FIT calculator: a multi-risk prediction framework for medical outcomes using cardiorespiratory fitness data.

Accurately predicting patients' risk for specific medical outcomes is paramount for effective healthcare management and personalized medicine. While a substantial body of literature addresses the prediction of diverse medical conditions, existing models predominantly focus on singular outcomes, limiting their scope to one disease at a time. However, clinical reality often entails patients concurrently facing multiple health risks across various medical domains. In response to this gap, our study proposes a novel multi-risk framework adept at simultaneous risk prediction for multiple clinical outcomes, including diabetes, mortality, and hypertension. Leveraging a concise set of features extracted from patients' cardiorespiratory fitness data, our framework minimizes computational complexity while maximizing predictive accuracy. Moreover, we integrate a state-of-the-art instance-based interpretability technique into our framework, providing users with comprehensive explanations for each prediction. These explanations afford medical practitioners invaluable insights into the primary health factors influencing individual predictions, fostering greater trust and utility in the underlying prediction models. Our approach thus stands to significantly enhance healthcare decision-making processes, facilitating more targeted interventions and improving patient outcomes in clinical practice. Our prediction framework utilizes an automated machine learning framework, Auto-Weka, to optimize machine learning models and hyper-parameter configurations for the simultaneous prediction of three medical outcomes: diabetes, mortality, and hypertension. Additionally, we employ a local interpretability technique to elucidate predictions generated by our framework. These explanations manifest visually, highlighting key attributes contributing to each instance's prediction for enhanced interpretability. Using automated machine learning techniques, the models simultaneously predict hypertension, mortality, and diabetes risks, utilizing only nine patient features. They achieved an average AUC of 0.90 ± 0.001 on the hypertension dataset, 0.90 ± 0.002 on the mortality dataset, and 0.89 ± 0.001 on the diabetes dataset through tenfold cross-validation. Additionally, the models demonstrated strong performance with an average AUC of 0.89 ± 0.001 on the hypertension dataset, 0.90 ± 0.001 on the mortality dataset, and 0.89 ± 0.001 on the diabetes dataset using bootstrap evaluation with 1000 resamples.

Cardiopulmonary exercise testing criteria for advanced therapies in patients with heart failure.

Many cardiology associations endorse the role of the cardiopulmonary exercise test (CPET) to define the severity of impairment of functional capacity in individuals with heart failure with reduced ejection fraction (HFrEF) and when evaluating the need for advanced therapies for these patients. The focus of the CPET within the cardiology community has been on peak volume of oxygen uptake (VO2). However, several CPET variables are associated with outcomes in individuals with and without chronic disease and can inform clinical decisions in individuals with HFrEF. In this manuscript, we will review the normal cardiopulmonary response to a graded exercise test and review current guideline recommendations relative to CPET in patients with HFrEF.

Improved cardiorespiratory fitness is associated with lower incident ischemic stroke risk: Henry Ford FIT project.

BACKGROUND: Change in cardiorespiratory fitness (CRF) modulates vascular disease risk; however, it's unclear if this adds further prognostic information, particularly for ischemic stroke. The objective of this analysis is to describe the association between the change in CRF over time and subsequent incident ischemic stroke. METHODS: This is a retrospective, longitudinal, observational cohort study of 9,646 patients (age=55±11 years; 41% women; 25% black) who completed 2 clinically indicated exercise tests (> 12 months apart) and were free of any stroke at the time of test 2. CRF was expressed as metabolic-equivalents-of-task (METs). Incident ischemic stroke was identified using ICD codes. The adjusted hazard ratio (aHR) was determined for risk of ischemic stroke associated with change in CRF. RESULTS: Mean time between tests was 3.7 years (IQR, 2.2, 6.0). During a median of 5.0 years (IQR, 2.7, 7.6 y) of follow-up, there were 873 (9.1%) ischemic stroke events. Each 1 MET increase between tests was associated with a 9% lower ischemic stroke risk (aHR 0.91 [0.88-0.94]; n = 9.646). There was an interaction effect by baseline CRF category, but not for sex or race. A sensitivity analysis which removed those who experienced an incident diagnosis known to be associated with an increased risk of ischemic vascular disease, validated our primary findings (aHR 0.91 [0.88, 0.95]; n= 6,943). CONCLUSIONS: Improvement in CRF over time is independently and inversely associated with a lower risk of ischemic stroke. Encouragement of regular exercise focused on improving CRF may reduce ischemic stroke risk.

Among Patients Taking Beta-Adrenergic Blockade Therapy, Use Measured (Not Predicted) Maximal Heart Rate to Calculate a Target Heart Rate for Cardiac Rehabilitation.

PURPOSE: Among patients in cardiac rehabilitation (CR) on beta-adrenergic blockade (ßB) therapy, this study describes the frequency for which target heart rate (THR) values computed using a predicted maximal heart rate (HR max ), correspond to a THR computed using a measured HR max in the guideline-based heart rate reserve (HR reserve ) method. METHODS: Before CR, patients completed a cardiopulmonary exercise test to measure HR max , with the data used to determine THR via the HR reserve method. Additionally, predicted HR max was computed for all patients using the 220 - age equation and two disease-specific equations, with the predicted values used to calculate THR via the straight percent and HR reserve methods. The THR was also computed using resting heart rate (HR) +20 and +30 bpm. RESULTS: Mean predicted HR max using the 220 - age equation (161 ± 11 bpm) and the disease-specific equations (123 ± 9 bpm) differed ( P < .001) from measured HR max (133 ± 21 bpm). Also, THR computed using predicted HR max resulted in values that were infrequently within the guideline-based HR reserve range calculated using measured HR max . Specifically, 0 to ≤61% of patients would have had an exercise training HR that fell within the guideline-based range of 50-80% of measured HR reserve . Use of standing resting HR +20 or +30 bpm would have resulted in 100% and 48%, respectively, of patients exercising below 50% of HR reserve . CONCLUSIONS: A THR computed using either predicted HR max or resting HR +20 or +30 bpm seldom results in a prescribed exercise intensity that is consistent with guideline recommendations for patients in CR.

Cardiac Rehabilitation Improves Fitness in Patients With Subclinical Markers of Cardiotoxicity While Receiving Chemotherapy: A RANDOMIZED CONTROLLED STUDY.

PURPOSE: Heart failure (HF) due to cardiotoxicity is a leading non-cancer-related cause of morbidity and mortality in cancer survivors. Cardiac rehabilitation (CR) improves cardiorespiratory fitness (CRF) and reduces morbidity and mortality in patients with HF, but little is known about its effects on cardiotoxicity in the cancer population. The objective of this study was to determine whether participation in CR improves CRF in patients undergoing treatment with either doxorubicin or trastuzumab who exhibit markers of subclinical cardiotoxicity. METHODS: Female patients with cancer (n = 28: breast, n = 1: leiomyosarcoma) and evidence of subclinical cardiotoxicity (ie, >10% relative decrease in global longitudinal strain or a cardiac troponin of >40 ng·L -1 ) were randomized to 10 wk of CR or usual care. Exercise consisted of 3 d/wk of interval training at 60-90% of heart rate reserve. RESULTS: Cardiorespiratory fitness, as measured by peak oxygen uptake (V˙ o2peak ), improved in the CR group (16.9 + 5.0 to 18.5 + 6.0 mL∙kg -1 ∙min -1 ) while it decreased in the usual care group (17.9 + 3.9 to 16.9 + 4.0 mL∙kg -1 ∙min -1 ) ( P = .009). No changes were observed between groups with respect to high-sensitivity troponin or global longitudinal strain. CONCLUSION: This study suggests that the use of CR may be a viable option to attenuate the reduction in CRF that occurs in patients undergoing cardiotoxic chemotherapy. The long-term effects of exercise on chemotherapy-induced HF warrant further investigation.

Relation of Exercise Capacity to Incident Heart Failure Among Men and Women With Coronary Heart Disease (from the Henry Ford Exercise Testing [FIT] Project).

Exercise capacity (EC) is inversely related to the risk of cardiovascular disease and incident heart failure (HF) in healthy subjects. However, there are no present studies that exclusively evaluate EC and the risk of incident HF in patients with known coronary heart disease (CHD). We aimed to determine the relation between EC and incident HF in patients with an established clinical diagnosis of CHD. We retrospectively identified 8,387 patients (age 61 ± 12 years; 30% women; 33% non-White) with a history of myocardial infarction (MI) or coronary revascularization procedure and no history of HF at the time of a clinically indicated exercise stress test completed between 1991 and 2009. EC was quantified in metabolic equivalents of task (METs) estimated from treadmill testing. Incident HF was identified through June 2010 from administrative databases based on ≥3 encounters with International Classification of Diseases, Ninth Revision 428.x. Cox regression analysis was used to evaluate the risk of incident HF associated with METs. Covariates included age; gender; race; hypertension, diabetes, hyperlipidemia, smoking, and MI; medications for CHD and lung diseases; and clinical indication for treadmill testing. During a median follow-up of 8.2 years (interquartile range 4.7 to 12.4 years) after the exercise test, 23% of the cohort experienced a new HF diagnosis. Lower EC categories were associated with higher HF incidence compared with METs ≥12, with nearly fourfold greater adjusted risk among patients with METs <6. Per unit increase in METs of EC was associated with a 12% lower adjusted risk for HF. There was no significant interaction based on race (p = 0.06), gender (p = 0.88), age ≤61 years (p = 0.60), history of MI (p = 0.31), or diabetes (p = 0.38). This study reveals that among men and women with CHD and no history of HF, EC is independently and inversely related to the risk of future HF.

Relation of a Maximal Exercise Test to Change in Exercise Tolerance During Cardiac Rehabilitation.

The purpose of this study was to test the hypothesis that an individualized exercise training target heart rate (HR) based on a maximal graded exercise test (GXT) is associated with greater improvements in exercise tolerance during cardiac rehabilitation (CR) compared with no GXT. In this retrospective study, we identified patients who completed 9 to 36 visits of CR between 2001 and 2016, with a length of stay ≤18 weeks and a visit frequency of 1 to 3 days per week. Patients were grouped based on whether their exercise was guided by a target HR determined from a GXT. To assess the relation between GXT and change in exercise training metabolic equivalents of task (METs), we used generalized linear models adjusted for age, gender, race, referral reason, CR visits, CR frequency, METs at start, CR location, and year of participation. Out of 4,455 patients (37% female, 48% White, median age = 62 years), 53% were prescribed a target HR based on a GXT. Compared with no GXT, a GXT was associated with a significantly greater increase in covariate-adjusted METs during CR and percentage change from start (+0.44 METs [95% confidence interval [CI] 0.38 to 0.51] and +17% [95% CI 14% to 19%], respectively). In a sensitivity analysis limited to patients with 24 to 36 visits at ≥2 days per week (n = 1,319), a GXT was associated with a significantly greater increase in covariate-adjusted exercise training METs (+0.51 [95% CI 0.36 to 0.66]; +19% [95% CI 13% to 24%]). In conclusion, to maximize the potential increase in exercise capacity during CR, patients should undergo a GXT to determine an individualized exercise training target HR.

Comparison of Ratings of Perceived Exertion and Target Heart Rate-Based Exercise Prescription in Cardiac Rehabilitation: A RANDOMIZED CONTROLLED PILOT STUDY.

PURPOSE: Although ratings of perceived exertion (RPE) are widely used to guide exercise intensity in cardiac rehabilitation (CR), it is unclear whether target heart rate ranges (THRRs) can be implemented in CR programs that predominantly use RPE and what impact this has on changes in exercise capacity. METHODS: We conducted a three-group pilot randomized control trial (#NCT03925493) comparing RPE of 3-4 on the 10-point modified Borg scale, 60-80% of heart rate reserve (HRR) with heart rate (HR) monitored by telemetry, or 60-80% of HRR with a personal HR monitor (HRM) for high-fidelity adherence to THRR. Primary outcomes were protocol fidelity and feasibility. Secondary outcomes included exercise HR, RPE, and changes in functional exercise capacity. RESULTS: Of 48 participants randomized, four patients dropped out, 20 stopped prematurely (COVID-19 pandemic), and 24 completed the protocol. Adherence to THRR was high regardless of HRM, and patients attended a median (IQR) of 33 (23, 36) sessions with no difference between groups. After randomization, HR increased by 1 ± 6, 6 ± 5, and 10 ± 9 bpm ( P = .02); RPE (average score 3.0 ± 0.05) was unchanged, and functional exercise capacity increased by 1.0 ± 1.0, 1.9 ± 1.5, 2.0 ± 1.3 workload METs (effect size between groups, ηp2 = 0.11, P = .20) for the RPE, THRR, and THRR + HRM groups, respectively. CONCLUSIONS: We successfully implemented THRR in an all-RPE CR program without needing an HRM. Patients randomized to THRR had higher exercise HR but similar RPE ratings. The THRR may be preferable to RPE in CR populations for cardiorespiratory fitness gains, but this needs confirmation in an adequately powered trial.

Tracking Cardiac Rehabilitation Utilization in Medicare Beneficiaries: 2017 UPDATE.

PURPOSE: This study updates cardiac rehabilitation (CR) utilization data in a cohort of Medicare beneficiaries hospitalized for CR-eligible events in 2017, including stratification by select patient demographics and state of residence. METHODS: We identified Medicare fee-for-service beneficiaries who experienced a CR-eligible event and assessed their CR participation (≥1 CR sessions in 365 d), engagement, and completion (≥36 sessions) rates through September 7, 2019. Measures were assessed overall, by beneficiary characteristics and state of residence, and by primary (myocardial infarction; coronary artery bypass surgery; heart valve repair/replacement; percutaneous coronary intervention; or heart/heart-lung transplant) and secondary (angina; heart failure) qualifying event type. RESULTS: In 2017, 412 080 Medicare beneficiaries had a primary CR-eligible event and 28.6% completed ≥1 session of CR within 365 d after discharge from a qualifying event. Among beneficiaries who completed ≥1 CR session, the mean total number of sessions was 25 ± 12 and 27.6% completed ≥36 sessions. Nebraska had the highest enrollment rate (56.1%), with four other states also achieving an enrollment rate >50% and 23 states falling below the overall rate for the United States. CONCLUSIONS: The absolute enrollment, engagement, and program completion rates remain low among Medicare beneficiaries, indicating that many patients did not benefit or fully benefit from a class I guideline-recommended therapy. Additional research and continued widespread adoption of successful enrollment and engagement initiatives are needed, especially among identified populations.

Exercise Prescription Methods and Attitudes in Cardiac Rehabilitation: A NATIONAL SURVEY.

PURPOSE: High-quality exercise training improves outcomes in cardiac rehabilitation (CR), but little is known about how most programs prescribe exercise. Thus, the aim was to describe how current CR programs prescribe exercise. METHODS: We conducted a 33-item anonymous survey of CR program directors registered with the American Association of Cardiovascular and Pulmonary Rehabilitation. We assessed the time, mode, and intensity of exercise prescribed, as well as attitudes about maximal exercise testing and exercise prescription. Results were summarized using descriptive statistics. Open-ended responses were coded and quantitated thematically. RESULTS: Of 1470 program directors, 246 (16.7%) completed the survey. In a typical session of CR, a median of 5, 35, 10, and 5 min was spent on warm-up, aerobic exercise, resistance training, and cooldown, respectively. The primary aerobic modality was the treadmill (55%) or seated dual-action step machine (40%). Maximal exercise testing and high-intensity interval training (HIIT) were infrequently reported (17 and 8% of patients, respectively). The most common method to prescribe exercise intensity was ratings of perceived exertion followed by resting heart rate +20-30 bpm, although 55 unique formulas for establishing a target heart rate or range (THRR) were reported. Moreover, variation in exercise prescription between staff members in the same program was reported in 40% of programs. Program directors reported both strongly favorable and unfavorable opinions toward maximal exercise testing, HIIT, and use of THRR. CONCLUSIONS: Cardiac rehabilitation program directors reported generally consistent exercise time and modes, but widely divergent methods and opinions toward prescribing exercise intensity. Our results suggest a need to better study and standardize exercise intensity in CR.

Prognostic Value of Cardiorespiratory Fitness in Patients with Chronic Kidney Disease: The FIT (Henry Ford Exercise Testing) Project.

PURPOSE: We conducted this study to investigate the association of cardiorespiratory fitness and all-cause mortality among patients with chronic kidney disease. METHODS: We studied a retrospective cohort of patients from the Henry Ford Health System who underwent clinically indicated exercise stress testing with baseline cardiorespiratory fitness and estimated glomerular filtration rate measurement. Cardiorespiratory fitness was expressed as metabolic equivalents of task, and kidney function was categorized into stages according to estimated glomerular filtration rate. Multivariable-adjusted Cox proportional hazard models were used to examine the association between metabolic equivalents of task and all-cause mortality among patients with chronic kidney disease stages 3-5. Discrimination of mortality was assessed using receiver operating characteristic curves, while reclassification was evaluated using net reclassification index (NRI). RESULTS: Among 50,121 participants, the mean age was 55 ± 12.6 years; 47.5% were women, 64.5% were white, and 6877 (13.7%) participants had chronic kidney disease stage 3-5. Over a median follow-up of 6.7 years, 6308 participants died (12.6%). Each 1-unit higher metabolic equivalents of task was associated with a significant 15% reduction in all-cause mortality (hazard ratio 0.85; 95% confidence interval [CI], 0.84-0.87). Metabolic equivalents of task improved discriminatory ability of mortality prediction when added to traditional risk factors and estimated glomerular filtration rate (area under the curve 0.7996; 95% CI, 0.789-0.810 vs 0.759; 95% CI, 0.748-0.770, respectively; P < .001). The addition of metabolic equivalents of task to traditional risk factors resulted in significant reclassification (6% for events, 5% for non-events: NRI = 0.13, P < .001). CONCLUSIONS: Cardiorespiratory fitness improves mortality risk prediction among patients with chronic kidney disease. Cardiorespiratory fitness provides incremental prognostic information when added to traditional risk factors and may help guide treatment options among patients with renal dysfunction.

Rethinking Rehabilitation: A REVIEW OF PATIENT POPULATIONS WHO CAN BENEFIT FROM CARDIAC REHABILITATION.

Although cardiac rehabilitation (CR) is safe and highly effective for individuals with various cardiovascular health conditions, to date there are only seven diagnoses or procedures identified by the Centers for Medicare & Medicaid Services that qualify for referral. When considering the growing number of individuals with cardiovascular disease (CVD), or other health conditions that increase the risk for CVD, it is important to determine the extent for which CR could benefit these populations. Furthermore, there are some patients who may currently be eligible for CR (spontaneous coronary artery dissection, left ventricular assistant device) but make up a relatively small proportion of the populations that are regularly attending and participating. Thus, these patient populations and special considerations for exercise might be less familiar to professionals who are supervising their programs. The purpose of this review is to summarize the current literature surrounding exercise testing and programming among four specific patient populations that either do not currently qualify for (chronic and end-stage renal disease, breast cancer survivor) or who are eligible but less commonly seen in CR (sudden coronary artery dissection, left ventricular assist device). While current evidence suggests that individuals with these health conditions can safely participate in and may benefit from supervised exercise programming, there is an immediate need for high-quality, multisite clinical trials to develop more specific exercise recommendations and support the inclusion of these populations in future CR programs.

Increasing the Availability of Automated External Defibrillators at Sporting Events: A Call to Action from the American College of Sports Medicine.

ABSTRACT: Given that most sudden cardiac arrests (SCAs) occur outside of a medical facility, often in association with exercise and sporting events, and given that early cardiopulmonary resuscitation (CPR) plus defibrillation is the strongest predictor of survival from SCA, this Call to Action from the American College of Sports Medicine recommends increasing the availability and effectiveness of early CPR plus defibrillation so that the time from collapse-to-first automated external defibrillator shock is less than 3 min.

Fitness and Mortality Among Persons 70 Years and Older Across the Spectrum of Cardiovascular Disease Risk Factor Burden: The FIT Project.

OBJECTIVE: To determine whether fitness could improve mortality risk stratification among older adults compared with cardiovascular disease (CVD) risk factors. METHODS: We examined 6509 patients 70 years of age and older without CVD from the Henry Ford ExercIse Testing Project (FIT Project) cohort. Patients performed a physician-referred treadmill stress test between 1991 and 2009. Traditional categorical CVD risk factors (hypertension, hyperlipidemia, diabetes, and smoking) were summed from 0 to 3 or more. Fitness was grouped as low, moderate, and high (<6, 6 to 9.9, and ≥10 metabolic equivalents of task). All-cause mortality was ascertained through US Social Security Death Master files. We calculated age-adjusted mortality rates, multivariable adjusted Cox proportional hazards, and Kaplan-Meier survival models. RESULTS: Patients had a mean age of 75±4 years, and 3385 (52%) were women; during a mean follow-up of 9.4 years, there were 2526 deaths. A higher fitness level (P<.001), not lower CVD risk factor burden (P=.31), was associated with longer survival. The age-adjusted mortality rate per 1000 person-years was 56.7 for patients with low fitness and 0 risk factors compared with 24.9 for high fitness and 3 or more risk factors. Among patients with 3 or more risk factors, the adjusted mortality hazard was 0.68 (95% CI, 0.61 to 0.76) for moderate and 0.51 (95% CI, 0.44 to 0.60) for high fitness compared with the least fit. CONCLUSION: Among persons aged 70 years and older, there was no significant difference in survival of patients with 0 vs 3 or more risk factors, but a higher fitness level identified older persons with good long-term survival regardless of CVD risk factor burden.

Fitness and prostate cancer screening, incidence, and mortality: Results from the Henry Ford Exercise Testing (FIT) Project.

BACKGROUND: The relation between cardiorespiratory fitness (CRF) and prostate cancer is not well established. The objective of this study was to determine whether CRF is associated with prostate cancer screening, incidence, or mortality. METHODS: The Henry Ford Exercise Testing Project is a retrospective cohort study of men aged 40 to 70 years without cancer who underwent physician-referred exercise stress testing from 1995 to 2009. CRF was quantified in metabolic equivalents of task (METs) (<6 [reference], 6-9, 10-11, and ≥12 METs), estimated from the peak workload achieved during a symptom-limited, maximal exercise stress test. Prostate-specific antigen (PSA) testing, incident prostate cancer, and all-cause mortality were analyzed with multivariable adjusted Poisson regression and Cox proportional hazard models. RESULTS: In total, 22,827 men were included, of whom 739 developed prostate cancer, with a median follow-up of 7.5 years. Men who had high fitness (≥12 METs) had an 28% higher risk of PSA screening (95% CI, 1.2-1.3) compared with those who had low fitness (<6 METs. After adjusting for PSA screening, fitness was associated with higher prostate cancer incidence (men aged <55 years, P = .02; men aged >55 years, P ≤ .01), but not with advanced prostate cancer. Among the men who were diagnosed with prostate cancer, high fitness was associated with a 60% lower risk of all-cause mortality (95% CI, 0.2-0.9). CONCLUSIONS: Although men with high fitness are more likely to undergo PSA screening, this does not fully account for the increased incidence of prostate cancer seen among these individuals. However, men with high fitness have a lower risk of death after a prostate cancer diagnosis, suggesting that the cancers identified may be low-risk with little impact on long-term outcomes.

Inverse Relationship of Maximal Exercise Capacity to Hospitalization Secondary to Coronavirus Disease 2019.

OBJECTIVE: To investigate the relationship between maximal exercise capacity measured before severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and hospitalization due to coronavirus disease 2019 (COVID-19). METHODS: We identified patients (≥18 years) who completed a clinically indicated exercise stress test between January 1, 2016, and February 29, 2020, and had a test for SARS-CoV-2 (ie, real-time reverse transcriptase polymerase chain reaction test) between February 29, 2020, and May 30, 2020. Maximal exercise capacity was quantified in metabolic equivalents of task (METs). Logistic regression was used to evaluate the likelihood that hospitalization secondary to COVID-19 is related to peak METs, with adjustment for 13 covariates previously identified as associated with higher risk for severe illness from COVID-19. RESULTS: We identified 246 patients (age, 59±12 years; 42% male; 75% black race) who had an exercise test and tested positive for SARS-CoV-2. Among these, 89 (36%) were hospitalized. Peak METs were significantly lower (P<.001) among patients who were hospitalized (6.7±2.8) compared with those not hospitalized (8.0±2.4). Peak METs were inversely associated with the likelihood of hospitalization in unadjusted (odds ratio, 0.83; 95% CI, 0.74-0.92) and adjusted models (odds ratio, 0.87; 95% CI, 0.76-0.99). CONCLUSION: Maximal exercise capacity is independently and inversely associated with the likelihood of hospitalization due to COVID-19. These data further support the important relationship between cardiorespiratory fitness and health outcomes. Future studies are needed to determine whether improving maximal exercise capacity is associated with lower risk of complications due to viral infections, such as COVID-19.

A Comparison of Exercise Intensity in Hybrid Versus Standard Phase Two Cardiac Rehabilitation.

PURPOSE: To compare exercise training intensity during standard cardiac rehabilitation (S-CR) versus hybrid-CR (combined clinic- and remote home-/community-based). METHODS: The iATTEND (improving ATTENDance to cardiac rehabilitation) trial is currently enrolling subjects and randomizing patients to S-CR versus hybrid-CR. This substudy involves the first 47 subjects who completed ≥18 CR sessions. Patients in S-CR completed all visits in a typical phase II clinic-based setting and patients in hybrid-CR completed up to 17 of their sessions remotely using telehealth (TH). Exercise training intensity in both CR settings is based on heart rate (HR) data from each CR session, expressed as percent HR reserve. RESULTS: Among patients in both study groups, there were no serious adverse events or falls that required hospitalization during or within 3 hr after completing a CR session. Expressed as a percentage of HR reserve, the overall mean exercise training intensities during both the S-CR sessions and the TH-CR sessions from hybrid-CR were not significantly different at 63 ± 12% and 65 ± 10%, respectively (P = .29). CONCLUSION: This study showed that hybrid-CR delivered using remote TH results in exercise training intensities that are not significantly different from S-CR.

Cardiorespiratory Fitness and Incident Stroke Types: The FIT (Henry Ford ExercIse Testing) Project.

OBJECTIVE: To study the association between cardiorespiratory fitness (CRF) and incident stroke types. PATIENTS AND METHODS: We studied a retrospective cohort of patients referred for treadmill stress testing in the Henry Ford Health System (Henry Ford ExercIse Testing Project) without history of stroke. CRF was expressed by metabolic equivalents of task (METs). Using appropriate International Classification of Diseases, Ninth Revision codes, incident stroke was ascertained through linkage with administrative claims files and classified as ischemic, hemorrhagic, and subarachnoid hemorrhage (SAH). Multivariable-adjusted Cox proportional hazards models examined the association between CRF and incident stroke. RESULTS: Among 67,550 patients, mean ± SD age was 54±13 years, 46% (n=31,089) were women, and 64% (n=43,274) were white. After a median follow-up of 5.4 (interquartile range 2.7-8.5) years, a total of 7512 incident strokes occurred (6320 ischemic, 2481 hemorrhagic, and 275 SAH). Overall, there was a graded lower incidence of stroke with higher MET categories. Patients with METs of 12 or more had lower risk of overall stroke [0.42 (95% CI, 0.36-0.49)], ischemic stroke [0.69 (95% CI, 0.58-0.82)], and hemorrhagic stroke [0.71 (95% CI, 0.52-0.95)]. CONCLUSION: In a large ethnically diverse cohort of patients referred for treadmill stress testing, CRF is inversely associated with risk for ischemic and hemorrhagic stroke.

The relationship between cardiorespiratory fitness, cardiovascular risk factors and atherosclerosis.

Cardiorespiratory fitness (CRF) refers to the ability of the cardiopulmonary system to supply oxygen to skeletal muscles during exercise. Regular physical activity optimizes these systems by physiologic means that not only decrease cardiovascular risk factors but also independently affect mortality. Importantly, CRF is an integrative measure of the effects of its upstream risk factors including physical activity and genetics. In this review, we summarize the main methods that are frequently used to estimate CRF. We cite findings from the major studies on CRF, which demonstrate a beneficial effect on prevalent cardiovascular risk factor burden, subclinical atherosclerosis, and incident adverse outcomes including death, myocardial infarction, stroke, and cancer. We conclude by suggesting the incorporation of CRF into clinical decision-making given the prognostic information it provides.