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Taxus brevifolia, the Pacific yew, is an evergreen shrub that is common to the Pacific Northwest of North America. The Taxus spp. are often seen in decorative hedging and topiary, though historically have been referred to as the "death tree" for its known toxicity. The yew contains cardiotoxic alkaloids including taxine A and B, which are present in all parts of the plant except the red arils. Deliberate ingestions can result in life threatening effects including cardiac dysrhythmias, hemodynamic instability, and death without intervention. Serious toxicity following accidental ingestion is rare. A 38 year old woman was assessed on scene after ingesting yew needles in a suicide attempt. Shortly after Emergency Medical Services (EMS) arrival, she became unresponsive and pulseless. A wide complex ventricular tachycardia followed by bradycardia was reported. She received epinephrine, atropine, amiodarone, and several cardiac defibrillations but ultimately expired in the field thirty minutes later. Postmortem serum samples confirmed the presence of taxine B and isotaxine B. This case highlights the severe and rapid characteristics of taxine poisoning, despite being generally considered less toxic than other Taxus spp. Patients require aggressive and immediate medical care following intentional ingestions. [ABSTRACT FROM AUTHOR]

Epidemic increases in opioid deaths prompted policies limiting access to prescription opioids in North America. Consequently, the over-the-counter opioids loperamide (Imodium A-D) and mitragynine, the herbal ingredient in kratom, are increasingly used to avert withdrawal or induce euphoria. Arrhythmia events related to these nonscheduled drugs have not been systematically studied. In this study, we sought to explore opioid-associated arrhythmia reporting in North America. The U.S. Food and Drug Administration Adverse Event Reporting System (FAERS), Center for Food Safety and Applied Nutrition Adverse Event Reporting System (CAERS), and Canada Vigilance Adverse Reaction (CVAR) databases were searched (2015-2021). Reports involving nonprescription drugs (loperamide, mitragynine) and diphenoxylate/atropine (Lomotil) were identified. Methadone, a prescription opioid (full agonist), served as a positive control owing to its established arrhythmia risk. Buprenorphine (partial agonist) and naltrexone (pure antagonist), served as negative controls. Reports were classified according to Medical Dictionary for Regulatory Activities terminology. Significant disproportionate reporting required a proportional reporting ratio (PRR) of ≥2, ≥3 cases, and chi-square ≥4. Primary analysis used FAERS data, whereas CAERS and CVAR data were confirmatory. Methadone was disproportionately associated with ventricular arrhythmia reports (PRR: 6.6; 95% CI: 6.2-7.0; n = 1,163; chi-square = 5,456), including 852 (73%) fatalities. Loperamide was also significantly associated with arrhythmia (PRR: 3.2; 95% CI: 3.0-3.4; n = 1,008; chi-square = 1,537), including 371 (37%) deaths. Mitragynine demonstrated the highest signal (PRR: 8.9; 95% CI: 6.7-11.7; n = 46; chi-square = 315), with 42 (91%) deaths. Buprenorphine, diphenoxylate, and naltrexone were not associated with arrhythmia. Signals were similar in CVAR and CAERS. The nonprescription drugs loperamide and mitragynine are associated with disproportionate reports of life-threatening ventricular arrhythmia in North America. [Display omitted] [ABSTRACT FROM AUTHOR]

Despite the wide adoption of insertable cardiac monitors (ICMs), high false‐positive rates, suboptimal signal quality, limited ability to detect atrial flutter, and lack of remote programming remain challenging. The LUX‐Dx PERFORM study was designed to evaluate novel technologies engineered to address these issues. Here, we present preliminary results from the trial focusing on the safety of ICM insertion, remote monitoring rates, and the feasibility of remote programming. LUX‐Dx PERFORM is a multicenter, prospective, single‐arm, post‐market, observational study with planned enrollment of up to 827 patients from 35 sites in North America. A preliminary cohort consisting of the first 369 patients who were enrolled between March and October 2021 was selected for analysis. Three hundred sixty‐three (363) patients had ICM insertions across inpatient and outpatient settings. The mean time followed was 103.4 ± 61.8 days per patient. The total infection rate was 0.8% (3/363). Interim results show high levels of remote monitoring with a median 94% of days with data transmission (interquartile range: 82–99). Thirteen (13) in‐clinic and 24 remote programming sessions were reported in 34 subjects. Reprogramming examples are presented to highlight signal quality, the ability to detect atrial flutter, and the positive impact of remote programming on patient management. Interim results from LUX‐Dx PERFORM study demonstrate the safety of insertion, high data transmission rates, the ability to detect atrial flutter, and the feasibility of remote programming to optimize arrhythmia detection and improve clinical workflow. Future results from LUX‐Dx PERFORM will further characterize improvements in signal quality and arrhythmia detection. [ABSTRACT FROM AUTHOR]

Aims Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVC) is characterized by ventricular arrhythmias (VAs) and sudden cardiac death (SCD). We aimed to develop a model for individualized prediction of incident VA/SCD in ARVC patients. Methods and results Five hundred and twenty-eight patients with a definite diagnosis and no history of sustained VAs/SCD at baseline, aged 38.2 ± 15.5 years, 44.7% male, were enrolled from five registries in North America and Europe. Over 4.83 (interquartile range 2.44–9.33) years of follow-up, 146 (27.7%) experienced sustained VA, defined as SCD, aborted SCD, sustained ventricular tachycardia, or appropriate implantable cardioverter-defibrillator (ICD) therapy. A prediction model estimating annual VA risk was developed using Cox regression with internal validation. Eight potential predictors were pre-specified: age, sex, cardiac syncope in the prior 6 months, non-sustained ventricular tachycardia, number of premature ventricular complexes in 24 h, number of leads with T-wave inversion, and right and left ventricular ejection fractions (LVEFs). All except LVEF were retained in the final model. The model accurately distinguished patients with and without events, with an optimism-corrected C-index of 0.77 [95% confidence interval (CI) 0.73–0.81] and minimal over-optimism [calibration slope of 0.93 (95% CI 0.92–0.95)]. By decision curve analysis, the clinical benefit of the model was superior to a current consensus-based ICD placement algorithm with a 20.3% reduction of ICD placements with the same proportion of protected patients (P < 0.001). Conclusion Using the largest cohort of patients with ARVC and no prior VA, a prediction model using readily available clinical parameters was devised to estimate VA risk and guide decisions regarding primary prevention ICDs (www.arvcrisk.com). [ABSTRACT FROM AUTHOR]

Over the past 50 years, pediatric and congenital electrophysiology has progressed from a rare subspecialty practiced at just a handful of centers to become an essential part of nearly every congenital heart program the world over. This paper traces the evolution of the subspecialty in North America by recognizing the individuals who dedicated their careers to this field and trained subsequent generations of practitioners, thereby establishing a legacy that insures continued progress in the treatment of arrhythmias for children and patients with congenital heart disease. Data were generated from a survey of the current membership of the Pediatric and Congenital Electrophysiology Society and were supplemented by review of archived Society records. Maps depicting the locations for clinicians and training centers over time provide a graphic display of progress in this field. [ABSTRACT FROM AUTHOR]

Background: Left ventricular (LV) fibrofatty infiltration in arrhythmogenic right ventricular (RV) dysplasia/cardiomyopathy (ARVD/C) has been reported, however, detailed cardiovascular magnetic resonance (CMR) characteristics and association with outcomes are uncertain. We aim to describe LV findings on CMR in ARVD/C patients and their relationship with arrhythmic outcomes. Methods: CMR of 73 subjects with ARVD/C according to the 2010 Task Force Criteria (TFC) were analyzed for LV involvement, defined as ≥ 1 of the following features: LV wall motion abnormality, LV late gadolinium enhancement (LGE), LV fat infiltration, or LV ejection fraction (LVEF) < 50%. Ventricular volumes and function, regional wall motion abnormalities, and the presence of ventricular fat or fibrosis were recorded. Findings on CMR were correlated with arrhythmic outcomes. Results: Of the 73 subjects, 50.7% had CMR evidence for LV involvement. Proband status and advanced RV dysfunction were independently associated with LV abnormalities. The most common pattern of LV involvement was focal fatty infiltration in the sub-epicardium of the apicolateral LV with a "bite-like" pattern. LGE in the LV was found in the same distribution and most often had a linear appearance. LV involvement was more common with non-PKP2 genetic mutation variants, regardless of proband status. Only RV structural disease on CMR (HR 3.47, 95% CI 1.13–10.70) and prior arrhythmia (HR 2.85, 95% CI 1.33–6.10) were independently associated with arrhythmic events. Conclusion: Among patients with 2010 TFC for ARVD/C, CMR evidence for LV abnormalities are seen in half of patients and typically manifest as fibrofatty infiltration in the subepicardium of the apicolateral wall and are not associated with arrhythmic outcomes. [ABSTRACT FROM AUTHOR]

Objective: Rare disease Background: Lyme borreliosis, caused by spirochetes of the Borrelia burgdorferi genospecies complex, is the most commonly reported tickborne infection in North America and those infected may present with cutaneous, cardiac, articular, and neuropsychiatric abnormalities. The protean nature of many of its clinical manifestations presents a diagnostic conundrum. Lyme disease can affect the heart, albeit rarely, with cardiac abnormalities usually manifesting as varying degrees of heart block or arrhythmias. Case Report: We present a case of complete heart block in a young man who participated in outdoor activities in a Lymeendemic area and developed fatigue and palpitations weeks after a flu-like illness. He noticed that his heart rate was low; he had an intermediate suspicious index in Lyme carditis (SILC) score with positive Lyme serologies. His initial electrocardiogram when he presented to the emergency department showed a complete heart block. In this case, he was successfully managed with intravenous ceftriaxone, amoxicillin, and a transcutaneous pacemaker, obviating the need for a permanent pacemaker. Conclusions: Electrocardiographic changes such as heart block and arrhythmias with or without symptoms may be the initial manifestation of Lyme carditis in a patient who may or may not remember a tick bite or have a typical skin rash. The SILC score may assist in recognizing these cases and prompt initiation of antibiotics usually leads to the resolution of these electrocardiographic abnormalities and symptoms that may be present. [ABSTRACT FROM AUTHOR]

Introduction: Atrial fibrillation (AF) is the commonest arrhythmia and a major cause of stroke and health care utilization. Researchers and administrators use electronic health data to assess disease burden, quality and variance in care, value of interventions and prognosis. We performed a systematic review and meta-analysis to assess the validity of AF case definitions in administrative databases. Methods: Medline was searched from 2000 to 2018. Extracted information included sensitivity, specificity, positive and negative predictive values (PPV and NPV) for various AF case definitions. Estimates were pooled using random-effects models due to significant heterogeneity between studies. Results: We identified 24 studies, including 21 from North America or Scandinavia. Hospital, ambulatory and mixed data sources were assessed in 10, 4 and 10 studies, respectively. Nine different AF case definitions were evaluated, most based on ICD-9 or 10 codes. Twenty-two studies assessed case definitions in patients diagnosed with AF and thus could generate PPV alone. Half the studies sampled unrestricted populations including a mix of those with and without AF to assess sensitivity. Only 13 studies included ECG confirmation as a gold standard. The pooled random effects estimates were: sensitivity 80% (95% CI 72–86%); specificity 98% (96–99%); PPV 88% (82–94%); NPV 97% (94–99%). Only 3 studies reported all accuracy parameters and included rhythm monitoring in the gold standard definition. Conclusion: Relatively few studies examined sensitivity, and fewer still included rhythm monitoring in the gold standard comparison. Administrative data may fail to identify a significant proportion of patients with AF. This, in turn, may bias estimates of quality of care and prognosis. [ABSTRACT FROM AUTHOR]

Background--Atrial fibrillation (AF) is the most common sustained arrhythmia; however, little is known about patients in a primary care setting from high-, middle-, and low-income countries. Methods and Results--This prospective registry enrolled patients presenting to an emergency department with AF at 164 sites in 46 countries representing all inhabited continents. Patient characteristics were compared among 9 major geographic regions. Between September 2008 and April 2011, 15 400 patients were enrolled. The average age was 65.9, standard deviation 14.8 years, ranging from 57.2, standard deviation 18.8 years in Africa, to 70.1, standard deviation 13.4 years in North America, P<0.001. Hypertension was globally the most common risk factor for AF, ranging in prevalence from 41.6% in India to 80.7% in Eastern Europe, P<0.001. Rheumatic heart disease was present in only 2.2% of North American patients, in comparison with 21.5% in Africa and 31.5% in India, P<0.001. The use of oral anticoagulation among patients with a CHADS2 score of ≤2 was greatest in North America (65.7%) but was only 11.2% in China, P<0.001. The mean time in the therapeutic range was 62.4% in Western Europe, 50.9% in North America, but only between 32% and 40% in India, China, Southeast Asia, and Africa, P<0.001. Conclusions--There is a large global variation in age, risk factors, concomitant diseases, and treatment of AF among regions. Improving outcomes globally requires an understanding of this variation and the conduct of research focused on AF associated with different underlying conditions and treatment of AF and predisposing conditions in different socioeconomic settings. [ABSTRACT FROM AUTHOR]

We describe the first case of cardiac arrhythmia ablation with the novel MediGuideTM non-fluoroscopic catheter tracking system in North America. This new technology uses electromagnetic field to track sensor integrated intracardiac electrophysiology catheters which are projected on pre-recorded fluoroscopy cine loops. This new technology permits catheter tracking in virtual biplane fluoroscopy and enhances spatial resolution of conventional 3D mapping systems while drastically reducing radiation exposure. [ABSTRACT FROM AUTHOR]

Background: The incidence of sudden cardiac death in persons under age 40 is roughly 3 per 100 000 persons per year in Germany and North America. Many of these deaths are found to be due to hereditary heart diseases, often a primary structural heart disease associated with arrhythmia or else a primary arrhythmia syndrome in a structurally normal heart. Such diseases are usually of autosomal dominant inheri -tance, often affect otherwise healthy persons, and can generally be well treated if recognized early. Patients commonly have affected relatives who are still asymptomatic. Methods: This review is based on articles up to May 2010 that were retrieved by a selective search of the Medline database via PubMed, with additional consideration of the relevant European and American guidelines and the German Law on Genetic Diagnosis. Results and conclusion: Hereditary arrhythmia syndromes are now found in more than half of all initially unexplained cases of sudden cardiac death in young persons. Among such cases, the hereditary arrhythmia syndrome is primary in 70% and caused by an arrhythmogenic structural heart disease in 30%. In addition to autopsy findings, a thorough family history, relevant medical findings obtained during life (if available), the examination of relatives, and directed molecular testing where appropiate enabled establishing the diagnosis. Arrthymia syndromes that can cause sudden death are often detectable during life if physicians and the public are appropriately sensitized. [ABSTRACT FROM AUTHOR]

Objectives: This study sought to examine the efficacy of empiric antiarrhythmic drugs in a rigorously characterized cohort of arrhythmogenic right ventricular cardiomyopathy (ARVC) patients. Background: Antiarrhythmic drugs are important in protecting against ventricular arrhythmias in ARVC, but no studies have provided data in a group rigorously screened for the disease. Methods: Antiarrhythmic medicines were examined in all subjects with implantable cardioverter-defibrillators (ICDs) enrolled in the North American ARVC Registry. A Cox proportional hazards model was used to account for time on each drug, and a hierarchical analysis was performed for repeated measures within individuals. Results: Ninety-five patients were studied, with a mean follow-up of 480 ± 389 days. Fifty-eight (61%) received beta-blockers, and these medicines were not associated with an increased or decreased risk of ventricular arrhythmias. Sotalol was associated with a greater risk of any clinically relevant ventricular arrhythmia as defined by sustained ventricular tachycardia or ICD therapy (hazard ratio [HR]: 2.55, 95% confidence interval [CI]: 1.02 to 6.39, p = 0.045), but this was not statistically significant after adjusting for potential confounders. An increased risk of any ICD shock and first clinically relevant ventricular arrhythmia while on sotalol remained significant after multivariable adjustment. Those on amiodarone (n = 10) had a significantly lower risk of any clinically relevant ventricular arrhythmia (HR: 0.25, 95% CI: 0.07 to 0.95, p = 0.041), a finding that remained significant after multivariable adjustment. Conclusions: In a cohort of well-characterized ARVC subjects, neither beta-blockers nor sotalol seemed to be protective. Evidence from a small number of patients suggests that amiodarone has superior efficacy in preventing ventricular arrhythmias. [Copyright &y& Elsevier]

To identify loci affecting the electrocardiographic QT interval, a measure of cardiac repolarisation associated with risk of ventricular arrhythmias and sudden cardiac death, we conducted a meta-analysis of three genome-wide association studies (GWAS) including 3,558 subjects from the TwinsUK and BRIGHT cohorts in the UK and the DCCT/EDIC cohort from North America. Five loci were significantly associated with QT interval at P<1x10-6. To validate these findings we performed an in silico comparison with data from two QT consortia: QTSCD (n = 15,842) and QTGEN (n = 13,685). Analysis confirmed the association between common variants near NOS1AP (P = 1.4x10-83) and the phospholamban (PLN) gene (P = 1.9x10-29). The most associated SNP near NOS1AP (rs12143842) explains 0.82% variance; the SNP near PLN (rs11153730) explains 0.74% variance of QT interval duration. We found no evidence for interaction between these two SNPs (P = 0.99). PLN is a key regulator of cardiac diastolic function and is involved in regulating intracellular calcium cycling, it has only recently been identified as a susceptibility locus for QT interval. These data offer further mechanistic insights into genetic influence on the QT interval which may predispose to life threatening arrhythmias and sudden cardiac death. [ABSTRACT FROM AUTHOR]

Atrial fibrillation is the most common sustained cardiac dysrhythmia treated in North America and Europe. As such, it is one of the current epidemics in cardiovascular disease. Findings from the AFFIRM (Atrial Fibrillation Follow-up: Investigation of Rhythm Management) and RACE (RAte Control versus Electrical cardioversion for persistent atrial fibrillation) clinical trials are presented and the current evidence for the management of atrial fibrillation using anticoagulation, rate-control, and rhythm-control strategies is outlined. Implications for nurses are discussed including physiologic and psychosocial interventions. [ABSTRACT FROM AUTHOR]

BACKGROUND There are several cardiac pacing options available to patients with sinus-node disease (SND), but each is associated with clinical disadvantages and the optimum strategy has not been identified. OBJECTIVE To test the hypothesis that DDD (dual-chamber) pacing with minimal right ventricular (RV) stimulation reduces the risk of atrial fibrillation (AF) in patients with SND, when compared with traditional DDD pacing. DESIGN AND INTERVENTION This was a randomized, controlled trial conducted at 72 treatment centers in the US and Canada between 15 January 2003 and 19 December 2006. All patients were older than 18 years of age, had SND with symptomatic bradycardia, and had a QRS interval of 120msec or less. Exclusion criteria were second or third-degree atrioventricular block, persistent AF, two or more cardioversions for AF in the 6 months prior to enrollment, and a life-expectancy of 2 years or less. All patients underwent implantation of a dual-chamber pacemaker (Kappa® 700, Kappa® 900, EnPulse®, or EnRhythm® [all Medtronic Inc., Minneapolis, MN]). Participants who passed an atrial pacing test were randomly assigned to receive conventional DDD pacing or DDD pacing with minimal RV stimulation. Ventricular pacing was suppressed using new pacemaker technology preserving the intrinsic atrioventricular conduction, thereby preventing ventricular desynchronization. Patients were followed up 1 month after enrollment and at 6-month intervals thereafter. OUTCOME MEASURES The primary outcome measure was time to first persistent episode of AE Secondary end points were proportion of atrial and ventricular beats paced and rate of heart-failure hospitalizations (HFH). RESULTS From a total of 1,321 screened patients, 1,065 were enrolled and randomly assigned to one of the treatment groups (conventional pacing=535; minimal RV pacing=530). The mean age of patients was 72 years. The mean ejection fraction in both groups was 58%, and 38% of all patients had a history of AE At baseline, more patients in the conventional-pacing group were receiving antiarrhythmic medication than were those in the minimal-RV-pacing group (22.8% vs 17.5%; P= 0.03). After a mean follow-up period of 1.7 years, the median proportion of paced ventricular beats was much higher (99.0% vs 9.1%; P<0.001) and there was a higher incidence of persistent AF (12.7% vs 7.9%; P=0.004) among patients in the conventional-pacing group than among those in the minimal-RV-pacing group. Multivariate analysis revealed that the minimal RV pacing strategy was associated with a 40% reduction in the relative risk of persistent AF when compared with conventional pacing (hazard ratio 0.60, 95% CI 0.41-0.88; P=0.009). There was no significant difference between the treatment groups in the rate of HFH. CONCLUSION Minimization of RV stimulation during DDD pacing reduces the risk of persistent AF in patients with SND when compared with traditional DDD pacing. [ABSTRACT FROM AUTHOR]

Background: In the ROCKET AF (Rivaroxaban-Once-daily, oral, direct Factor Xa inhibition Compared with vitamin K antagonism for prevention of stroke and Embolism Trial in Atrial Fibrillation) trial, marked regional differences in control of warfarin anticoagulation, measured as the average individual patient time in the therapeutic range (iTTR) of the international normalized ratio (INR), were associated with longer inter-INR test intervals. The standard Rosendaal approach can produce biased low estimates of TTR after an appropriate dose change if the follow-up INR test interval is prolonged. We explored the effect of alternative calculations of TTR that more immediately account for dose changes on regional differences in mean iTTR in the ROCKET AF trial., Methods and Results: We used an INR imputation method that accounts for dose change. We compared group mean iTTR values between our dose change-based method with the standard Rosendaal method and determined that the differences between approaches depended on the balance of dose changes that produced in-range INRs ("corrections") versus INRs that were out of range in the opposite direction ("overshoots"). In ROCKET AF, the overall mean iTTR of 55.2% (Rosendaal) increased up to 3.1% by using the dose change-based approach, depending on assumptions. However, large inter-regional differences in anticoagulation control persisted., Conclusions: TTR, the standard measure of control of warfarin anticoagulation, depends on imputing daily INR values for the vast majority of follow-up days. Our TTR calculation method may better reflect the impact of warfarin dose changes than the Rosendaal approach. In the ROCKET AF trial, this dose change-based approach led to a modest increase in overall mean iTTR but did not materially affect the large inter-regional differences previously reported., Clinical Trial Registration: URL: ClinicalTrials.gov. Unique identifier: NCT00403767., (© 2015 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.)

Objective: Operation for infective endocarditis is associated with the highest mortality of any valve disease, with overall rates of in-hospital mortality exceeding 20%. The Society of Thoracic Surgeons Adult Cardiac Surgery Database was examined to develop a simple risk scoring system and identify areas for quality improvement. Methods: From 2002 through 2008, 19,543 operations were performed for infective endocarditis. Logistic regression analysis related baseline characteristics to both operative mortality and a composite of mortality and major morbidity within 30 days. Points were assigned to each risk factor, and estimated risk was obtained by averaging events for all patients having the same number of points. Results: Overall unadjusted mortality was 8.2%, and complications occurred in 53%. Significant preoperative risk factors for mortality (associated points) were as follows: emergency, salvage status, or cardiogenic shock (17), preoperative hemodialysis, renal failure, or creatinine level less than 2.0 (12), preoperative inotropic or balloon pump support (10), active (vs treated) endocarditis (10), multiple valve involvement (9), insulin-dependent diabetes (8), arrhythmia (8), previous cardiac surgery (7), urgent status without cardiogenic shock (6), non–insulin-dependent diabetes (6), hypertension (5), and chronic lung disease (5), with a C statistic of 0.7578 (all P < .001). Risk-adjusted mortality and major morbidity were unchanged over the course of the study. In the entire data set, mortality was better if “any valve” was repaired (odds ratio = 0.76; P = .0023). Conclusions: Operative mortality for surgically treated infective endocarditis is substantially lower than reported in-hospital mortality rates for infective endocarditis. The described risk scoring system will inform clinical decision-making in these complex patients. [ABSTRACT FROM AUTHOR]

Presents information on congresses involving the North American Society of Pacing and Electrophysiology from June 1999 to May 2000. Topics; Congress titles; Venues and dates; Atrial fibrillation; Cardiac arrhythmia management; Arrhythmology; Cardioversion defibrillation.