Summary
Background
Cardiovascular events related to high-intensity sport practice are rare but dramatic. Coronary artery disease (CAD) is the leading cause of these events after the age of 35 years. The value of a maximal exercise test (ET) for detection of athletes at risk remains a matter of debate.
Aim
The aim of this prospective multicentre study was to clarify the medical value and cost-effectiveness of an ET in middle-aged white asymptomatic athletes who participate in high-intensity sport.
Methods
All athletes had a physical examination, assessment of cardiovascular risk factors, a resting electrocardiogram and an ET. In case of abnormal ET, complementary cardiovascular evaluation was performed, when requested, to detect potential cardiovascular disease.
Results
1361 asymptomatic athletes (mean age 50.4 ± 9.6 years; mean training 5.1 ± 3.2 h/week; 10.4% women) with a normal resting electrocardiogram and without cardiovascular disease were consecutively included. An abnormal ET was reported in 144 subjects (94% men); this was positively related to the subject’s age and cardiovascular risk level. Cardiac arrhythmias (48%) and CAD symptoms (33.3%) were mainly reported. Cardiovascular disease was confirmed in 24 cases (1.7% from the whole population; 16.7% from those with an abnormal ET) – mainly CAD ( n = 12) and arterial hypertension ( n = 8). Seventy athletes presented significant unexplained arrhythmias. The cost was approximately €8450 for every confirmed case of cardiovascular disease.
Conclusions
In this multicentre study in middle-aged athletes, a systematic ET was abnormal in 10.6% of cases. About 2% of subjects had cardiovascular disease, mainly arrhythmias and CAD. From these results, it seems that in a trained population aged >35 years, ET should be targeted at men with at least two cardiovascular risk factors, with acceptable cost-effectiveness.
Résumé
Contexte
Après 35 ans, les évènements cardiovasculaires (CV) graves liés à une pratique sportive intense sont rares et le plus souvent dus à une coronaropathie (CAD). Leur détection chez ces sportifs est primordiale et la place de l’épreuve d’effort (ET) est débattue.
Objectifs
Cette étude prospective et multicentrique a étudié les paramètres médicaux et économiques de l’ET chez des athlètes asymptomatiques d’âge moyen pratiquant un sport intense.
Méthodes
Tous les sportifs ont bénéficié d’un examen physique, d’une évaluation des facteurs de risque CV, d’un ECG repos et d’une ET. Un bilan CV complémentaire ciblé était réalisé en cas d’ET anormale.
Résultats
1361 sportifs asymptomatiques (50,4 ± 9,6 ans ; 5,1 ± 3,2 h/sem d’entraînement ; 10,4 % femmes), avec ECG de repos normal et sans maladie CV ont été inclus. 144 sportifs (94 % hommes) ont présenté une ET anormale (arythmies 48 %, symptômes de CAD 33,3 %), positivement corrélée avec leur âge et leur niveau de risque CV. Une pathologie a été confirmée par le bilan CV dans 24 cas (1,7 % de la population totale ; 16,7 % des ET anormales). Hypertension artérielle ( n = 8) et CAD ( n = 12) étaient les plus fréquentes. Des arythmies catécholergiques non expliquées ont été observées chez 70 sportifs. Le coût moyen du bilan pour chaque maladie confirmée a été de €8450.
Conclusions
Plus de 10 % des ET systématiques réalisées dans cette population étaient anormales. Une maladie CV a été confirmée dans 2 %. A partir de ces données, chez les sportifs masculins de plus de 35 ans une EE apparaît indiquée chez les hommes porteurs d’au moins 2 facteurs de risque CV.
Background
Physical activity is described as a “double-edged sword” . Several epidemiological studies have shown the cardiovascular benefits of regular and moderate sports activity . However, an increased risk of cardiovascular events and sudden death during intense exercise – particularly competitive sport – has also been reported . Classically, before the age of 35 years, the most common causes of sudden death are arrhythmogenic cardiac diseases . After 35 years of age, acute events are mainly the result of coronary artery disease (CAD), and primarily affect men . Two recent prospective French studies in the general population reported a daily incidence of 3 for sudden death and 4 for myocardial infarction .
From ethical, medical and legal points of view, the prevention of sport-related sudden death is justifiable . However, the necessary preparticipation evaluation (PPE) for high-intensity sport practice is a matter of debate, especially for athletes aged <35 years . After the age of 35 years, the main objective of the PPE concerns detection of CAD .
A maximal or symptom-limited exercise stress test (ET) is a classical non-invasive examination proposed for CAD detection in the PPE . However, the positive predictive value of an ET in asymptomatic people at low risk of CAD is relatively low . Current recommendations from Europe and the USA call for a sport preparticipation ET in asymptomatic athletes considered to have a “moderate CAD risk” evaluated using classical cardiovascular risk factors (CVRFs), who want to practice high-intensity exercise . Concerning the age of the subject, guidelines from the USA recommend the age of 45 years for men and 55 years for women, while the European guidelines recommend the age of 35 years for everyone . To our knowledge, only a few studies have evaluated the predictive value of an ET in asymptomatic healthy trained subjects, and none included a large sample of athletes aged >35 years . Thus, the aims of this study were to evaluate the added value and cost-effectiveness of a systematic ET performed for sport PPE in asymptomatic middle-aged trained men and women.
Methods
Population
This prospective multicentre ( n = 8) study involved middle-aged subjects (men aged >35 years; postmenopausal women) who had been training (>2 h per week) for at least 1 year, and who underwent a medical PPE for high-intensity (>6 METs) sport participation . To be included, subjects had to be asymptomatic, with a normal resting electrocardiogram and no known cardiac disease, including arterial hypertension. Subjects who wanted to start or resume sport practice were excluded. All subjects gave verbal informed consent to participate.
PPE
In each centre, one qualified cardiologist performed all PPEs. The PPE included family and personal history, a physical examination, a resting electrocardiogram (GE HealthCare, Fairfield, CT, USA; or Schiller, Baar, Switzerland) and an ET. Smoking habits, biological CVRFs, diabetes (plasma glucose ≥ 126 mg/dL) and hypercholesterolaemia (plasma total cholesterol 6.2 mmol/L [≥240 mg/dL]) were determined during the 3 months before the ET . The electrocardiogram was analysed using the criteria proposed recently .
ET protocol and interpretation criteria
All ETs were performed on an electrically braked bicycle ergometer (Ergoline, Bitz, Germany; or Tech Med, Paris, France) with the same triangular progressive protocol. The first step was 30 W for women and 50 W for men, with an increase of 30 W per 2 min. During the ET, an electrocardiogram was recorded continuously (CASE, GE HealthCare, Fairfield, CT, USA; or CS-200, Schiller, Baar, Switzerland) and manual blood pressure (BP) was measured every 2 min. The ET was stopped in case of subject exhaustion or the observation of cardiovascular abnormality. Thus, the ET was classified as abnormal in case of marked clinical symptoms (typical chest pain, syncope), abnormal BP evolution (systolic BP > 250 mmHg and/or diastolic BP > 110 mmHg or persistent BP decrease), cardiac arrhythmias, bundle branch block, atrioventricular block, significant cardiac arrhythmias or repolarization abnormality. Supraventricular arrhythmias were considered as significant in case of tachycardia (more than three successive ectopic beats), atrial fibrillation or atrial flutter. Ventricular arrhythmias were considered as significant in case of more than five non-successive monomorphic ventricular premature beats (VPBs), polymorphic VPBs, doublet of VPBs, non-sustained ventricular tachycardia (NSVT; at least three consecutive VPBs at a rate of >100 beats/min and a duration of ≤30 s) or sustained ventricular tachycardia (SVT; when >30 s) . Repolarization was classified as abnormal in case of horizontal or down-sloping ST-segment depression ≥1 mm at 60 ms after J point, associated with chest pain, or any isolated ST-segment depression >1 mm or inversion of T waves observed during exercise and/or recovery . The maximal workload and maximal heart rate (beats/min) were recorded for each ET.
Complementary examinations arising from an abnormal ET
For each abnormal ET, the cardiology team concerned analysed the patient’s medical file and, when requested, programmed complementary cardiovascular examinations, including resting and/or exercise echocardiography, myocardial stress scintigraphy, computed tomography scan of coronary arteries, stress cardiac magnetic resonance imaging, coronary angiography, 24-h ambulatory BP monitoring and 24-h electrocardiography (Holter). From the assessment of the complementary cardiovascular evaluation, a diagnosis was proposed, including no significant cardiovascular disease, isolated exercise cardiac arrhythmias, isolated exercise conduction abnormality, CAD, valvular disease or cardiomyopathy. All subjects who had an abnormal ET, as described above, were disqualified from intensive training and competitive sports until completion of the medical workup. The overall cost of the cardiovascular evaluation was calculated according to French medical rates.
Statistical analysis
Quantitative values are expressed as means ± standard deviations; Student’s t test was used, when adapted, for between-group comparisons. Qualitative values are expressed as numbers and/or percentages, when appropriate; the χ 2 test was used for between-group comparisons. The significance level was set at 0.05. Data were analysed using Statistica version 8.0 (Systat Software, Inc., Chicago, IL, USA).
Results
Population
From June 2013 to October 2014, 1361 consecutive white subjects (10.4% women) were enrolled in the study. All subjects trained regularly for a mean of 5.1 ± 3.2 h/week (5.2 ± 3.3 h/week for men and 4.7 ± 2.6 h/week for women; P = not significant). The characteristics of the population are detailed in Table 1 .
| Total | Men | Women | |
|---|---|---|---|
| ( n = 1361) | ( n = 1219; 89.6%) | ( n = 142; 10.4%) | |
| Age (years) | 50.4 ± 9.6 | 49.5 ± 9.5 | 57.4 ± 7.0 |
| Median [range] (years) | 49 [35–82] | 48 [35–82] | 57 [44–79] |
| Height (cm) | 174.5 ± 7.7 | 175.5 ± 6.9 | 166.2 ± 9.7 |
| Weight (kg) | 75.1 ± 11.2 | 76.3 ± 10.4 | 65.0 ± 13.1 |
| Body mass index (kg/m 2 ) | 24.6 ± 2.9 | 24.7 ± 2.8 | 23.4 ± 3.3 |
| Arterial hypertension | 0 (0) | 0 (0) | 0 (0) |
| Current smoker | 186 (13.6) | 168 (13.8) | 18 (12.7) |
| Hypercholesterolaemia | 214 (15.7) | 184 (15.1) | 30 (21.1) |
| Diabetes | 41 (3) | 39 (3.2) | 2 (1.4) |
| Familial history of CAD | 267 (19.6) | 234 (19.2) | 33 (23.2) |
The ET was classified as abnormal in 144 subjects (10.6%), 135 (94%) of whom were men. The frequency of abnormal ET increased with age (6.6% in age range 35–44 years [ n = 410], 7.8% in age range 45–54 years [ n = 512], 14.9% in age range 55–64 years [ n = 323], 22.7% in age range 65–74 years [ n = 101] and 40% in those aged ≥ 75 years [ n = 15]; P < 0.001) and with the number of CVRFs (9.8% for 1 CVRF, 10.7% for 2 CVRFs and 19% for ≥3 CVRFs; P < 0.001). Comparison between subjects with an abnormal ET and those with a normal ET showed no difference in the prevalence of smokers, diabetes and known hypercholesterolaemia. Subjects with a body mass index ≥ 30 kg/m 2 had no more abnormal ETs than those with a lower body mass index.
The abnormalities observed during the ET are summarized in Table 2 . Cardiac arrhythmias were the most frequent abnormality observed ( n = 70; 48%). Cardiac arrhythmias were associated with no other ET abnormality in nearly all cases ( n = 67). Ventricular arrhythmias were mainly monomorphic and non-repetitive (58%). NSVT was observed in four subjects, and no case of SVT was reported. Concerning supraventricular arrhythmias, atrial fibrillation was observed in five men with an age range of 53–72 years (1.6% of this age range). The frequency of arrhythmias increased with age (3.2% in age range 35–44 years, 4.1% in age range 45–54 years, 7.4% in age range 55–64 years, 14.8% in age range 65–74 years and 26.6% in those aged ≥75 years; P < 0.001). No significant relationship was observed between arrhythmias and number of CVRFs.
