Maximal Predicted Heart Rate Research Articles

Low chronotropic response in post-myocardial infarction exercise test predicts worse prognosis in patients with preserved or mildly reduced left ventricular ejection fraction

Abstract Background Chronotropic incompetence is common in post-myocardial infarction (MI) patients and is associated with reduced exercise capacity. However, its prognostic significance and a determination of threshold values for prognosis remain unclear. Methods & Results We assessed 96 post-MI patients 4 weeks after their initial event with left ventricular ejection fraction (LVEF) ≥ 40%. All patients underwent combined stress echocardiography and cardiopulmonary exercise tests. The chronotropic response was measured as a percent of the maximal predicted heart rate at peak exercise (%MPHR). Exclusion criteria included patients with exercise limitations for pulmonary or peripheral reasons and those who declined to complete the study. Follow-up was conducted in 86 patients. The primary outcome measured was a composite of all-cause mortality or hospitalization for ischemic heart disease events (acute MI, unstable angina, or revascularization procedures) or heart failure exacerbation. The median follow-up duration was 4.0 (IQR 2, 5.6) years. The median patient age was 60 (IQR 53, 65) years, 64% of patients were males, and 84% were on beta-blockers. Median LVEF was 57 (IQR 51, 62)%, and median peak VO2 was 19 (IQR 15, 22) mL/kg/min. There were 15 composite end-point events, including 3 deaths, during the follow-up period. The %MPHR threshold of 67% had the best predictive value with an area under the curve (AUC) of 77% for predicting the primary outcome (PPV 31%, NPV 97%, sensitivity 93%, specificity 55%). A significant difference (p = 0.0022) in the occurrence of the composite end-point was noted between patients with a %MPHR below versus above this threshold (Figure. Kaplan-Meier curves for survival free of primary outcome). In the multivariate Cox regression analysis adjusting for demographic, clinical variables, and beta-blocker doses, only chronotropic response and current smoking correlated with the primary end-point (Table. The Cox proportional hazards regression model for prediction of the primary outcome). Conclusions A low chronotropic response to exercise is a negative prognostic marker in post-myocardial infarction patients with either preserved or mildly reduced left ventricular ejection fraction.Figure.Table.

Association of Smartwatch-Based Heart Rate and Physical Activity With Cardiorespiratory Fitness Measures in the Community: Cohort Study.

Resting heart rate (HR) and routine physical activity are associated with cardiorespiratory fitness levels. Commercial smartwatches permit remote HR monitoring and step count recording in real-world settings over long periods of time, but the relationship between smartwatch-measured HR and daily steps to cardiorespiratory fitness remains incompletely characterized in the community. This study aimed to examine the association of nonactive HR and daily steps measured by a smartwatch with a multidimensional fitness assessment via cardiopulmonary exercise testing (CPET) among participants in the electronic Framingham Heart Study. Electronic Framingham Heart Study participants were enrolled in a research examination (2016-2019) and provided with a study smartwatch that collected longitudinal HR and physical activity data for up to 3 years. At the same examination, the participants underwent CPET on a cycle ergometer. Multivariable linear models were used to test the association of CPET indices with nonactive HR and daily steps from the smartwatch. We included 662 participants (mean age 53, SD 9 years; n=391, 59% women, n=599, 91% White; mean nonactive HR 73, SD 6 beats per minute) with a median of 1836 (IQR 889-3559) HR records and a median of 128 (IQR 65-227) watch-wearing days for each individual. In multivariable-adjusted models, lower nonactive HR and higher daily steps were associated with higher peak oxygen uptake (VO2), % predicted peak VO2, and VO2 at the ventilatory anaerobic threshold, with false discovery rate (FDR)-adjusted P values <.001 for all. Reductions of 2.4 beats per minute in nonactive HR, or increases of nearly 1000 daily steps, corresponded to a 1.3 mL/kg/min higher peak VO2. In addition, ventilatory efficiency (VE/VCO2; FDR-adjusted P=.009), % predicted maximum HR (FDR-adjusted P<.001), and systolic blood pressure-to-workload slope (FDR-adjusted P=.01) were associated with nonactive HR but not associated with daily steps. Our findings suggest that smartwatch-based assessments are associated with a broad array of cardiorespiratory fitness responses in the community, including measures of global fitness (peak VO2), ventilatory efficiency, and blood pressure response to exercise. Metrics captured by wearable devices offer a valuable opportunity to use extensive data on health factors and behaviors to provide a window into individual cardiovascular fitness levels.

Moderate- to vigorous-intensity physical activities for hemophilia A patients during low-dose pharmacokinetic-guided extended half-life factor VIII prophylaxis

BackgroundLow-dose pharmacokinetic (PK)-guided extended half-life (EHL) factor VIII (FVIII) prophylaxis can reduce the bleeding risk in hemophilia A (HA) patients. An increase in physical activities for promoting musculoskeletal health may enhance the benefits of prophylactic therapy.ObjectivesTo determine the clinical impact of moderate- to vigorous-intensity physical activities in HA patients during low-dose PK-guided EHL FVIII prophylaxis.Patients/MethodsThis prospective study enrolled patients with moderate/severe HA (baseline FVIII levels ≤ 5 IU/dL) who had received low-dose PK-guided EHL FVIII prophylaxis for ≥ 6 months. An individualized exercise protocol was introduced to each participant, targeting a 65% increase in the maximum predicted heart rate for ≥ 150 min/week, while continuing low-dose PK-guided EHL FVIII prophylaxis for 6 months. Before and after implementing the intervention, annualized bleeding rates (ABR), annualized joint bleeding rates (AJBR), Hemophilia Joint Health Scores (HJHS), skeletal muscle mass, hemophilia-specific quality-of-life (QoL) scores and annualized FVIII consumption were compared.ResultsOf 13 participants (mean age ± standard deviation [SD]: 20.1 ± 6.8 years), ABR, AJBR, and HJHS were significantly reduced (mean differences [MD] ± SD: −5.7 ± 2.6 bleeds/year, −4.2 ± 2.6 joint bleeds/year, and −4.3 ± 3.2 marks, respectively; P < 0.05) after applying the 6-month exercise protocol. Skeletal muscle mass and QoL scores had also improved (P = 0.001), while FVIII usage had decreased (MD ± SD: −129.1 ± 208.7 IU/kg/year; P < 0.05).ConclusionsThe combination of moderate- to vigorous-intensity physical activities with low-dose PK-guided EHL FVIII prophylaxis improves bleeding prevention, musculoskeletal status and QoL in patients with moderate/severe HA. By minimizing FVIII consumption, this strategy helps optimize hemophilia care in countries with budget constraints. ClinicalTrials.gov NCT05728528.

Effects of a cardiopulmonary rehabilitation programme on submaximal exercise in Tunisian patients with long-COVID19: A randomized clinical trial.

There is a lack of randomized clinical trials (RCTs) exploring the outcomes of cardiopulmonary rehabilitation programmes (CPRPs) on submaximal aerobic capacity of long COVID-19 patients (LC19Ps). This RCT aimed to evaluate the effect of an ambulatory CPRP on the 6-min walk test (6MWT) data (main outcome: 6-min walk distance (6MWD)) of LC19Ps. Conducted as a single-blinded RCT, the study included Tunisian LC19Ps with persistent dyspnoea (i.e. modified medical research council (mMRC) level ≥2) at least three months postdiagnosis. LC19Ps were randomly assigned to the intervention (IG, n = 20) or control (CG, n = 10) groups. Pre- and post-CPRP evaluations included dyspnoea assessments (Borg and mMRC scales), anthropometric data, spirometry, and 6MWT. The CPRP (i.e. 18 sessions over six weeks) encompassed warm-up, aerobic training, resistance training, respiratory exercises, and therapeutic education. The CPRP significantly improved i) dyspnoea, i.e. IG exhibited larger reductions compared to the CG in Borg (-3.5 ± 2.0 vs. -1.3 ± 1.5) and mMRC (-1.5 ± 0.8 vs. -0.1 ± 0.3) scales, and ii) 6MWD, i.e. IG demonstrated larger improvements compared to the CG in 6MWD (m, %) (168 ± 99 vs. 5 ± 45 m, 28 ± 8 vs. 1 ± 8%, respectively), and resting heart rate (bpm, % maximal predicted heart rate) (-9 ± 9 vs. 1 ± 7 bpm; -5 ± 6 vs. 0 ± 4%, respectively), with small effect sizes. In the IG, the 1.5-point decrease in mMRC and the 168 m increase in 6MWD exceeded the recommended minimal clinical important differences of 1 point and 30 m, respectively. CPRP appears to be effective in enhancing the submaximal exercise capacity of LC19Ps, particularly in improving 6MWD, dyspnoea, and resting heart rate. RCT registration: www.pactr.org; PACTR202303849880222.

The RAPID-10 score: a new risk score from the retrospective analysis of maximal workload predictors of survival in ischemic heart disease at 10 years

Abstract Background Cardiac stress testing (CST) is valuable in the management of ischemic heart disease (IHD). The FIT Treadmill Score from the largest study of physical fitness - the Henry Ford Exercise Testing Project– is among the most accurate model in predicting survival. Recent data from our group showed that workload-indexed blood pressure (WPBR) is a strong and independent predictor of survival in IHD, a variable not included in the FIT score. Purpose Therefore, our purpose was to create a new score that includes WBPR and other maximal exercise variables and compare with the FIT score. Methods The study comprised 713 patients with IHD that performed CST on treadmill between 2009-2010. The follow-up period was 10±2 years. WBPR (systolic blood pressure / (metabolic equivalent of task(met)-1)) and the FIT score were calculated at baseline as previously described 1,2. Continuous variables were fitted using linear and nonlinear regressions. Time-to-event (death and major adverse cardiovascular events (MACE)) were correlated with baseline variables through logistic regression models. The new score was built using a backward stepwise regression of clinical and CST variables. Score accuracy was assessed with receiver operating characteristic (ROC) curves. Event-free survival analyses used Cox regression models. Data are: mean ± standard deviation; 95% confidence interval (CI) for hazard ratios (HR); significance level p&amp;lt;0.05. Results Relevant baseline characteristics were: age 59±10 years, 87% male, 74% dyslipidemia, 65% hypertension,body mass index 29±4 kg/m2, 31% diabetes, 16% chronic kidney disease, 45% smokers, 5% stroke, 76% myocardial infarction. During follow-up, 109 patients died (16%), 342 (49%) had MACE, 183 (26%) de novo heart failure (HF) and 100 (14%) myocardial infarction (MI). The final score (RAPID-10) combines four predictive variables of survival: binary WBPR (1 if ≥ 5.15 mmHg/met) and sex (1 if female); continuous maximal predicted heart rate (MPHR) and age-squared. The adjusted final model is: 4WPBR + 0.008age^2 + 20MPHR + 6sex. The median score was 11 points, ranging from -13 to 40 points. After adjusting for comorbidities and medication, each 10-point increase in RAPID-10 was associated with mortality (HR 1.85, CI 1.42-2.42, p&amp;lt;0.0001), MACE (HR 1.26, CI 1.42-2.42, p&amp;lt;0.0001), and HF (HR 1.4, CI 1.19-1.56, p&amp;lt;0.0001) but not MI (HR 0.91, CI 0.77-1.01, p=0.239). Discriminative power of RAPID-10 was good in ROC curves (AUC = 0.75), and slightly higher than FIT score (AUC = 0.73). Conclusions The RAPID-10 score is a robust tool, with good discriminative power to predict 10-year survival in IHD patients. Further studies are needed to validate the model in other populations.

Examination of The Applicability and Intensity of Nintendo Wiitm Exergaming For Children With Acute Lymphoblastic Leukemia: A Preliminary Study

Aims: Exploring the applicability and intensity of exergaming for children with cancer is essential. This study aimed to examine the applicability of Nintendo WiiTM exergames and determine the intensity of Physical Activity (PA) provided by these exergames for children with acute lymphoblastic leukemia.Methods: In this preliminary study, 31 children aged 6-14 years of both sexes were asked to play Wii exergames for a 60-minute research session. Using the Arabic video game applicability questionnaire, the children were instructedto score seven statements regarding usability, engagement, and enjoyment of exergames. In addition, heart rate (HR), predicted heart rate maximum (pred. HRmax), rating of perceived exertion (RPE), and oxygen saturation (SpO2) were measured at baseline and every 15 min during the session.Results: About 74.2%, 83.9%, and 93.6% of the children agreed that the games were usable, engaging, and enjoyable, respectively. Exergames were of moderate intensity as the children reached 59.22±8.40 % of age-predicted HRmax: the HR and its percentage of increase from the pred. HRmax (% pred. HRmax) was significantly higher in girls than in boys (P=0.01). The level of perceived exertion was moderate (5.74± 0.63).Conclusion: Implementation of Nintendo Wii exergames for 60 minutes was found to be applicable. In addition, it resulted in PA of moderate intensity.

Chronotropism in CPET - Is incompetence limiting functional capacity?

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Chronotropic incompetence (CI) is defined as the inability to reach 80% of the expected reserve frequency for age during exertion, and it is frequently observed in stress tests of patients undergoing cardiac rehabilitation programs due to a combination of factors, that include the use of betablockers. Despite the theoretical basis for suggesting that a lower peak heart rate is related to a lower tolerance to exertion, we lack data correlating the CI to the maximal functional capacity, measured in cardiopulmonary tests as the maximal oxygen volume consumption (peak VO2). Purpose To correlate the impact of CI on functional capacity in patients (pts) undergoing a cardiac rehabilitation program and try to find the best value of chronotropic incompetence that could predict a worse prognosis. Methods Prospective cohort study which included consecutive pts who were submitted to cardiopulmonary exercise test (CPET) during 5 years in a tertiary hospital. Demographic data were analyzed and medication with beta blocker was registered. CI and chronotropic index were calculated using the equation (220-age) for estimating maximum HR. ROC curve method and Kaplan-Meier survival analysis were used to evaluate the cut-off efficacy. Results We analyzed 358 CPET and 74,1% patients (n=206) were under beta blocker therapy (7,6% high dose). The majority of the patients had CI (83.5%); CI was more frequent in pts under BB therapy although it didn’t reach statistical significance (p=0.12). A low maximum predicted heart rate (mpHR) was associated with low peak VO2 (p=0.02) and a mpHR &amp;lt; 61% was the best value to predict peak VO2&amp;lt; 12mL/(kg.min) (AUC=0.746, S=72; E=65), despite not showing association with cardiovascular events. Regarding the chronotropism, 96.9% of the pts were categorized as having a low chronotropic index . A CI &amp;lt; 0.38 was the best cut-off to predict a peak VO2&amp;lt;12 mL/(kg.min) (AUC=0.81, S=72, E 76) and it was predictor of all-cause hospitalizations (p=0.015). Conclusion This study shows a high percentage of pts with CI. A low cronotropic index was associatated with low peak VO2 and was a predictor of all-cause hospitalizations.

The influence of chronotropic incompetence on maximum aerobic capacity and heart rate responses during boxing in Parkinson’s disease

Non-contact boxing (NCB) is a popular form of high-intensity interval training used to improve aerobic capacity (VO2peak) which may be reduced in people with Parkinson’s disease (PD). However, heart rate (HR) responses are likely to vary in this population due to chronotropic incompetence (CI), described as the inability to raise HR to at least 85% of predicted maximum HR (HRmax), and is present in 40-50% of the PD population. In this presentation, I describe the impact of CI on VO2peak and HR responses during NCB. 25 people with PD and 16 age-matched controls underwent a cardiopulmonary exercise test (CPET) to identify the presence of CI and to determine VO2peak, HRmax, and %HRmax. Two boxing sessions then were performed on different days, during which HR response was measured via Polar H10 and further expressed as %HRmax predicted (220-age), and %HRmax obtained during CPET. Results from this study show that CI was present in 11 participants with PD (PDCI), with peak HR on average 30 beats lower than those without CI (PDnonCI). There was also a trend for lower VO2peak in the PDCI group and a significantly lower HR during each boxing round (p≤0.001). However, data from CPET shows that all groups were able to exercise in the high-intensity training zone. This study is the first to show that people with PD have the capacity to exercise in a high-intensity zone during NCB despite the presence of CI, which is encouraging. The results also show that %HRmax based on predicted equations do not accurately reflect exercise intensity, especially for people with CI. They should therefore be used with caution as a basis for high-intensity training regimes.

Abstract 13469: A Risk Score Model to Identify Patients With High Likelihood of Left Main or 3-vessel Coronary Artery Disease

Introduction: Revascularization improves outcomes only for stable coronary artery disease (CAD) patients with high-risk coronary anatomy (HRCA). While exercise stress test (EST) is the screening modality for CAD, identifying HRCA noninvasively is challenging. We aimed to derive a prediction model, incorporating clinical and EST characteristics, to screen for HRCA. Methods: We included adult patients who underwent EST followed by elective invasive coronary angiography (ICA) at our center between 2017 and 2019. HRCA was defined as left main (LM) or 3-vessel disease on ICA. Significant CAD was defined as ≥50% stenosis in the LM and/or ≥70% stenosis in the 3 main vessels. We excluded patients with acute coronary syndrome or ejection fraction &lt;50%. Variables with p&lt;0.1 at univariable analysis were selected as candidates to enter a multivariable stepwise backward regression model to derive a HRCA risk model. Results: 304 consecutive patients met inclusion criteria (64[13]years, 81.6% M). 15.5% were found to have HRCA on ICA. Median time from EST to ICA was 11[31]days. The following hit the threshold for inclusion into the multivariable model: hypertension, maximal predicted heart rate (MPHR), diabetes, rate pressure product, metabolic equivalents, exercise time, chronotropic response index ≥0.8, heart rate recovery, Duke Treadmill Score (DTS). After backward selection, hypertension (OR 17.08, p=0.008), MPHR (0.98, p=0.048), and very abnormal DTS (8.26, p=0.001) were the only significant predictors of HRCA ( Fig.1A ). The fully adjusted model showed good discrimination for HRCA (AUC 0.74, p&lt;0.001, Fig.1B ). Conclusions: In an era of declining emphasis on EST in favor of imaging stress test, we identified a risk model based on clinical and EST-derived parameters, that can accurately predict likelihood of HRCA, enabling personalized risk-stratification. Further studies are needed to externally validate our model.

Abstract 11380: Exercise Induced ST Segment Elevation Caused by Coronary Vasospasm

Case Presentation: A 52-year-old male with no known medical history was seen in the cardiology clinic for occasional pressure-like chest pain on exertion. Due to an intermediate pretest probability of CAD, ischemic workup with a nuclear perfusion exercise stress test was planned. Patient achieved maximum predicted heart rate after 12 minutes of exercising, with no anginal symptoms, ST segment changes or arrhythmias during the entire period. However, 3 minutes into the recovery phase, he developed chest pain and diaphoresis, with EKG now showing 7mm ST elevations in the inferior leads and BP falling to 77/56 mmHg. STEMI code was called, and patient was emergently taken to the cardiac cath lab for coronary angiogram and possible PCI. Angiogram found the coronary arteries to be non-obstructive but revealed vessels possibly having vasospasm. Intra coronary nitroglycerin was given with no further PCI. The patient’s symptoms subsided after the angiogram, and he remained asymptomatic thereupon and was eventually discharged on Verapamil and nitrate therapy. Discussion: Typically, vasospastic angina occurs at rest. Exercise induced and post-exercise recovery phase ST segment elevation on EKG is associated with severe atherosclerotic disease with significant coronary obstruction. However, exercise induced ST elevations in the post exercise recovery phase caused by non-obstructive, vasospastic coronary arteries, as seen in this patient, is a rare occurrence. The vasospasm is hypothesized to be due to coronary vascular smooth muscle hyperactivity and endothelial cell dysfunction. Treatment is usually with calcium channel blockers, nitrates and lifestyle modification such as smoking cessation and alcohol restriction. This case illustrates the importance of identifying the etiology of the angina, noting that post exercise ST segment elevations are not always associated with coronary vessel obstruction and vasospasm should be considered as a possible etiology.

Effects of mask-wearing on treadmill exercise test

Abstract Background Concerning about the spread of COVID-19, World Health Organization recommends wearing facemasks to minimize viral transmission. Patients are required to wear facemasks while conducting treadmill exercise tests in hospitals. The effects of mask-wearing on the results of stress exercise testing remain uncertain. Purpose This study aims to assess the impact of mask-wearing on the physiological parameters during treadmill exercise testing. Methods Patients who underwent treadmill exercise test using the Bruce protocol for the diagnosis of ischemic heart disease were retrospectively examined between 2020 and 2021. A propensity score matching was performed to adjust the baseline characteristics of patients with and without mask. Blood pressure, heart rate, exercise duration, and the interpretation of stress test were compared. The ischemic ST-segment response was defined as flat or downsloping depression of the ST seg-ment &amp;gt;0.1 mV below baseline and lasting longer than 0.08 second. Nondiagnostic result of treadmill exercise test was defined as absence of ischemic ST-segment response in which the 90% of maximal predicted heart rate for age and sex was not achieved. Results Following 1:1 propensity score matching, a total of 3,996 patients were enrolled for analysis, including 1,998 patients who performed treadmill exercise testing with masks, and 1,998 without masks. Baseline characteristics were similar between the two groups (mean age, 56.1±12.1 years; 38.7% female; mean body mass index, 25.5±3.9 kg/m2). At baseline, patients with masks had significantly higher heart rate (84.8±14.7 bpm vs. 82.5±14.0 bpm; p&amp;lt;0.001) and lower systolic blood pressure (130.4±19.0 mmHg vs. 132.4±18.7 mmHg; p=0.001) than those without masks. Patients with masks conducted significantly shorter duration of exercise (435±128 seconds vs. 481±133 seconds; p&amp;lt;0.001), achieved significantly lower measurement of peak heart rate (149.5±17.1 bpm vs. 152.7±17.0 bpm; p&amp;lt;0.001), and had significantly lower rate-pressure products (26,366±5,207 mmHg·bpm vs. 27,629±5,242 mmHg*bpm; p&amp;lt;0.001) than those without masks. The proportion of patients who were unable to complete stage II of the Bruce protocol was significantly higher among patients with masks (15.1% vs. 9.0%; p&amp;lt;0.001). The proportion of nondiagnostic result was significantly higher among patients with mask (12.2% vs. 8.8%; p&amp;lt;0.001), whereas the proportion of positive ischemic ST-segment response rate was significantly higher among patients without mask (28.1% vs. 23.3%; p=0.001). Conclusions Our study demonstrated that performing treadmill exercise test with mask could significantly decrease the duration of exercise, reduce the maximal achieved heart rate, decease the rate-pressure product, and thus reduce the diagnostic power of treadmill exercise testing. Funding Acknowledgement Type of funding sources: None.

Chronotropic incompetence in end-stage liver disease.

BackgroundCirrhosis causes alterations in the cardiovascular and autonomic nervous systems and leads to cirrhotic cardiomyopathy (CCM). CCM is defined as cardiac dysfunction characterized by an impaired systolic responsiveness to stress or exercise, and/or impaired diastolic function, as well as electrophysiological abnormalities, including chronotropic incompetence (CI), in the absence of other known cardiac disease. CI is a common feature of autonomic neuropathy in cirrhosis. The aim of the study is to assess the role of cardiac exercise stress test in the diagnosis of CCM.MethodsThe analysis included 160 end-stage liver disease (ESLD) patients who underwent a cardiac exercise stress test prior to the orthotopic liver transplantation. CI was defined as the inability to achieve the heart rate reserve (HRR). Pertaining to the therapy with beta-blockers: 80% of HRR was achieved in patients not taking beta-blockers and 62% in patients taking beta-blockers.ResultsIn the analyzed population, 68.8% of patients met the criteria for CI. CI was more frequent in the more severe ESLD (with a higher MELD score and in a higher Child-Pugh class). In comparison to the viral hepatitis and other etiologies of ESLD, patients with alcoholic cirrhosis had a significantly lower rest heart rate (HR), lower maximal HR, lower median achieved percentage of maximal predicted HR (MPHR), a smaller percentage of patients achieved ≥ 85% of MPHR and a lower heart rate reserve. No significant relationship between the survival of OLT recipients and presence of chronotropic incompetence regarding to class of Child-Pugh scale, MELD score and etiology of ESLD were found.ConclusionsThe prevalence of CI is higher among liver transplant candidates than previously described. The altered chronotropic response may differ in regard to the severity of liver disease correlating with both the Child-Pugh and MELD scores, however CI does not seem to influence the long-term survival post OLT. Exercise stress test is a reliable, safe and useful tool for the diagnosis of CCM in liver transplant candidates and should be included in the standard cardiovascular assessment prior to OLT.

Usefulness of the 6-minute walk test vs cardiopulmonary exercise test for exercise prescription in coronary artery disease patients going into a phase III cardiac rehabilitation program

Abstract Funding Acknowledgements Type of funding sources: None. Background/Introduction Determining the intensity of exercise is a very important component to obtain the dose-benefits associated with exercise, while maitaining the safaty of the patient with coronary artery disease (CAD) in a cardiovascular rehabilitation (CR) programme. The cardiopulmonary exercise test (CPET) is the gols standard for exercise prescription according to the intend intensisty of aerobic workout. However, its availability is not a reality in many CR centres. The 6-minute walk test (6MWT) is a valid and widely used method because it is low-cost and simple to apply. Nevertheless, it is still unknown the corresponding intensity reached on a 6MWT compared to the one reached on a CPET in already physically active patients with CAD starting a CR phase III programme. Purpose To use the peak heart rate (HR) of the 6MWT as a method to prescribe the intensity of aerobic exercise in CAD patients starting a phase III CR programme and to compare it with the ventilatory threshold (VT) of the CPET. Methods In this retrospective study, a cohort of patients with CAD enrolled in a phase III CR programme. At the beginning of the programme, all patients performed a 6MWT and a CPET in the same week with at least 48-hour difference. The HR on the 6MWT was recorded continuously using a HR polar (H10 Polar) and on CPET using a twelve-lead ECG. Other parameters were assessed such as objective physical activity (accelerometer) and body composition. Results Eighty patients (87.5% males, 60.8 ± 9.4 years old) with CAD were included in this study. Patients were, on average, physically active (361 ± 182 minutes/week of moderate to vigorous physical activity) and overweight (body mass index: 27.7 ± 3.5 kg/m2). The VO2 peak reached on the CPET was 20.3 ± 5.4 ml/kg/min and the percentage of predicted maximum HR was 78.3 ± 11.4 %. The first and second VT corresponded to 75.6 ± 7.8% and 91.2 ± 4.5% of the peak HR obtained with CPET, respectively. The 6MWT HR peak was 113 ± 16 bpm (90.0 ± 13.0 HR peak CPET) and did not differ from the HR of the second VT with a mean value of 115 ± 16 bpm (91.2 ± 4.5% HR peak CPET), p&amp;gt;0.05. Although, the 6MWT HR peak was significantly higher than the HR oh the first VT (95 ± 14 bpm, p&amp;lt;0.001). In a subgroup analysis, the patients who, during the 6MWT, reached more the 90% of the HR peak CPET (n=35, 44% oof the sample) were the ones with lower functional capacity (VO2 peak: 18.4 ± 5.4 ml/kg/min vs 21.7 ± 5.0 ml/kg/min, p=0.006) and higher age (64.4 ± 8.7 years old vs 60.8 ± 9.4 years old, p=0.002). Conclusion(s) In the absence of a CPET, the use of a 6MWT HR peak in physically active patients with CAD starting a phase III CR programme has shown to be an efficient method to prescribe moderate to vigorous exercise intensity, corresponding to the second VT. Higher intensities on the 6MWT might be reached in active elderly patients with reduced functional capacity.

Effects of Cardiac Telerehabilitation During COVID-19 on Cardiorespiratory Capacities in Patients With Coronary Artery Disease.

BackgroundThe COVID-19 pandemic led to the closure of most cardiac therapy centers. One of the solutions was to adapt the existing cardiac rehabilitation (CR) program in an institute to a remote approach offered by home-based telerehabilitation. The aim of this study was to measure the cardiorespiratory effects of telerehabilitation compared to conventional center-based CR.MethodsPatients were assigned to two 3-week CR programs: telerehabilitation and conventional center-based CR. The telerehabilitation group wore a connected watch to monitor heart rate (HR) and gave their perception of effort according to a modified Borg scale. The exercise training (four sessions/week) consisted of 1-h aerobic endurance and strength training session at the target HR zone determined by results based on cardiopulmonary exercise test (CPET) and perception of effort, respectively. The exercise protocol was the same for conventional CR participants except the duration of session that lasted 2 h instead of one. The week before and after the training program, peak oxygen uptake (VO2 peak), oxygen uptake at first ventilatory threshold (VO2 at VT1), peak workload, percent of predicted maximum HR, and the absolute differences in HR and systolic blood pressure between maximum and recovery at 1 and 3 min were measured using a CPET. A two-way ANOVA with one repeated measure and one independent factor was performed.ResultsFifty-four patients (mean age: 61.5 ± 8.6 years, 10 women) equally split in the two groups were included in this experiment. A significant increase was observed in both groups on VO2 peak (telerehabilitation: 8.1 ± 7.8% vs. conventional: 10.1 ± 9.7%, p < 0.001), VO2 at VT1 (telerehabilitation: 8.8 ± 4.4% vs. conventional: 7.3 ± 19.0%, p = 0.02) and peak workload (telerehabilitation: 16.6 ± 18.9% vs. conventional: 17.2 ± 7.0%, p < 0.001) after the 3-week telerehabilitation and conventional CR, respectively. No significant difference was noticed between both groups.ConclusionA 3-week exercise program improved patients’ cardiorespiratory fitness. Telerehabilitation was as effective and represents a safe alternative CR program during the COVID-19 period. In the future, this approach could facilitate the continuity of care for patients unable to participate in center-based CR.

Exercise test in patients with asymptomatic aortic stenosis – clinically useful or not?

Aortic valve replacement (AVR) is recommended for symptomatic patients with severe aortic stenosis (AS). In asymptomatic AS (AAS), exercise testing (ET) is recommended; however, it remains controversial. The aim of our study was to assess the importance of ET in patients with AAS. A total of 89 patients with AAS (53 men; mean [SD] age, 59.5 [11.7] years) underwent 244 symptom‑limited ETs. All ETs were clinically negative. During the median (interquartile range) follow‑up of 22 (12) months, 39 patients (22 men) developed symptoms (the AVR group). This group was compared with 50 asymptomatic non‑AVR patients. In the multivariable Cox analysis, the maximal heart rate during ET less than 85% of age- and sex-adjusted maximal predicted heart rate (THR less than 85%) was related to AVR (P = 0.01). After adjusting for the use of β‑blockers, this was not significant (P = 0.08). In the β‑blocker subgroup, the THR less than 85% was significantly related to AVR in the univariable Cox analysis (hazard ratio, 2.2; 95% CI, 1.07-4.9; P = 0.03) and after adjusting for age (P = 0.047). This relationship was not observed in patients who did not receive β‑blockers. In patients with AAS, ET is safe; however, in our study group, the results were not cru‑ cial in making a decision to perform AVR. Patients treated with β‑blockers who did not achieve 85% of predicted maximal heart rate had a higher probability of AVR. The influence of the use of β‑blockers on the decision to perform AVR in this patient population warrants further revision.

Physiological stress of basketball referees during a national competition

abstract The aim of this study was to examine the physiological demands of seven referees during a national basketball competition. We recorded heart rate (HR), relative exercise intensity as a percentage of age – predicted maximum HR (HRmax), proportion of playing time within the exercise intensity categories defined by the ACSM during each of the tournament matches for each referee per period, as well as the entire game. None of the variables shows significant differences between periods. Based on a format of three referees per match, referees worked with an average HR of 150 bpm (range 110-181 bpm) for each quarter of the match, which equals a relative intensity&gt; 70% of HRmax for most (∼76%) of each quarter. Other studies will assist in developing appropriate training programs for elite basketball referees to maintain and / or maximize performance.

A Follow-Up Study on the Effects of Football Scrimmages on Blink Reflex Parameters in Division I Athletes

The objective was to conduct a follow-up study to access the effects of football scrimmages on blink reflex parameters using the Eyestat. Eyestat is a noninvasive diagnostic tool measuring changes in blink reflex parameters. Prior research cited significant differences in various blink reflex parameters between active play, concussion, and baseline; however, the number of subjects for the active play population was small and within a football practice versus a football scrimmage. Fifty-eight division I male football players, between the ages of 18 and 22 years, participated in multiple sessions during a 3 week period of football scrimmages and a spring game. In addition, a subgroup of these subjects (N = 20) provided a minimal of 3 or more scans throughout the study. During various points of play, subjects completed the blink test and had heart rates assessed. For the blink test, subjects placed their face against the apparatus, which directed a puff of air to the corner of the subject's eye to stimulate the blink. Five puffs were administered in a random fashion over a 20-second period while videography captured and recorded the blink. The results of the study cited significant differences in heart rates above 55% of predicted heart rate maximum in excursions only (p = 0.00), while significant differences were found in under the threshold (p = 0.05) and excursions (p = 0.00) in heart rates less than 55% of maximum heart rate. In those athletes (N = 20) where 3 scans were taken, there were no significant differences within subjects in any of the blink reflex parameters. Future studies should continue to evaluate the timing of post exercise visual tracking assessments within healthy populations to determine the effects on ocular changes as eye-tracking devices are becoming increasingly popular to assess neurological health.

Creation of physiologic rhythm by closed loop stimulation in heart failure patients with severe chronotropic incompetence: worldwide first results of a pilot study

Abstract Background The prevalence of chronotropic incompetence (CI) in heart failure (HF) population is high and negatively impacts prognosis. In HF patients with an implanted cardiac resynchronisation therapy (CRT) device and severe CI, the effect of rate adaptive pacing on patient outcomes is unclear. Closed loop stimulation (CLS) based on cardiac impedance measurement may be an optimal method of heart rate adaptation according to metabolic need in HF patients with severe CI. Purpose This is the first study evaluating the effect of CLS on the established prognostic parameters assessed by the cardio-pulmonary exercise (CPX) testing and on quality of life (QoL) of the patients. Methods A randomised, controlled, double-blind and crossover pilot study has been performed in CRT patients with severe CI defined as the inability to achieve 70% of the age-predicted maximum heart rate (APMHR). After baseline assessment, patients were randomised to either DDD-CLS pacing (group 1) or DDD pacing at 40 bpm (group 2) for a 1-month period, followed by crossover for another month. At baseline and at 1- and 2-month follow-ups, a CPX was performed and QoL was assessed using the EQ-5D-5L questionnaire. The main endpoints were the effect of CLS on ventilatory efficiency (VE) slope (evaluated by an independent CPX expert), the responder rate defined as an improvement (decrease) of the VE slope by at least 5%, percentage of maximal predicted heart rate reserve (HRR) achieved, and QoL. Results Of the 36 patients enrolled in the study, 20 fulfilled the criterion for severe CI and entered the study follow-up (mean age 68.9±7.4 years, 70% men, LVEF=41.8±9.3%, 40%/60% NYHA class II/III). Full baseline and follow-up datasets were obtained in 17 patients. The mean VE slope and HRR at baseline were 34.4±4.4 and 49.6±23.8%, respectively, in group 1 (n=7) and 34.5±12.2 and 54.2±16.1% in group 2 (n=10). After completing the 2-month CPX, the mean difference between DDD-CLS and DDD-40 modes was −2.4±8.3 (group 1) and −1.2±3.5 (group 2) for VE slope, and 17.1±15.5% (group 1) and 8.7±18.8% (group 2) for HRR. Altogether, VE slope improved by −1.8±2.95 (p=0.31) in DDD-CLS versus DDD-40, and HRR improved by 12.9±8.8% (p=0.01). The VE slope decreased by ≥5% in 47% of patients (“responders to CLS”). The mean difference in the QoL between DDD-CLS and DDD-40 was 0.16±0.25 in group 1 and −0.01±0.05 in group 2, resulting in an overall increase by 0.08±0.08 in the DDD-CLS mode (p=0.13). Conclusion First results of the evaluation of the effectiveness of CLS in CRT patients with severe CI revealed that CLS generated an overall positive effect on well-established surrogate parameters for prognosis. About one half of the patients showed CLS response in terms of improved VE slope. In addition, CLS improved quality of life. Further clinical research is needed to identify predictors that can increase the responder rate and to confirm improvement in clinical outcomes. Funding Acknowledgement Type of funding source: Private company. Main funding source(s): Biotronik SE &amp; Co. KG

Heart rate monitoring improves clinical assessment during 6-min walk.

Right ventricular (RV) function is a predictor of outcomes in pulmonary arterial hypertension (PAH). The 6-min walk test (6MWT) is likely an indirect measure of RV function during exercise, but changes in absolute walk distance can also be influenced by factors like effort and musculoskeletal disease. Paired 6MWT with continuous electrocardiogram monitoring was performed in stable PAH patients, patients adding PAH therapies, and healthy controls. Heart rate expenditure (HRE) was calculated (integrating pulse during 6MWT) and then divided by walk distance (HRE/d). We also evaluated changes in peak heart rate, time above age-adjusted maximum predicted heart rate, and heart rate at 6 min. HRE/d was compared to invasive hemodynamic measures in patients who had right heart catheterization performed within seven days, WHO functional class assessment, and Emphasis 10 questionnaire. We measured two 6MWT in 15 stable PAH patients, 13 treatment intensification patients, and 8 healthy controls. HRE/d was reproducible in the stable PAH group (median difference, −0.79%), while it decreased (median difference, 23%, p = 0.0001) after adding vasodilator therapy. In 11 patients with right heart catheterization, HRE/d correlated strongly with stroke volume, r = −0.72, p = 0.01. Peak heart rate decreased after adding vasodilator therapy. HRE/d also correlated with WHO functional class and Emphasis 10 score. Continuous heart rate monitoring during 6MWT provides valuable physiologic data accounting for effort. HRE/d appears to enhance test reproducibility in stable patients while detecting change after adding therapy as compared to walk distance alone.

Postexercise troponin I levels in patients with suspected stable ischemic heart disease.

Previous studies showed that troponin blood levels may increase after exercise. In this study, we assessed whether, among patients with suspected of having stable angina, the increase in troponin I (TnI) levels after exercise stress test (EST) might help identify those with obstructive coronary artery disease (CAD) and myocardial ischemia. We performed maximal treadmill EST in 50 patients (age 64 ± 9 years; 38 men) admitted to our Cardiology Department to undergo elective coronary angiography because of a suspicion of stable angina. TnI was measured before and 12 h after EST. TnI increased after EST compared with baseline in the whole population (from 0.44 ± 0.76 to 0.84 ± 1.12 ng/dl, P < 0.001). No difference in TnI increase was observed between patients with obstructive CAD (n = 29; 0.61 ± 0.90-1.13 ± 1.33 ng/dl) and no obstructive CAD (NO-CAD; n = 21; 0.21 ± 0.46-0.44 ± 0.54 ng/dl; P = 0.51). There was also no significant difference in post-EST TnI increase between patients with positive EST (n = 34; 0.56 ± 0.89-1.05 ± 1.28 ng/dl) or negative EST (n = 16; 0.19 ± 0.26-0.39 ± 0.43 ng/dl; P = 0.16). Moreover, no significant difference was observed in the post-EST TnI increase among groups of patients with positive EST and obstructive CAD, positive EST and NO-CAD, negative EST and obstructive CAD and negative EST and NO-CAD (P = 0.12). No clinical or EST variable was associated with post-EST TnI increase, although there was a tendency for a greater increase in those achieving a heart rate more than 85 vs. less than 85% of maximal predicted heart rate during EST (P = 0.075). TnI increase after EST in patients with suspected stable angina is largely independent of the results of coronary angiography and EST.