Legionella pneumophila were compared using molecular methods. Results We identified 403 cases, 377 of which were confirmed, 14 patients died. Patients became ill between 14 October and 2 December. A NE wind and thermal inversion were recorded during the estimated period of exposure. Disease risk was highest in people living south west from all of the industries identified and decreased with distance (p < 0.001). 71 clinical isolates demonstrated an identical SBT profile to an isolate from a cooling tower. Whole genome sequencing identified an unusual L. pneumophila subsp. fraseri serogroup 1 as the outbreak causative strain, and confirmed isolates’ relatedness. Conclusions Industrial wet cooling systems, bacteria with enhanced survival characteristics and a combination of climatic conditions contributed to the second largest outbreak of Legionnaires’ disease recorded internationally.info:eu-repo/semantics/publishedVersio

A prospective survey in European Society of Cardiology member countries of atrial fibrillation management: baseline results of EURO bservational Research Programme Atrial Fibrillation (EORP-AF) Pilot General Registry

Aims: Given the advances in atrial fibrillation (AF) management and the availability of new European Society of Cardiology (ESC) guidelines, there is a need for the systematic collection of contemporary data regarding the management and treatment of AF in ESC member countries. Methods and results: We conducted a registry of consecutive in- and outpatients with AF presenting to cardiologists in nine participating ESC countries. All patients with an ECG-documented diagnosis of AF confirmed in the year prior to enrolment were eligible. We enroled a total of 3119 patients from February 2012 to March 2013, with full data on clinical subtype available for 3049 patients (40.4% female; mean age 68.8 years). Common comorbidities were hypertension, coronary disease, and heart failure. Lone AF was present in only 3.9% (122 patients). Asymptomatic AF was common, particularly among those with permanent AF. Amiodarone was the most common antiarrhythmic agent used (~20%), while beta-blockers and digoxin were the most used rate control drugs. Oral anticoagulants (OACs) were used in 80% overall, most often vitamin K antagonists (71.6%), with novel OACs being used in 8.4%. Other antithrombotics (mostly antiplatelet therapy, especially aspirin) were still used in one-third of the patients, and no antithrombotic treatment in only 4.8%. Oral anticoagulants were used in 56.4% of CHA 2DS2-VASc = 0, with 26.3% having no antithrombotic therapy. A high HAS-BLED score was not used to exclude OAC use, but there was a trend towards more aspirin use in the presence of a high HAS-BLED score. Conclusion: The EURObservational Research Programme Atrial Fibrillation (EORP-AF) Pilot Registry has provided systematic collection of contemporary data regarding the management and treatment of AF by cardiologists in ESC member countries. Oral anticoagulant use has increased, but novel OAC use was still low. Compliance with the treatment guidelines for patients with the lowest and higher stroke risk scores remains suboptimal. © The Author 2013