Defibrillation Strategies for Refractory Ventricular Fibrillation.

BACKGROUND: Despite advances in defibrillation technology, shock-refractory ventricular fibrillation remains common during out-of-hospital cardiac arrest. Double sequential external defibrillation (DSED; rapid sequential shocks from two defibrillators) and vector-change (VC) defibrillation (switching defibrillation pads to an anterior-posterior position) have been proposed as defibrillation strategies to improve outcomes in patients with refractory ventricular fibrillation. METHODS: We conducted a cluster-randomized trial with crossover among six Canadian paramedic services to evaluate DSED and VC defibrillation as compared with standard defibrillation in adult patients with refractory ventricular fibrillation during out-of-hospital cardiac arrest. Patients were treated with one of these three techniques according to the strategy that was randomly assigned to the paramedic service. The primary outcome was survival to hospital discharge. Secondary outcomes included termination of ventricular fibrillation, return of spontaneous circulation, and a good neurologic outcome, defined as a modified Rankin scale score of 2 or lower (indicating no symptoms to slight disability) at hospital discharge. RESULTS: A total of 405 patients were enrolled before the data and safety monitoring board stopped the trial because of the coronavirus disease 2019 pandemic. A total of 136 patients (33.6%) were assigned to receive standard defibrillation, 144 (35.6%) to receive VC defibrillation, and 125 (30.9%) to receive DSED. Survival to hospital discharge was more common in the DSED group than in the standard group (30.4% vs. 13.3%; relative risk, 2.21; 95% confidence interval [CI], 1.33 to 3.67) and more common in the VC group than in the standard group (21.7% vs. 13.3%; relative risk, 1.71; 95% CI, 1.01 to 2.88). DSED but not VC defibrillation was associated with a higher percentage of patients having a good neurologic outcome than standard defibrillation (relative risk, 2.21 [95% CI, 1.26 to 3.88] and 1.48 [95% CI, 0.81 to 2.71], respectively). CONCLUSIONS: Among patients with refractory ventricular fibrillation, survival to hospital discharge occurred more frequently among those who received DSED or VC defibrillation than among those who received standard defibrillation. (Funded by the Heart and Stroke Foundation of Canada; DOSE VF ClinicalTrials.gov number, NCT04080986.).

Stroke risk in women with atrial fibrillation.

BACKGROUND AND AIMS: Female sex is associated with higher rates of stroke in atrial fibrillation (AF) after adjustment for other CHA2DS2-VASc factors. This study aimed to describe sex differences in age and cardiovascular care to examine their relationship with stroke hazard in AF. METHODS: Population-based cohort study using administrative datasets of people aged ≥66 years diagnosed with AF in Ontario between 2007 and 2019. Cause-specific hazard regression was used to estimate the adjusted hazard ratio (HR) for stroke associated with female sex over a 2-year follow-up. Model 1 included CHA2DS2-VASc factors, with age modelled as 66-74 vs. ≥ 75 years. Model 2 treated age as a continuous variable and included an age-sex interaction term. Model 3 further accounted for multimorbidity and markers of cardiovascular care. RESULTS: The cohort consisted of 354 254 individuals with AF (median age 78 years, 49.2% female). Females were more likely to be diagnosed in emergency departments and less likely to receive cardiologist assessments, statins, or LDL-C testing, with higher LDL-C levels among females than males. In Model 1, the adjusted HR for stroke associated with female sex was 1.27 (95% confidence interval 1.21-1.32). Model 2 revealed a significant age-sex interaction, such that female sex was only associated with increased stroke hazard at age >70 years. Adjusting for markers of cardiovascular care and multimorbidity further decreased the HR, so that female sex was not associated with increased stroke hazard at age ≤80 years. CONCLUSION: Older age and inequities in cardiovascular care may partly explain higher stroke rates in females with AF.

Self-administered intranasal etripamil using a symptom-prompted, repeat-dose regimen for atrioventricular-nodal-dependent supraventricular tachycardia (RAPID): a multicentre, randomised trial.

BACKGROUND: Etripamil is a fast-acting, intranasally administered calcium-channel blocker in development for on-demand therapy outside a health-care setting for paroxysmal supraventricular tachycardia. We aimed to evaluate the efficacy and safety of etripamil 70 mg nasal spray using a symptom-prompted, repeat-dose regimen for acute conversion of atrioventricular-nodal-dependent paroxysmal supraventricular tachycardia to sinus rhythm within 30 min. METHODS: RAPID was a multicentre, randomised, placebo-controlled, event-driven trial, conducted at 160 sites in North America and Europe as part 2 of the NODE-301 study. Eligible patients were aged at least 18 years and had a history of paroxysmal supraventricular tachycardia with sustained, symptomatic episodes (≥20 min) as documented by electrocardiogram. Patients were administered two test doses of intranasal etripamil (each 70 mg, 10 min apart) during sinus rhythm; those who tolerated the test doses were randomly assigned (1:1) using an interactive response technology system to receive either etripamil or placebo. Prompted by symptoms of paroxysmal supraventricular tachycardia, patients self-administered a first dose of intranasal 70 mg etripamil or placebo and, if symptoms persisted beyond 10 min, a repeat dose. Continuously recorded electrocardiographic data were adjudicated, by individuals masked to patient assignment, for the primary endpoint of time to conversion of paroxysmal supraventricular tachycardia to sinus rhythm for at least 30 s within 30 min after the first dose, which was measured in all patients who administered blinded study drug for a confirmed atrioventricular-nodal-dependent event. Safety outcomes were assessed in all patients who self-administered blinded study drug for an episode of perceived paroxysmal supraventricular tachycardia. This trial is registered at ClinicalTrials.gov, NCT03464019, and is complete. FINDINGS: Between Oct 13, 2020, and July 20, 2022, among 692 patients randomly assigned, 184 (99 from the etripamil group and 85 from the placebo group) self-administered study drug for atrioventricular-nodal-dependent paroxysmal supraventricular tachycardia, with diagnosis and timing confirmed. Kaplan-Meier estimates of conversion rates by 30 min were 64% (63/99) with etripamil and 31% (26/85) with placebo (hazard ratio 2·62; 95% CI 1·66-4·15; p<0·0001). Median time to conversion was 17·2 min (95% CI 13·4-26·5) with the etripamil regimen versus 53·5 min (38·7-87·3) with placebo. Prespecified sensitivity analyses of the primary assessment were conducted to test robustness, yielding supporting results. Treatment-emergent adverse events occurred in 68 (50%) of 99 patients treated with etripamil and 12 (11%) of 85 patients in the placebo group, most of which were located at the administration site and were mild or moderate, and all of which were transient and resolved without intervention. Adverse events occurring in at least 5% of patients treated with etripamil were nasal discomfort (23%), nasal congestion (13%), and rhinorrhea (9%). No serious etripamil-related adverse events or deaths were reported. INTERPRETATION: Using a symptom-prompted, self-administered, initial and optional-repeat-dosing regimen, intranasal etripamil was well tolerated, safe, and superior to placebo for the rapid conversion of atrioventricular-nodal-dependent paroxysmal supraventricular tachycardia to sinus rhythm. This approach could empower patients to treat paroxysmal supraventricular tachycardia themselves outside of a health-care setting, and has the potential to reduce the need for additional medical interventions, such as intravenous medications given in an acute-care setting. FUNDING: Milestone Pharmaceuticals.

The Effect of Time to Treatment With Antiarrhythmic Drugs on Survival and Neurological Outcomes in Shock Refractory Out-of-Hospital Cardiac Arrest.

OBJECTIVES: Examining the association of time to treatment (drug or placebo) with survival to hospital discharge and neurologic outcome. DESIGN: Post hoc analysis of the Resuscitation Outcomes Consortium Amiodarone, Lidocaine, Placebo randomized controlled trial. SETTING: Emergency medical services enrolled patients with out-of-hospital cardiac arrest (OHCA) at multiple North American sites. PATIENTS: Adults with nontraumatic OHCA and an initial rhythm of ventricular fibrillation or pulseless ventricular tachycardia refractory to at least one defibrillation attempt were included. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We used logistic regression to examine the association of time to treatment with survival to hospital discharge and favorable neurologic status at discharge (modified Rankin Scale ≤ 3) for the three treatment groups including an interaction term between treatment and time to treatment to determine the effect of time on treatment effects. Time to treatment data were available for 2,994 out of 3,026 patients (99%). The proportion of patients who survived to hospital discharge decreased as time to drug administration increased, in amiodarone (odds ratio [OR], 0.91; 95% CI, 0.90-0.93 per min), lidocaine (OR, 0.93; 95% CI, 0.91-0.96), and placebo (OR, 0.91; 95% CI, 0.90-0.93). Comparing amiodarone to placebo, there was improved survival at all times of drug administration (OR, 1.32; 95% CI, 1.05-1.65). Comparing lidocaine to placebo, survival was not different with shorter times to drug administration (< 11 min), whereas survival was higher with lidocaine at longer times to drug administration with an interaction between treatment effect and time to treatment (p = 0.048). Survival with good neurologic outcome showed similar results for all analyses. CONCLUSIONS: Survival and favorable neurologic outcomes decreased with longer times to drug administration. Amiodarone improved survival at all time points whereas lidocaine improved survival only at later time points, compared with placebo.

Does cardiovascular preparticipation screening cause psychological distress in athletes? A systematic review.

OBJECTIVE: To evaluate the psychological implications of cardiovascular preparticipation screening (PPS) in athletes. DESIGN: Systematic review. DATA SOURCES: MEDLINE, EMBASE, PubMed, CINAHL, SPORTDiscus, APA PsycInfo, Cochrane Library and grey literature sources. STUDY ELIGIBILITY CRITERIA: Observational and experimental studies assessing a population of athletes who participated in a cardiovascular PPS protocol, where psychological outcomes before, during and/or after PPS were reported. METHODS: Results of included studies were synthesised by consolidating similar study-reported measures for key psychological outcomes before, during and/or after screening. Summary measures (medians, ranges) were computed across studies for each psychological outcome. RESULTS: A total of eight studies were included in this review (median sample size: 479). Study cohorts consisted of high school, collegiate, professional and recreational athletes (medians: 59% male, 20.5 years). Most athletes reported positive reactions to screening and would recommend it to others (range 88%-100%, five studies). Increased psychological distress was mainly reported among athletes detected with pathological cardiac conditions and true-positive screening results. In comparison, athletes with false-positive screening results still reported an increased feeling of safety while participating in sport and were satisfied with PPS. A universal conclusion across all studies was that most athletes did not experience psychological distress before, during or after PPS, regardless of the screening modality used or accuracy of results. CONCLUSION: Psychological distress associated with PPS in athletes is rare and limited to athletes with true-positive findings. To mitigate downstream consequences in athletes who experience psychological distress, appropriate interventions and resources should be accessible prior to the screening procedure. PROSPERO REGISTRATION NUMBER: CRD42021272887.

Gender-Based Differences in Outcomes Among Resuscitated Patients With Out-of-Hospital Cardiac Arrest.

BACKGROUND: Studies examining gender-based differences in outcomes of patients experiencing out-of-hospital cardiac arrest have demonstrated that, despite a higher likelihood of return of spontaneous circulation, women do not have higher survival. METHODS: Patients successfully resuscitated from out-of-hospital cardiac arrest enrolled in the CCC trial (Trial of Continuous or Interrupted Chest Compressions during CPR) were included. Hierarchical multivariable logistic regression models were constructed to evaluate the association between gender and survival after adjustment for age, gender, cardiac arrest rhythm, witnessed status, bystander cardiopulmonary resuscitation, episode location, epinephrine dose, emergency medical services response time, and duration of resuscitation. Do not resuscitate (DNR) and withdrawal of life-sustaining therapy (WLST) order status were used to assess whether differences in postresuscitation outcomes were modified by baseline prognosis. The analysis was replicated among ALPS trial (Amiodarone, Lidocaine, or Placebo in Out-of-Hospital Cardiac Arrest) participants. RESULTS: Among 4875 successfully resuscitated patients, 1825 (37.4%) were women and 3050 (62.6%) were men. Women were older (67.5 versus 65.3 years), received less bystander cardiopulmonary resuscitation (49.1% versus 54.9%), and had a lower proportion of cardiac arrests that were witnessed (55.1% versus 64.5%) or had shockable rhythm (24.3% versus 44.6%, P<0.001 for all). A significantly higher proportion of women received DNR orders (35.7% versus 32.1%, P=0.009) and had WLST (32.8% versus 29.8%, P=0.03). Discharge survival was significantly lower in women (22.5% versus 36.3%, P<0.001; adjusted odds ratio, 0.78 [95% CI, 0.66-0.93]; P=0.005). The association between gender and survival to discharge was modified by DNR and WLST order status such that women had significantly reduced survival to discharge among patients who were not designated DNR (31.3% versus 49.9%, P=0.005; adjusted odds ratio, 0.74 [95% CI, 0.60-0.91]) or did not have WLST (32.3% versus 50.7%, P=0.002; adjusted odds ratio, 0.73 [95% CI, 0.60-0.89]). In contrast, no gender difference in survival was noted among patients receiving a DNR order (6.7% versus 7.4%, P=0.90) or had WLST (2.8% versus 2.4%, P=0.93). Consistent patterns of association between gender and postresuscitation outcomes were observed in the secondary cohort. CONCLUSIONS: Among patients resuscitated after experiencing out-of-hospital cardiac arrest, discharge survival was significantly lower in women than in men, especially among patients considered to have a favorable prognosis.

Design and Rationale of a Phase 2 Study of NeurOtoxin (Botulinum Toxin Type A) for the PreVention of Post-Operative Atrial Fibrillation - The NOVA Study.

BACKGROUND: Post-operative AF (POAF) is the most common complication following cardiac surgery, occurring in 30% to 60% of patients undergoing bypass and/or valve surgery. POAF is associated with longer intensive care unit/hospital stays, increased healthcare utilization, and increased morbidity and mortality. Injection of botulinum toxin type A into the epicardial fat pads resulted in reduction of AF in animal models, and in two clinical studies of cardiac surgery patients, without new safety observations. METHODS: The objective of NOVA is to assess the use of AGN-151607 (botulinum toxin type A) for prevention of POAF in cardiac surgery patients. This randomized, multi-site, placebo-controlled trial will study one-time injections of AGN-151607 125 U (25 U / fat pad) and 250 U (50 U / fat pad) or placebo during cardiac surgery in ∼330 participants. Primary endpoint: % of patients with continuous AF ≥ 30 s. Secondary endpoints include several measures of AF frequency, duration, and burden. Additional endpoints include clinically important tachycardia during AF, time to AF termination, and healthcare utilization. Primary and secondary efficacy endpoints will be assessed using continuous ECG monitoring for 30 days following surgery. All patients will be followed for up to 1 year for safety. CONCLUSIONS: The NOVA Study will test the hypothesis that injections of AGN-151607 will reduce the incidence of POAF and associated resource utilization. If demonstrated to be safe and effective, the availability of a one-time therapy for the prevention of POAF would represent an important treatment option for patients undergoing cardiac surgery.

Bystander interventions and survival after exercise-related sudden cardiac arrest: a systematic review.

OBJECTIVE: To evaluate the provision of bystander interventions and rates of survival after exercise-related sudden cardiac arrest (SCA). DESIGN: Systematic review. DATA SOURCES: MEDLINE, EMBASE, PubMed, CINAHL, SPORTDiscus, Cochrane Library and grey literature sources were searched from inception to November/December 2020. STUDY ELIGIBILITY CRITERIA: Observational studies assessing a population of exercise-related SCA (out-of-hospital cardiac arrests that occurred during exercise or within 1 hour of cessation of activity), where bystander cardiopulmonary resuscitation (CPR) and/or automated external defibrillator (AED) use were reported, and survival outcomes were ascertained. METHODS: Among all included studies, the median (IQR) proportions of bystander CPR and bystander AED use, as well as median (IQR) rate of survival to hospital discharge, were calculated. RESULTS: A total of 29 studies were included in this review, with a median study duration of 78.7 months and a median sample size of 91. Most exercise-related SCA patients were male (median: 92%, IQR: 86%-96%), middle-aged (median: 51, IQR: 39-56 years), and presented with a shockable arrest rhythm (median: 78%, IQR: 62%-86%). Bystander CPR was initiated in a median of 71% (IQR: 59%-87%) of arrests, whereas bystander AED use occurred in a median of 31% (IQR: 19%-42%) of arrests. Among the 19 studies that reported survival to hospital discharge, the median rate of survival was 32% (IQR: 24%-49%). Studies which evaluated the relationship between bystander interventions and survival outcomes reported that both bystander CPR and AED use were associated with survival after exercise-related SCA. CONCLUSION: Exercise-related SCA occurs predominantly in males and presents with a shockable ventricular arrhythmia in most cases, emphasising the importance of rapid access to defibrillation. Further efforts are needed to promote early recognition and a rapid bystander response to exercise-related SCA.

Survival After Intravenous Versus Intraosseous Amiodarone, Lidocaine, or Placebo in Out-of-Hospital Shock-Refractory Cardiac Arrest.

BACKGROUND: Antiarrhythmic drugs have not proven to significantly improve overall survival after out-of-hospital cardiac arrest from shock-refractory ventricular fibrillation/pulseless ventricular tachycardia. How this might be influenced by the route of drug administration is not known. METHODS: In this prespecified analysis of a randomized, placebo-controlled clinical trial, we compared the differences in survival to hospital discharge in adults with shock-refractory ventricular fibrillation/pulseless ventricular tachycardia out-of-hospital cardiac arrest who were randomly assigned by emergency medical services personnel to an antiarrhythmic drug versus placebo in the ALPS trial (Resuscitation Outcomes Consortium Amiodarone, Lidocaine or Placebo Study), when stratified by the intravenous versus intraosseous route of administration. RESULTS: Of 3019 randomly assigned patients with a known vascular access site, 2358 received ALPS drugs intravenously and 661 patients by the intraosseous route. Intraosseous and intravenous groups differed in sex, time-to-emergency medical services arrival, and some cardiopulmonary resuscitation characteristics, but were similar in others, including time-to-intravenous/intrasosseous drug receipt. Overall hospital discharge survival was 23%. In comparison with placebo, discharge survival was significantly higher in recipients of intravenous amiodarone (adjusted risk ratio, 1.26 [95% CI, 1.06-1.50]; adjusted absolute survival difference, 5.5% [95% CI, 1.5-9.5]) and intravenous lidocaine (adjusted risk ratio, 1.21 [95% CI, 1.02-1.45]; adjusted absolute survival difference, 4.7% [95% CI, 0.7-8.8]); but not in recipients of intraosseous amiodarone (adjusted risk ratio, 0.94 [95% CI, 0.66-1.32]) or intraosseous lidocaine (adjusted risk ratio, 1.03 [95% CI, 0.74-1.44]). Survival to hospital admission also increased significantly when drugs were given intravenously but not intraosseously, and favored improved neurological outcome at discharge. There were no outcome differences between intravenous and intraosseous placebo, indicating that the access route itself did not demarcate patients with poor prognosis. The study was underpowered to assess intravenous/intraosseous drug interactions, which were not statistically significant. CONCLUSIONS: We found no significant effect modification by drug administration route for amiodarone or lidocaine in comparison with placebo during out-of-hospital cardiac arrest. However, point estimates for the effects of both drugs in comparison with placebo were significantly greater for the intravenous than for the intraosseous route across virtually all outcomes and beneficial only for the intravenous route. Given that the study was underpowered to statistically assess interactions, these findings signal the potential importance of the drug administration route during resuscitation that merits further investigation.

Exercise in hypertrophic cardiomyopathy: restrict or rethink.

The detailed physiological consequences of aerobic training, in patients with hypertrophic cardiomyopathy (HCM), are not well understood. In athletes and nonathletes with HCM, there are two hypothetical concerns with respect to exercise: exercise-related worsening of the phenotype (e.g., promoting hypertrophy and fibrosis) and/or triggering of arrhythmia. The former concern is unproven and animal studies suggest an opposite effect, where exercise has been shown to be protective. The main reason for exercise restriction in HCM is fear of exercise-induced arrhythmia. Although the safety of sports in HCM has been reviewed, even more recent data suggest a substantially lower risk for sudden cardiac death (SCD) in HCM than previously thought, and there is an ongoing debate about restrictions of exercise imposed on individuals with HCM. This review outlines the pathophysiology of HCM, the impact of acute and chronic exercise (and variations of exercise intensity, modality, and athletic phenotype) in HCM including changes in autonomic function, blood pressure, cardiac dimensions and function, and cardiac output, and the underlying mechanisms that may trigger exercise-induced lethal arrhythmias. It provides a critical evaluation of the evidence regarding risk of SCD in athletes and the potential benefits of targeted exercise prescription in adults with HCM. Finally, it provides considerations for personalized recommendations for sports participation based on the available data.

Cardiac remodeling in middle-aged endurance athletes: relation between signal-averaged electrocardiogram and LV mass.

The relationship between structural and electrical remodeling in the heart, particularly after long-standing endurance training, remains unclear. Signal-averaged electrocardiogram (SAECG) may provide a more sensitive method to evaluate cardiac remodeling than a 12-lead electrocardiogram (ECG). Accurate measures of electrical function (SAECG filtered QRS duration (fQRSd) and late potentials (LP) and left-ventricular (LV) mass (cardiac magnetic resonance, CMR) can allow an assessment of structural remodeling and QRS prolongation. Endurance athletes (45-65 yr old, >10 yr of endurance sport), screened to exclude cardiac disease, had standardized 12-lead ECG, SAECG, resting echocardiogram (ECHO), and CMR performed. SAECG fQRSd was correlated with QRS duration on the 12-lead ECG, and ECHO and CMR-derived LV mass. Participants (n = 82, 67% male, mean age: 54 ± 6 yr, mean V̇o2max: 50 ± 7 mL/kg/min) had a CMR-derived LV mass of 118 ± 28 g/m2 and a fQRSd of 112 ± 8 ms (46% had abnormal fQRSd (>114 ms), and 51% met clinical threshold for abnormal SAECG). fQRSd was positively correlated with the 12-lead ECG QRS duration (r = 0.83), ECHO-derived LV mass (r = 0.60), CMR-derived LV mass (r = 0.58) and LV end-diastolic volume (r = 0.63, P < 0.001 for all). fQRSd had higher correlations with ECHO and CMR-derived LV mass than 12-lead ECG (P < 0.0008 and P < 0.0005, respectively). In conclusion, in a healthy cohort of middle-aged endurance athletes, the SAECG is often abnormal by conventional criteria, and is correlated with structural remodeling, but CMR evaluation does not indicate pathologic structural remodeling. SAECG fQRSd is superior to the 12-lead ECG for the electrocardiographic evaluation of LV mass.NEW & NOTEWORTHY Study findings indicate that a positive correlation exists between electrical (SAECG fQRSd) and structural indices (LV mass) in middle-aged endurance athletes with normal physiological LV adaptation, in the absence of known cardiac pathology. SAECG fQRSd may also provide an alternative, superior method for identifying increased LV mass compared to other 12-lead ECG criteria.

Right Ventricular Function at Cardiac MRI Predicts Cardiovascular Events in Patients with an Implantable Cardioverter-Defibrillator.

Background Right ventricular ejection fraction (RVEF) is an independent predictor of death and adverse cardiovascular outcomes in patients with various cardiac conditions. Purpose To investigate whether RVEF, measured with cardiac MRI, is a predictor of appropriate shock or death in implantable cardioverter-defibrillator (ICD) recipients for primary and secondary prevention of sudden cardiac death. Materials and Methods This retrospective, multicenter, observational study included patients who underwent cardiac MRI before ICD implantation between January 2007 and May 2017. Right ventricular end-diastolic and end-systolic volumes and RVEF were measured with cardiac MRI. The primary end point was a composite of all-cause mortality or appropriate ICD shock. The secondary end point was all-cause mortality. The association between RVEF and primary and secondary outcomes was evaluated by using multivariable Cox regression analysis. Potential interactions were tested between primary prevention, ischemic cause, left ventricular ejection fraction (LVEF), and RVEF. Results Among 411 patients (mean age ± standard deviation, 60 years; 315 men) during a median follow-up of 63 months, 143 (35%) patients experienced an appropriate ICD shock or died. In univariable analysis, lower RVEF was associated with greater risks for appropriate ICD shock or death and for death alone (log-rank trend test, P = .003 and .005 respectively). In multivariable Cox regression analysis adjusting for age at ICD implantation, LVEF, ICD indication (primary vs secondary), ischemic heart disease, and late gadolinium enhancement, RVEF was an independent predictor of the primary outcome (hazard ratio [HR], 1.21 per 10% lower RVEF; 95% CI: 1.04, 1.41; P = .01) and all-cause mortality (HR, 1.25 per 10% lower RVEF; 95% CI: 1.01, 1.55; P = .04). No evidence of significant interactions was found between RVEF and primary or secondary prevention (P = .49), ischemic heart disease (P = .78), and LVEF (P = .29). Conclusion Right ventricular ejection fraction measured with cardiac MRI was a predictor of appropriate implantable cardioverter-defibrillator shock or death. © RSNA, 2021 See also the editorial by Nazarian and Zghaib in this issue. An earlier incorrect version of this article appeared online. This article was corrected on August 24, 2021.

Myocardial strain assessment using cardiovascular magnetic resonance imaging in recipients of implantable cardioverter defibrillators.

BACKGROUND: Cardiovascular magnetic resonance (CMR) is increasingly used in the evaluation of patients who are potential candidates for implantable cardioverter-defibrillator (ICD) therapy to assess left ventricular (LV) ejection fraction (LVEF), myocardial fibrosis, and etiology of cardiomyopathy. It is unclear whether CMR-derived strain measurements are predictive of appropriate shocks and death among patients who receive an ICD. We evaluated the prognostic value of LV strain parameters on feature-tracking (FT) CMR in patients who underwent subsequent ICD implant for primary or secondary prevention of sudden cardiac death. METHODS: Consecutive patients from 2 Canadian tertiary care hospitals who underwent ICD implant and had a pre-implant CMR scan were included. Using FT-CMR, a single, blinded, reader measured LV global longitudinal (GLS), circumferential (GCS), and radial (GRS) strain. Cox proportional hazards regression was performed to assess the associations between strain measurements and the primary composite endpoint of all-cause death or appropriate ICD shock that was independently ascertained. RESULTS: Of 364 patients (mean 61 years, mean LVEF 32%), 64(17.6%) died and 118(32.4%) reached the primary endpoint over a median follow-up of 62 months. Univariate analyses showed significant associations between GLS, GCS, and GRS and appropriate ICD shocks or death (all p < 0.01). In multivariable Cox models incorporating LVEF, GLS remained an independent predictor of both the primary endpoint (HR 1.05 per 1% higher GLS, 95% CI 1.01-1.09, p = 0.010) and death alone (HR 1.06 per 1% higher GLS, 95% CI 1.02-1.11, p = 0.003). There was no significant interaction between GLS and indication for ICD implant, presence of ischemic heart disease or late gadolinium enhancement (all p > 0.30). CONCLUSIONS: GLS by FT-CMR is an independent predictor of appropriate shocks or mortality in ICD patients, beyond conventional prognosticators including LVEF. Further study is needed to elucidate the role of LV strain analysis to refine risk stratification in routine assessment of ICD treatment benefit.

Long-term outcomes of chronic coronary syndrome worldwide: insights from the international CLARIFY registry.

AIMS: Over the last decades, the profile of chronic coronary syndrome has changed substantially. We aimed to determine characteristics and management of patients with chronic coronary syndrome in the contemporary era, as well as outcomes and their determinants. METHODS AND RESULTS: Data from 32 703 patients (45 countries) with chronic coronary syndrome enrolled in the prospective observational CLARIFY registry (November 2009 to June 2010) with a 5-year follow-up, were analysed. The primary outcome [cardiovascular death or non-fatal myocardial infarction (MI)] 5-year rate was 8.0% [95% confidence interval (CI) 7.7-8.3] overall [male 8.1% (7.8-8.5); female 7.6% (7.0-8.3)]. A cox proportional hazards model showed that the main independent predictors of the primary outcome were prior hospitalization for heart failure, current smoking, atrial fibrillation, living in Central/South America, prior MI, prior stroke, diabetes, current angina, and peripheral artery disease. There was an interaction between angina and prior MI (P = 0.0016); among patients with prior MI, angina was associated with a higher primary event rate [11.8% (95% CI 10.9-12.9) vs. 8.2% (95% CI 7.8-8.7) in patients with no angina, P < 0.001], whereas among patients without prior MI, event rates were similar for patients with [6.3% (95% CI 5.4-7.3)] or without angina [6.4% (95% CI 5.9-7.0)], P > 0.99. Prescription rates of evidence-based secondary prevention therapies were high. CONCLUSION: This description of the spectrum of chronic coronary syndrome patients shows that, despite high rates of prescription of evidence-based therapies, patients with both angina and prior MI are an easily identifiable high-risk group who may deserve intensive treatment. CLINICAL REGISTRY: ISRCTN43070564.

Multi-centre implementation of an Educational program to improve the Cardiac Arrest diagnostic accuracy of ambulance Telecommunicators and survival outcomes for sudden cardiac arrest victims: the EduCATe study design and methodology.

BACKGROUND: Sudden cardiac death remains a leading cause of mortality in Canada, resulting in more than 35,000 deaths annually. Most cardiac arrest victims collapse in their own home (85% of the time) and 50% are witnessed by a family member or bystander. Survivors have a quality of life similar to the general population, but the overall survival rate for out-of-hospital cardiac arrest (OHCA) rarely exceeds 8%. Victims are almost four times more likely to survive when receiving bystander CPR, but bystander CPR rates have remained low in Canada over the past decade, not exceeding 15-25% until recently. Telecommunication-assisted CPR instructions have been shown to significantly increase bystander CPR rates, but agonal breathing may be misinterpreted as a sign of life by 9-1-1 callers and telecommunicators, and is responsible for as much as 50% of missed OHCA diagnoses. We sought to improve the ability and speed with which ambulance telecommunicators can recognize OHCA over the phone, initiate timely CPR instructions, and improve survival. METHODS: In this multi-center national study, we will implement and evaluate an educational program developed for ambulance telecommunicators using a multiple baseline interrupted time-series design. We will compare outcomes 12 months before and after the implementation of a 20-min theory-based educational video addressing barriers to recognition of OHCA while in the presence of agonal breathing. Participating Canadian sites demonstrated prior ability to collect standardized data on OHCA. Data will be collected from eligible 9-1-1 recordings, paramedic documentation and hospital medical records. Eligible cases will include suspected or confirmed OHCA of presumed cardiac origin in patients of any age with attempted resuscitation. DISCUSSION: The ability of telecommunication-assisted CPR instructions to improve bystander CPR and survival rates for OHCA victims is undeniable. The ability of telecommunicators to recognize OHCA over the phone is unequivocally impeded by relative lack of training on agonal breathing, and reluctance to initiate CPR instructions when in doubt. Our pilot data suggests the potential impact of this project will be to increase absolute OHCA recognition and bystander CPR rates by at least 10%, and absolute out-of-hospital cardiac arrest survival by 5% or more. TRIAL REGISTRATION: Prospectively registered on March 28, 2019 at ClinicalTrials.gov identifier: NCT03894059 .

Hypertrophic Cardiomyopathy-Related Sudden Cardiac Death in Young People in Ontario.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is considered a leading cause of sudden cardiac death (SCD) in younger people. The incidence of HCM-related SCD and its relationship to exercise have not been well studied in large comprehensive studies outside of tertiary care settings. This study sought to estimate the incidence of HCM-related SCD and its association with exercise in a large unselected population. METHODS: Using the Office of the Chief Coroner of Ontario database encompassing all deaths attended by the coroner, we identified all HCM-related SCDs in individuals 10 to 45 years of age between 2005 and 2016 (70 million person-years). Confirmation of HCM was based on typical macroscopic and microscopic features (definite HCM-related SCD). Sudden deaths with a prior clinical diagnosis of HCM but no autopsy were considered probable HCM-related SCDs. Cases with typical features but no myofiber disarray were considered possible HCM. The completeness of data was verified in a subset of patients in the Toronto area with the use of a registry of all emergency medical services-attended cardiac arrests, with an autopsy rate of 94%. To estimate the number of HCM-related aborted cardiac arrests and lives potentially saved by implantable cardioverter-defibrillators, all de novo implantations for secondary prevention and all implantations and appropriate shocks for primary prevention in patients with HCM 10 to 45 years of age, respectively, were identified with the use of a registry containing data on implantable cardioverter-defibrillator implantations from all implanting sites throughout Ontario. RESULTS: Forty-four, 3, and 6 cases of definite, probable, and possible HCM-related SCDs, respectively, were identified, corresponding to estimated annual incidence rates of 0.31 per 1000 HCM person-years (95% CI, 0.24-0.44) for definite HCM-related SCD, 0.33 per 1000 HCM person-years (95% CI, 0.34-0.62) for definite or probable HCM-related SCD, and 0.39 per 1000 HCM person-years (95% CI, 0.28-0.49) for definite, probable, or possible HCM-related SCD (estimated 140 740 HCM person-years of observation). The estimated annual incidence rate for HCM-related SCD plus aborted cardiac arrest and HCM-related life-threatening arrhythmia (SCD, aborted cardiac arrest, and appropriate implantable cardioverter-defibrillator shocks) was 0.84 per 1000 HCM person-years (95% CI, 0.70-1.0). The majority (70%) of SCDs occurred in previously undiagnosed individuals. Most SCDs occurred during rest (64.8%) or light activity (18.5%). CONCLUSIONS: The incidence of HCM-related SCD in the general population 10 to 45 years of age is substantially lower than previously reported, with most cases occurring in previously undiagnosed individuals. SCDs are infrequently related to exercise.

Sudden Cardiac Arrest during Participation in Competitive Sports.

BACKGROUND: The incidence of sudden cardiac arrest during participation in sports activities remains unknown. Preparticipation screening programs aimed at preventing sudden cardiac arrest during sports activities are thought to be able to identify at-risk athletes; however, the efficacy of these programs remains controversial. We sought to identify all sudden cardiac arrests that occurred during participation in sports activities within a specific region of Canada and to determine their causes. METHODS: In this retrospective study, we used the Rescu Epistry cardiac arrest database (which contains records of every cardiac arrest attended by paramedics in the network region) to identify all out-of-hospital cardiac arrests that occurred from 2009 through 2014 in persons 12 to 45 years of age during participation in a sport. Cases were adjudicated as sudden cardiac arrest (i.e., having a cardiac cause) or as an event resulting from a noncardiac cause, on the basis of records from multiple sources, including ambulance call reports, autopsy reports, in-hospital data, and records of direct interviews with patients or family members. RESULTS: Over the course of 18.5 million person-years of observation, 74 sudden cardiac arrests occurred during participation in a sport; of these, 16 occurred during competitive sports and 58 occurred during noncompetitive sports. The incidence of sudden cardiac arrest during competitive sports was 0.76 cases per 100,000 athlete-years, with 43.8% of the athletes surviving until they were discharged from the hospital. Among the competitive athletes, two deaths were attributed to hypertrophic cardiomyopathy and none to arrhythmogenic right ventricular cardiomyopathy. Three cases of sudden cardiac arrest that occurred during participation in competitive sports were determined to have been potentially identifiable if the athletes had undergone preparticipation screening. CONCLUSIONS: In our study involving persons who had out-of-hospital cardiac arrest, the incidence of sudden cardiac arrest during participation in competitive sports was 0.76 cases per 100,000 athlete-years. The occurrence of sudden cardiac arrest due to structural heart disease was uncommon during participation in competitive sports. (Funded by the National Heart, Lung, and Blood Institute and others.).

Impact of electrical cardioversion on quality of life for patients with symptomatic persistent atrial fibrillation: Is there a treatment expectation effect?

It is assumed that electrical cardioversion (ECV) improves the quality of life (QoL) of patients with atrial fibrillation (AF) by restoring sinus rhythm (SR). OBJECTIVE: We examined the effect of ECV and rhythm status on QoL of patients with symptomatic persistent AF in a randomized controlled trial. METHOD: The elective cardioversion for prevention of symptomatic atrial fibrillation trial examined the efficacy of dronedarone around the time of ECV in maintaining SR. Quality of life was measured with the University of Toronto Atrial Fibrillation Severity Scale. The primary outcome was the change in AF symptom severity (∆AFSS) score over 6 months (0-35 points, with higher scores reflecting worse QoL and a minimal clinically important difference defined as ∆AFSS ≥3 points). Multivariable linear regression was performed to identify factors associated with changes in QoL. RESULTS: We included 148 patients with complete AFSS scores at baseline and 6 months. Over 6 months, QoL improved irrespective of rhythm status (ΔAFSS scores for patients who (i) maintained SR; (ii) had AF relapse after successful ECV; and (iii) had unsuccessful ECV were -6.8 ±â€¯6.4 points, -4.1 ±â€¯6.2 points, and -4.0 ±â€¯5.8 points respectively, P < .01 for all subgroups). After adjustment of baseline covariates, maintenance of SR was associated with QoL improvement (ΔAFSS: -3.8 points, 95% CI: -6.0 to -1.6 points, P < .01). CONCLUSIONS: Maintenance of SR was associated with clinically relevant improvement in patients' QoL at 6 months. Patients with AF recurrence had a small but still relevant improvement in their QoL, potentially due to factors other than sinus rhythm.