Do Clinical Exercise Tests Permit Exercise Threshold Identification in Patients Referred to Cardiac Rehabilitation?

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.

Optimal Usage of Sacubitril/Valsartan for the Treatment of Heart Failure: The Importance of Optimizing Heart Failure Care in Canada.

BACKGROUND: Heart failure (HF) with reduced ejection fraction represents approximately 50% of the 600,000 Canadians currently living with HF and over 90,000 new cases diagnosed each year. The angiotensin receptor neprilysin inhibitor, sacubitril/valsartan, demonstrated superior efficacy in reducing cardiovascular death and HF hospitalization over standard of care therapy. METHODS: The potential magnitude of benefit in Canada with respect to preventing or postponing deaths and reducing hospitalizations resulting from its optimal implementation in patients with HF with an ejection fraction <40% was estimated based on published sources. RESULTS: Of the potentially eligible 225,562 patients, this would amount to the prevention of 4699 cardiovascular deaths and first HF hospitalizations, 3698 thirty-day HF readmissions, and 2820 deaths due to all-cause mortality. The number of patients receiving sacubitril/valsartan nationally in 2018 was 27,267. This represents approximately 12% of the calculated eligible population for this therapy in Canada. CONCLUSIONS: The findings from this analysis suggest that a substantial number of deaths, hospitalizations, and HF readmissions could potentially be avoided by optimal usage of sacubitril/valsartan therapy in Canada. This emphasizes the importance of rapidly and appropriately implementing evidence-based medications into routine clinical practice, to achieve the best possible outcomes for our patients with HF and to reduce the high burden and cost of HF in Canada.

CONTEXTE: L'insuffisance cardiaque (IC) avec diminution de la fraction d'éjection touche actuellement environ 50 % des 600 000 Canadiens qui sont atteints d'IC, et plus de 90 000 nouveaux cas de cette affection sont diagnostiqués chaque année. L'association sacubitril-valsartan (inhibiteur de la néprilysine et antagoniste des récepteurs de l'angiotensine) a démontré une efficacité supérieure à celle du traitement de référence au chapitre de la réduction de la mortalité d'origine cardiovasculaire et des hospitalisations dues à l'IC. MÉTHODOLOGIE: L'ampleur potentielle des bienfaits du médicament au Canada en matière de prévention ou de report des décès et de réduction des hospitalisations par suite de son utilisation optimale chez les patients atteints d'IC présentant une fraction d'éjection < 40 % a été estimée sur la base de sources publiées. RÉSULTATS: Chez les 225 562 patients potentiellement admissibles au traitement, le médicament permettrait de prévenir 4 699 décès d'origine cardiovasculaire et premières hospitalisations pour cause d'IC, 3 698 réhospitalisations pour cause d'IC dans les 30 jours suivant la sortie de l'hôpital et 2 820 décès toutes causes confondues. À l'échelle nationale en 2018, 27 267 patients ont été traités par l'association sacubitril-valsartan. Cela représente environ 12 % de la population admissible au traitement selon les calculs s'appliquant au Canada. CONCLUSIONS: Les résultats de cette analyse permettent de penser que beaucoup de décès, d'hospitalisations et de réhospitalisations pour cause d'IC pourraient être évités par suite de la mise en œuvre optimale du traitement par l'association sacubitril-valsartan au Canada. Sous cet éclairage, force est de constater l'importance que revêt l'intégration rapide et appropriée des pharmacothérapies factuelles à la pratique clinique courante, dans l'optique d'une démarche visant à obtenir les meilleurs résultats possible chez nos patients atteints d'IC et à réduire le lourd fardeau de cette affection au Canada.

Therapies for Advanced Heart Failure Patients Ineligible for Heart Transplantation: Beyond Pharmacotherapy.

Globally, there are ∼ 26 million people living with heart failure (HF), 50% of them with reduced ejection fraction, costing countries billions of dollars each year. Improvements in treatment of cardiovascular diseases, including advanced HF, have allowed an unprecedented number of patients to survive into old age. Despite these advances, patients with HF deteriorate and often require advanced therapies. As the proportion of elderly patients in the population increases, there will be an increasing number of patients to be evaluated for advanced therapies and an increasing number that do not qualify for, won't be considered for, or decline orthotopic heart transplantation. The purpose of this article is to review the benefits of palliative care (PC), exercise-based cardiac rehabilitation (ExCR), device therapy (cardiac resynchronization therapy and mitral clip), and mechanical circulatory support (MCS) in advanced HF patients who are transplant ineligible. PC interventions should be introduced early in the course of a patient's diagnosis to manage symptoms, address goals of care, and improve patient-centered outcomes. Further improvement in health-related quality of life as well as functional capacity can be achieved safely in patients with advanced HF through patient participation in ExCR. Device therapy and MCS can reduce HF hospitalizations and improve survival. In fact, early survival with MCS approaches that of heart transplantation. Despite their being transplant ineligible, there are a variety of treatment options available to patients to improve their quality of life, decrease hospitalizations, and potentially improve mortality.

Antithrombotic treatment after coronary artery bypass graft surgery: systematic review and network meta-analysis.

OBJECTIVE: To assess the effects of different oral antithrombotic drugs that prevent saphenous vein graft failure in patients undergoing coronary artery bypass graft surgery. DESIGN: Systematic review and network meta-analysis. DATA SOURCES: Medline, Embase, Web of Science, CINAHL, and the Cochrane Library from inception to 25 January 2019. ELIGIBILITY CRITERIA: for selecting studies Randomised controlled trials of participants (aged ≥18) who received oral antithrombotic drugs (antiplatelets or anticoagulants) to prevent saphenous vein graft failure after coronary artery bypass graft surgery. MAIN OUTCOME MEASURES: The primary efficacy endpoint was saphenous vein graft failure and the primary safety endpoint was major bleeding. Secondary endpoints were myocardial infarction and death. RESULTS: This review identified 3266 citations, and 21 articles that related to 20 randomised controlled trials were included in the network meta-analysis. These 20 trials comprised 4803 participants and investigated nine different interventions (eight active and one placebo). Moderate certainty evidence supports the use of dual antiplatelet therapy with either aspirin plus ticagrelor (odds ratio 0.50, 95% confidence interval 0.31 to 0.79, number needed to treat 10) or aspirin plus clopidogrel (0.60, 0.42 to 0.86, 19) to reduce saphenous vein graft failure when compared with aspirin monotherapy. The study found no strong evidence of differences in major bleeding, myocardial infarction, and death among different antithrombotic therapies. The possibility of intransitivity could not be ruled out; however, between-trial heterogeneity and incoherence were low in all included analyses. Sensitivity analysis using per graft data did not change the effect estimates. CONCLUSIONS: The results of this network meta-analysis suggest an important absolute benefit of adding ticagrelor or clopidogrel to aspirin to prevent saphenous vein graft failure after coronary artery bypass graft surgery. Dual antiplatelet therapy after surgery should be tailored to the patient by balancing the safety and efficacy profile of the drug intervention against important patient outcomes. STUDY REGISTRATION: PROSPERO registration number CRD42017065678.

Improving Electrocardiography Diagnostic Accuracy in Emergency Medical Services Personnel.

BACKGROUND: Accuracy of electrocardiogram (ECG) interpretation is important for identification of ST-elevation myocardial infarction (STEMI) by Emergency Medical Services (EMS) personnel who recognize STEMI in the field and activate the coronary catheterization laboratory. According to previous research, there is improvement in diagnosis of STEMIs for healthcare providers who read an average of > 20 ECGs per week. This study evaluated the effectiveness of online ECG modules on improving diagnostic accuracy. METHODS: EMS personnel received 25 ECGs per week to interpret via an online program. Diagnostic accuracy was assessed for improvement via completion of an ECG evaluation package before and after the intervention. Job satisfaction data were collected to determine the impact of the educational initiative. RESULTS: A total of 64 participants completed the study. Overall, there was an improvement in ECG diagnostic accuracy from 50.8% to 61.2% (95% confidence interval [CI], 7.7-13.2; P < 0.0001). Specifically, there was significant improvement in the diagnosis of STEMI (8.5%; 95% CI, 4.9-12.3; P < 0.003) and supraventricular tachycardia (39.0%; 95% CI, 17.2-60.8; P < 0.008), with a trend toward improvement in all other diagnoses. These effects were sustained to 3 months (9.6%; 95% CI, 6.4-12.7; P < 0.0001). Improvement was seen regardless of employment experience and training. There was no significant impact on job satisfaction. CONCLUSIONS: ECG exposure remains an important factor in improving the accuracy of ECG diagnosis in EMS personnel. Online education modules provide an easily accessible way of improving ECG interpretation with the opportunity for positive downstream effects on patient outcomes and resource use.

INTRODUCTION: L'interprétation de l'électrocardiogramme (ECG) doit être précise pour détecter l'infarctus du myocarde avec élévation du segment ST (STEMI) puisque le personnel des services médicaux d'urgence (SMU) doit reconnaître sur le terrain le STEMI et faire démarrer le processus vers le laboratoire de cathétérisme coronarien. Selon une étude antérieure, on note une amélioration dans le diagnostic du STEMI chez les prestataires de soins de santé qui lisent en moyenne > 20 ECG par semaine. La présente étude a permis d'évaluer l'efficacité des modules d'ECG en ligne en fonction de l'amélioration de la précision du diagnostic. MÉTHODES: Le personnel des SMU recevait chaque semaine 25 ECG à interpréter au moyen d'un programme en ligne. On évaluait la précision du diagnostic en fonction de son amélioration en remplissant un module d'évaluation d'ECG avant et après l'intervention. Les données sur la satisfaction professionnelle étaient collectées pour déterminer les répercussions de l'initiative éducative. RÉSULTATS: Un total de 64 participants ont complété l'étude. Dans l'ensemble, on a noté une amélioration de la précision du diagnostic à l'ECG, soit de 50,8 % à 61,2 % (intervalle de confiance [IC] à 95 %, 7,7-13,2; P < 0,0001). Notamment, on a noté une amélioration importante dans le diagnostic du STEMI (8,5 %; IC à 95 %, 4,9-12,3; P < 0,003) et de la tachycardie supraventriculaire (39,0 %; IC à 95 %, 17,2-60,8; P < 0,008), ainsi qu'une tendance à l'amélioration pour tous les autres diagnostics. Ces effets se sont maintenus jusqu'à 3 mois (9,6 %; IC à 95 %, 6,4-12,7; P < 0,0001). On a observé une amélioration, quelles que soient l'expérience professionnelle et la formation. Il n'y a eu aucune répercussion importante sur la satisfaction professionnelle. CONCLUSIONS: L'exposition à l'ECG demeure un facteur important dans l'amélioration de la précision du diagnostic à l'ECG chez le personnel des SMU. Les modules éducatifs en ligne constituent des outils facilement accessibles pour améliorer l'interprétation de l'ECG en plus d'offrir la possibilité d'effets positifs en aval sur les résultats cliniques des patients et l'utilisation des ressources.

The Spoke-Hub-and-Node Model of Integrated Heart Failure Care.

Heart failure (HF) is a significant public health concern. Specialized HF clinics provide the optimal environment to address the complex needs of these patients and improve outcomes. The current and growing population of patients with HF outstrips the ability of these clinics to deliver care. Integrated care is defined as health services that are managed and delivered so that people receive a seamless continuum of health promotion, disease prevention, diagnosis, treatment, disease management, rehabilitation, and palliative care services. This approach requires coordination across different levels and sites of care within and beyond the health sector, according to changing patient needs throughout their lives. The spoke-hub-and-node (SHN) model represents an organization of care that works collaboratively with the primary care sector and is highly integrated with community-based multidisciplinary teams of health care professionals and specialty care. The purpose of this article is to analyze the requirements for successful implementation of SHN models. We consider the respective roles of HF clinics, HF nurse specialists, pharmacists, palliative care teams, telemonitoring, and solo practitioners. We also discuss levels of care delivery and the importance of patient stratification and patient flow. The SHN approach has the potential to build on and improve the chronic care model (CCM) to deliver centralized services to preserve high-quality patient-centred care at affordable costs.

Clinical presentation and outcome of patients with ST-segment elevation myocardial infarction without culprit angiographic lesions.

Patients diagnosed with ST-segment elevation myocardial infarction (STEMI) are occasionally found to have no culprit lesion on coronary angiography and are classified as presenting with false-positive STEMI. The clinical presentation and outcomes of these patients need to be further explored. In this case-controlled study, 259 consecutive patients with true code STEMI were compared to 104 consecutive STEMI patients without culprit lesions on emergent coronary angiography. We compared the clinical presentation, electrocardiographic features, etiology, and outcomes of the two groups. STEMI patients without culprit lesions were less likely to have typical chest pain (46% vs. 79%, P < 0.01). The ST-elevation in the group without culprit lesion was more likely to be concave (56% vs. 31%, P < 0.01), with less reciprocal ST-depression (19% vs. 71%, P < 0.01). The group without culprit lesions had a higher rate of ventilator support requirement (12.4% vs. 5.4%, P = 0.02), and higher rate of 30-day mortality (11.0% vs. 5.9%, P = 0.02). However, after excluding the patients with out-of-hospital cardiac arrests from both groups, the difference was no longer significant (P = 0.40 and 0.34 respectively). The relative poor outcomes of patients with false-positive code STEMI reflect the severity of their underlying medical condition. Careful history and review of ECG may help differentiate this group from true STEMI.

Diagnostic accuracy of ST-segment elevation myocardial infarction by various healthcare providers.

BACKGROUND: This study aimed to compare the accuracy of ECG interpretation for diagnosis of STEMI by different groups of healthcare professionals involved in the STEMI program at our institution. METHODS: We selected 21 ECGs from patients with typical symptoms of MI that were diagnosed with STEMI, and 10 ECGs of STEMI mimics. STEMI mimic ECGs were repeated in the package with a story of typical and atypical chest pain. ECGs were interpreted to diagnose STEMI and identify need for initiation of the cardiac catheterization lab (CCL). Participants identified confidence in STEMI recognition, and average number of ECGs read per week. RESULTS: A total of 64 participants completed the study package. Cardiologists were more likely to provide correct interpretation compared to other groups. False positive diagnoses were more likely made by paramedics when compared to cardiologists (p < 0.01). There was a positive correlation between increased exposure to ECGs and accurate STEMI diagnosis (r = 0.482, p < 0.001). A threshold of ≥ 20 ECGs read per week showed a statistically significant improvement in accuracy (p < 0.001). Self-reported confidence correlated positively with accuracy (r = 0.402, p =< 0.001). Changing the ECG narrative of the STEMI mimic ECGs had a significant effect on interpretation between groups (p = 0.043). CONCLUSIONS: Our study showed that healthcare profession and number of ECGs reviewed per week are predictive of the accuracy of ECG interpretation of STEMI. Cardiologists are the most accurate diagnosticians, and are the least likely to falsely activate the CCL. Weekly exposure of ≥ 20 ECGs may improve diagnostic accuracy regardless of underlying experience.