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Chagas' disease and Lyme disease are two endemic, vector-borne zoonotic infectious diseases that impact multiple organ systems, including the heart. Chagas' cardiomyopathy is a progressive process that can evolve into a dilated cardiomyopathy and heart failure several decades after the acute infection; in contrast, although early-disseminated Lyme carditis has been relatively well characterized, the sequelae of Lyme disease on the heart are less well-defined. A century of research on Chagas' cardiomyopathy has generated compelling data for pathophysiological models, evaluated the efficacy of therapy in large randomized controlled trials, and explored the social determinants of health impacting preventative measures. Recognizing the commonalities between Chagas' disease and Lyme disease, we speculate on whether some of the lessons learned from Chagas' cardiomyopathy may be applicable to Lyme carditis.

In December 2019, reports of an unknown pneumonia not responsive to traditional treatments arose in Wuhan, China. The pathogen was subsequently identified as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), known to be responsible for the coronavirus disease-2019 (COVID-19) illness, and public health emergency of international concern was declared by the World Health Organization. There is increasing awareness of the cardiovascular manifestations of COVID-19 disease, and the adverse impact of cardiovascular involvement on its prognosis. In this setting, the electrocardiogram (ECG) is one of the leading tools to assess the extent of cardiac involvement in COVID-19 patients, due to its wide disponibility, low cost, and the possibility of remote evaluation. In this article, we review the role of the ECG in the identification of cardiac involvement in COVID-19, highlighting relevant clinical implications.

Chagas disease is an important public health problem in Latin America. However, migration and globalisation have resulted in the increased presence of Chagas disease worldwide. Sudden cardiac death is the leading cause of death in people with Chagas disease, most often due to ventricular fibrillation. Although more common in patients with documented ventricular arrhythmias, sudden cardiac death can also be the first manifestation of Chagas disease in patients with no previous symptoms or known heart failure. Major predictors of sudden cardiac death include cardiac arrest, sustained and non-sustained ventricular tachycardia, left ventricular dysfunction, syncope and bradycardia. The authors review the predictors and risk stratification score developed by Rassi et al. for death in Chagas heart disease. They also discuss the evidence for anti-arrhythmic drugs, catheter ablation, ICDs and pacemakers for the prevention of sudden cardiac death in these patients. Given the widespread global burden, understanding the risk stratification and prevention of sudden cardiac death in Chagas disease is of timely concern.

Lyme disease, a tickborne infection caused by Borrelia burgdorferi, can affect cardiac tissue causing Lyme carditis. Patients with Lyme carditis most commonly present with varying degrees of atrioventricular block and rarely with sick sinus syndrome. A previously healthy 22 year-old male presented with syncope. His 2 week Holter monitor showed sinus pauses of 6.5 and 6.8 s. Lyme serology, including Western blot, was positive. A stress test, completed after 8 days of intravenous antibiotics for Lyme carditis, revealed no conduction abnormalities. He was discharged on 3 weeks of oral antibiotics and had no conduction abnormalities on subsequent follow-up.

The incidence of Lyme disease, a tick-borne bacterial infection, is dramatically increasing in North America. The diagnosis of Lyme carditis (LC), an early disseminated manifestation of Lyme disease, has important implications for patient management and preventing further extracutaneous complications. High-degree atrioventricular block is the most common presentation of LC, and usually resolves with antibiotic therapy. A systematic approach to the diagnosis of LC in patients with high-degree atrioventricular block will facilitate the identification of this usually transient condition, thus preventing unnecessary implantation of permanent pacemakers in otherwise healthy young individuals.

As cardiovascular implantable electronic devices (CIEDs) are increasingly indicated in older patients, and the burden of cancer is rising with the aging population, the management of patients with CIEDs who require radiotherapy (RT) is a timely concern. The objective of the study was to evaluate the management of, and malfunctions in, patients with CIEDs undergoing RT. A retrospective study of patients with CIEDs receiving RT at Kingston Health Sciences Center from March 2007–April 2018 was conducted. Data on demographics, RT, devices, and management were compared for the primary outcome of device malfunction. Of the 189 patients with CIEDs receiving a total of 297 courses of RT, 4 patients (2.1%) experienced device malfunctions. Higher beam energy was associated with a malfunction (p

Proficiency-based knot-tying curricula have been developed for square knots for medical students, but, to our knowledge, no such curriculum exists for the reverse half hitch alternating-post (RHAP) knot. We aimed to compare medical students' knot-tying proficiency, knot-tying self-confidence and final knot characteristics for RHAP and square knots in a simulated deep body cavity.We performed a within-subject prospective crossover study of novice medical students who received 30 minutes of training in tying both RHAP and square knots. Participant performance was assessed via a knot-tying checklist, and knot configuration, tensile strength, tightness (loop circumference) and mechanism of failure were also assessed. Participants' self-reported confidence in knot tying was captured.Twenty-one students participated in the study. Mean scores on the knot-tying checklist were significantly higher for RHAP knots than for square knots (6.9 [standard deviation (SD) 2.1] v. 5.2 [SD 2.3],Novice medical students were more proficient in tying RHAP knots than square knots in a simulated deep body cavity. Students were able to construct RHAP knots more securely and reported increased confidence in tying RHAP knots at depth compared to square knots.Des programmes d'enseignement fondés sur la compétence dans l'exécution de nœuds chirurgicaux par les étudiants en médecine ont été créés pour les nœuds plats, mais autant que nous sachions, un tel programme n'existe pas pour le nœud de type demi-clé inversée alternée. Nous avons comparé les aptitudes d'exécution de nœuds et la confiance des étudiants en médecine, ainsi que les caractéristiques des nœuds résultants, pour les nœuds de type demi-clé inversée alternée et les nœuds plats, dans une simulation de cavité profonde.Nous avons réalisé une étude croisée prospective intra-sujet portant sur des étudiants en médecine débutants, qui ont reçu une formation de 30 minutes sur l'exécution de nœuds de type demi-clé inversée alternée et de nœuds plats. Le travail des participants a été évalué à l'aide d'une liste de vérification d'exécution des nœuds; la configuration des nœuds, la résistance à la traction, le serrage (circonférence de la boucle) et le mécanisme de défaillance ont aussi été évalués. La confiance en soi rapportée par les participants quant à leurs aptitudes d'exécution de nœuds a aussi été examinée.Vingt-et-un étudiants ont pris part à cette étude. Les scores moyens de la liste de vérification d'exécution des nœuds étaient significativement plus élevés pour les nœuds de type demi-clé inversée alternée que pour les nœuds plats (6,9 [écart-type (É.T.) : 2,1] contre 5,2 [É.T. : 2,3],Les aptitudes des étudiants en médecine débutants pour l'exécution de nœuds de type demi-clé inversée alternée étaient supérieures à leurs aptitudes pour l'exécution de nœuds plats, lors d'une simulation de cavité profonde. Les étudiants ont pu réaliser des nœuds de type demi-clé inversée alternée plus solides et ont rapporté une confiance plus grande quant à l'exécution de ce type de nœuds que pour l'exécution de nœuds plats en profondeur.

Atrial fibrillation (AF) is a risk factor for ischemic stroke and reported to be associated with severe obstructive sleep apnea (OSA). The aim of this study was to determine the occurrence of newly detected AF in patients with severe OSA and no previous history of AF. Prospective observational study included patients with severe OSA (Apnea-Hypopnea Index [AHI] ≥ 30) and no history of AF. Primary outcome was detection of AF lasting ≥10 seconds. Patients were subjected to 2 24-hour Holter monitors, and if no AF was detected, implanted with a Medtronic Reveal XT implantable loop recorder. Follow-up was done every 6 months for a total of 3years. Implantable loop recorder was explanted if the primary outcome was detected (AF) or the battery was exhausted. Of the 31 patients enrolled, 6 withdrew participation in the study before implantation. Mean age was 57 ± 10years, mean body mass index was 35 ± 6; 52% male patients. Hypertension 56% and coronary artery disease 24%. Mean AHI was 55 ± 18. AF was detected in 5 patients (20%). AF mean duration was 4.8hours (range 20 seconds to 15.3 hours). Mean time to diagnosis was 11 ± 7 months. Male gender was predictive for AF detection (p = 0.04). Continuous positive airway pressure therapy was used by 96% of patients with 68% total adherence. Mean follow-up was 27 months. In conclusion, extended cardiac monitoring of patients with severe OSA may facilitate the identification of newly detected AF.

Prolonged QRS duration, which reflects a higher degree of mechanical dysynchrony, is a predictor of response to CRT. However, the association of QRS narrowing after biventricular pacing with CRT response rates is not clear. Our aim was to conduct a systematic review and meta-analysis on the association between QRS narrowing after cardiac resynchronization therapy (CRT) and clinical and echocardiographic response to CRT in patients with heart failure. Two independent investigators searched MedLine and EMBASE databases through July 2018 without any limitations. Studies providing estimates (continuous data) on the association of QRS shortening with either clinical (defined as New York Heart Association (NYHA) reduction ≥ 1) or echocardiographic (defined as left ventricular end-systolic volume (LVESV) reduction ≥ 15%) response to CRT were finally included in the quantitative synthesis. We included 32 studies (14 studies (1274 patients mean age 64 years old, males 79.3%) using clinical CRT response and 18 studies (1270 patients, mean age 64 years old, males 69.1%) using echocardiographic CRT response). A significant association between QRS narrowing and shorter attained QRS duration with clinical and echocardiographic CRT response was observed. The observed association was independent of the timing of QRS width measurement after CRT implantation. Acute and late improvement of electrical dysynchrony as depicted by QRS narrowing following biventricular pacing is associated with clinical and echocardiographic response to CRT. However, large prospective studies are needed to further examine our findings.

Background The risk stratification of coronary heart disease (CHD) and/or heart failure (HF) patients with easily measured electrocardiographic markers is of clinical importance. The aim of this meta‐analysis is to indicate whether increased QT dispersion (QTd) is associated with fatal and nonfatal outcomes in patients with CHD and/or HF. Methods We systematically searched MEDLINE and Cochrane databases without restrictions until August 15, 2018 using the keyword “QT dispersion”. Studies including data on the association between QTd and all‐cause mortality, sudden cardiac death (SCD) or arrhythmic events in patients with HF and/or CHD were classified as eligible. Results In the analysis including patients with CHD and/or HF, we found that QTd did not differ significantly in patients with SCD compared to no SCD patients while QTd was significantly greater in the group of all‐cause mortality patients and in patients who experienced a sustained ventricular arrhythmia. Subgroup analysis showed that in myocardial infarction studies, QTd was significantly higher in patients with an arrhythmic event compared to arrhythmic event‐free patients while a nonsignificant difference was found in QTd in patients who died from any cause compared to survivors. Similarly, in HF patients, the QTd was significantly greater in patients with an arrhythmic event while a nonsignificant difference was found regarding all‐cause mortality and SCD outcomes. Conclusions QTd has a prognostic role for stratifying myocardial infarction or HF patients who are at higher risk of arrhythmic events. However, no prognostic role was found regarding all‐cause mortality or SCD in this patient population., QTd has a prognostic role for stratifying myocardial infarction or HF patients who are at higher risk of arrhythmic events. However, no prognostic role was found regarding all‐cause mortality or SCD in this patient population.

Background Obstructive sleep apnea (OSA) is strongly associated with atrial fibrillation (AF). Long-term ECG monitoring with implantable loop recorders facilitates the identification of undiagnosed AF in 20% of severe OSA cases. However, ambulatory ECG (AECG) monitoring is less resource intensive, and various parameters have been shown to predict AF. The aim of this study was to assess the efficacy of such AECG-based AF predictors in identifying patients with severe OSA most at risk. Methods Prospective observational study including patients with severe OSA and no history of AF. Patients had two 24-h AECG recordings, and if no AF was detected, implanted with a loop recorder (maximum 3 years). Results Of 25 patients implanted, AF ≥ 10 s was detected in 5 patients. None of the parameters from the AECG recordings were significantly different between patients who did and did not develop AF. Conclusions AECG-based parameters were not effective for the prediction of AF in this severe OSA cohort.

Background Atrial fibrillation (AF), which affects 1% to 4% of the general population, is an important risk factor for stroke. New technologies for AF screening are now available, but their real-world application in clinical settings has not yet been thoroughly investigated. The aim of this project was to describe the introduction and feasibility of a mobile electrocardiogram (ECG) device for AF screening in a large-scale, undifferentiated population. Methods A total of 184 Canadian primary care physicians were provided with a KardiaMobile ECG device (AliveCor) for 3 months. Physicians were asked to obtain a single 30-second ECG recording of all patients seen in their daily practice who were ≥65 years old and not previously diagnosed with AF. Evaluation of the Kardia device by physicians was measured using a Likert scale–based questionnaire. Results One hundred thirty-three physicians (72%) reported their findings and completed the survey. A total of 7585 patients were screened (42% of eligible patients). AF was detected in 471 patients (6.2%). Anticoagulation therapy was initiated in 270 patients (57%). Physicians generally reported a high perceived clinical value (94%) and ease of integration (89%) of the device. Conclusions Previously undiagnosed AF is common in older individuals attending primary care clinics. The KardiaMobile ECG device appears to be an effective screening tool for AF with high physician acceptability. More research on the feasibility of such novel technologies is warranted for future consideration of integration in population-based screening programs.

BACKGROUND: Lyme carditis (LC), an early manifestation of Lyme disease that most commonly presents as high‐degree atrioventricular block (AVB), usually resolves with antibiotic treatment. When LC is not identified as the cause of AVB, a permanent pacemaker may be inappropriately implanted in a reversible cardiac conduction disorder. HYPOTHESIS: The likelihood that a patient's high‐degree AVB is caused by LC can be evaluated by clinical characteristics incorporated into a risk stratification tool. METHODS: A systematic review of all published cases of LC with high‐degree AVB, and five cases from the authors' experience, was conducted. The results informed the development of a new risk stratification tool, the Suspicious Index in LC (SILC) score. The SILC score was then applied to each case included in the review. RESULTS: Of the 88 cases included, 51 (58%) were high‐risk, 31 (35.2%) intermediate‐risk, and 6 (6.8%) low‐risk for LC according to the SILC score (sensitivity 93.2%). For the subset of 32 cases that reported on all SILC variables, 24 (75%) cases were classified as high‐risk, 8 (25%) intermediate‐risk, and 0 low‐risk (sensitivity 100%). Specificity could not be assessed (no control group). Notably, 6 of the 11 patients who received permanent pacemakers had reversal of AVB with antibiotic treatment. CONCLUSION: The SILC risk score and COSTAR mnemonic (constitutional symptoms; outdoor activity; sex = male; tick bite; age

See related articles at [[www.cmaj.ca/lookup/doi/10.1503/cmaj.191279][2]][2] and [[www.cmaj.ca/lookup/doi/10.1503/cmaj.191194][3]][3] A 56-year-old woman presented to the emergency department with a new well-defined erythematous patch on her right clavicular region ([Figure 1][3]), myalgia and

Lyme carditis (LC) is a manifestation of the early disseminated stage of Lyme disease and often presents as high-degree atrioventricular (AV) block. High-degree AV block in LC can be treated with antibiotics, usually resolving with a highly favorable prognosis, thus preventing the unnecessary implantation of permanent pacemakers. We present a systematic approach to the diagnosis and management of LC that implements the Suspicious Index in Lyme Carditis (SILC) risk stratification score.

We read with interest the paper by Asghar et al. [(1)][1] on gender differences in authorship of cardiology literature. This paper highlights the value of mentorship in promoting gender equity and reported a significant increase in the proportion of female first and senior authors over time. The

Atrial fibrillation (AF) often complicates the course of inherited cardiomyopathies and, in some cases, may be the presenting feature. Each inherited cardiomyopathy has its own peculiar pathogenetic characteristics that can contribute to the development and maintenance of AF. Atrial fibrillation may occur as a consequence of disease-specific defects, non-specific cardiac chamber changes secondary to the primary illness, or a combination thereof. The presence of AF can denote a turning point in the progression of the disease, promoting clinical deterioration and increasing morbidity and mortality. Furthermore, the management of AF can be particularly challenging in patients with inherited cardiomyopathies. In this article, we review the current information on the prevalence, pathophysiology, risk factors, and treatment of AF in three different inherited cardiomyopathies: hypertrophic cardiomyopathy, arrhythmogenic right ventricular dysplasia/cardiomyopathy, familial dilated cardiomyopathy, and left ventricular non-compaction cardiomyopathy.

Because cardiovascular implantable electronic devices are increasingly indicated in older patients, and the burden of cancer is rising with the growth and aging of the world population, the management of patients with cardiac devices who require radiotherapy for cancer treatment is a timely concern. Device malfunctions might occur in as high as 3% of radiotherapy courses, posing a substantial issue in clinical practice. A nonsystematic comprehensive review was undertaken. We searched PubMed and the MEDLINE database for randomized controlled trials, meta-analyses, systematic reviews, observational studies, in vitro / in vivo studies, and case reports. Articles were selected by 2 independent reviewers, and emphasis was given to information of interest to a general medical readership. The pathophysiology and predictors of cardiovascular implantable electronic device malfunction due to radiotherapy are reviewed, recommendations for the management of patients with such devices undergoing radiotherapy are summarized, and the clinical significance and future directions of this field are discussed. Radiotherapy-induced device malfunctions are rare, but because of the potential complications, the development of evidence-based guidelines for the management of patients with cardiovascular implantable electronic devices undergoing radiotherapy is a timely concern.

Atrial fibrillation (AF) is an important risk factor for ischemic stroke and reported to be associated with severe obstructive sleep apnea (OSA). The aim of this study was to determine the occurrence of new onset AF in patients with severe OSA and no prior history of AF. Prospective observational

© 2017 Osteoarthritis Research Society International Objective Whole-body vibration (WBV) is a popular fitness trend based on claims of increased muscle mass, weight loss and reduced joint pain. Following its original implementation as a treatment to increase bone mass in patients with osteoporosis, WBV has been incorporated into clinical practice for musculoskeletal disorders, including back pain. However, our recent studies revealed damaging effects of WBV on joint health in a murine model. In this report, we examined potential mechanisms underlying disc degeneration following exposure of mice to WBV. Methods Ten-week-old male mice were exposed to WBV (45 Hz, 0.3 g peak acceleration, 30 min/day, 5 days/week) for 4 weeks, 8 weeks, or 4 weeks WBV followed by 4 weeks recovery. Micro-computed tomography (micro-CT), histological, and gene expression analyses were used to assess the effects of WBV on spinal tissues. Results Exposure of mice to 4 or 8 weeks of WBV did not alter total body composition or induce significant changes in vertebral bone density. On the other hand, WBV-induced intervertebral disc (IVD) degeneration, associated with decreased disc height and degenerative changes in the annulus fibrosus (AF) that did not recover within 4 weeks after cessation of WBV. Gene expression analysis showed that WBV for 8 weeks induced expression of Mmp3, Mmp13, and Adamts5 in IVD tissues, changes preceded by increased expression of Il-1β. Conclusions Progressive IVD degeneration induced by WBV was associated with increased expression of Il-1β within the IVD that preceded Mmp and Adamts gene induction. Moreover, WBV-induced IVD degeneration is not reversed following cessation of vibration.

Summary Objective Low-amplitude, high-frequency whole-body vibration (WBV) has been adopted for the treatment of musculoskeletal diseases including osteoarthritis (OA); however, there is limited knowledge of the direct effects of vibration on joint tissues. Our recent studies revealed striking damage to the knee joint following exposure of mice to WBV. The current study examined the effects of WBV on specific compartments of the murine tibiofemoral joint over 8 weeks, including microarchitecture of the tibia, to understand the mechanisms associated with WBV-induced joint damage. Design Ten-week-old male CD-1 mice were exposed to WBV (45 Hz, 0.3 g peak acceleration; 30 min/day, 5 days/week) for 4 weeks, 8 weeks, or 4 weeks WBV followed by 4 weeks recovery. The knee joint was evaluated histologically for tissue damage. Architecture of the subchondral bone plate, subchondral trabecular bone, primary and secondary spongiosa of the tibia was assessed using micro-CT. Results Meniscal tears and focal articular cartilage damage were induced by WBV; the extent of damage increased between 4 and 8-week exposures to WBV. WBV did not alter the subchondral bone plate, or trabecular bone of the tibial spongiosa; however, a transient increase was detected in the subchondral trabecular bone volume and density. Conclusions The lack of WBV-induced changes in the underlying subchondral bone suggests that damage to the articular cartilage may be secondary to the meniscal injury we detected. Our findings underscore the need for further studies to assess the safety of WBV in the human population to avoid long-term joint damage.