Reference values for exercise tests with continuous increase in load

Incremental Value of Exercise ECG to Myocardial Perfusion Single-Photon Emission Computed Tomography for Prediction of Cardiac Events

Background Both myocardial perfusion single-photon emission computed tomography (MPS) and exercise ECG (Ex-ECG) carry prognostic information in patients with stable chest pain. However, it is not fully understood if combining the findings of MPS and Ex-ECG improves risk prediction. Current guidelines no longer recommend Ex-ECG for diagnostic evaluation of chronic coronary syndrome, but Ex-ECG could still be of incremental prognostic importance. Methods and Results This study comprised 908 consecutive patients (age 63.3±9.4 years, 49% male) who performed MPS with Ex-ECG. Subjects were followed for 5 years. The end point was a composite of cardiovascular death, acute myocardial infarction, unstable angina, and unplanned percutaneous coronary intervention. National registry data and medical charts were used for end point allocation. Combining the findings of MPS and Ex-ECG resulted in concordant evidence of ischemia in 72 patients or absence of ischemia in 634 patients. Discordant results were found in 202 patients (MPS-/Ex-ECG+, n=126 and MPS+/Ex-ECG-, n=76). During follow-up, 95 events occurred. Annualized event rates significantly increased across groups (MPS-/Ex-ECG- =1.3%, MPS-/Ex-ECG+ =3.0%, MPS+/Ex-ECG- =5.1% and MPS+/Ex-ECG+ =8.0%). In multivariable analyses MPS was the strongest predictor regardless of Ex-ECG findings (MPS+/Ex-ECG-, hazard ratio [HR], 3.0, P=0.001 or MPS+/Ex-ECG+, HR,4.0, P<0.001). However, an abnormal Ex-ECG almost doubled the risk in subjects with normal MPS (MPS-/Ex-ECG+, HR, 1.9, P=0.04). Conclusions In patients with chronic coronary syndrome, combining the results from MPS and Ex-ECG led to improved risk prediction. Even though MPS is the stronger predictor, there is an incremental value of adding data from Ex-ECG to MPS, especially in patients with normal MPS.

Low risk patients with acute atrial fibrillation and elevated high-sensitivity troponin do not have increased incidence of pathological stress tests

OBJECTIVES

Many patients with atrial fibrillation (AF) or atrial flutter (AFL) and rapid ventricular response (RVR) have elevated high-sensitivity troponin T (hsTnT) values. Elevated hsTnT is an independent risk marker for cardiovascular events and mortality. The aim was to examine if AF/AFL patients with RVR and elevated hsTnT have an increased incidence of pathological cardiac stress tests, indicating need of further evaluation for coronary artery disease (CAD). Design: We prospectively included 90 AF/AFL patients without known heart failure and CAD presenting with AF/AFL and RVR. Half of the patients had elevated hsTnT (cases) and half had levels below the 99th percentile (controls). All patients were discharged in sinus rhythm. After approximately one week in sinus rhythm a new hsTnT was analysed and the patients performed a bicycle exercise stress test within the 30 day follow-up. The primary endpoint was a pathological stress test confirmed by a pathological SPECT myocardial perfusion imaging or a coronary angiography. Results: None of the controls reached the primary endpoint. Two patients (4%) out of the 45 cases reached the primary endpoint (p = .49 vs controls), but only one was found to have significant CAD at subsequent coronary angiography. Conclusion: Patients with paroxysmal AF/AFL, without a history of CAD and heart failure, who present with a RVR and minor hsTnT elevations were not found to have an increased incidence of pathological stress tests compared to patients with hsTnT values below the 99th percentile.

Performance and cardiac evaluation before and after a 3-week training camp for 400-meter sprinters - An observational, non-randomized study

Objective

To study the performance and cardiovascular function after a 3-week training camp in athletes competing in an anaerobically dominant sport.

Methods

Twenty-three competitive 400-m athletes were enrolled in this non-randomized study, 17 took part in a 3-week training camp in South-Africa (intervention), but one declined follow-up assessment, while 6 pursued in-door winter training in Sweden and served as controls. Electrocardiography, transthoracic echocardiography, blood test analyses, maximal exercise tolerance test, and a 300-m sprint test with lactate measurements ([La]peak) were performed before and after the training camp period.

Results

At baseline, there were no clinically significant pathological findings in any measurements. The training period resulted in improved 300m-sprint performance [n = 16; running time 36.71 (1.39) vs. 35.98 (1.13) s; p<0.01] and higher peak lactate values. Despite 48% more training sessions than performed on home ground (n = 6), myocardial biomarkers decreased significantly (NT-pro BNP -38%; p<0.05, troponin T -16%; p<0.05). Furthermore, resting heart rate (-7%; p<0.01) and left ventricular systolic and diastolic volumes decreased -6% (p<0.01) and -10% (p<0.05), respectively.

Conclusions

Intense physical activity at training camp improved the performance level, likely due to improved anaerobic capacity indicated by higher [La]peak. There were no clinically significant adverse cardiac changes after this period of predominantly anaerobic training.

Randomized clinical trial studying effects of a personalized supervised lifestyle intervention program on cardiovascular status in physically inactive healthy volunteers

Background

The impact of personalized exercise training and a healthy dietary lifestyle in healthy volunteers on coronary flow reserve and cardiovascular function remains to be investigated in a controlled study setting.

Purpose

To examine the effects of a Mediterranean-inspired diet combined with regular physical exercise (standard) and a personalized supervised exercise program (DAPS) on coronary flow reserve and cardiovascular function.

Results

The number of males were 10 (59%) and 9 (47%) and mean age was 54 ± 12 and 55 ± 5 years in standard versus DAPS group, respectively. Primary outcomes were in addition to improved body composition and aerobic capacity, increased TDE-CFR (5.0%, CI:1.62,8.64, p = 0.005) and left ventricle ejection fraction (LVEF) during hyperemia (10.2%, CI:1.62,19.4, p = 0.022) in DAPS adjusted for the control period. Also, plasma fibrinogen decreased (−12.1%, CI:-22.0,–0.92, p = 0.035) in the DAPS group. Secondary outcomes, after adjusting DAPS intervention effects for the standard-training period, TDE-CFR and hyperemic LVEF remained significantly improved.

Materials and Methods

This randomized, controlled clinical trial (URL: http://www.clinicaltrials.gov NCT02713724) included 36 healthy volunteers who underwent exercise ECG before randomization to standard or DAPS groups. Standard-group was given gym-membership with limited instructions and general dietary advice. DAPS-group received personalized supervised exercise programs and more detailed dietary advice with regular contact with a personal trainer. Effects were evaluated after 3 months. All participants underwent coronary flow reserve by transthoracic ultrasound (TDE-CFR), blood marker analysis and examinations of vascular function. Standard-group was evaluated pre-control, post-control (=pre-intervention) and post-intervention. DAPS-group was examined at pre-intervention and post-intervention.

Conclusions

A personalized supervised training- and diet program improves cardiovascular status in healthy subjects with a physically inactive lifestyle and may be a promising approach for cardiovascular prevention in the general population.

Exercise capacity in young adults after hematopoietic cell transplantation in childhood

A symptom-limited incremental cycle ergometer test was performed in 17 young adult patients treated with hematopoietic cell transplantation and total body irradiation for hematologic malignancies during childhood. These 17 young adult patients were compared with 17 sex- and age-matched healthy control subjects. Assessments of pulmonary function, cardiac function, body composition, and levels of growth hormone were made. The median follow-up was 17.7 years. Patients achieved 63.2% of the predicted peak workload, whereas controls achieved 96.1% (P < .001). All patients, but only 1 control, failed to achieve a peak workload >80% (P < .001). Fat-free mass was significantly lower (43.5 vs 57.6 kg, P < .001) and fat mass percentage was significantly higher (31.8% vs 24.2%, P = .011) in the patients. The peak workload adjusted for fat-free mass was significantly lower in the patients (3.3 vs 4.3, P < .001). In the patients, peak workload correlated significantly with total lung capacity (r = .54, P = .025). In summary, long-term survivors have significantly decreased exercise capacity compared with healthy individuals. Together with their altered body composition, this may predispose them to cardiovascular disease.

Gender aspects on exercise-induced ECG changes in relation to scintigraphic evidence of myocardial ischaemia

BACKGROUND

This retrospective study aimed to determine the diagnostic performance of exercise-induced ST response in relation to findings by myocardial perfusion single photon emission computed tomography (MPS), with focus on gender differences, in patients with suspected or established stable ischemic heart disease.

METHODS

MPS findings of 1 021 patients (518 females) were related to the exercise-induced ST response alone (blinded and unblinded to gender) and ST response together with additional exercise stress test (EST) variables (exercise capacity, blood pressure and heart rate response).

RESULTS

Exercise-induced ischaemia by MPS was found in 9% of females and 23% of males. Diagnostic performance of exercise-induced ST response in relation to MPS findings in females versus males was: sensitivity = 48%,70%; specificity = 67%, 64%; PPV = 13%, 38%; NPV = 93%, 87%. Adding more EST variables to the ST response interpretation yielded in females vs males: sensitivity = 44%, 51%; specificity = 84%, 83%; PPV = 22%, 48% and NPV = 93%, 85%.

CONCLUSIONS

In patients who have performed EST in conjunction with MPS, there is a gender difference in the diagnostic performance of ST response at stress, with a significantly lower PPV in females compared to males. For both genders, specificity can be significantly improved, and a higher PPV can be obtained, while the sensitivity might be compromised by considering more EST variables, in addition to the ST response.

Exercise testing for long-term follow-up in arrhythmogenic right ventricular cardiomyopathy

OBJECTIVES

We investigated arrhythmia, electrocardiography and physical work capacity (PWC) in the follow-up of ARVC.

DESIGN

Twenty-three patients (13 men; age 41±12years) fulfilling diagnostic criteria were re-investigated after at least five years.

RESULTS

Ventricular arrhythmia during exercise testing (ET) was present in 14 patients (61%) and showed variation between examinations. In eleven (48%), complex ventricular ectopic activity was observed at peak exercise or immediately thereafter. Mutations known to be pathogenic in ARVC were present in 13 patients (57%) of which 11 developed complex ventricular arrhythmia at ET. PWC at baseline was 190±66W (104±26%) decreasing to 151±61W (91±23%, p=0.008) after 10.7years.

CONCLUSION

The appearance of ventricular arrhythmia during exercise testing showed temporal variation but was frequent in patients with relevant genetic mutation. Physical exercise capacity decreased over time in patients with ARVC in excess to the age-related deterioration and regardless of medication.

Use of exercise tests in primary care: importance for referral decisions and possible bias in the decision process; a prospective observational study

Background

The utility of clinical exercise tests depends on their support of treatment decisions. We sought to assess the utility of exercise tests for the selection of primary-care patients for referral to cardiologic care, and to determine whether referral decisions were biased by gender or socioeconomic status. We also evaluated referral rates and cardiovascular events in patients with positive exercise tests.

Methods

We designed a prospective observational study of 438 men and 427 women from 28 Swedish primary-care clinics who were examined with exercise testing for suspected coronary disease. All participants were followed-up with respect to cardiologist referrals and cardiovascular events (hospitalisation for unstable angina, myocardial infarction, and cardiovascular death) within six months and revascularisation within 250 days. Variables associated with referral were identified by multivariable logistic regression. Socioeconomic status was determined by educational level and employment.

Results

Positive/inconclusive exercise tests and exertional chest pain predicted referral in men and women. Of 865 participants, patients with positive, inconclusive, or negative exercise tests were referred to cardiologists in 67.3%, 26.1%, and 3.5% of cases, respectively. Overall, there was no significant difference in referral rates related to gender or socioeconomic level. Self-employed women were referred more frequently compared to other women (odds ratio (OR) 3.62, 95% confidence interval (CI) 1.19-10.99). Among non-manual employees, women were referred to cardiologic examination less frequently than men (OR 0.40, 95% CI 0.16-1.00; p = 0.049; ORs adjusted for age, exertional chest pain, and exercise test result). In patients with positive exercise tests, the referral rate decreased continuously with age (OR 0.48, 95% CI 0.23-0.97; adjusted for cardiovascular co-morbidity). Cardiovascular events occurred in 22.2% (4/18) of non-referred patients with positive exercise tests; 56% (10/18) of these patients were not considered for cardiologic care, with continuity problems in primary care as one possible contributing cause.

Conclusions

Exercise tests are important for selecting patients for referral to cardiologic care. Interactions related to gender and socioeconomic status affected referral rates. In patients with positive exercise tests, referral rates decreased with age. An increased awareness of possible bias regarding age, gender, and socioeconomic status, which may influence medical decisions, is therefore necessary.

Electronic supplementary material

The online version of this article (doi:10.1186/s12875-014-0182-9) contains supplementary material, which is available to authorized users.

Criterion validation of two submaximal aerobic fitness tests, the self-monitoring Fox-walk test and the Åstrand cycle test in people with rheumatoid arthritis

Background

Aerobic capacity tests are important to evaluate exercise programs and to encourage individuals to have a physically active lifestyle. Submaximal tests, if proven valid and reliable could be used for estimation of maximal oxygen uptake (VO_2max). The purpose of the study was to examine the criterion-validity of the submaximal self-monitoring Fox-walk test and the submaximal Åstrand cycle test against a maximal cycle test in people with rheumatoid arthritis (RA). A secondary aim was to study the influence of different formulas for age predicted maximal heart rate when estimating VO_2max by the Åstrand test.

Methods

Twenty seven subjects (81% female), mean (SD) age 62 (8.1) years, diagnosed with RA since 17.9 (11.7) years, participated in the study. They performed the Fox-walk test (775 meters), the Åstrand test and the maximal cycle test (measured VO_2max test). Pearson’s correlation coefficients were calculated to determine the direction and strength of the association between the tests, and paired t-tests were used to test potential differences between the tests. Bland and Altman methods were used to assess whether there was any systematic disagreement between the submaximal tests and the maximal test.

Results

The correlation between the estimated and measured VO_2max values were strong and ranged between r = 0.52 and r = 0.82 including the use of different formulas for age predicted maximal heart rate, when estimating VO_2max by the Åstrand test. VO_2max was overestimated by 30% by the Fox-walk test and underestimated by 10% by the Åstrand test corrected for age. When the different formulas for age predicted maximal heart rate were used, the results showed that two formulas better predicted maximal heart rate and consequently a more precise estimation of VO_2max.

Conclusions

Despite the fact that the Fox-walk test overestimated VO_2max substantially, the test is a promising method for self-monitoring VO_2max and further development of the test is encouraged. The Åstrand test should be considered as highly valid and feasible and the two newly developed formulas for predicting maximal heart rate according to age are preferable to use when estimating VO_2max by the Åstrand test.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2474-15-305) contains supplementary material, which is available to authorized users.

Diagnostic characteristics and prognoses of primary-care patients referred for clinical exercise testing: a prospective observational study

Background

Evaluation of angina symptoms in primary care often includes clinical exercise testing. We sought to identify clinical characteristics that predicted the outcome of exercise testing and to describe the occurrence of cardiovascular events during follow-up.

Methods

This study followed patients referred to exercise testing for suspected coronary disease by general practitioners in the County of Jämtland, Sweden (enrolment, 25 months from February 2010). Patient characteristics were registered by pre-test questionnaire. Exercise tests were performed with a bicycle ergometer, a 12-lead electrocardiogram, and validated scales for scoring angina symptoms. Exercise tests were classified as positive (ST-segment depression >1 mm and chest pain indicative of angina), non-conclusive (ST depression or chest pain), or negative. Odds ratios (ORs) for exercise-test outcome were calculated with a bivariate logistic model adjusted for age, sex, systolic blood pressure, and previous cardiovascular events. Cardiovascular events (unstable angina, myocardial infarctions, decisions on revascularization, cardiovascular death, and recurrent angina in primary care) were recorded within six months. A probability cut-off of 10% was used to detect cardiovascular events in relation to the predicted test outcome.

Results

We enrolled 865 patients (mean age 63.5 years, 50.6% men); 6.4% of patients had a positive test, 75.5% were negative, 16.4% were non-conclusive, and 1.7% were not assessable. Positive or non-conclusive test results were predicted by exertional chest pain (OR 2.46, 95% confidence interval (CI) 1.69-3.59), a pathologic ST-T segment on resting electrocardiogram (OR 2.29, 95% CI 1.44-3.63), angina according to the patient (OR 1.70, 95% CI 1.13-2.55), and medication for dyslipidaemia (OR 1.51, 95% CI 1.02-2.23). During follow-up, cardiovascular events occurred in 8% of all patients and 4% were referred to revascularization. Cardiovascular events occurred in 52.7%, 18.3%, and 2% of patients with positive, non-conclusive, or negative tests, respectively. The model predicted 67/69 patients with a cardiovascular event.

Conclusions

Clinical characteristics can be used to predict exercise test outcome. Primary care patients with a negative exercise test have a very low risk of cardiovascular events, within six months. A predictive model based on clinical characteristics can be used to refine the identification of low-risk patients.

Simulation of dilated heart failure with continuous flow circulatory support

Lumped parameter models have been employed for decades to simulate important hemodynamic couplings between a left ventricular assist device (LVAD) and the native circulation. However, these studies seldom consider the pathological descending limb of the Frank-Starling response of the overloaded ventricle. This study introduces a dilated heart failure model featuring a unimodal end systolic pressure-volume relationship (ESPVR) to address this critical shortcoming. The resulting hemodynamic response to mechanical circulatory support are illustrated through numerical simulations of a rotodynamic, continuous flow ventricular assist device (cfVAD) coupled to systemic and pulmonary circulations with baroreflex control. The model further incorporated septal interaction to capture the influence of left ventricular (LV) unloading on right ventricular function. Four heart failure conditions were simulated (LV and bi-ventricular failure with/without pulmonary hypertension) in addition to normal baseline. Several metrics of LV function, including cardiac output and stroke work, exhibited a unimodal response whereby initial unloading improved function, and further unloading depleted preload reserve thereby reducing ventricular output. The concept of extremal loading was introduced to reflect the loading condition in which the intrinsic LV stroke work is maximized. Simulation of bi-ventricular failure with pulmonary hypertension revealed inadequacy of LV support alone. These simulations motivate the implementation of an extremum tracking feedback controller to potentially optimize ventricular recovery.

Exercise training in chronic kidney disease patients

Chronic kidney disease (CKD) is a major public health problem that affects an estimated 1.7 million Australians. Patients with CKD commonly progress to end-stage kidney disease (ESKD) requiring dialysis and/or kidney transplantation. They are at high risk of cardiovascular disease and many die from this prior to reaching ESKD. Few therapies are available to slow CKD progression and reduce cardiovascular morbidity and mortality. The benefit of exercise training has been well demonstrated in a range of disease conditions including ESKD and was recently highlighted by a systematic review in haemodialysis patients and a recent Cochrane review of all stages of CKD. However, the effects of exercise training in patients with CKD have not been extensively investigated. Our systematic search of the literature found only ten clinical trials in this area. The aim of this review is to review these studies, and to discuss the findings, safety considerations and suggest future areas of research. Overall, the majority of the studies are small, non-randomized, non-controlled trials. They have found that exercise training can increase exercise capacity, improve muscle strength and function, decrease blood pressure, and improve inflammation and oxidative stress biomarkers. The effects of exercise training on kidney function, cardiovascular disease and quality of life are unknown. Studies are needed to answer these questions and develop evidence-based exercise training guidelines for individuals with CKD.

Adrenergic and cardiac dysfunction in primary hyperparathyroidism

OBJECTIVE

Primary hyperparathyroidism (PHPT) is associated with cardiovascular morbidity and premature death, but the underlying mechanisms are incompletely understood. The aim of this study was to investigate whether adrenergic dysfunction may be a contributing factor.

PATIENTS AND METHODS

Forty-nine patients with mild PHPT (serum calcium 2·7 ± 0·1 mM) and 48 control subjects, matched for age and sex, were examined; patients within 1 month before parathyroidectomy (PTX) and 6 months postoperatively; control subjects at inclusion. Heart rate variability (HRV) was analysed in 24-h electrocardiograms, and plasma concentrations of epinephrine and norepinephrine were measured at rest and immediately after standardized physical tests.

RESULTS

At baseline, the patients showed, compared to the controls, reduced stress-related increase of circulating epinephrine (P < 0·05) and norepinephrine (P < 0·05). No significant change was observed 6 months after PTX. At baseline, there were no significant differences between patients and controls in HRV or heart rate, but 6 months after curative PTX, the patients showed significantly reduced HRV in both frequency and time domain, and their maximum and average heart rate had decreased (P = 0·011 and P = 0·018, respectively). The patients with the highest preoperative levels of circulating parathyroid hormone showed the greatest changes in heart rate and HRV postoperatively.

CONCLUSIONS

This study demonstrates a previously unknown impairment of catecholamine response to physical stress in PHPT along with changes of HRV, also indicating adrenergic dysfunction. These factors should be considered in the ongoing controversy regarding the management of patients with mild 'asymptomatic' PHPT.

Factors limiting physical working capacity in predialytic uraemic patients

The exercise capacity of 20 predialytic uraemic patients (mean age 43 +/- 12 years) was studied prospectively. Nine of these patients were examined twice in a longitudinal study. The maximal working capacity, measured by standardized exercise test on a bicycle ergometer, averaged 74 +/- 19% of the expected normal. Normal exercise ECG were registered in 16 out of 20 patients. Total hemoglobin/kg body weight (THb) was 67 +/- 16% of the expected normal and serum parathyroid hormone concentration (PTH) was 39 +/- 39 micrograms/l (normal range 0.5-1.5). Partial correlation showed a correlation between exercise capacity and PTH (p less than 0.05). In the longitudinal study the decrease in steady state exercise capacity was correlated to the decrease in THb (p less than 0.05), but not to the increase in PTH. In conclusion, patients with predialytic uraemia have a reduced maximal working capacity, due to several possible factors one of which is a reduced THb. Ischaemic heart disease seems to be of minor importance.

ECMO in ARDS: a long-term follow-up study regarding pulmonary morphology and function and health-related quality of life

BACKGROUND

A high survival rate can be achieved in patients with severe acute respiratory distress syndrome (ARDS) using extracorporeal membrane oxygenation (ECMO). The technique and the costs are, however, debated and follow-up studies in survivors are few. The aim of this study was to evaluate long-term pulmonary health after ECMO and severe ARDS.

METHODS

Twenty-one long-term survivors of severe ARDS and ECMO were studied in a follow-up program including high-resolution computed tomography (HRCT) of the lungs, extensive pulmonary function tests, pulmonary scintigraphy and the pulmonary disease-specific St George's Respiratory Questionnaire (SGRQ).

RESULTS

The majority of patients had residual lung parenchymal changes on HRCT suggestive of fibrosis, but the extension of morphologic abnormalities was limited and without the typical anterior localization presumed to indicate ventilator-associated lung injury. Pulmonary function tests revealed good restitution with mean values in the lower normal range, while T(1/2) for outwash of inhaled isotope was abnormal in all patients consistent with subclinical obstructivity. Most patients had reduced health-related quality of life (HRQoL), according to the SGRQ, but were stating less respiratory symptoms than conventionally treated ARDS patients in previous studies. The majority were integrated in normal work.

CONCLUSION

The majority of ECMO-treated ARDS patients have good physical and social functioning. However, lung parenchymal changes on HRCT suggestive of fibrosis and minor pulmonary function abnormalities remain common and can be detected more than 1 year after ECMO. Furthermore, most patients experience a reduction in HRQoL due to the pulmonary sequelae.

Response to changing plasma concentrations of isosorbide-bound NO2 during acute and sustained treatment with isosorbide dinitrate in patients with coronary artery disease

BACKGROUND

The mechanisms behind development of tolerance to nitrate effects during sustained, asymmetric isosorbide dinitrate (ISDN) therapy are not fully understood.

HYPOTHESIS

The study was undertaken to investigate the changes of the relationships between left ventricular (LV) function and plasma concentrations of ISDN and its vasoactive metabolites (2- and 5-ISMO) during acute and sustained, asymmetric ISDN therapy.

METHODS

Left ventricular function and plasma concentrations of ISDN, 2- and 5-isosorbide mononitrates (P-ISDN, P-2- and 5-ISMO) were measured at rest and at supine exercise before and for 4 h after peroral 30 mg ISDN in 15 patients with coronary artery disease, all with initial exercise pulmonary artery wedge pressure (PAWP) > 25 mmHg. Seven patients were untreated (acute group), while eight received 30 mg ISDN b.i.d. for 2 weeks before the invasive study. P-ISDN and the concentration of available isosorbide-bound nitrate (NO2) in plasma (P-ISDN.2 + P-2-ISMO + P-5-ISMO) (P-NO2) were used as measures of the nitric oxide (NO) offer to the tissues.

RESULTS

Throughout the study, after administration of medication, all plasma concentrations, in particular P-ISDN, were higher in the chronic than in the acute group. Peak P-ISDN was reached after 15 min in the chronic group and after 25 min in the acute group, while P-2- and 5-ISMO reached maximum only after 40 min in both groups. At rest, the full effect on PAWP was observed after 10 min in both groups, but at markedly higher levels of P-ISDN and P-NO2 in the chronic group. Afterward, no further changes in PAWP were observed. During exercise, 1 h after medication, PAWP and stroke index to PAWP ratio (SI/PAWP) were normal in both groups. Thereafter, at slowly declining P-NO2, PAWP rose and SI/PAWP declined toward the initial level in the chronic group, but remained unchanged in the acute group, in spite of higher P-NO2 and greater NO release in the former.

CONCLUSIONS

Patients receiving sustained, asymmetric 30 mg ISDN b.i.d. dosing had the same immediate beneficial effects on LV function during exercise after a morning dose as did untreated patients. However, in spite of higher P-NO2 and higher rate of NO release during sustained treatment, the effects deteriorated gradually 2 to 3 h after medication. The changes in metabolism and/or distribution of isosorbide-bound NO2 may possibly be part of the tolerance induced by long-term treatment, even with asymmetric dosing.

Effects of isosorbide dinitrate on electrocardiography, hemodynamics, and ventilation in patients with exercise-induced elevation of pulmonary artery wedge pressure

BACKGROUND

The mechanisms underlying exertional hyperpnea in patients with coronary artery disease and transient left ventricular dysfunction are still not fully understood.

HYPOTHESIS

The study was undertaken to investigate whether the ventilatory response to exercise reflects the effects of acute medical treatment of exercise-induced left ventricular dysfunction, and to evaluate mechanisms relevant to excessive exertional ventilation.

METHODS

In 11 male patients, aged 65.2 +/- 6.0 years, all with pulmonary artery wedge pressure (PAWP) > 25 mmHg and ST depression > 2 mm during moderate supine exercise, ventilation (V), oxygen uptake (VO2), hemodynamics, electrocardiogram (ECG), and arterial and mixed venous blood gases were examined during supine rest and exercise, before and at hourly intervals after peroral intake of 30 mg isosorbide dinitrate (ISDN). Six similar patients were examined with the same protocol without ISDN administration and comprised a control group.

RESULTS

Before administration of ISDN, exercise PAWP was 35.3 +/- 5.9 mmHg, ECG showed 2.77 +/- 1.06 mm ST depression, and V/VO2 was 31.8 +/- 4.8 l/l. One h after ISDN administration, exercise mean PAWP was 11.0 +/- 2.5 mmHg (p < 0.001), ST depression 0.59 +/- 0.8 mm (p < 0.001), whereas V/VO2 was unchanged, 30.1 +/- 5.3 l/l. Two h later, PAWP remained reduced and there were only minor ST depressions, while V/VO2 remained high. Exercise cardiac index (CI) and mixed venous oxygen tension (PvO2), initially 4.7 +/- 0.67 l/min/m2 and 3.54 +/- 0.35 kPa, respectively, remained at the same low level throughout the study. In the six nontreated patients, there were no significant changes in ST depression, exercise PAWP, or exertional ventilation.

CONCLUSION

Isosorbide dinitrate treatment markedly improved exercise-induced left heart dysfunction, whereas excessive ventilatory response was unaffected, even after 3 h. Thus, measurements of the exercise hyperpnea did not properly reflect effective reduction of myocardial ischemia.

Impact of impaired aerobic capacity on liver transplant candidates

BACKGROUND

Oxygen consumption at peak exercise (peak VO2) is the most accurate index of aerobic capacity (AC), which reflects the physical condition of an individual and is currently considered the gold standard for cardiorespiratory fitness. Evaluation of peak VO2 to identify high-risk candidates for liver transplantation (LT) may represent an interesting approach. The aims of this study were (a) to describe AC and identify factors independently associated with peak VO2; (b) to analyze the prognostic value of peak VO2 in patients referred for preliminary evaluation of LT; and (c) to provide preliminary data on the influence of peak VO2 on length of hospitalization and the need for oxygen support after LT.

RESULTS

Peak VO2 was determined in patients referred for preliminary evaluation for LT. One hundred thirty-five candidates were included. More than half had severe alterations in peak VO2. Age, gender, model-for-end-stage liver disease (MELD) score, tobacco use, and hemoglobin were independently associated with peak VO2. Candidates with severe alterations in peak VO2 had a lower 1-year survival than others. Model-for-end-stage liver disease score and peak VO2 were independently associated with survival. In patients with a MELD above 17, those with severe alterations of peak VO2 AC had lower 1-year survival than the others. Among patients who underwent LT, those with severe impairment of peak VO2 showed a trend toward a higher mean length of hospitalization after LT and had significantly longer need for oxygen support.

CONCLUSIONS

Peak VO2 is severely impaired in candidates for LT and affects survival and post-LT course. Perioperative respiratory rehabilitation programs validated in lung and heart transplantation must be tested.

Nonfearful panic disorder in chest-pain patients: status after nine-year follow-up

BACKGROUND

Nonfearful panic disorder (NFPD) is a type of panic disorder (PD) that was first described in 1987 among cardiology patients who had panic attacks without the experience of fear. NFPD may be considered a subtype of PD with significant impact on the long-term outcome of chest pain patients.

OBJECTIVE

The authors sought to explore the long-term outcome of NFPD and PD.

METHOD

Authors studied 199 patients previously referred to cardiology outpatient investigation because of chest pain. Assessments comprising cardiological and psychiatric (SCID-I) examinations were conducted after 9 years.

RESULTS

At follow-up, no patients suffered from NFPD, but 18% had panic disorder with fear (PD). There were no significant differences between the baseline NFPD (N=11) and PD (N=44) patients regarding psychiatric comorbidity, chest pain, healthcare utilization, and health-related quality of life at follow-up.

CONCLUSION

NFPD can have a significant impact on the long-term outcome of chest pain patients even though they may not seek psychiatric treatment.

Maximum oxygen uptake and body composition of healthy Hong Kong Chinese adult men and women aged 20 - 64 years

The aims of the present study were to assess the maximal oxygen uptake and body composition of adult Chinese men and women, and to determine how these variables relate to age. The cross-sectional sample consisted of 196 men and 221 women aged 20 - 64 years. Maximal oxygen uptake (VO2max) was determined by indirect calorimetry during a maximal exercise test on an electrically braked cycle ergometer. The correlations between VO2max and fat mass were -0.52 in men and -0.58 in women. Linear regression defined the cross-sectional age-related decline in VO2max as 0.35 ml kg(-1) min(-1) year(-1) in men and 0.30 ml kg(-1) min(-1) year(-1) in women. Multiple regression analysis showed that more than 50% of this cross-sectional decline in VO2max was due to fat mass, lean mass, and age. Adding fat mass and lean mass to the multiple regression models reduced the age regression mass from 0.35 to 0.24 ml kg(-1) min(-1) year(-1) in men and from 0.30 to 0.15 ml kg(-1) min(-1) year(-1) in women. We conclude that age, fat mass, and lean mass are independent determinants of maximal oxygen uptake in Chinese adults.

A long-term follow-up study of chest pain patients: effect of panic disorder on mortality, morbidity, and quality of life

AIMS

The aim was to assess the association between panic disorder (PD) and the long-term outcome of chest pain patients with or without coronary artery disease (CAD).

METHODS

Patients (n = 199) consecutively referred to a cardiology outpatient clinic because of chest pain were reassessed after 9 years. At the initial examination 16% suffered from CAD and 38% from PD. Data were collected on mortality, cardiac events, cardiac risk factors, chest pain, anxiety and depression (SCL-90-R), and health-related quality of life (SF-36).

RESULTS

The death rate in the study population was not significantly different from that in the general population and no significant associations were found between PD at baseline and mortality and cardiac morbidity at follow-up. PD was associated with significantly higher follow-up scores of chest pain intensity (p = 0.025), depression (p = 0.005), anxiety (p = 0.039), and poorer health-related quality of life: physical functioning (p = 0.004), role physical (p = 0.001), body pain (p = 0.007), and general health (p < 0.001).

CONCLUSIONS

PD has a negative long-term effect on psychological and physical well-being of chest pain patients which emphasizes the necessity of identifying PD patients and offering them adequate treatment.

Exercise testing and myocardial perfusion scintigraphy in primary care patients with chest pain of new onset

OBJECTIVE

To analyse the outcome of exercise testing and myocardial perfusion scintigraphy (MPS) in primary care patients with chest pain of new onset.

DESIGN

Prospective, observational. Patients aged 20-79 years, consulting due to chest pain of new onset, were enrolled consecutively.

SETTING

Three primary care health centres in south-eastern Sweden.

PATIENTS

191 patients where the possibility of stable ischaemic heart disease (IHD) could not be excluded by clinical examination alone.

MAIN OUTCOME MEASURES

Exercise test results, when equivocal completed by MPS.

RESULTS

Exercise testing revealed IHD in 14 (7%) and no IHD in 134 (70%) of the cases. In 43 (23%) the exercise test results were equivocal. Thirty-nine of these patients underwent MPS, which showed IHD in 19 and no IHD in 20 cases. Among previously diagnosed cardiovascular disease and risk factors only atrial fibrillation in the male group showed a significant correlation to the outcome IHD.

CONCLUSION

Exercise testing and MPS are both useful when investigating chest pain patients in primary care.

Biologically relevant sex differences for fitness-related parameters in active octogenarians

The number of elderly people is growing in western populations, but only few maximal performance data exist for people >75 years, in particular for European octogenarians. This study was performed to characterize maximal performance of 55 independently living subjects (32 women, 81.1 +/- 3.4 years; 23 men, 81.7 +/- 2.9 years) with a focus on sex differences. Maximal performance was determined in a ramp test to exhaustion on a bicycle ergometer with ergospirometry, electrocardiogram and blood lactate measurements. Maximal isometric extension strength of the legs (MEL) was measured on a force platform in a seated position. Body composition was quantified by X-ray absorptiometry. In >25% of the subjects, serious cardiac abnormalities were detected during the ramp test with men more frequently being affected than women. Maximal oxygen consumption and power output were 18.2 +/- 3.2 versus 25.9 +/- 5.9 ml min(-1) kg(-1) and 66 +/- 12 versus 138 +/- 40 W for women versus men, with a significant sex difference for both parameters. Men outperformed women for MEL with 19.0 +/- 3.8 versus 13.6 +/- 3.3 N kg(-1). Concomitantly, we found a higher proportion of whole body fat in women (32.1 +/- 6.2%) compared to men (20.5 +/- 4.4%). Our study extends previously available maximal performance data for endurance and strength to independently living European octogenarians. As all sex-related differences were still apparent after normalization to lean body mass, it is concluded that it is essential to differentiate between female and male subjects when considering maximal performance parameters in the oldest segment of our population.

A 1-year follow-up study of chest-pain patients with and without panic disorder

OBJECTIVE

The aims of this study were to (a) study the persistence of panic disorder (PD); (b) investigate the association between PD at baseline and outcome [chest pain, psychiatric morbidity, health care utilization, suicidal thoughts, work impairment and health-related quality of life (HRQOL)]; (c) study the course of pain, distress, symptom attribution and HRQOL; and (d) describe treatment and perceived treatment needs of patients with PD.

METHOD

A 1-year follow-up study of 199 chest-pain patients referred to cardiac outpatient investigation was completed. Assessments included Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (SCID), Short-Form McGill Pain Questionnaire, Symptom Checklist-90-Revised, the Illness Attitude Scales, the 36-item Short-Form Health Survey and a chest-pain questionnaire.

RESULTS

At follow-up, 57 of the 153 patients reassessed with the SCID suffered from PD. Forty-three of the 55 patients (78%) who were diagnosed with PD at baseline still suffered from PD at follow-up. PD at baseline was associated with pain persistence, psychiatric morbidity (current major depression, pain disorder and simple phobia), significantly higher scores on psychological distress, hypochondriasis, negative outcome expectation, lower scores on seven of the eight dimensions of HRQOL and more general practitioner consultations. Only 6% of the patients with PD used effective treatment, and 3% reported a treatment need at follow-up.

CONCLUSION

Despite chronic distress and impairment, we found significant undertreatment of PD, which needs to be addressed in future studies.

Working Capacity and Well-Being after Radical Cystectomy with Continent Cutaneous Diversion

OBJECTIVES

The primary aim was to compare the working capacity in patients with continent urinary diversion with a control group. Secondary aims were to assess the changes in electrolyte and acid-base homeostasis and the functional status during strenuous physical activity, and finally, the well-being in the two groups.

METHODS

Eleven patients who had undergone radical cystectomy and continent cutaneous diversion using an ileocolonic segment participated. The control group consisted of 12 men, matched for age and activity level. Working capacity was assessed by ergospirometry on an exercise bicycle. Venous blood samples were taken before the test, when the expiratory exchange ratio (RER) was about 1.0 and immediately after completion of the test. SF-36 was used to evaluate the subject's functional status and well-being.

RESULTS

The median working capacity in the patient group was 155 (85-190) W and 155 (125-215) W in the control group (n.s.) corresponding to 72 (43-97) % and 80 (59-97) % respectively of predicted values. Peak oxygen uptake was somewhat low in both groups when compared to P-O Astrands norms. Blood tests revealed that patients developed a slight metabolic hyperchloremic acidosis, not seen in the control group. There were no differences between the groups as assessed with SF-36.

CONCLUSION

Patients with a continent urinary diversion have a working capacity equal to a control group despite a slight metabolic hyperchloremic acidosis. Quality of life was similar in the two groups and corresponded well with the norms for the general Swedish population aged 65 to 74.

A comparison between three rating scales for perceived exertion and two different work tests

In the present article, three scales developed by Borg are compared on bicycle ergometer work. In the first study, comparing the Borg Ratings of Perceived Exertion (RPE) and Category scales with Ratio properties (CR10) scales, 40 healthy subjects (12 men and eight women for each scale) with a mean age of about 30 years (SD approximately 6) participated. A work-test protocol with step-wise increase of work loads every minute was used (20 W increase for men and 15 W for women). Ratings and heart rates (HRs) were recorded every minute and blood lactates every third minute. Data obtained with the RPE scale were described with linear regressions, with individual correlations of about 0.98. Data obtained with the CR10 scale could also be described by linear regressions, but when described by power functions gave exponents of about 1.2 (SD approximately 0.4) (with one additional constant included in the power function). This was significantly lower than the exponent of between 1.5 and 1.9 that has previously been observed. Mean individual correlations were 0.98. Blood lactate concentration grew with monotonously increasing functions that could be described by power functions with a mean exponent of about 2.6 (SD approximately 0.6) (with two additional constants included in the power functions). In the second study, where also the more recently developed Borg CR100 scale (centiMax) was included, 24 healthy subjects (12 men and 12 women) with a mean age of about 29 years (SD approximately 3) participated in a work test with a step-wise increase of work loads (25 W) every third minute. Ratings and HRs were recorded. RPE values were described by linear regressions with individual correlations of about 0.97. Data from the two CR scales were described by power functions with mean exponents of about 1.4 (SD approximately 0.5) (with a-values in the power functions). Mean individual correlations were about 0.98. In both studies, a tendency for a deviation from linearity between RPE values and HRs was observed. The obtained deviations from what has previously been obtained for work of longer duration (4-6 min) points to a need for standardization of work-test protocols and to the advantage of using CR scales.

Improved capacity of exercise electrocardiography in the detection of coronary artery disease by focusing on diagnostic variables during the early recovery phase

The temporal distribution of the diagnostic information for the detection of coronary artery disease (CAD) provided by exercise-induced electrocardiographic (ECG) ST-segment amplitude changes in different ECG leads in men and women has not been fully investigated. To shed further light in this area, 1877 electrocardiograms selected from 8322 patients undergoing a routine exercise test on a bicycle ergometer were evaluated. ST-segment amplitude and the difference between heart rate-matched recovery and exercise ST-segment amplitudes (ST/HR difference) were measured. Coronary artery disease was verified angiographically in 669 patients and excluded in 1208 patients by angiography (n = 119), by myocardial scintigraphy (n = 250), or on clinical grounds (n = 839). The diagnostic performance of the 2 ECG methods used was assessed by constructing receiver operating characteristic curves for each sampling point every 12 seconds during 10 minutes of recovery as well as the last 4 minutes of exercise for the ST-segment amplitude. ST-segment amplitude performed better after exercise than during exercise and best within the first 2 minutes of recovery. Its diagnostic ability did not differ from the ST-amplitude hysteresis assessed by the difference between recovery ST-segment amplitude and exercise ST-segment amplitude at matched heart rate. Both methods performed better in men and the diagnostic information appeared mainly in leads I, -aVR, II, V 4 , V 5 , and V 6 . The best discrimination of CAD is provided by analysis of ST-segment amplitude changes in 6 specific leads early during the recovery phase. This information should be targeted by exercise ECG diagnostic methods.

Psychological factors, pain attribution and medical morbidity in chest-pain patients with and without coronary artery disease

This cross-sectional psychiatric and cardiological study compared patients with and without coronary artery disease (CAD) with respect to psychiatric morbidity, psychological factors, pain characteristics, medical morbidity and the prevalence of coronary risk factors. The 199 participants had been referred to cardiological outpatient clinics for the investigation of chest pain and had no history of heart disease. Current panic disorder occurred significantly more often in non-CAD patients (41% vs. 22%). No significant differences were found for other psychiatric disorders and psychological variables. Non-CAD patients reported significantly longer histories of pain and a higher prevalence of atypical chest pain. In other respects, there were surprisingly few differences between the groups. High morbidity of both psychiatric disease (pain disorder, 19%; any current psychiatric disorder, 72%) and somatic conditions (musculoskeletal disease, 33%; dyspepsia, 23%) was found with no significant differences between the groups. In these patients, multifactorial complaints may explain chest pain in both patient groups. The physicians should attend to psychiatric disorders in non-CAD as well as in CAD patients.

Normal annual increase of bone mineral density during two years in patients with cystic fibrosis

OBJECTIVES

To determine prospectively for 2 years the change in bone mineral density (BMD) in patients with cystic fibrosis (CF) and to correlate clinical data and routine biochemical parameters of bone metabolism and infection with BMD.

METHODS

Fifty-four patients with CF, aged 6 to 33 years, were included. BMD was measured using dual-energy x-ray absorptiometry in lumbar spine (LS) and femoral neck (FN). Anthropometric data and biochemical markers of bone metabolism and infection were measured. The number of intravenous antibiotic courses per year (ivAC) and pulmonary function were assessed.

RESULTS

The patients had normal anthropometric data and normal growth, but 36% and 33% of the patients had BMD z score <-1 standard deviation in LS and in FN, respectively. Nevertheless, BMD increased at a normal rate during the 2 years and was correlated to weight and lung function. Intact parathyroid hormone was positively correlated with the increase of BMD in both LS and FN during childhood. Blood sedimentation rate, serum concentration of immunoglobulin G, and ivAC were negatively correlated with BMD in FN. Patients with 2 more severe CF transmembrane conductance regulator mutations had significantly lower BMD in FN than other genetic combinations.

CONCLUSION

The study suggests that low BMD in CF is multifactorial and depends on infection and nutritional parameters. Differences in BMD of LS and FN suggested higher susceptibility to infection in FN at all ages. Longitudinal studies starting early before bacterial colonization would be valuable to determine the relative role of infection in the development of BMD in CF.

Working capacity and resting energy expenditure after ileal pouch-anal anastomosis

BACKGROUND

The aim was to evaluate the working capacity and resting energy expenditure in patients who had undergone restorative proctocolectomy.

METHODS

Of 72 patients operated on between April 1990 to September 1998, 51 were eligible and 38 participated in the study. Resting energy was assessed by indirect calorimetry, and working capacity by ergospirometry on an exercise bicycle.

RESULTS

The median functional score was 2 (range 0-7). Oxygen uptake during rest was reduced for men compared with predicted values. The corresponding values for women were in keeping with predicted values. The median working capacity was 96 (range 59-102) per cent for women and 91 (range 51-113) per cent for men, compared with reference values of maximum workload based on age, height and sex. There was no correlation between functional score and any other variable measured.

CONCLUSION

Patients who have undergone restorative proctocolectomy for ulcerative colitis have normal resting energy expenditure and working capacity.

Eighteen years of fair glycemic control preserves cardiac autonomic function in type 1 diabetes

OBJECTIVE

To study the association between 18 years of mean HbA(1c) and cardiac autonomic function in type 1 diabetic patients having used intensive insulin treatment.

RESEARCH DESIGN AND METHODS

A total of 39 patients with type 1 diabetes were followed during 18 years, and HbA(1c) was measured yearly. At 18 years follow-up heart rate variability (HRV) measurements were used to assess cardiac autonomic function. Standard cardiac autonomic tests during normal breathing, deep breathing, the Valsalva maneuver, and the tilt test were performed. Maximal heart rate increase during exercise electrocardiogram and minimal heart rate during sleep were also used to describe cardiac autonomic function.

RESULTS

We present the results for patients with mean HbA(1c) <8.4% (two lowest HbA(1c) tertiles) compared with those with HbA(1c) > or = 8.4% (highest HbA(1c) tertile). All of the cardiac autonomic tests were significantly different in the high- and the low-HbA(1c) groups, and the most favorable scores for all tests were seen in the low-HbA(1c) group. In the low-HbA(1c) group, the HRV was 40% during deep breathing, and in the high-HbA(1c) group, the HRV was 19.9% (P = 0.005). Minimal heart rate at night was significantly lower in the low-HbA(1c) groups than in the high-HbA(1c) group (P = 0.039). With maximal exercise, the increase in heart rate was significantly higher in the low-HbA(1c) group compared with the high-HbA(1c) group (P = 0.001).

CONCLUSIONS

Mean HbA(1c) during 18 years was associated with cardiac autonomic function. Cardiac autonomic function was preserved with HbA(1c) <8.4%, whereas cardiac autonomic dysfunction was impaired in the group with HbA(1c) > or = 8.4%.

Nonfearful Panic Disorder in Chest Pain Patients

The prevalence of non-fearful panic disorder (panic attacks without the experience of fear) was estimated in 199 patients consecutively referred to outpatient cardiac investigation for chest pain. Fifty-nine patients met the criteria for panic disorder, and 17 patients fulfilled the criteria for non-fearful panic disorder. The patients with non-fearful panic disorder had lower scores on self-reported panic symptoms and lower frequencies of agoraphobia and comorbid axis I disorders than the patients with panic disorder and had a higher prevalence of somatic disorders than the patients without panic disorder. The patients with non-fearful panic disorder did not differ significantly from the patients with panic disorder in health-related quality of life.

A refined technique for determining the respiratory gas exchange responses to anaerobic metabolism during progressive exercise - repeatability in a group of healthy men

The respiratory gas exchange and ventilation during an incremental cycle exercise test were analysed in a group of 19 healthy, moderately fit men. Different computer algorithms were used to estimate the VO2 values where: (i) the rate of VCO(2) increase just exceeds the rate of VO(2) increase (DX, derivative crossing), (ii) VCO(2)/VO(2) = 1.00 (PX, point of crossing) and (iii) ventilation (VE) increases disproportionately in relation to VCO(2) (PQ, point of VCO(2) equivalent rise). The DX and PQ measurements were analysed using a new approach employing polynomial regression and the value of PX was determined following low-pass filtration of raw data. The repeatability of the measurements was evaluated with a 5-6 week interval between the tests. The correlations between tests were 0.75 at DX, 0.85 at PX and 0.62 at PQ. The mean differences between the repeated tests were not statistically significant. The repeatability of VO2, in absolute values expressed as +/-2 SD of the differences between the tests, had values of 5.0, 6.1 and 9.5 ml min(-1) kg(-1) for DX, PX and PQ, respectively. The mean value of VO(2) for each measurement point expressed as a percentage of VO(2 max) was 54% at DX, 68% at PX and 70% at PQ. The most common sequence of the measured values was DX < PX < PQ, but the sequence DX < PQ < PX was also observed. It is concluded that the gas exchange responses to developing anaerobic metabolism during progressive exercise can be characterized by a series of thresholds. However, the considerable variation in absolute values in the two testing occasions requires further attention.

Muscle metabolism in fibromyalgia studied by P-31 magnetic resonance spectroscopy during aerobic and anaerobic exercise

OBJECTIVE

To investigate mechanisms underlying the reduced work capacity of fibromyalgia (FM) patients were compared to healthy controls at specified workloads, using P-31 magnetic resonance spectroscopy (MRS).

METHODS

The forearm flexor muscle group was examined with MRS at rest, at sub maximal and at maximal controlled dynamic work as well as at maximal isometric contraction. Aerobic fitness was determined by bicycle ergonometry.

RESULTS

Metabolite concentrations and muscle pH were similar for patients and controls at lower workloads. At maximal dynamic and static contractions the concentration of inorganic phosphate was lower and at static contractions the pH decrease was smaller in patients. The performed work by patients was only 50% compared to controls and the patients experienced more pain. Maximal oxygen uptake was lower in the fibromyalgia group. Expired gas-analysis in this group showed ventilatory equivalents at similar relative levels of maximal work capacity.

CONCLUSION

Fibromyalgia patients seem to utilise less of the energy rich phosphorous metabolites at maximal work despite pH reduction. They seemed to be less aerobic fitted and reached the anaerobic threshold earlier than the controls.

Reference values for the physical work capacity on a bicycle ergometer for men -- a comparison with a previous study on women

The aim of the study was to collect new reference values for the clinical ramp exercise test on bicycle, because in our experience, the commonly used values were too low. A group of healthy men (n = 81, 20-80 years) was randomly selected from the local municipal register to achieve an even distribution in age. Data were compared with those obtained in a similar, previous study on women (n = 87). The subjects were encouraged to cycle until exhaustion (19 on the Borg scale) when maximal load, heart rate and systolic blood pressure were recorded. Maximal load (W(max)) was related to age (years) and height (m) using a non-linear function: W(max) = (244.6 x height - 92.1)/[1 + exp[0.038 x (age - 77.3)]]. Maximal heart rate (HRmax) was described by a similar function: HRmax = 203.7/[1 + exp[0.033 x (age - 104.3)]]. The maximal systolic blood pressure (BP(max)) was described by a linear function based on age: BP(max) = 0.505 x age + 192. Similar functions for the women are also given. It is suggested that 80-120% of the predicted maximal load can be taken as a reference interval for both men and women and similarly 90-110% of the maximal heart rate. In this study, 84% of the men reached a maximal load within the reference interval and 93% maximal heart rate within the reference interval. The reported values for maximal load were 104-132% of the reference values published by others.

Exercise blood pressure in congenital heart disease and in patients after coarctation repair

Cardiologists have often described aortic coarctation as "simple" rather than "complex" congenital heart disease; nothing could be further from the truth.

Depression as a predictor of return to work in patients with coronary artery disease

The importance of depression in coronary artery disease (CAD) outcomes is being increasingly recognized. The aim of this study was to investigate the power of depression as a predictor of return to work, both at full time and at reduced working hours, within 12 months of participation in a behaviorally oriented rehabilitation program in Sweden. The sample comprised 198 employed patients who had recently experienced an acute myocardial infarction (AMI, n=85), or had been treated with coronary by-pass surgery (CABG, n=73) or coronary angioplasty (PTCA, n=40). The results showed that clinical depression before intervention (>or=16 as measured by the Beck Depression Inventory) exerted a great influence on work resumption both at full-time (odds ratio 9.43, CI=3.15-28.21) and at reduced working-hours (odds ratio 5.44, CI=1.60-18.53), while mild depression (BDI 10-15) influenced only work resumption at full-time (odds ratio 2.89, CI=1.08-7.70). Education and, at full-time hours, age also predicted work resumption. This highlights the importance of depressive symptoms in relation to return to work after a CAD event. More research is needed in order to elaborate the degree to which treatment of depression enhances work resumption rates.

Silent coronary atheromatosis in type 1 diabetic patients and its relation to long-term glycemic control

Type 1 diabetic patients have a pronounced risk of premature coronary artery disease and death. We sought to evaluate the prevalence of silent coronary atheromatosis and to evaluate the relation between coronary atheromatosis and glycemic control. Coronary atheromatosis was evaluated in type 1 diabetic patients with no symptoms of coronary artery disease by exercise electrocardiogram (ECG) in 39 patients and quantitative coronary angiography and by intravascular ultrasound (IVUS) examinations in 29 patients. The findings from the IVUS examinations were related to mean HbA(1c) collected prospectively over 18 years. Abnormal exercise ECGs were found in 15% of patients, and angiographic diameter stenosis of >50% in one or more of the main coronary arteries was found in 34% of patients. All patients examined with intracoronary ultrasound had developed atherosclerotic plaques with an increased intimal thickness (>0.5 mm) in one or more of the coronary arteries. Coronary artery plaque formation, as judged by ultrasound, was significantly related to mean HbA(1c) during 18 years (P < 0.05) after adjustment for total cholesterol and age. This study demonstrates a high prevalence of silent coronary atheromatosis in type 1 diabetic patients with no symptoms of coronary heart disease. Long-term glycemic control was shown to be associated with coronary atheromatosis.

Repeatability of measurements of oxygen consumption, heart rate and Borg's scale in men during ergometer cycling

The coefficient of repeatability (COR), expressed as 2-SD of differences, was calculated between two measurements of oxygen consumption (V O2), heart rate (HR) and rating of perceived exertion (RPE) during ergometer cycling by men. The two sets of measurements were performed 5 to 6 weeks apart. Nineteen healthy men performed an incremental maximal exercise test on an ergometer cycle. The load started at 50 W and increased by 5 W 20 s-1 until exhaustion was reached. At 40% of the individual maximum load of the pretest, the load was kept constant for 4 min in order to reach steady state. Gas measurements were recorded continuously by computerized instrumentation. The HR was monitored with electrocardiography (ECG) and the perceived exertion was evaluated using Borg's scale. The COR of V O2 at sub-maximal load was 14% and at maximum load 11%. The values in absolute figures were 209 and 332 ml min-1. The corresponding COR of the HR was 16% at sub-maximum load and 6% at maximum load, and an evaluation of the perceived exertion yielded CORs in absolute values of 4.8 and 1.3, respectively. The COR for V O2, HR and ratings of perceived exertion when cycling on an ergometer cycle thus indicate a better agreement between the measurements at maximum load. The COR of the heart at sub-maximal loads must be kept in mind when using HR for estimation of V O2max. The reported findings should be considered when using tests on an ergometer cycle for evaluating exercise capacity.

Retained fibrinolytic response and no coagulation activation after acute physical exercise in middle-aged women with previous myocardial infarction

Sudden physical exertion is associated with an increased risk of acute myocardial infarction (MI) and sudden cardiac death. In addition, activation of the coagulation cascade and/or reduced fibrinolytic capacity after physical exercise has been reported in patients with cardiovascular disease. We investigated the haemostatic responses to an acute submaximal physical exercise in middle-aged women with a history of MI compared with healthy, age-matched controls. Resting plasma von Willebrand factor antigen (vWF Ag) and tissue plasminogen activator (tPA) antigen concentrations and plasminogen activator inhibitor-1 (PAI-1) activity were higher in the patients compared with control subjects. After 30 min of submaximal exercise on a bicycle ergometer, small, but still significant, increases in fibrinogen and vWF Ag concentrations were found in both groups. However, exercise did not induce thrombin generation and fibrin formation, as assessed by thrombin-antithrombin complex and fibrin D-dimer, in either group. Both tPA antigen concentration and activity increased and PAI-1 activity decreased significantly with exercise in both groups. Interestingly, the magnitude of changes in these latter variables did not differ between the groups (P=.99, P=.88 and P=.24, respectively). The present study demonstrates that some middle-aged women with previous MI have no signs of coagulation activation and retained fibrinolytic response after submaximal exercise. The clinical implication of these results might be that women with stable coronary heart disease can participate in rehabilitative exercise training without exhibiting a procoagulative state.

Value of exercise data for the interpretation of myocardial perfusion SPECT

BACKGROUND

Artificial neural networks have successfully been applied for automated interpretation of myocardial perfusion images. So far the networks have used data from the myocardial perfusion images only. The purpose of this study was to investigate whether the automated interpretation of myocardial perfusion images with the use of artificial neural networks was improved if clinical data were assessed in addition to the perfusion images.

METHODS AND RESULTS

A population of 229 patients who had undergone both rest-stress myocardial perfusion scintigraphy in conjunction with an exercise test and coronary angiography, with no more than 3 months elapsing between the 2 examinations, were studied. The networks were trained to detect coronary artery disease or myocardial ischemia with the use of 2 different gold standards. The first was based on coronary angiography, and the second was based on all data available (including perfusion scintigrams, coronary angiography, exercise test, resting electrocardiography, patient history, etc). The performance of the neural networks was quantified as areas under the receiver operating characteristic curves. The results showed that the neural networks trained with perfusion images performed better than those trained with exercise data (0.78 vs 0.55, P <.0001), with coronary angiography used as the gold standard. Furthermore, the networks did not improve when data from the exercise test were used as input in addition to the perfusion images (0.78 vs 0.77, P =.6).

CONCLUSIONS

The results show that the clinically important information in combined exercise test and myocardial scintigraphy could be found in the perfusion images. Exercise test information did not improve upon the accuracy of automated neural network interpretation of myocardial perfusion images in a receiver operator characteristic analysis of test accuracy.