Effects of β-Blockers on Maximal Heart Rate Prediction Equations in a Cardiac Population

Effects of a physical therapist-driven individualized hybrid model of the exercise component of cardiac rehabilitation on patient outcomes: a prospective single group, time-series design

PURPOSE

The aim of this prospective single group, time-series study was to determine the feasibility, adherence, and effectiveness of an individualized physical therapist (PT)-driven hybrid model of the exercise component of cardiac rehabilitation (CR) that uses a novel intensity-recovery progression protocol (IRPP) and cardiac testing template (CTT) to assess achieved heart rate (HR) intensity, HR recovery, and intensity-recovery total to guide treatment.

METHODS

Assessment of a questionnaire, treadmill 6-min walk (6MW), 1-min sit-to-stand (1STS), 1-min step, and 1-min agility square tests were assessed on 100 participants. Compared to traditional CR the 36-visit 1:1 hybrid model was individualized using the IRPP program and CTT.

RESULTS

Adherence was 35% (timely) and 44% (overall) completion. The per-protocol analysis (PPA) and intent-to-treat (ITT) analysis suggest significant improvement in objective assessments baseline to visit 15 (PPA = 11 of 14) (ITT = 13 of 14), baseline to visit 30 (PPA = 12 of 14) (ITT = 12 of 14) and visit 15 to visit 30 (PPA = 9 of 14) (ITT = 10 of 14). Improvement beyond the minimal clinically important difference (MCID) was 94.3% in the 6MW and 91.4% in the 1STS.

CONCLUSIONS

The PT-driven IRPP program was feasible in terms of adherence and safety, showing significant improvement in a majority of assessments. Analysis of HR using the CTT may help clinical decision making for progression in CR.Implications for rehabilitationCardiac rehabilitation (CR) is an underutilized means of improving health for people recovering from cardiac surgery.People recovering from cardiac surgery have complex reasons for why they choose to enroll in, drop out from, or complete a CR program.Reporting of outcomes in CR and progression in intensity is not often individualized.An individualized physical therapist driven CR program using both subjective and objective assessments may be successful at improving adherence and effectiveness in this cohort.

The beneficial effects of exercise on glucose and lipid metabolism during statin therapy is partially mediated by changes of the intestinal flora

Recent research has confirmed that moderate-intensity exercise affects the gut microbiome composition and improves cardiac function in an animal model after myocardial infarction (MI). However, few studies have investigated the effects of exercise on glucose and lipid metabolism in patients with coronary heart disease (CHD) receiving a statin treatment and successful percutaneous coronary intervention (PCI). Meanwhile, since statin therapy may lead to the risk of an increase in blood glucose level in CHD patients, we hypothesized that moderate-intensity exercise may be helpful for regulating glucose-lipid metabolism and stabilizing the blood glucose level in CHD patients. Therefore, to confirm our conjecture, we conducted a clinical retrospective study and animal experiment, respectively. The clinical study involved a total of 501 statin-treated patients with CHD after PCI. According to the study protocol, patients were divided into the following three groups: a non-exercise group, exercise at the recommended standard group, and exercise not at the recommended standard group. We found that qualified moderate-intensity exercise decreased blood glucose and lipid levels at follow-up at a mean of 2.2 years, and the incidence of new-onset diabetes showed a downward trend compared with the non-exercise and exercise not at the recommended standard groups. Furthermore, we used a high-fat rat model to explore an additional mechanism of the beneficial effects of exercise-based management on glucose-lipid metabolism apart from the known mechanism. We used 16S rRNA high-throughput sequencing technology to analyze the changes induced by exercise in the composition of intestinal flora in experimental rats. We found that rats that exercised with or without statin administration had lower plasma glucose and lipid levels and that these parameters were higher in the control and statin-treated rats that did not exercise. These results were consistent with the human study. The results from high-throughput sequencing of the intestinal flora of rats showed, to the best of our knowledge, that exercise leads to an increased relative abundance of Akkermansia muciniphila, which contributes to improved glucose and lipid metabolism. Based on our current results, we suggest that moderate-intensity exercise can improve glucose and lipid metabolism and prevent statin treatment-related side effects, such as hyperglycemia, in patients after PCI. Exercise could facilitate the applicability of statins for lower lipid levels. Exercise training also provides additional benefits, such as alteration of the gut microbiota, which contributes to improved glucose and lipid metabolism.

U-DECIDE: Utilising technology for Diet & Exercise Change In complex chronic conditions across Diverse Environments: Protocol for a Randomised Controlled Trial (Preprint)

Background

The metabolic syndrome is common across many complex chronic disease groups. Advances in health technology have provided opportunities to support lifestyle interventions.

Objective

The purpose of this study is to test the feasibility of a health technology-assisted lifestyle intervention in a patient-led model of care.

Methods

The study is a single-center, 26-week, randomized controlled trial. The setting is specialist kidney and liver disease clinics at a large Australian tertiary hospital. The participants will be adults with a complex chronic condition who are referred for dietetic assessment and display at least one feature of the metabolic syndrome. All participants will receive an individualized assessment and advice on diet quality from a dietitian, a wearable activity monitor, and standard care. Participants randomized to the intervention group will receive access to a suite of health technologies from which to choose, including common base components (text messages) and optional components (online and mobile app–based nutrition information, an online home exercise program, and group-based videoconferencing). Exposure to the optional aspects of the intervention will be patient-led, with participants choosing their preferred level of engagement. The primary outcome will be the feasibility of delivering the program, determined by safety, recruitment rate, retention, exposure uptake, and telehealth adherence. Secondary outcomes will be clinical effectiveness, patient-led goal attainment, treatment fidelity, exposure demand, and participant perceptions. Primary outcome data will be assessed descriptively and secondary outcomes will be assessed using an analysis of covariance. This study will provide evidence on the feasibility of the intervention in a tertiary setting for patients with complex chronic disease exhibiting features of the metabolic syndrome.

Results

The study was funded in 2019. Enrollment has commenced and is expected to be completed by June 2022. Data collection and follow up are expected to be completed by December 2022. Results from the analyses based on primary outcomes are expected to be submitted for publication by June 2023.

Conclusions

The study will test the implementation of a health technology–assisted lifestyle intervention in a tertiary outpatient setting for a diverse group of patients with complex chronic conditions. It is novel in that it embeds patient choice into intervention exposure and will inform health service decision-makers in regards to the feasibility of scale and spread of technology-assisted access to care for a broader reach of specialist services.

Trial Registration

Australian New Zealand Clinical Trial Registry ACTRN12620001282976; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=378337

International Registered Report Identifier (IRRID)

DERR1-10.2196/37556

New Formula to Predict Heart Rate at Anaerobic Threshold That Considers the Effects of β-Blockers in Patients With Myocardial Infarction: MULTI-INSTITUTIONAL RETROSPECTIVE CROSS-SECTIONAL STUDY

PURPOSE

It is recommended that patients with myocardial infarction (MI) be prescribed exercise by target heart rate (HR) at the anaerobic threshold (AT) via cardiopulmonary exercise testing (CPX). Although percent HR reserve using predicted HRmax (%HRRpred) is used to prescribe exercise if CPX or an exercise test cannot be performed, %HRRpred is especially difficult to use when patients take β-blockers. We devised a new formula to predict HR at AT (HRAT) that considers β-blocker effects in MI patients and validated its accuracy.

METHODS

The new formula was created using the data of 196 MI patients in our hospital (derivation sample), and its accuracy was assessed using the data of 71 MI patients in other hospitals (validation sample). All patients underwent CPX 1 mo after MI onset, and resting HR, resting systolic blood pressure (SBP), and HRAT were measured during CPX.

RESULTS

The results of multiple regression analysis in the derivation sample gave the following formula (R2 = 0.605, P < .001): predicted HRAT = 2.035 × (≥65 yr:-1, <65 yr:1) + 3.648 × (body mass index <18.5 kg/m2:-1, body mass index ≥18.5 kg/m2:1) + 4.284 × (β1-blocker(+):-1, β1-blocker(-):1) + 0.734 × (HRrest) + 0.078 × (SBPrest) + 36.812. This formula consists entirely of predictors that can be obtained at rest. HRAT and predicted HRAT with the new formula were not significantly different in the validation sample (mean absolute error: 5.5 ± 4.1 bpm).

CONCLUSIONS

The accuracy of the new formula appeared to be favorable. This new formula may be a practical method for exercise prescription in MI patients, regardless of their β-blocker treatment status, if CPX is unavailable.

Exercise ECG Testing and Stress Cardiac Magnetic Resonance for Risk Prediction in Patients With Chronic Coronary Syndrome

PURPOSE

Vasodilator stress cardiac magnetic resonance (VS-CMR) has become crucial in the workup of patients with known or suspected chronic coronary syndrome (CCS). Whether traditional exercise ECG testing (ExECG) contributes prognostic information beyond VS-CMR is unclear.

METHODS

We retrospectively included 288 patients with known or suspected CCS who had undergone ExECG and subsequent VS-CMR in our institution. Clinical, ExECG, and VS-CMR variables were recorded. We defined the serious adverse events (SAE) as a combined endpoint of acute coronary syndrome, admission for heart failure, or all-cause death.

RESULTS

During a mean follow-up of 4.2 ± 2.15 yr, we registered 27 SAE (15 admissions for acute coronary syndrome, eight admissions for heart failure, and four all-cause deaths). Once adjusted for clinical, ExECG, and VS-CMR parameters associated with SAE, the only independent predictors were HRmax in ExECG (HR = 0.98: 95% CI, 0.96-0.99; P = .01) and more extensive stress-induced perfusion defects (PDs, number of segments) in VS-CMR (HR = 1.19: 95% CI, 1.07-1.34; P < .01). Adding HRmax significantly improved the predictive power of the multivariable model for SAE, including PDs (continuous reclassification improvement index: 0.47: 95% CI, 0.10-0.81; P < .05). The annualized SAE rate was 1% (if PD < 2 segments and HRmax > 130 bpm), 2% (if PD < 2 segments and HRmax ≤ 130 bpm), 3.2% (if PD ≥ 2 segments and HRmax > 130 bpm), and 6.3% (if PD ≥ 2 segments and HRmax ≤ 130 bpm), P < .01, for the trend. In patients on β-blocker therapy, however, only PDs in VS-CMR, but not HRmax, predicted SAE.

CONCLUSIONS

We conclude that ExECG contributes significantly to prognostic information beyond VS-CMR in patients with known or suspected CCS.

Cardiac rehabilitation and improvement of chronotropic incompetence: Is it the exercise or just the beta blockers?

INTRODUCTION

Clinical use of chronotropic response has been limited due to lack of consensus on the appropriate formula for chronotropic index (Ci) calculation and the definition of chronotropic incompetence.

OBJECTIVES

To assess the effects of cardiac rehabilitation programs (CRP) on Ci, irrespective of betablockers (BB) use and dosage. Assess the relative contribution of change in Ci on improvement in functional capacity.

METHODS

Retrospective analysis of a sample of patients admitted to a CRP after acute coronary syndrome, with at least 12 months of follow-up. Ci was calculated using the conventional (CCi) and the Brawner formula (BCi) for age-predicted maximum heart rate. Ci and functional capacity were estimated at three time points: T1 and T2, before and at the end of the CRP, and T3, at 12 months. The sample was categorized according to BB dosage modification between T1 and T3: G1 - reduced; G2 - no change; G3 - increased.

RESULTS

In G1, CCi increased from 63.5% in T1 to 77.9% in T3; in G2, from 67.3% to 77.9%; in G3, from 71.2% to 75.4%. In G1, BCi increased from 110.4% to 140.0%; in G2, from 122.8% to 140.1%; in G3, from 133.3% to 139.2%. An average increase in 1.0% in CCi was associated with an average increase in functional capacity of 0.37 METS.

CONCLUSIONS

Chronotropic index significantly improves with CRP, irrespective of BB dose changes. CCi is more closely related with improvement in functional capacity than BCi. Improvement of Ci is an important predictor of functional capacity and prognosis in cardiovascular disease patients.

Impact of equine assisted therapy on the cardiovascular parameters of the elderly

Introduction: Physical activity programs in the elderly aim to prevent and/or reduce the functional decline resulting from the senescence process. Several studies provide evidence that Equine Assisted Therapy (EAT) is an effective means of improving health. However, studies addressing the effects of EATon the cardiovascular system are scarce. Objective: To evaluate the effect of Equine Assisted Therapyon the cardiovascular responses of participants divided into two groups: normotensive and hypertensive. Methods: Twenty individuals participated, aged between 60 and 79 years, divided into three groups: Normotensive Group (n=14), Hypertensive Group (n=6) and all participants, Total Group (n=20). The Omron® HEM 742 blood pressure monitor was used to measure blood pressure and the Gerathem® portable finger oximeter to measure heart rate and blood oxygen saturation. Ten visits were made once a week, lasting 30 minutes. Results: Between the first and tenth interventions, there was a reduction in blood pressure and heart rate, with statistical significance of systolic blood pressure for the Hypertensive Group (p=0.0478), the Total Group (p=0.0201) and diastolic pressure for the Total Group (p=0.0421). There was also a statistically significant difference in systolic blood pressure and heart rate during some visits. Blood oxygen saturation increased after the intervention, but without statistical significance. Conclusion: Equine Assisted Therapy can promote a reduction in blood pressure in the elderly, especially hypertensive individuals.

Cardiopulmonary exercise testing in severe osteoarthritis: a crossover comparison of four exercise modalities

Cardiopulmonary exercise testing is performed increasingly for cardiorespiratory fitness assessment and pre-operative risk stratification. Lower limb osteoarthritis is a common comorbidity in surgical patients, meaning traditional cycle ergometry-based cardiopulmonary exercise testing is difficult. The purpose of this study was to compare cardiopulmonary exercise testing variables and subjective responses in four different exercise modalities. In this crossover study, 15 patients with osteoarthritis scheduled for total hip or knee arthroplasty (mean (SD) age 68 (7) years; body mass index 31.4 (4.1) kg.m^-2 ) completed cardiopulmonary exercise testing on a treadmill, elliptical cross-trainer, cycle and arm ergometer. Mean (SD) peak oxygen consumption was 20-30% greater on the lower limb modalities (treadmill 21.5 (4.6) (p < 0.001); elliptical cross-trainer (21.2 (4.1) (p < 0.001); and cycle ergometer (19.4 (4.2) ml.min^-1 .kg^-1 (p = 0.001), respectively) than on the arm ergometer (15.7 (3.7) ml.min^-1 .kg^-1 ). Anaerobic threshold was 25-50% greater on the lower limb modalities (treadmill 13.5 (3.1) (p < 0.001); elliptical cross-trainer 14.6 (3.0) (p < 0.001); and cycle ergometer 10.7 (2.9) (p = 0.003)) compared with the arm ergometer (8.4 (1.7) ml.min^-1 .kg^-1 ). The median (95%CI) difference between pre-exercise and peak-exercise pain scores was greater for tests on the treadmill (2.0 (0.0-5.0) (p = 0.001); elliptical cross-trainer (3.0 (2.0-4.0) (p = 0.001); and cycle ergometer (3.0 (1.0-5.0) (p = 0.001)), compared with the arm ergometer (0.0 (0.0-1.0) (p = 0.406)). Despite greater peak exercise pain, cardiopulmonary exercise testing modalities utilising the lower limbs affected by osteoarthritis elicited higher peak oxygen consumption and anaerobic threshold values compared with arm ergometry.