Exercise stress testing. An overview of current guidelines

Modeling personalized heart rate response to exercise and environmental factors with wearables data

Heart rate (HR) response to workout intensity reflects fitness and cardiorespiratory health. Physiological models have been developed to describe such heart rate dynamics and characterize cardiorespiratory fitness. However, these models have been limited to small studies in controlled lab environments and are challenging to apply to noisy-but ubiquitous-data from wearables. We propose a hybrid approach that combines a physiological model with flexible neural network components to learn a personalized, multidimensional representation of fitness. The physiological model describes the evolution of heart rate during exercise using ordinary differential equations (ODEs). ODE parameters are dynamically derived via a neural network connecting personalized representations to external environmental factors, from area topography to weather and instantaneous workout intensity. Our approach efficiently fits the hybrid model to a large set of 270,707 workouts collected from wearables of 7465 users from the Apple Heart and Movement Study. The resulting model produces fitness representations that accurately predict full HR response to exercise intensity in future workouts, with a per-workout median error of 6.1 BPM [4.4-8.8 IQR]. We further demonstrate that the learned representations correlate with traditional metrics of cardiorespiratory fitness, such as VO2 max (explained variance 0.81 ± 0.003). Lastly, we illustrate how our model is naturally interpretable and explicitly describes the effects of environmental factors such as temperature and humidity on heart rate, e.g., high temperatures can increase heart rate by 10%. Combining physiological ODEs with flexible neural networks can yield interpretable, robust, and expressive models for health applications.

Exercise Stress Echocardiography in Kawasaki Disease Patients with Coronary Aneurysms

The most significant sequelae of Kawasaki disease (KD) are coronary artery aneurysms, which can lead to risk of future myocardial ischemia. Exercise stress echocardiography allows for non-invasive assessment of myocardial dysfunction. We reviewed our single center experience with exercise stress echocardiography in patients with previous history of KD with coronary aneurysms. We reviewed the records of 53 KD patients who underwent exercise stress echocardiography from 2000 to 2020. Abnormal stress echocardiograms were defined as those showing no increase in biventricular systolic function post-exercise or regional wall motion abnormalities. Computed tomography angiography and cardiac magnetic resonance imaging were reviewed for patients with abnormal stress echocardiograms. Clinical data were reviewed and correlated with stress echocardiogram results. Of the 53 patients, three (5.7%) had an abnormal exercise stress echocardiogram. All three patients were classified as AHA Risk Level 4 or 5 by coronary Z-score (internal dimension normalized for body surface area) and were confirmed to have coronary aneurysms, stenosis, or myocardial tissue perfusion defects on advanced cardiac imaging that could account for the results seen on stress echocardiogram. Exercise stress echocardiography detected signs of myocardial ischemia in a subset of high-risk patients with Kawasaki disease and coronary aneurysms and may be considered as a useful screening tool for this complex patient cohort.

Association between maximal aerobic capacity and heart rate variability

Relevance. Сardiovascular status could be assessed by maximal aerobic capacity (VO2max) through direct analysis of the gases involved in pulmonary ventilation and monitoring fluctuations in intervals between beats over time as heart rate variability. The aim of the study was to investigate the relationship between VO2max and heart rate variability in young adults. Materials and Methods. A total of 100 young adults between the ages of 18 and 25 were included in observational study, who did not engage in any strenuous physical activity, 50 of whom were male and 50 of whom were female.There were measured Heart rate variability in the frequency domain; LF, HF, LF/HF, and time domain; SDNN, RMSSD, pNN 50, and VO2max were assessed using a treadmill test according to Graded Exercise Protocol. Results and Discussion. There was weak positive correlation of VO2max with LF ( r = 0.177) and weak negative correlation with HF ( r = -0.141). Male participants had a weak negative relationship between VO2 max and LF ( r = -0.075), whereas female respondents had a weak positive relationship(r = 0.286). There was weak negative correlation of VO2max with LF/HF ratio for male subjects but weak positive correlation ( r = -0.101) for female subjects. For male and female participants, there was a weak negative association of VO2max with SDNN ( r = -0.170) and ( r = -0.301), respectively. Male and female participants had a weak negative association of VO2max with RMSSD, with ( r = -0.154) and ( r = -0.284) respectively. Male and female participants had a slight negative association of VO2max with pNN 50, with ( r = -0.062) and ( r = -0.441) respectively. Conclusion. Significant variations were found in the time domain and frequency domain indices including HF and LF/HF ratio which represents the balance between sympathetic and parasympathetic responses.

Exercise Stress Testing in Athletes

Exercise stress testing (EST) is indicated for diagnostic and prognostic purposes in the general population. In athletes, stress tests can also be useful to inform the risk of high-intensity training and competition, to assess athletic conditioning, and to refine training regimens. Many specific indications for EST are unique to athletes. Treadmill and cycle ergometer protocols each have their strengths and disadvantages; extensive protocol customization may be necessary to answer the clinical question at hand. A comprehensive understanding of the available tools for exercise testing, their strengths, and their limitations is crucial to providing cardiovascular care to athletic individuals.

Evaluation of a Treadmill-Based Submaximal Fitness Test in Pugs, and Collecting Breed-Specific Information on Brachycephalic Obstructive Airway Syndrome

Simple Summary

In the present study, a submaximal fitness test on a treadmill was evaluated to assess its feasibility under standardised conditions. Moreover, its effectiveness in identifying pugs with clinical signs of brachycephalic obstructive airway syndrome was examined. It was apparent that respiratory symptoms can be exposed during the fitness test, and intensified with an increased duration of exercise. This method of testing improves the clinical evaluation of the dogs and helps identify restrictions due to brachycephalic obstructive airway syndrome. Since most of the dogs could be familiarised with the treadmill, it may be a feasible option for performing fitness tests in brachycephalic dogs. Major benefits, therefore, are that each dog can be closely monitored during the entire process, and that the examination can be conducted under standardised conditions.

Abstract

Despite efforts of veterinarians and breeders, brachycephalic obstructive airway syndrome (BOAS) is still a common problem in pugs, underlining the need for objective tests to identify and prevent breeding with affected dogs. In the current study, a submaximal, treadmill-based fitness test was evaluated as a tool to identify signs of airway obstruction not recognisable under rest conditions. In addition to this, different body conformation and measurements were assessed regarding their association with BOAS. A total of 62 pugs and 10 mesocephalic dogs trotted with an individual comfort speed on a treadmill for 15 min. Before and during the examination, dogs were examined for signs of respiratory distress, and a functional BOAS grading was applied. The influence of body conformation on BOAS grading was tested in a univariable and multivariable logistic regression model. During exercise, more respiratory noises were observed, and existing respiratory noises became more apparent in comparison to when at rest. In the multivariable logistic regression model, no factor had a statistically significant influence on BOAS classification. Submaximal fitness testing helped to identify signs of respiratory distress not apparent under resting conditions, and could be a valuable addition for identifying dogs with BOAS. Performing testing on a treadmill facilitates continuous observation of the patients, and enables standardisation of the test regarding the test environment, as well as provides an uninterrupted, steady workload.

Cardiopulmonary exercise testing in neuromuscular disease: a systematic review

INTRODUCTION

Cardiopulmonary exercise testing (CPET) is increasingly used to determine aerobic fitness in health and disability conditions. Patients with neuromuscular diseases (NMDs) often present with symptoms of cardiac and/or skeletal muscle dysfunction and fatigue that might impede the ability to deliver maximal cardiopulmonary effort. Although an increasing number of studies report on NMDs' physical fitness, the applicability of CPET remains largely unknown.

AREAS COVERED

This systematic review synthesized evidence about the quality and feasibility of CPET in NMDs and patient's aerobic fitness. The review followed the PRISMA guidelines (PROSPERO number CRD42020211068). Between September and October 2020 one independent reviewer searched the PubMed/MEDLINE, EMBASE, SCOPUS, and Web of Science databases. Excluding reviews and protocol description articles without baseline data, all study designs using CPET to assess adult or pediatric patients with NMDs were included. The methodological quality was assessed according to the American Thoracic Society/American College of Chest Physicians (ATS/ACCP) recommendations.

EXPERT OPINION

CPET is feasible for ambulatory patients with NMDs when their functional level and the exercise modality are taken into account. However, there is still a vast potential for standardizing and designing disease-specific CPET protocols for patients with NMDs. Moreover, future studies are urged to follow the ATS/ACCP recommendations.

Obesity and Cardiovascular Disease: A Scientific Statement From the American Heart Association

The global obesity epidemic is well established, with increases in obesity prevalence for most countries since the 1980s. Obesity contributes directly to incident cardiovascular risk factors, including dyslipidemia, type 2 diabetes, hypertension, and sleep disorders. Obesity also leads to the development of cardiovascular disease and cardiovascular disease mortality independently of other cardiovascular risk factors. More recent data highlight abdominal obesity, as determined by waist circumference, as a cardiovascular disease risk marker that is independent of body mass index. There have also been significant advances in imaging modalities for characterizing body composition, including visceral adiposity. Studies that quantify fat depots, including ectopic fat, support excess visceral adiposity as an independent indicator of poor cardiovascular outcomes. Lifestyle modification and subsequent weight loss improve both metabolic syndrome and associated systemic inflammation and endothelial dysfunction. However, clinical trials of medical weight loss have not demonstrated a reduction in coronary artery disease rates. In contrast, prospective studies comparing patients undergoing bariatric surgery with nonsurgical patients with obesity have shown reduced coronary artery disease risk with surgery. In this statement, we summarize the impact of obesity on the diagnosis, clinical management, and outcomes of atherosclerotic cardiovascular disease, heart failure, and arrhythmias, especially sudden cardiac death and atrial fibrillation. In particular, we examine the influence of obesity on noninvasive and invasive diagnostic procedures for coronary artery disease. Moreover, we review the impact of obesity on cardiac function and outcomes related to heart failure with reduced and preserved ejection fraction. Finally, we describe the effects of lifestyle and surgical weight loss interventions on outcomes related to coronary artery disease, heart failure, and atrial fibrillation.

Effects of physical exercise on macular vessel density and choroidal thickness in children

We used swept-source (SS) optical coherence tomography (OCT) and OCT angiography (OCTA) to investigate the effects of moderate physical exercise on retinal and choroidal vessel densities (VDs) and thicknesses in children. One eye in each of 40 myopic children (mean age, 11.70 years) and 18 emmetropic children (mean age, 11.06 years) were included. SS-OCT 6 × 6-mm radial scans and SS-OCTA 3 × 3-mm images were centered on the macula. Heart rate (HR), systolic and diastolic blood pressure, and intraocular pressure (IOP) were recorded before and immediately after a 20-min stationary cycling exercise and after a 30-min rest. The subfoveal choroidal thickness (SFCT), choroidal thickness (CT), and VD at the superficial and deep retinal layers, choriocapillaris, and deeper choroidal vessels were determined. SFCT and CT were significantly lower at all locations immediately after exercise (p < 0.001) and did not fully recover after rest (p < 0.05). VD was lower in the deep retinal layer after exercise (p = 0.02) and higher in the superficial layer after rest (p = 0.03) in myopic eyes while it was higher in the superficial (p < 0.01) and deep layer (p < 0.01) after rest in emmetropic eyes. No significant exercise-related changes in the superficial retinal VD, choroidal VD, or IOP were observed. ΔCT% and ΔSFCT% were significantly correlated with increases in HR in myopic group (p = 0.04 and p = 0.03, respectively). Exercise increased retinal VD after rest in emmetropic eyes, and caused significant CT thinning that lasted for at least 30 min in both emmetropic and myopic eyes.

Effect of a phase 2 cardiac rehabilitation program on obese and non-obese patients with stable coronary artery disease

Background

Obesity is associated with significant cardiovascular morbidity and mortality effects. Cardiac rehabilitation programs cause a significant reduction in cardiovascular mortality and a reduction in all cardiovascular risk factors. Up to 80% of patients referred to cardiac rehabilitation programs are either overweight or obese. This study aimed to compare the effects of a phase 2 cardiac rehabilitation program on obese and non-obese patients with stable coronary artery disease following total revascularization by coronary angioplasty.

Results

This was a prospective study including 120 patients with stable coronary artery disease. Patients were enrolled in a 12-week phase 2 cardiac rehabilitation program. Patients were classified into two groups based on their body mass index (BMI): those with a BMI < 30 kg/m² were considered non-obese (n = 58) while those with a BMI ≥ 30 kg/m² were considered obese (n = 62). At baseline, BMI and blood pressure (BP) were recorded; fasting blood sugar, triglyceride levels, total cholesterol, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) levels were assessed; and echocardiography was used to measure left ventricular ejection fraction (LVEF). These were re-assessed after completion of the program. At baseline, there were more females in the obese group 20 (32.25%) vs 6 (10.13%) (p = 0.04), more hypertensives (p = 0.023), and less smokers 32 (51%) vs 46 (79%) (p = 0.025). Obese patients achieved fewer metabolic equivalent of tasks (METs) 7.97 ± 2.4 vs 9.74 ± 2.47 (p = 0.007) and had higher LDL-C levels 121.63 ± 36.52 mg/dl vs 95.73 ± 31.51 mg/dl (p = 0.005). At the end of the program, obese patients showed more reduction in BMI − 1.78 ± 1.46 kg/m² vs − 0. 60 ± 0.70 kg/m² (p < 0.001) and systolic and diastolic BP (p = 0.016 and 0.038, respectively). LDL-C level was more reduced in the obese group − 25.76 ± 14.19 mg/dl vs − 17.37 ± 13.28 mg/dl (p = 0.022). Non-obese patients had more increase in LVEF (p = 0.024). There was no difference between obese and non-obese patients in the magnitude of increase in METs achieved (p = 0.21).

Conclusion

Cardiac rehabilitation programs lead to an improvement in cardiovascular disease risk factors with more reduction in BMI, BP, and LDL-C levels in obese patients compared to non-obese ones. LVEF was more increased in non-obese individuals. Exercise capacity in the form of METs achieved was equally improved in both groups.

Criterion validity of the Ekblom-Bak and the Åstrand submaximal test in an elderly population

Purpose

The aim of this study was to validate the submaximal Ekblom-Bak test (EB-test) and the Åstrand test (Å-test) for an elderly population.

Methods

Participants (n = 104), aged 65–75 years, completed a submaximal aerobic test on a cycle ergometer followed by an individually adjusted indirect calorimetry VO₂max test on a treadmill. The HR from the submaximal test was used to estimate VO₂max using both the EB-test and Å-test equations.

Results

The correlation between measured and estimated VO₂max using the EB method and Å method in women was r = 0.64 and r = 0.58, respectively and in men r = 0.44 and r = 0.44, respectively. In women, the mean difference between estimated and measured VO₂max was − 0.02 L min⁻¹ (95% CI − 0.08 to 0.04) for the EB method and − 0.12 L min⁻¹ (95% CI − 0.22 to − 0.02) for the Å method. Corresponding values for men were 0.05 L min⁻¹ (95% CI − 0.04 to 0.14) and − 0.28 L min⁻¹ (95% CI − 0.42 to − 0.14), respectively. However, the EB method was found to overestimate VO₂max in men with low fitness and the Å method was found to underestimate VO₂max in both women and men. For women, the coefficient of variance was 11.1%, when using the EB method and 19.8% when using the Å method. Corresponding values for men were 11.6% and 18.9%, respectively.

Conclusion

The submaximal EB-test is valid for estimating VO₂max in elderly women, but not in all elderly men. The Å-test is not valid for estimating VO₂max in the elderly.

Electronic supplementary material

The online version of this article (10.1007/s00421-019-04275-7) contains supplementary material, which is available to authorized users.

A systematic comparison of exercise training protocols on animal models of cardiovascular capacity

Cardiovascular disease (CVD) is a major global cause of mortality, which has prompted numerous studies seeking to reduce the risk of heart failure and sudden cardiac death. While regular physical activity is known to improve CVD associated morbidity and mortality, the optimal duration, frequency, and intensity of exercise remains unclear. To address this uncertainty, various animal models have been used to study the cardioprotective effects of exercise and related molecular mechanism such as the mice training models significantly decrease size of myocardial infarct by affecting Kir6.1, VSMC sarc-K_ATP channels, and pulmonary eNOS. Although these findings cement the importance of animal models in studying exercise induced cardioprotection, the vast assortment of exercise protocols makes comparison across studies difficult. To address this issue, we review and break down the existent exercise models into categories based on exercise modality, intensity, frequency, and duration. The timing of sample collection is also compared and sorted into four distinct phases: pre-exercise (Phase I), mid-exercise (Phase II), exercise recovery (Phase III), and post-exercise (Phase IV). Finally, because the life-span of animals so are limited, small changes in animal exercise duration can corresponded to untenable amounts of human exercise. To address this limitation, we introduce the Life-Span Relative Exercise Time (RET_{life span}) as a method of accurately defining short-term, medium-term and long-term exercise relative to the animal's life expectancy. Systematic organization of existent protocols and this new system of defining exercise duration will allow for a more solid framework from which researchers can extrapolate animal model data to clinical application.

Exercise-Induced Anaphylaxis: Literature Review and Recent Updates

PURPOSE OF REVIEW

This paper will review the pathophysiology, diagnosis, and treatment of exercise-induced anaphylaxis and food-dependent, exercise-induced anaphylaxis with an emphasis on novel studies published in the past several years.

RECENT FINDINGS

Exercise-induced anaphylaxis (EIAn) is a clinical syndrome characterized by anaphylaxis during or shortly after physical exertion. The syndrome is broadly grouped into two categories: exercise-induced anaphylaxis and food-dependent, exercise-induced anaphylaxis (FDEIAn). Recent literature indicates that FDEIAn is a primary IgE-mediated food allergy which is augmented by several cofactors. Cofactors such as exercise, NSAIDs, and alcohol increase intestinal permeability and allow increased antigen uptake, thereby causing symptoms. The pathophysiology of EIAn is still under investigation. EIAn and FDEIAn are rare clinical syndromes characterized by symptoms during or shortly after exercise. Despite recent advances in the understanding of EIAn and FDEIAn, the pathophysiology of both conditions is not fully understood.

Left ventricular functional parameters by gated SPECT myocardial perfusion imaging in a Latin American country

BACKGROUND

There is paucity of data on left ventricular (LV) functional parameters using gated SPECT myocardial perfusion imaging (MPI) from the Latin American region. This study provides detailed information in low-risk patients both at rest and during exercise.

METHODS AND RESULTS

We studied 90 patients (50 men) with a very low likelihood of coronary artery disease. Gated-SPECT MPI was performed with Tc-99m MIBI using a 2-day protocol, with 16 frames/R-R cycle. The LV ejection fraction and volumes were not different between the rest and post-stress images. LVEF was 68 ± 7% post-stress and 70 ± 7% at rest in women, and 62 ± 7% and 63 ± 7%, respectively, in men (P = .19, .26). LV volumes were larger in men than women (P < .01). There were no differences in most variables obtained at rest or post-stress. Transient ischemic dilatation was similar, with upper limits of 1.20 and 1.19 in women and men, respectively (P = NS).

CONCLUSIONS

These data could prove helpful for the interpretation of gated SPECT MPI data in Latin America using identical protocol as used in this study.

Cardiovascular Response to Recreational Hockey in Middle-Aged Men

The present study examined the hemodynamic response to recreational pick-up hockey relative to maximal exercise testing in middle-aged men. A total of 23 men with a mean age of 53 ± 7 years were studied. Graded exercise testing on a cycle ergometer determined maximal oxygen consumption, blood pressure (BP), and heart rate (HR). Ambulatory BP and Holter electrocardiographic monitoring was performed during one of their weekly hockey games (mean duration = 45 ± 7.2 minutes): for "On-Ice" responses (PLAY; data recorded while standing immediately after a shift; 8.0 ± 1.4 shifts per game) and during seated recovery (BENCH), 15 minutes after the game. On-Ice HRs and BPs were significantly higher than values obtained during maximal cycle exercise, respectively (HR 174 ± 8.9 vs 163 ± 11.0 beats/min) (systolic blood pressure 202 ± 20 vs 173 ± 31 mm Hg; p <0.05). Both systolic and diastolic blood pressures decreased significantly throughout the duration of the game, whereas HR increased from 139 ± 20 to 155 ± 16 beats/min during the game. The myocardial oxygen demand (myocardial time tension index) increased significantly during PLAY concurrent with a decrease in estimated myocardial oxygen supply (diastolic pressure time index), with the endocardial viability ratio during PLAY demonstrating a significant decrease during the third quarter of the game (1.25 ± 0.24) versus the first quarter (1.56 ± 0.30), which remained depressed 15 minutes post-game (p <0.05). In conclusion, recreational pick-up hockey in middle-aged men is an extremely vigorous interval exercise with increasing relative intensity as the game progresses. Hockey elicits peak BPs and HRs that can exceed values observed during maximal exercise testing and is characterized by progressive increases in myocardial oxygen demand and lowered supply during PLAY and BENCH time. Given the progressive and high cardiovascular demands, caution is warranted when estimating the cardiovascular demands of hockey from clinical stress testing, particularly in those whom coronary reserve may be compromised.

Comparison of 1- Versus 3-Minute Stage Duration During Arm Ergometry in Individuals With Spinal Cord Injury

OBJECTIVE

To investigate the effect of stage duration on peak physiological response to arm ergometry incremental exercise testing in individuals with spinal cord injury or disease (SCI/D) in support of developing a more individualized approach to testing.

DESIGN

Parallel reliability study.

SETTING

University research laboratory.

PARTICIPANTS

Individuals with SCI/D (N=38) performed 2 peak oxygen consumption assessments comprised of 1-minute or 3-minute stages on 1 day.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Heart rate and oxygen consumption were recorded continuously from baseline through recovery. Every 1 minute or 3 minutes, resistance increased at an individualized level, and participants continued until volitional fatigue. The highest 30-second average was selected as peak oxygen consumption (Vo₂peak) and peak heart rate. The highest workload achieved for ≥30 seconds was recorded as peak power output (PO).

RESULTS

Intraclass correlation coefficients (ICCs) were >.95 for the following variables: absolute Vo₂peak (mean ± SD, 1min: 1.2±0.7, 3min: 1.2±.62L/min; 95% CI, .91-.98), relative Vo₂peak (mean ± SD, 1min: 16.6±9.4, 3min: 15.8±8.0mL/kg/min; 95% CI, .90-.98), absolute peak PO (mean ± SD, 1min: 61±41, 3min: 66±41W; 95% CI, .92-.98), and relative peak PO (mean ± SD, 1min: .80±56, 3min: .90±.55W/kg; 95% CI, .91-.98). There was no significant difference in peak heart rate between 3 minutes (132±27 beats per minute [bpm]) and 1 minute (130±28 bpm); however, the ICC lower limit was <.75 (0.67-0.90). Total test time was significantly longer in the 3-minute (8:17±2:52min:s) than in the 1-minute (6:29±2:21min:s) protocol.

CONCLUSIONS

For measuring peak physiological values in an incremental arm ergometry test, stage duration is of little consequence because similar values were obtained for the main outcome measures in both protocols.

Health resorts as gateways for regional, standardised, sports club based exercise programmes to increase the weekly time of moderate- to vigorous-intensity physical activity: study protocol

Background

More than 10 % (approximately 60,000) of the adult population in Styria, a federal state in the south of Austria, is granted a residential stay in a health resort each year. The target group for these stays is the general population aged between 30 and 65 years with minor symptoms such as risk factors for cardio-metabolic diseases. Stays are financed by health insurance companies and last up to three weeks. The treatment during the stays consists of exercise and nutritional intervention as well as psychological support when needed. However, because of the absence of regional programmes linked with the residential stay, the sustainability of the interventions is questionable.

Methods/Design

This prospective, controlled, multicentre, open-label study will compare two groups. Participants will be included in the study if they live in any of eight predefined Styrian regions and do not meet the minimal WHO physical activity guidelines. Those allocated to the intervention group will receive a voucher for 12 regional, standardised, sports club based exercise sessions. The members of the control group will come from different but matched Styrian regions and will receive an informative written brochure. The primary outcome will be the weekly level of health-enhancing physical activity, which will be objectively measured with an accelerometer and supplemented by an activity log book. Together with potential determinants of physical activity it will be assessed before, 10 weeks after and 12 months after the residential stay. Additionally, psychosocial determinants will be assessed by questionnaire and fitness (cardiorespiratory fitness, handgrip, balance) will be measured. In addition to the changes in measurable parameters, processes will be evaluated to learn about the facilitators and barriers of the implementation of the programme.

Discussion

It is known that during the residential stay, participants are receptive to new opportunities supporting health behaviour change, but that these measures are not sustained after discharge. The structured cooperation between the health sector that has to inform the participants and the sports sector that provides the wide network of standardised programmes is the strength of the study, but at the same time a challenge.

Trial registration

ClinicalTrials.gov (Identifier: NCT02552134; date of registration: 15 September 2015)

The Potential of "Wii Fit Free Jogging" as an Exercise Test

OBJECTIVE

The aim of this study was to investigate the potential use of "Wii™ Fit Free Jogging" (Nintendo(®), Kyoto, Japan) as a tool to estimate aerobic fitness in healthy young adults. It was hypothesized that virtual distance achieved, an outcome reported by the "Wii Fit Free Jogging" game, may be used to estimate aerobic fitness.

MATERIALS AND METHODS

Two exercise tests using "Wii Fit Free Jogging" were developed: the Wii Jogging Test and the Wii Step Test. For the Wii Jogging Test participants were required to jog on the spot with the aim of achieving the highest virtual distance possible in a given time. For the Wii Step Test participants had the same aim but were required to step up and down a 30-cm step. The construct and criterion validities of these tests were examined in two separate studies. Results were compared with maximal oxygen consumption (VO2max), which was established using the Bruce treadmill protocol. Oxygen consumption and heart rate were measured using an Oxycon™ Mobile indirect calorimeter (Jaeger™; Viasys Healthcare, Hoechberg, Germany) and a Polar heart rate monitor (Polar Electro Oy, Kempele, Finland).

RESULTS

There was no difference between the highest oxygen consumption reached during the Wii Step Test and VO2max (P=0.101). In regression analysis virtual distance results from neither the Wii Jogging Test nor the Wii Step Test contributed to the prediction of VO2max (P=0.235 and P=0.396, respectively).

CONCLUSIONS

In its current form, "Wii Fit Free Jogging" is not suitable for use as an exercise test. Although it elicited near-maximal exertion, there was no valid method of estimating aerobic fitness from virtual distance results.

Evaluation of health promotion programmes in severe mental illness: theory and practice

Health promotion programmes for patients with severe mental illness (HPP) are not uniformly evaluated. We discuss the evaluation of HPP in theory and practice, as a prerequisite for future uniform evaluation. We explored the expected outcome and mechanism of HPP in the current literature. Based on this theoretical exploration we selected measures assessing the expected outcome and mechanism in current practice. The individual properties of these measures were described. Based on our theoretical exploration the outcome of HPP can be expressed in several aspects of health. Health can be improved through several mechanisms. In the current evaluation of HPP only some of the expected outcomes were evaluated. The measures used for evaluation were not all representative for the constructs they should assess. Important aspects of HPP are currently not evaluated, based on a comparison between our theoretical exploration of expected outcome and mechanism and current practice. Additionally, not all measures in use are suitable for evaluation of HPP. Therefore, development and identification of suitable measures is necessary. Our framework offers valuable directions for the development of such measures and the future evaluation of HPP.

Obesity and coronary artery disease: evaluation and treatment

With the increasing prevalence of obesity, clinicians are now facing a growing population of patients with specific features of clinical presentation, diagnostic challenges, and interventional, medical, and surgical management. After briefly discussing the effect of obesity on atherosclerotic burden in this review, we will focus on strategies clinicians might use to ensure better outcomes when performing revascularization in obese and severely obese patients. These patients tend to present comorbidities at a younger age, and their anthropometric features might limit the use of traditional cardiovascular risk stratification approaches for ischemic disease. Alternative techniques have emerged, especially in nuclear medicine. Positron emission tomography-computed tomography might be the diagnostic imaging technique of choice. When revascularization is considered, features associated with obesity must be considered to guide therapeutic strategies. In percutaneous coronary intervention, a radial approach should be favoured, and adequate antiplatelet therapy with new and more potent agents should be initiated. Weight-based anticoagulation should be contemplated if needed, with the use of drug-eluting stents. An "off-pump" approach for coronary artery bypass grafting might be preferable to the use of cardiopulmonary bypass. For patients who undergo bilateral internal thoracic artery grafting, harvesting using skeletonization might prevent deep sternal wound infections. In contrast to percutaneous coronary intervention, lower surgical bleeding has been observed when lean body mass is used for perioperative heparin dose determination.

Exercise Hemodynamics and Quality of Life after Aortic Valve Replacement for Aortic Stenosis in the Elderly Using the Hancock II Bioprosthesis

Background and Aim. While aortic valve replacement for aortic stenosis can be performed safely in elderly patients, there is a need for hemodynamic and quality of life evaluation to determine the value of aortic valve replacement in older patients who may have age-related activity limitation. Materials and Methods. We conducted a prospective evaluation of patients who underwent aortic valve replacement for aortic stenosis with the Hancock II porcine bioprosthesis. All patients underwent transthoracic echocardiography (TTE) and completed the RAND 36-Item Health Survey (SF-36) preoperatively and six months postoperatively. Results. From 2004 to 2007, 33 patients were enrolled with an average age of 75.3 ± 5.3 years (24 men and 9 women). Preoperatively, 27/33 (82%) were New York Heart Association (NYHA) Functional Classification 3, and postoperatively 27/33 (82%) were NYHA Functional Classification 1. Patients had a mean predicted maximum V_O2 (mL/kg/min) of 19.5 ± 4.3 and an actual max V_O2 of 15.5 ± 3.9, which was 80% of the predicted V_O2. Patients were found to have significant improvements (P ≤ 0.01) in six of the nine SF-36 health parameters. Conclusions. In our sample of elderly patients with aortic stenosis, replacing the aortic valve with a Hancock II bioprosthesis resulted in improved hemodynamics and quality of life.

Development of a prediction model to predict VO2(peak) in adolescent girls using the Bruce protocol to exhaustion

PURPOSE

The purpose of this study was to develop a prediction model based on a submaximal workload during the Bruce treadmill protocol to estimate peak oxygen consumption (VO2(peak)) in adolescent girls.

METHOD

Adolescent girls (N = 116, M(age) = 13.2 +/- 2.0 years) performed a Bruce Treadmill Test to exhaustion. Expired respiratory gases and heart rate (HR) were collected and measured continuously via indirect calorimetry and telemetry. To be included in the analysis, each participant met 2 of 3 criteria: attain 95% of age-predicted HR(peak), respiratory exchange ratio > 1.05, or plateau of VO2. VO2 and HR at Stage 1 and Stage 2 of the Bruce test were entered into a regression model to predict VO2(peak).

RESULTS

A regression model, constructed using the predicted sum of squares statistic, was developed using VO2 (VO(2)2) and HR (HR2) attained at the 2nd 3-min stage of the Bruce treadmill protocol: VO2(peak) = 46.77 - (0.2854155 x HR2) + (1.46732912 x VO(2)2). Actual average (+/- SD) VO2(peak) was 36.2 +/- 6.9 ml x kg(-1) x min(-1) (range = 22.9-55.9). Predicted VO2(peak) was 36.2 +/- 5.5 ml x kg(-1) x min(-1) (range = 24.3-56.2). The correlation between actual and predicted VO2(peak) was r = .80, standard error of estimate = 4.2 ml x kg(-1) x min(-1), with no bias relative to participant aerobic fitness.

CONCLUSION

Based on this model, the VO2(peak) of healthy adolescent girls can be predicted within 4.2 ml x kg(-1) x min(-1) using submaximal Bruce data.

The impact of modern noninvasive cardiac imaging on coronary intervention rates

OBJECTIVES

It remains still unclear whether the use of modern noninvasive diagnostic modalities for evaluation of coronary artery disease (computed tomography coronary angiography (CTCA), nuclear myocardial perfusion imaging (MPI)) were able to change the "diagnostic yield" of invasive coronary angiography (ICA).

METHODS

The total number of ICA in the years 2000-2009 was related to the number of percutaneous interventions (PCIs) and we assessed whether there was a significant trend over time using time series analyses. We compared these data with the number of patients undergoing CTCA and nuclear MPI in the same time period.

RESULTS

During the 10-year observational period, 23,397 ICA were performed. The proportion of purely diagnostic ICA (without PCI) remained stable over the whole study period (tau = -0.111, P = 0.721). A CTCA program was initiated in 2005 and 1,407 examinations were performed until 2009. Similarly, the number of nuclear MPI increased from 2,284 in the years 2000-2004 to 5,260 in the years 2005-2009 (P = 0.009).

CONCLUSION

Despite increasing availability, noninvasive testing modalities did not significantly alter the rate of purely diagnostic ICA, and still are underused as gatekeeper to ICA. Further effort is needed to optimize the use of noninvasive imaging modalities in the work-up process for coronary artery disease.

Latent pulmonary hypertension in atrial septal defect: Dynamic stress echocardiography reveals unapparent pulmonary hypertension and confirms rapid normalisation after ASD closure

Objective

Closure of atrial septal defects (ASD) prevents pulmonary hypertension, right heart failure and thromboembolic stroke. The exact timing for ASD closure is controversial.

Methods

In a prospective study to address the question whether unapparent pulmonary hypertension can be revealed prior to right ventricular (RV) remodelling, patients were investigated before and 6, 12, and 24 months after ASD closure using exercise stress echocardiography (ESE) and ergospirometry (n = 24).

Results

At rest, RV systolic pressure (RVSP) was normal in 58.8 %, slightly elevated in 26.5 %, and moderately elevated in 11.8 %. One patient showed severe pulmonary hypertension. During ESE, all patients with normal RVSP at rest exhibited an increase (25.7 ± 1.2 mmHg vs. 45.3 ± 2.3 mmHg, p < 0.001). After closure the RVSP was lower, both at rest and ESE. RV diameters decreased too. Tricuspid annulus plane systolic excursion (TAPSE) at rest remained lower after closure (24.0 ± 0.9 vs. 22.0 ± 0.9 mm, p < 0.05). TAPSE in ESE was elevated, and stayed stable after closure (30.1 ± 1.8 mm vs. 29.3 ± 1.6 mm). Before closure, RV systolic tissue velocities (s^a) at rest were normal and decreased after closure (14.0 ± 1.0 cm/s vs. 11.5 ± 0.7 (6 month) vs. 10.6 ± 0.5 cm/s (12 month), p < 0.05). During ESE, s^a velocity was similar before and after closure (23.0 ± 1.3 cm/s vs. 23.3 ± 1.9 cm/s). Maximal oxygen uptake (VO₂/kg) did not differ between baseline and follow-ups.

Conclusion

Latent pulmonary hypertension may become apparent in ESE. ASD closure leads to a significant reduction in this stress-induced pulmonary hypertension and to a decrease in the right heart diameters indicating reverse RV remodelling. RV functional parameters at rest did not improve. The VO₂/kg did not change after ASD closure.

Pacing to reduce refractory angina in patients with severe coronary artery disease: a crossover pilot trial

Biventricular pacing (BiV) has been shown to reduce wall stress and workload in regions near the pacing sites. This trial investigated if BiV near the ischemic region would reduce chest pain in patients with refractory angina due to severe coronary artery disease (CAD). Eleven patients were implanted with BiV devices with leads positioned at or adjacent to their ischemic regions as detected by single-photon emission computed tomography (SPECT) and randomized to either pacing turned ON or OFF for 3 months, and then crossed over for 3 months. With pacing turned ON, a Dynamic atrioventricular (AV) delay was set for approximately 90% and 70% of the intrinsic AV delay at the resting heart rate and at the onset of symptoms, respectively. One patient was excluded from the analysis due to a large amount of RV pacing during the OFF periods (24-64%) and due to an inability to properly deliver therapy because of an excessive number of ventricular premature complexes. Overall, with the device ON vs. OFF, the number of angina episodes (0.8 ± 0.4 vs. 1.2 ± 0.7 per week, P = 0.03) and amount of nitroglycerin used (0.2 ± 0.1 vs. 1.0 ± 0.7 per week, P = 0.11) was lower with BiV pacing. Furthermore, the treadmill exercise time to symptoms trended higher (427 ± 65 vs. 408 ± 64 s, P = 0.19), and the sum of fluorodeoxyglucose-positron emission tomography (FDG-PET) scores trended lower (7.9 ± 3.5 vs. 12.0 ± 4.0, P = 0.11) with the device ON vs. OFF. Nevertheless, there were no significant differences in SPECT myocardial perfusion scores, left ventricle ejection fraction, wall motion score index, and quality of life scores with device programmed ON vs. OFF (all P > 0.05). In conclusion, this pilot study demonstrated that BiV-P at or near the ischemic region was feasible and associated with significant reductions in angina in patients with severe CAD. Adequately powered prospective studies are needed to confirm these findings.

Impact of exercise on heart rate recovery

BACKGROUND

Abnormal heart rate recovery (HRR) has been shown to predict mortality. Although small studies have found that HRR can be improved with cardiac rehabilitation, it is unknown whether an improvement would affect mortality. The aim of this study was to determine whether HRR could be improved with cardiac rehabilitation and whether it would be predictive of mortality.

METHODS AND RESULTS

We evaluated 1070 consecutive patients who underwent exercise stress testing before and after completion of a phase 2 cardiac rehabilitation program. Heart rate recovery, defined as the difference between heart rate at peak exercise and exactly 1 minute into the recovery period, and mortality were followed up as the primary end points. Of 544 patients with abnormal baseline HRR, 225 (41%) had normal HRR after rehabilitation. Of the entire cohort, 197 patients (18%) died. Among patients with an abnormal HRR at baseline, failure to normalize after rehabilitation predicted a higher mortality (P<0.001). After multivariable adjustment, the presence of an abnormal HRR at exit was predictive of death in all patients (hazard ratio, 2.15; 95% confidence interval 1.43-3.25). Patients with abnormal HRR at baseline who normalized afterward had survival rates similar to those of the group with normal HRR at baseline and after cardiac rehabilitation (P=0.143).

CONCLUSIONS

Heart rate recovery improved after phase 2 cardiac rehabilitation in the overall cohort. There was a strong association of abnormal HRR at exit with all-cause mortality. Patients with abnormal HRR at baseline who normalized HRR with exercise had a mortality similar to that of individuals with baseline normal HRR.

Breathing abnormalities in children with breathlessness

Dysfunctional breathing, hyperventilation and vocal cord dysfunction are frequently seen in children and adults. The prevalence is unknown. There are no standardized diagnostic criteria, and for now, effective exclusion of organic disease leaves the diagnosis of dysfunctional breathing. Therapy is mainly focussed on explanation of a benign condition and reassurance. Since dysfunctional breathing is a possible chronic condition, other therapies should be evaluated. In adults physiotherapy and breathing retraining appear beneficial. In childhood there is lack of evidence, and further research is necessary in order to optimise the outcome for children with dysfunctional breathing.

cAMP sensitivity of HCN pacemaker channels determines basal heart rate but is not critical for autonomic rate control

BACKGROUND

HCN channels activate the pacemaker current I(f), which is thought to contribute significantly to generation and regulation of heart rhythm. HCN4 represents the dominant isotype in the sinoatrial node and binding of cAMP was suggested to be necessary for autonomic heart rate regulation.

METHODS AND RESULTS

In a candidate gene approach, a heterozygous insertion of 13 nucleotides in exon 6 of the HCN4 gene leading to a truncated cyclic nucleotide-binding domain was identified in a 45-year-old woman with sinus bradycardia. Biophysical properties determined by whole-cell patch-clamp recording of HEK293 cells demonstrated that mutant subunits (HCN4-695X) were insensitive to cAMP. Heteromeric channels composed of wild-type and mutant subunits failed to respond to cAMP-like homomeric mutant channels, indicating a dominant-negative suppression of cAMP-induced channel activation by mutant subunits. Pedigree analysis identified 7 additional living carriers showing similar clinical phenotypes, that is, sinus node dysfunction with mean resting heart rate of 45.9±4.6 bpm (n=8) compared with 66.5±9.1 bpm of unaffected relatives (n=6; P<0.01). Clinical evaluation revealed no ischemic or structural heart disease in any family member. Importantly, mutant carriers exhibited normal heart rate variance and full ability to accelerate heart rate under physical activity or pharmacological stimulation. Moreover, mutant carriers displayed distinctive sinus arrhythmias and premature beats linked to adrenergic stress.

CONCLUSIONS

In humans, cAMP responsiveness of I(f) determines basal heart rate but is not critical for maximum heart rate, heart rate variability, or chronotropic competence. Furthermore, cAMP-activated I(f) may stabilize heart rhythm during chronotropic response.

Real-time cine and myocardial perfusion with treadmill exercise stress cardiovascular magnetic resonance in patients referred for stress SPECT

BACKGROUND

To date, stress cardiovascular magnetic resonance (CMR) has relied on pharmacologic agents, and therefore lacked the physiologic information available only with exercise stress.

METHODS

43 patients age 25 to 81 years underwent a treadmill stress test incorporating both Tc99m SPECT and CMR. After rest Tc99m SPECT imaging, patients underwent resting cine CMR. Patients then underwent in-room exercise stress using a partially modified treadmill. 12-lead ECG monitoring was performed throughout. At peak stress, Tc99m was injected and patients rapidly returned to their prior position in the magnet for post-exercise cine and perfusion imaging. The patient table was pulled out of the magnet for recovery monitoring. The patient was sent back into the magnet for recovery cine and resting perfusion followed by delayed post-gadolinium imaging. Post-CMR, patients went to the adjacent SPECT lab to complete stress nuclear imaging. Each modality's images were reviewed blinded to the other's results.

RESULTS

Patients completed on average 9.3 +/- 2.4 min of the Bruce protocol. Stress cine CMR was completed in 68 +/- 14 sec following termination of exercise, and stress perfusion CMR was completed in 88 +/- 8 sec. Agreement between SPECT and CMR was moderate (kappa = 0.58). Accuracy in eight patients who underwent coronary angiography was 7/8 for CMR and 5/8 for SPECT (p = 0.625). Follow-up at 6 months indicated freedom from cardiovascular events in 29/29 CMR-negative and 33/34 SPECT-negative patients.

CONCLUSIONS

Exercise stress CMR including wall motion and perfusion is feasible in patients with suspected ischemic heart disease. Larger clinical trials are warranted based on the promising results of this pilot study to allow comparative effectiveness studies of this stress imaging system vs. other stress imaging modalities.

Effects of altitude on exercise level and heart rate in patients with coronary artery disease and healthy controls

Background. To evaluate the safety and effects of high altitude on exercise level and heart rate in patients with coronary artery disease compared with healthy controls.Methods. Eight patients with a history of an acute myocardial infarction (ejection fraction >5%) with a low-risk score were compared with seven healthy subjects during the Dutch Heart Expedition at the Aconcagua in Argentina in March 2007. All subjects underwent a maximum exercise test with a cycle ergometer at sea level and base camp, after ten days of acclimatisation, at an altitude of 4200 m. Exercise capacity and maximum heart rate were compared between groups and within subjects.Results. There was a significant decrease in maximum heart rate at high altitude compared with sea level in both the patient and the control group (166 vs. 139 beats/min, p<0.001 and 181 vs. 150 beats/min, p<0.001). There was no significant difference in the decrease of the exercise level and maximum heart rate between patients and healthy controls (-31 vs. -30%, p=0.673).Conclusion. Both patients and healthy controls showed a similar decrease in exercise capacity and maximum heart rate at 4200 m compared with sea level, suggesting that patients with a history of coronary artery disease may tolerate stay and exercise at high altitude similarly to healthy controls. (Neth Heart J 2010;18:118-21.).

Genetic polymorphisms of beta1 adrenergic receptor and their influence on the cardiovascular responses to metoprolol in a South Indian population

BACKGROUND AND OBJECTIVE

Beta-blockers show interindividual and interethnic variability in their response. Such variability might be due to the polymorphic variations in the beta1 adrenergic receptor genes viz, Ser49Gly and Arg389Gly. The study evaluated the influence of Ser49Gly and Arg389Gly polymorphisms on the cardiovascular responses to metoprolol in a South Indian population.

MATERIALS AND METHODS

Forty-one genetically prescreened healthy male volunteers participated in the study. They were divided on the basis of genotype of each polymorphism: Ser49Ser, Ser49Gly, and Gly49Gly and Arg389Arg, Arg389Gly, and Gly389Gly. They were also grouped into combination genotypes viz, S49S R389R, S49G R389R, G49G R389R, S49S R389G, S49S G389G, and S49G R389G. They were subjected to treadmill exercise testing, and cardiovascular parameters were measured before and after metoprolol administration. Metoprolol concentration was determined by reversed phase high-performance liquid chromatography method.

RESULTS

The diastolic blood pressure (DBP) was significantly lower in S49S/G389G group when compared to S49S/A389A group. The cardiac parameters were significantly increased in all the genotype groups during treadmill exercise test done for a period of 9 minutes. During predrug treadmill exercise at the end of third and sixth minute, Gly49Gly showed a higher increase in heart rate and volume of oxygen consumption compared to Ser49Ser. Same group showed a higher increase of volume of oxygen consumption at the end of ninth minute of exercise compared to the Ser49Ser. Systolic and diastolic blood pressures were not different between Ser49Gly polymorphisms. However, there was no statistical difference between the genotype groups of both polymorphisms at any stage of post-drug treadmill exercise. The analysis of combination of genotypes showed no significant difference during predrug and postdrug exercise testing.

CONCLUSION

The increase in cardiac responses to treadmill test was influenced by Ser49Gly polymorphism. Nevertheless, the above polymorphisms did not alter the beta-blocker response during treadmill exercise in South Indian population.

Orthopaedic surgeons' cardiovascular response during total hip arthroplasty

The literature contains limited and contradictory information regarding the amount of physical effort and/or emotional stress needed to perform surgery. We therefore investigated cardiovascular response to psychophysical stress in orthopaedic surgeons while they were performing surgery. We monitored 29 male orthopaedic surgeons from four university centers while they performed total hip arthroplasties. Changes in their cardiovascular parameters were recorded by ambulatory monitoring methods. Exercise stress testing of each participant was used as a control state. We compared the cardiovascular response during surgery to energy requirements of everyday activities. Preoperative and postoperative testing showed lower values of cardiovascular parameters than during physically less difficult parts of the operation; physically more difficult phases of the operation additionally increased the values of parameters. We concluded performing total hip arthroplasty increases surgeons' cardiovascular parameters because of psychologic stress and physical effort. Excitement of the cardiovascular system during total hip arthroplasty appears similar to the excitement during moderate-intensity daily activities, such as walking the dog, leisurely bicycling, or climbing stairs.

Peptide glutamine supplementation for tolerance of intermittent exercise in soccer players

OBJECTIVE

To investigate whether supplementation of carbohydrate together with peptide glutamine would increase exercise tolerance in soccer players.

METHODS

Nine male soccer players (mean age: 18.4 +/- 1.1 years; body mass: 69.2 +/- 4.6 kg; height: 175.5 +/- 7.3 cm; and maximum oxygen consumption of 57.7 +/- 4.8 ml x kg(-1) x min(-1)) were evaluated. All of them underwent a cardiopulmonary exercise test and followed a protocol that simulated the movements of a soccer game in order to evaluate their tolerance to intermittent exercise. By means of a draw, either carbohydrate with peptide glutamine (CARBOGLUT: 50 g of maltodextrin + 3.5 g of peptide glutamine in 250 ml of water) or carbohydrate alone (CARBO: 50 g of maltodextrin in 250 ml of water) was administered in order to investigate the enhancement of the soccer players' performances. The solution was given thirty minutes before beginning the test, which was performed twice with a one-week interval between tests.

RESULTS

A great improvement in the time and distance covered was observed when the athletes consumed the CARBOGLUT mixture. Total distance covered was 12750 +/- 4037m when using CARBO, and 15571 +/- 4184m when using CARBOGLUT (p<0.01); total duration of tolerance was 73 +/- 23 min when using CARBO and 88 +/- 24 min when using CARBOGLUT (p<0.01).

CONCLUSION

The CARBOGLUT mixture was more efficient in increasing the distance covered and the length of time for which intermittent exercise was tolerated. CARBOGLUT also reduced feelings of fatigue in the players compared with the use of the CARBO mixture alone.

Cardiac function and myocardial perfusion immediately following maximal treadmill exercise inside the MRI room

Treadmill exercise stress testing is an essential tool in the prevention, detection, and treatment of a broad spectrum of cardiovascular disease. After maximal exercise, cardiac images at peak stress are typically acquired using nuclear scintigraphy or echocardiography, both of which have inherent limitations. Although CMR offers superior image quality, the lack of MRI-compatible exercise and monitoring equipment has prevented the realization of treadmill exercise CMR. It is critical to commence imaging as quickly as possible after exercise to capture exercise-induced cardiac wall motion abnormalities. We modified a commercial treadmill such that it could be safely positioned inside the MRI room to minimize the distance between the treadmill and the scan table. We optimized the treadmill exercise CMR protocol in 20 healthy volunteers and successfully imaged cardiac function and myocardial perfusion at peak stress, followed by viability imaging at rest. Imaging commenced an average of 30 seconds after maximal exercise. Real-time cine of seven slices with no breath-hold and no ECG-gating was completed within 45 seconds of exercise, immediately followed by stress perfusion imaging of three short-axis slices which showed an average time to peak enhancement within 57 seconds of exercise. We observed a 3.1-fold increase in cardiac output and a myocardial perfusion reserve index of 1.9, which agree with reported values for healthy subjects at peak stress. This study successfully demonstrates in-room treadmill exercise CMR in healthy volunteers, but confirmation of feasibility in patients with heart disease is still needed.

Randomised controlled trial of a supervised exercise rehabilitation program for colorectal cancer survivors immediately after chemotherapy: study protocol

BACKGROUND

Colorectal cancer (CRC) diagnosis and the ensuing treatments can have a substantial impact on the physical and psychological health of survivors. As the number of CRC survivors increases, so too does the need to develop viable rehabilitation programs to help these survivors return to good health as quickly as possible. Exercise has the potential to address many of the adverse effects of CRC treatment; however, to date, the role of exercise in the rehabilitation of cancer patients immediately after the completion of treatment has received limited research attention. This paper presents the design of a randomised controlled trial which will evaluate the feasibility and efficacy of a 12-week supervised aerobic exercise program (ImPACT Program) on the physiological and psychological markers of rehabilitation, in addition to biomarkers of standard haematological outcomes and the IGF axis.

METHODS/DESIGN

Forty CRC patients will be recruited through oncology clinics and randomised to an exercise group or a usual care control group. Baseline assessment will take place within 4 weeks of the patient completing adjuvant chemotherapy treatment. The exercise program for patients in the intervention group will commence a week after the baseline assessment. The program consists of three supervised moderate-intensity aerobic exercise sessions per week for 12 weeks. All participants will have assessments at baseline (0 wks), mid-intervention (6 wks), post-intervention (12 wks) and at a 6-week follow-up (18 wks). Outcome measures include cardio-respiratory fitness, biomarkers associated with health and survival, and indices of fatigue and quality of life. Process measures are participants' acceptability of, adherence to, and compliance with the exercise program, in addition to the safety of the program.

DISCUSSION

The results of this study will provide valuable insight into the role of supervised exercise in improving life after CRC. Additionally, process analyses will inform the feasibility of implementing the program in a population of CRC patients immediately after completing chemotherapy.

TRIAL REGISTRATION

ACTRN012606000395538.

A Pilot Study to Assess the Feasibility of a Submaximal Exercise Test to Measure Individual Response to Cardiac Medication in Dogs with Acquired Heart Failure

Exercise testing is not commonly used in canine medicine because of several limitations. The aim of this study was to investigate the suitability of a treadmill test to measure the exercise capacity of untrained canine cardiac patients and to measure some biological parameters that might reflect the tolerance of dogs with heart failure to submaximal exercise. The exercise capacity of seven dogs with naturally occurring heart failure was evaluated before the institution of cardiac medication and 7 days after the beginning of the study. An additional re-examination was requested after 28 days. The exercise test was performed on a motorized treadmill at three different speeds (0.5 m/s, 1.0 m/s and 1.5 m/s). The following parameters were measured at the end of each stage and after 20 min recovery: heart rate, rectal temperature, glucose, lactate, aspartate aminotransferase, creatine kinase, PvO(2), PvCO(2), pH, haematocrit, bicarbonate, sodium, potassium and chloride. Serum cardiac troponin-I was also measured at the beginning of the test and at the end of the recovery period. Owners' perception reflected the ability of their dogs to exercise on the treadmill. Lactate level increased noticeably with the intensity of the exercise test, and its variation coincided with different exercise tolerance observed by the owners. Heart rate seemed to follow a similar trend in the few dogs presented in sinus rhythm. None of the remaining parameters appeared to be sensitive indicators of activity level in the dogs used in this study. The treadmill exercise test in dogs with acquired heart failure is feasible and might provide useful information for assessing individual response to cardiac medication. Lactate and heart rate seemed to reflect individual levels of exercise tolerance, although further studies are necessary to confirm the reliability and repeatability of this test.

Peak oxygen uptake. Myth and truth about an internationally accepted reference value

This article critically examines the execution of VO(2)-peak testing in cardiac patients and questions their appropriate interpretation. In the first part, the most common clinical implications of VO(2)peak measurements are discussed: assessment of (changes in) functional capacity, evaluation of the necessity of invasive diagnostic/therapeutic measures, reference for exercise prescriptions, determination of prognosis. In the second part, important methodological problems and constraints are addressed and illustrated by references to scientific studies. Finally, recommendations are given for meaningful VO(2)peak testing. It is evident that failure to strictly follow such recommendations might result in misleading ergometric findings and, thus, in over- or underestimation of endurance capacity and/ or training effects.

Promoting physical activity in medical education

The challenges in public health associated with sedentary lifestyle underline the need to prepare physicians to give appropriate medical counselling and exercise prescription. In addition, the medical students' lifestyle and physical fitness suggest changes in medical education. Physical education as a criterion subject in our medical school curriculum serves to direct students' attitude toward regular physical activity. The knowledge of exercise counselling is promoted by a credit course of human movement sciences.