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Amit G.,Hamilton Health Sciences | Wang J.,Hamilton Health Sciences | Connolly S.J.,Hamilton Health Sciences | Glikson M.,Leviev Heart Center | And 15 more authors.
Journal of Cardiovascular Electrophysiology | Year: 2016

ICD Lead Position and Outcome Introduction We aim to compare the acute and long-term success of defibrillation between non-apical and apical ICD lead position. Methods and Results The position of the ventricular lead was recorded by the implanting physician for 2,475 of 2,500 subjects in the Shockless IMPLant Evaluation (SIMPLE) trial, and subjects were grouped accordingly as non-apical or apical. The success of intra-operative defibrillation testing and of subsequent clinical shocks were compared. Propensity scoring was used to adjust for the impact of differences in baseline variables between these groups. There were 541 leads that were implanted at a non-apical position (21.9%). Patients implanted with a non-apical lead had a higher rate of secondary prevention indication. Non-apical location resulted in a lower mean R-wave amplitude (14.0 vs. 15.2, P < 0.001), lower mean pacing impedance (662 ohm vs. 728 ohm, P < 0.001), and higher mean pacing threshold (0.70 V vs. 0.66 V, P = 0.01). Single-coil leads and cardiac resynchronization devices were used more often in non-apical implants. The success of intra-operative defibrillation was similar between propensity score matched groups (89%). Over a mean follow-up of 3 years, there were no significant differences in the yearly rates of appropriate shock (5.5% vs. 5.4%, P = 0.98), failed appropriate first shock (0.9% vs. 1.0%, P = 0.66), or the composite of failed shock or arrhythmic death (2.8% vs. 2.3% P = 0.35) according to lead location. Conclusion We did not detect any reduction in the ICD efficacy at the time of implant or during follow-up in patients receiving a non-apical RV lead. © 2016 Wiley Periodicals, Inc. Source


Rundell K.W.,The Commonwealth Medical College | Anderson S.D.,Royal Prince Alfred Hospital | Sue-Chu M.,Norwegian University of Science and Technology | Bougault V.,University of Lille Nord de France | Boulet L.-P.,Institute University Of Cardiologie Et Of Pneumologie Of Quebecqc
Comprehensive Physiology | Year: 2015

Exercise-induced bronchoconstriction (EIB) is exaggerated constriction of the airways usually soon after cessation of exercise. This is most often a response to airway dehydration in the presence of airway inflammation in a person with a responsive bronchial smooth muscle. Severity is related to water content of inspired air and level of ventilation achieved and sustained. Repetitive hyperpnea of dry air during training is associated with airway inflammatory changes and remodeling. A response during exercise that is related to pollution or allergen is considered EIB. Ozone and particulate matter are the most widespread pollutants of concern for the exercising population; chronic exposure can lead to new-onset asthma and EIB. Freshly generated emissions particulate matter less than 100 nm is most harmful. Evidence for acute and long-term effects from exercise while inhaling high levels of ozone and/or particulate matter exists. Much evidence supports a relationship between development of airway disorders and exercise in the chlorinated pool. Swimmers typically do not respond in the pool; however, a large percentage responds to a dry air exercise challenge. Studies support oxidative stress mediated pathology for pollutants and a more severe acute response occurs in the asthmatic. Winter sport athletes and swimmers have a higher prevalence of EIB, asthma and airway remodeling than other athletes and the general population. Because of fossil fuel powered ice resurfacers in ice rinks, ice rink athletes have shown high rates of EIB and asthma. For the athlete training in the urban environment, training during low traffic hours and in low traffic areas is suggested. © 2015 American Physiological Society. Source


Boothroyd L.J.,Institute National dExcellence en Sante et en Services Sociaux | Lambert L.J.,Institute National dExcellence en Sante et en Services Sociaux | Segal E.,Sir Mortimer B. Davis Jewish General Hospital | Segal E.,Corporation dUrgences sante | And 9 more authors.
American Journal of Cardiology | Year: 2014

In a systematic province-wide evaluation of care and outcomes of ST elevation myocardial infarction (STEMI), we sought to examine whether a previously documented association between ambulance use and outcome remains after control for clinical risk factors. All 82 acute care hospitals in Quebec (Canada) that treated at least 30 acute myocardial infarctions annually participated in a 6-month evaluation in 2008 to 2009. Medical record librarians abstracted hospital chart data for consecutive patients with a discharge diagnosis of myocardial infarction who presented with characteristic symptoms and met a priori study criteria for STEMI. Linkage to administrative databases provided outcome data (to 1 year) and co-morbidities. Of 1,956 patients, 1,222 (62.5%) arrived by ambulance. Compared with nonusers of an ambulance, users were older, more often women, and more likely to have co-morbidities, low systolic pressure, abnormal heart rate, and a higher Thrombolysis In Myocardial Infarction risk index at presentation. Ambulance users were less likely to receive fibrinolysis or to be sent for primary angioplasty (78.5% vs 83.2% for nonusers, p = 0.01), although if they did, treatment delays were shorter (p <0.001). The 1-year mortality rate was 18.7% versus 7.1% for nonusers (p <0.001). Greater mortality persisted after adjusting for presenting risk factors, co-morbidities, reperfusion treatment, and symptom duration (hazard ratio 1.56, 95% confidence interval 1.30 to 1.87). In conclusion, ambulance users with STEMI were older and sicker than nonusers. Mortality of users was substantially greater after adjustment for clinical risk factors, although they received faster reperfusion treatment overall. © 2014 Elsevier Inc. All rights reserved. Source


Boivin J.,University Laval | Beddar S.,University of Houston | Guillemette M.,University Laval | Guillemette M.,Institute University Of Cardiologie Et Of Pneumologie Of Quebecqc | Beaulieu L.,University Laval
IFMBE Proceedings | Year: 2015

A plastic scintillation detector (PSD) has been developed and optimized to measure dose rate in real-time for low energy beams. The PSD is composed of a scintillating fiber coupled to a clear optical fiber transmitting the scintillator’s light to a photodetector. A spectrometer was used to characterize the scintillator’s spectrum under low and high energy exposures. Seven photodetectors were then evaluated to identify their operating range and potential applications. They comprise a photomultiplier tube (PMT), an avalanche photodiode, two passive diodes of which, and a set of three CCD cameras. The scintillator was exposed to low energy potential beams (120 kVp, 180 kVp, and 220 kVp) of an orthovoltage unit. The source-to-detector distance was varied to explore a broad dose rate range likely to be used in radiology and superficial treatment. Every detector could measure dose rate down to 10 mGy/s while keeping a relative standard deviation below 2%. The CCD cameras were the less sensitive devices, but they allow multiple fibers to be read simultaneously. Among the photodetectors, the PMT was found to be the most sensitive detector with a relative standard deviation of less than 1% at the lowest dose rate available. The PMT was then included in the PSD design for an in vivo study in interventional radiology where low dose rate sensitivity is essential. The PSD was located inside a plastic water phantom to measure skin and depth dose from 1 mm down to 24 cm. There was less than a 2% difference between the PSD measured dose rate and the ion chamber reading located at the same depth. These results indicate that a broad range of photodetectors can be used in the PSD design, but low dose rate measurements require very sensitive devices such as a PMT. © Springer International Publishing Switzerland 2015. Source


Ritchie A.J.,University of British Columbia | Sanghera C.,University of British Columbia | Jacobs C.,Royal Brisbane Hospital | Zhang W.,University of British Columbia | And 17 more authors.
Journal of Thoracic Oncology | Year: 2016

Objectives: To implement a cost-effective low-dose computed tomography (LDCT) lung cancer screening program at the population level, accurate and efficient interpretation of a large volume of LDCT scans is needed. The objective of this study was to evaluate a workflow strategy to identify abnormal LDCT scans in which a technician assisted by computer vision (CV) software acts as a first reader with the aim to improve speed, consistency, and quality of scan interpretation. Methods: Without knowledge of the diagnosis, a technician reviewed 828 randomly batched scans (136 with lung cancers, 556 with benign nodules, and 136 without nodules) from the baseline Pan-Canadian Early Detection of Lung Cancer Study that had been annotated by the CV software CIRRUS Lung Screening (Diagnostic Image Analysis Group, Nijmegen, The Netherlands). The scans were classified as either normal (no nodules ≥1 mm or benign nodules) or abnormal (nodules or other abnormality). The results were compared with the diagnostic interpretation by Pan-Canadian Early Detection of Lung Cancer Study radiologists. Results: The overall sensitivity and specificity of the technician in identifying an abnormal scan were 97.8% (95% confidence interval: 96.4-98.8) and 98.0% (95% confidence interval: 89.5-99.7), respectively. Of the 112 prevalent nodules that were found to be malignant in follow-up, 92.9% were correctly identified by the technician plus CV compared with 84.8% by the study radiologists. The average time taken by the technician to review a scan after CV processing was 208 ± 120 seconds. Conclusions: Prescreening CV software and a technician as first reader is a promising strategy for improving the consistency and quality of screening interpretation of LDCT scans. © 2016 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved. Source

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