Background: In the emergency setting, many diagnostic pathways incorporate change in high-sensitivity cardiac troponin (hs-cTn) concentrations (i.e., the delta) to classify patients as low-risk (rule-out) or high-risk (rule-in) for possible myocardial infarction (MI). However, the impact of analytical variation on the delta for correct classification is unknown, especially at concentrations below and around the 99th percentile. Our objective was to assess the impact of delta variation for correct risk classification across the European Society of Cardiology (ESC 0/1 h and 0/2 h), the High-STEACS, and the common change criteria (3C) pathways. Methods: A yearlong accuracy study for hs-cTnT was performed where laboratories across Canada tested three patient-based samples (level 1 target value = 6 ng/L, level 2 target value = 9 ng/L, level 3 target value = 12 ng/L) monthly across 41 different analyzers. The assigned low-delta between levels 1 and 2 was 3 ng/L (i.e., 9 − 6 = 3 ng/L) and the assigned high-delta between levels 1 and 3 was 6 ng/L (i.e., 12 − 6 = 6 ng/L). The low- and high-deltas for each analyzer were determined monthly from the measured values, with the difference calculated from the assigned deltas. The obtained deltas were then assessed via the different pathways on correct classification (i.e., percent correct with 95% confidence intervals, CI) and using non-parametric analyses. Results: The median (interquartile range) difference between the measured versus assigned low-delta (n = 436) and high-delta (n = 439) was −1 ng/L (−1 to 0). The correct classification differed among the pathways. The ESC 0/1 h pathway yielded the lowest percentage of correct classification at 35.3% (95% CI: 30.8 to 40.0) for the low-delta and 90.0% (95% CI: 86.8 to 92.6) for the high-delta. The 3C and ESC 0/2 h pathways yielded higher and equivalent estimates on correct classification: 95.2% (95% CI: 92.7 to 97.0) for the low-delta and 98.2% (95% CI: 96.4 to 99.2) for the high-delta. The High-STEACS pathway yielded 99.5% (95% CI: 98.4 to 99.9) of correct classifications for the high-delta but only 36.2% (95% CI: 31.7 to 40.9) for the low-delta. Conclusions: Analytical variation will impact risk classification for MI when using hs-cTn deltas alone per the pathways. The 3C and ESC 0/2 h pathways have <5% misclassification when using deltas for hs-cTnT in this dataset. Additional studies with different hs-cTnI assays at concentrations below and near the 99th percentile are warranted to confirm these findings.

INTRODUCTION/PURPOSE:The oxygen uptake (V̇O 2 )-power output (PO) relationship from incremental exercise needs to be adjusted to accurately prescribe constant-intensity exercise training. We assessed the accuracy of a "step-ramp-step" (SRS) protocol for prescribing constant PO exercise within moderate-intensity (below estimated lactate threshold, θ LT ), heavy-intensity (between θ LT and respiratory compensation point, RCP), and severe-intensity (above RCP) domains in 14 patients with coronary artery disease (CAD). METHODS:The SRS protocol included the following: 6 min of cycling at 25-40 W, a ramp-incremental test until task failure (5-15 W · min -1 ), and, after a 20 min recovery, 12 min of cycling at ~50%-60% of peak ramp PO. On separate days, patients performed three domain-specific constant PO exercises at 80% θ LT (moderate intensity [MOD]), 70% of the difference between θ LT and RCP (heavy intensity [HVY]), and 115% RCP (severe intensity [SEV]). Measured V̇O 2 values for MOD and HVY were compared with those predicted using either SRS-corrected or uncorrected approaches and, for SEV, were compared with peak ramp V̇O 2 . RESULTS:The PO values for MOD, HVY, and SEV were 53 ± 27, 96 ± 50, and 116 ± 56 W, respectively, eliciting V̇O 2 of 1012 ± 362, 1541 ± 638, and 1944 ± 744 mL·min -1 . The SRS-corrected predictions did not differ from measured V̇O 2 for MOD (-25 ± 61 mL·min -1 ; P = 0.201) or HVY (-40 ± 89 mL·min -1 ; P = 0.208), whereas uncorrected predictions underestimated V̇O 2 by -128 ± 72 mL·min -1 ( P = 0.002) and -199 ± 99 mL·min -1 ( P = 0.001) in MOD and HVY, respectively. Peak V̇O 2 from SEV did not differ from the ramp (1906 ± 766 mL·min -1 ; P = 0.759). CONCLUSIONS:In CAD, the V̇O 2 -PO relationship from incremental exercise must be corrected to prescribe constant-intensity training. The SRS protocol is an accurate approach to ensure prescriptive accuracy.

PURPOSE:Improving aerobic fitness through exercise training is recommended for the treatment of cardiovascular disease (CVD). However, strong justifications for the criteria of assessing improvement in key parameters of aerobic function including estimated lactate threshold (θ LT ), respiratory compensation point (RCP), and peak oxygen uptake (V˙ o2peak ) at the individual level are not established. We applied reliable change index (RCI) statistics to determine minimal meaningful change (MMC RCI ) cutoffs of θ LT , RCP, and V˙ o2peak for individual patients with CVD. METHODS:Sixty-six stable patients post-cardiac event performed three exhaustive treadmill-based incremental exercise tests (modified Bruce) ∼1 wk apart (T1-T3). Breath-by-breath gas exchange and ventilatory variables were measured by metabolic cart and used to identify θ LT , RCP, and V˙ o2peak . Using test-retest reliability and mean difference scores to estimate error and test practice/exposure, respectively, MMC RCI values were calculated for V˙ o2 (mL·min -1. kg -1 ) at θ LT , RCP, and V˙ o2peak . RESULTS:There were no significant between-trial differences in V˙ o2 at θ LT ( P = .78), RCP ( P = .08), or V˙ o2peak ( P = .74) and each variable exhibited excellent test-retest variability (intraclass correlation: 0.97, 0.98, and 0.99; coefficient of variation: 6.5, 5.4, and 4.9% for θ LT , RCP, and V˙ o2peak , respectively). Derived from comparing T1-T2, T1-T3, and T2-T3, the MMC RCI for θ LT were 3.91, 3.56, and 2.64 mL·min -1. kg -1 ; 4.01, 2.80, and 2.79 mL·min -1. kg -1 for RCP; and 3.61, 3.83, and 2.81 mL·min -1. kg -1 for V˙ o2peak . For each variable, MMC RCI scores were lowest for T2-T3 comparisons. CONCLUSION:These MMC RCI scores may be used to establish cutoff criteria for determining meaningful changes for interventions designed to improve aerobic function in individuals with CVD.

The present study aimed to explore the perspectives of older adults and health providers on cardiac rehabilitation care provided virtually during COVID-19. A qualitative exploratory methodology was used. Semi-structured interviews were conducted with 15 older adults and 6 healthcare providers. Five themes emerged from the data: (1) Lack of emotional intimacy when receiving virtual care, (2) Inadequacy of virtual platforms, (3) Saving time with virtual care, (4) Virtual care facilitated accessibility, and (5) Loss of connections with patients and colleagues. Given that virtual care continues to be implemented, and in some instances touted as an optimal option for the delivery of cardiac rehabilitation, it is critical to address the needs of older adults living with cardiovascular disease and their healthcare providers. This is particularly crucial related to issues accessing and using technology, as well as older adults' need to build trust and emotional connection with their providers.

Background Ischemic heart disease (IHD) is linked to brain white matter (WM) breakdown but how age or disease effects WM integrity, and whether it is reversible using cardiac rehabilitation (CR), remains unclear. Purpose To assess the effects of brain aging, cardiovascular disease, and CR on WM microstructure in brains of IHD patients following a cardiac event. Study Type Retrospective. Population Thirty‐five IHD patients (9 females; mean age = 59 ± 8 years), 21 age‐matched healthy controls (10 females; mean age = 59 ± 8 years), and 25 younger controls (14 females; mean age = 26 ± 4 years). Field Strength/Sequence 3 T diffusion‐weighted imaging with single‐shot echo planar imaging acquired at 3 months and 9 months post‐cardiac event. Assessment Tract‐based spatial statistics (TBSS) and tractometry were used to compare fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) in cerebral WM between: 1) older and younger controls to distinguish age‐related from disease‐related WM changes; 2) IHD patients at baseline (pre‐CR) and age‐matched controls to investigate if cardiovascular disease exacerbates age‐related WM changes; and 3) IHD patients pre‐CR and post‐CR to investigate the neuroplastic effect of CR on WM microstructure. Statistical Tests Two‐sample unpaired t ‐test (age: older vs. younger controls; IHD: IHD pre‐CR vs. age‐matched controls). One‐sample paired t ‐test (CR: IHD pre‐ vs. post‐CR). Statistical threshold: P < 0.05 (FWE‐corrected). Results TBSS and tractometry revealed widespread WM changes in older controls compared to younger controls while WM clusters of decreased FA in the fornix and increased MD in body of corpus callosum were observed in IHD patients pre‐CR compared to age‐matched controls. Robust WM improvements (increased FA, increased AD) were observed in IHD patients post‐CR. Data Conclusion In IHD, both brain aging and cardiovascular disease may contribute to WM disruptions. IHD‐related WM disruptions may be favorably modified by CR. Level of Evidence 3 Technical Efficacy Stage 2

BACKGROUND:Reliable change indices can determine pre-post intervention changes at an individual level that are greater than chance or practice effect. We applied previously developed minimal meaningful change (MMCRCI) scores for oxygen uptake (V̇O2) values associated with estimated lactate threshold (θLT), respiratory compensation point (RCP), and peak oxygen uptake (V̇O2peak) to evaluate the effectiveness of exercise training in cardiovascular disease patients. METHODS:303 patients (65 ± 11 yrs.; 27% female) that completed a symptom-limited cardiopulmonary exercise test (CPET) before and after 6-months of guideline-recommended exercise training were assessed to determine absolute and relative V̇O2 at θLT, RCP, and V̇O2peak. Using MMCRCI ∆V̇O2 scores of ±3.9 mL·kg-1·min-1, ±4.0 mL·kg-1·min-1, and ± 3.6 mL·kg-1·min-1 for θLT, RCP, and V̇O2peak, respectively, patients were classified as "positive" (ΔθLT, ΔRCP, and/or ΔV̇O2peak ≥ +MMCRCI), "non-" (between ±MMCRCI), or "negative" responders (≤ -MMCRCI). RESULTS:Mean RCP (n = 86) and V̇O2peak (n = 303) increased (p < 0.05) from 19.4 ± 3.6 mL·kg-1·min-1 and 18.0 ± 6.3 mL·kg-1·min-1 to 20.1 ± 3.8 mL·kg-1·min-1 and 19.2 ± 7.0 mL·kg-1·min-1 at exit, respectively, whereas θLT (n = 140) did not change (15.5 ± 3.4 mL·kg-1·min-1 versus 15.7 ± 3.8 mL·kg-1·min-1, p = 0.324). For changes in θLT, 6% were classified as "positive" responders, 90% as "non-responders", and 4% as "negative" responders. For RCP, 10% exhibited "positive" changes, 87% were "non-responders", and 2% were "negative" responders. For ΔV̇O2peak, 57 patients (19%) were classified as "positive" responders, 229 (76%) as "non-responders", and 17 (6%) as "negative" responders. CONCLUSION:Most patients that completed the exercise training program did not achieve reliable improvements greater than that of chance or practice at an individual level in θLT, RCP and V̇O2peak.

We aimed to determine the influence of ischemic heart disease (IHD) and cardiac rehabilitation (CR) on cerebrovascular compliance index (Ci). Eleven (one female) patients with IHD (mean[SD]: 61[11] yr, 29[4] kg/m2) underwent 6 mo of CR, which consisted of ≥3 sessions/wk of aerobic and resistance training (20-60 min each). Ten (three female) similarly aged controls (CON) were tested at baseline as a comparator group. Middle cerebral artery velocity (MCAv) and mean arterial pressure were monitored continuously using transcranial Doppler ultrasound and finger photoplethysmography, respectively, during a rapid sit-to-stand maneuver. A Windkessel model was used to estimate cerebrovascular Ci every five cardiac cycles for a duration of 30 s. Cerebrovascular resistance was calculated as the quotient of MAP and MCAv. Two-way ANOVAs were used to determine whether cerebrovascular variables differ during postural transitions between groups and after CR. Baseline MCAv was higher in CON versus IHD (P = 0.014) and a time × group interaction was observed (P = 0.045) where MCAv decreased more in CON after standing. Compared with the precondition, CR had no effect on MCAv (condition P = 0.950) but a main effect of time indicated that MCAv decreased from the seated position in both conditions (time P = 0.013). Baseline cerebrovascular Ci was greater in IHD versus CON (P = 0.049) and the peak cerebrovascular Ci during the transition to standing was significantly higher in IHD compared with CON (interaction P = 0.047). CR did not affect cerebrovascular compliance (P = 0.452) and no time-by-condition interaction upon standing was present (P = 0.174). Baseline cerebrovascular Ci is higher in IHD at baseline compared with CON, but 6 mo of CR did not modify the transient increase in cerebrovascular Ci during sit-to-stand maneuvers.NEW & NOTEWORTHY Post-cardiac event cognitive impairment is common and exercise-based rehabilitation may be an effective intervention to mitigate cognitive decline. Microvascular damage due to high blood pressure pulsatility entering the brain is the putative mechanism of vascular dementia. Whether patients with ischemic heart disease exhibit lower cerebrovascular compliance, and if cardiac rehabilitation can improve cerebrovascular compliance is unknown. We observed that patients with ischemic heart disease have paradoxically higher cerebrovascular compliance, which is not affected by cardiac rehabilitation.

Introduction: Reduced ejection fraction (REF) in patients is prevalent, utilizing substantial health care resources. Goal Directed Therapy (GDT) reduces hospitalization, morbidity, and mortality but use is suboptimal. Care in subspecialty clinics following discharge reduces readmission, but is not scaled for longitudinal care of the larger REF population. Canadian guidelines support integration of primary, specialist, and non-physician care in systems to improve outcomes. Hypothesis: A protocol-guided intervention will achieve high rates of GDT for REF patients in a community health care setting. Goal: To evaluate a pragmatic quality-of-care intervention to achieve GDT for REF patients and assess barriers to GDT. Methods: Patients referred for imaging and cardiology consultation at a community facility (Jan 1/15-Dec 31/22) were screened. Patients with LVEF <41% on echocardiogram were included if their cardiologist consented to study protocol GDT and were enrolled at the next scheduled, usual care cardiologist visit. 2 project nurses confirmed patient status and assisted GDT management using medical directives at 9 protocol-specified visits between usual care visits over 32 weeks. The primary target was achieving GDT or maximally tolerated GDT (>0 mg). A secondary endpoint, clinical inertia, was defined as not achieving GDT due to physician or patient choice. Results: 864 patients (13 cardiologists) participated: median age 71 (28-102) years, diabetes 25%, hypertension 60%, atrial fibrillation 22%. At intake: NYHA class ≥2 (60%), EF <30% (45%), 30-35% (27%), 36-40% (29%), REF etiology ischemic (47%), non-ischemic (43%), mixed (10%). The majority achieved GDT in each class; inertia, not intolerance predominantly accounted for those who did not achieve GDT. Conclusion: This pragmatic community-based intervention achieved high rates of GDT that could improve longitudinal care for REF patients, and is potentially scalable and generalizable.

Transitional care to cardiac rehabilitation during the pandemic was a complex process for older adults, with additional challenges for decision-making and participation. This study aimed to explore the perspectives of older adults and health providers on transitional care from the hospital to cardiac rehabilitation, focusing on patient participation in decision-making. A qualitative exploratory design was used. Semi-structured interviews were conducted with 15 older adults and 6 healthcare providers. Document analysis and reflexive journaling were used to support triangulation of findings. Six themes emerged from the data, related to insufficient follow-up from providers, the importance of patients’ emotional and psychological health and the support provided by family members, the need for information tailored to patients’ needs and spaces for participation in decision-making, as well as challenges during COVID-19, including delayed medical procedures, rushed discharge and isolating hospital stays. The findings of this study indicated a number of potential gaps in the provision of transitional care services as reported by older adults who had a cardiovascular event, often during the first few weeks post hospital discharge.

A multicentre prospective observational study (36 sites in 8 Canadian provinces), imbedded in the CODE-MI trial, had clinical laboratories at these sites test 3 samples (normal, female 99th-percentile, and male 99th-percentile concentrations) monthly for 1 year on 67 instruments, producing 2142 results from 6 distinct troponin assays. Mean differences varied per assay with maximum values being & PLUSMN; 4, & PLUSMN; 8, and & PLUSMN; 9 ng/L for the normal, female 99th-percentile, and male 99th-percentile sample, respectively. Using a pragmatic approach, combining all assays, the maximum analytic result variation was & PLUSMN; 3 ng/L for target concentrations less than 10 ng/L and & PLUSMN; 30% at concen-trations slightly above.

BACKGROUND:To evaluate the feasibility of "threshold-based" aerobic exercise prescription in cardiovascular disease, we aimed to quantify the proportion of patients whose clinical cardiopulmonary exercise test (CPET) permit identification of estimated lactate threshold (θLT) and respiratory compensation point (RCP) and to characterize the variability at which these thresholds occur. METHODS:Breath-by-breath CPET data of 1102 patients (65 ± 12 years) referred to cardiac rehabilitation were analyzed to identify peak O2 uptake (V˙O2peak; mL·min-1 and mL·kg-1·min-1) and θLT and RCP (reported as V˙O2, %V˙O2peak, and %peak heart rate [%HRpeak]). Patients were grouped by the presence or absence of thresholds: group 0: neither θLT nor RCP; group 1: θLT only; and group 2: both θLT and RCP. RESULTS:Mean V˙O2peak was 1523 ± 627 mL·min-1 (range: 315-3789 mL·min-1) or 18.0 ± 6.5 mL·kg-1·min-1 (5.2-46.5 mL·kg-1·min-1) and HRpeak was 123 ± 24 beats per minute (bpm) (52 bpm-207 bpm). There were 556 patients (50%) in group 0, 196 (18%) in group 1, and 350 (32%) in group 2. In group 1, mean θLT was 1240 ± 410 mL·min-1 (580-2560 mL·min-1), 75% ± 8%V˙O2peak (52%-92%V˙O2peak), or 84% ± 6%HRpeak (64%-96%HRpeak). In group 2, θLT was 1390 ± 360 mL·min-1 (640-2430 mL·min-1), 70% ± 8%V˙O2peak (41%-88%V˙O2peak), or 78% ± 7%HRpeak (52%-96%HRpeak), and RCP was 1680 ± 440 mL·min-1 (730-3090 mL·min-1), 84% ± 7%V˙O2peak (54%-99%V˙O2peak), or 87% ± 6%HRpeak (59%-99%HRpeak). Compared with group 1, θLT in group 2 occurred at a higher V˙O2 but lower %V˙O2peak and %HRpeak (P < 0.05). CONCLUSIONS:Only 32% of CPETs exhibited both θLT and RCP despite flexibility in protocol options. Commonly used step-based protocols are suboptimal for "threshold-based" exercise prescription.

White matter (WM) breakdown is linked to cognitive impairment in coronary artery disease (CAD). We used diffusion MRI tractometry to assess the effects of cardiac disease, brain aging, and cardiac rehabilitation (CR) on regional WM macrostructure in brains of CAD patients. WM disruptions were found in CAD patients at baseline (pre-CR) compared to controls and in old controls compared to young controls. WM improvements, especially in regions linked to cognition, were observed in CAD patients following CR. Both cardiac disease and brain aging may contribute to WM dysfunction in CAD, and these WM disruptions may be favourably modified by CR.

Heart function clinics (HFCs) are a cornerstone of heart failure management, yet they remain largely integrated into tertiary care environments, with few HFCs existing in the primary care community. This study examined the roles of HFCs in each setting by exploring referral patterns, the patient populations, outcomes, provision of care, and how each clinic aligned with the Canadian Cardiovascular Society Heart Failure national quality indicators. The clinical characteristics of patients at both sites revealed a high level of disease comorbidity and complexity, although referral and discharge patterns differed markedly. Both sites reasonably achieved quality patient care. There are unique roles for HFCs in each setting, which supports the further creation of specialized heart failure centres within the community in alignment with the proposed spokehub-node integrated care model. RésuméLes cliniques de la fonction cardiaque constituent la pierre angulaire de la prise en charge de l’insuffisance cardiaque, mais elles demeurent en grande partie intégrées dans les milieux de soins tertiaires, quelques-unes seulement se trouvant dans les milieux de soins primaires. Cette étude examine les rôles des cliniques de la fonction cardiaque dans chacun de ces milieux en explorant les modes d’orientation des patients, les populations de patients, les résultats, la prestation des soins et la conformité de chaque clinique aux indicateurs de qualité nationaux de la Société canadienne de cardiologie en matière d’insuffisance cardiaque. Dans les deux milieux, les caractéristiques cliniques des patients révèlent un degré élevé d’affections comorbides et de complexité de la maladie, bien que les modes d’orientation et de sortie de l’hôpital soient très différents. La presta-tion des soins est de qualité satisfaisante dans les deux milieux. De toute évidence, les cliniques de la fonction cardiaque ont un rôle unique à jouer dans chaque milieu, ce qui justifie la création de centres spécialisés en insuffisance cardiaque dans la collectivité selon le modèle en étoile (spokehub-node) de soins intégrés proposé.

Background: Despite well-established efficacy for patients with a cardiovascular diagnosis or event, exercise-based cardiac rehabilitation program participation and completion has remained alarmingly low due to both system-level barriers and patient-level factors. Patient mental health, particularly depression, is now recognized as significantly associated with reduced enrollment, participation, attendance, and completion of a cardiac rehabilitation program. More recently, anxiety sensitivity has emerged as an independent construct, related to but distinct from both depression and anxiety. Anxiety sensitivity has been reported to be adversely associated with participation in exercise and, thus, may be important for patients in cardiac rehabilitation. Accordingly, the objective of this study was to conduct a scoping review to summarize the evidence for associations between anxiety sensitivity and cardiovascular disease risk factors, exercise, and clinical outcomes in cardiac rehabilitation. Methods: A formal scoping review, following PRISMA-ScR guidelines, was undertaken. Searches of MEDLINE, Web of Science, CINAHL, PSYCINFO, and Scopus databases were conducted, supplemented by hand searches; studies published through December of 2020 were included. The initial screening was based on titles and abstracts and the second stage of screening was based on full text examination. Results: The final search results included 28 studies. Studies reported statistically significant associations between anxiety sensitivity and exercise, cardiovascular disease, and participation in cardiac rehabilitation. Many studies, however, were conducted in non-clinical, community-based populations; there were few studies conducted in cardiovascular disease and cardiac rehabilitation clinical patient populations. Additionally, significant gaps remain in our understanding of the sex-based differences in the complex relationships between anxiety sensitivity, exercise and cardiac rehabilitation. Conclusion: More research is needed to understand specific associations between anxiety sensitivity and clinical outcomes among clinical cardiovascular disease patients and participants in cardiac rehabilitation programs. Treatment of anxiety sensitivity to optimize clinical outcomes in cardiac rehabilitation programs should be investigated in future studies.

Background:The primary goal of this study was to determine the time spent completing moderate-to-vigorous intensity physical activity (MVPA) among adults with atrial fibrillation (AF). Secondary aims examined MVPA and sitting time (ST) by AF subtypes (ie, paroxysmal, persistent, long-standing persistent, and permanent) and associations between MVPA or ST and knowledge, task self-efficacy, and outcome expectations. Methods:An observational study was conducted in the Champlain region of Ontario, Canada. AF patients completed a survey to determine MVPA and ST using the Short-Form International Physical Activity Questionnaire. Results:A total of 619 patients (66% male; median age 65 years [95% CI 64-67 years]) completed the survey. Median MVPA and ST were 100 (60-120) min/wk and 6 (5-6) h/d; 56% of patients were not meeting the Canadian 24H Movement Guidelines. Most patients (54%) did not know/were unsure of the MVPA recommendations, yet 72% thought physical activity should be part of AF management. Positive correlations were found between higher MVPA levels and the following: (i) speaking to a healthcare professional about engaging in physical activity for managing AF (ρ = 0.108, P = 0.017); (ii) greater confidence regarding ability to perform physical activity and muscle-strengthening exercise (ρ = 0.421, P < 0.01); and (iii) patient agreement that AF would be better managed if they were active (ρ = 0.205, P < 0.01). Conclusions:Many AF patients do not meet the MVPA recommendations, which may be due to lack of physical activity knowledge. Exercise professionals may help educate patients on the benefits of physical activity, improve task-self efficacy, and integrate MVPA into patient lifestyles.