[Exercise test in athletes]. / Epreuves d'effort chez les sportifs.

The particularities of exercise tests in athletes concern mainly the exertion protocols adapted to their increased physical capacities and the interpretation of ECG tracing which can sometimes be very special at rest and also misleading during exercise. In the great majority of cases, the test used is both cardiac and pulmonary, in order to assess the aerobic capacities, the maximal aerobic power, and the determination of ventilation thresholds (programming and follow-up of training...). More infrequently, the test is used to detect cardiovascular diseases, especially during a longitudinal follow-up of high-level athletes, or to exclude it in case of cardiovascular symptoms, atypical resting ECG or even in case of suspicion of disease (arrhythmia, cardiac chamber hypertrophy or dilation at echocardiography). In more aged sportsmen (athletes masters), exercise tests performed are usually required for screening coronary heart disease. In this case the test protocols should be more adapted for screening than for the assessment of sportive capacities.

[Unusual cause of myocardial infarction]. / Une cause rare d'infarctus du myocarde.

The authors report the case of a woman with an acute myocardial infarction in whom coronary angiography performed a few hours earlier was completely normal. Transoesophageal echocardiography showed two thrombi in the left atrial appendage confirming the thromboembolic mechanism of this infarct.

[Bi-ventricular synchronous pacing and heart failure]. / Resincronizzazione ventricolare e insufficenza cardiaca.

After initial trials of conventional DDD pacing in dilated cardiomyopathies, the concept of multisite stimulation was introduced in 1994. This new indication of heart failure treatment is based on the correction of myocardial contraction and relaxation asynchronies. European pilot studies including few patients were followed by two multicenters randomized trials (MUSTIC and MIRACLE) that confirmed a significant improvement of functional capacity, quality of life and hemodynamic status. Intraventricular delay and QRS duration shortening seems to be the best predictor of clinical success. Patients with more depressed functional and hemodynamic status seems to benefit most from this therapeutic approach. Two studies (CARE HF and COMPANION) are still conducted which will provide further insight into the effectiveness in terms of prognosis of cardiac resynchronisation therapy in this patient population.

[Exercise tolerance tests in athletes, then what?]. / Tests d'effort chez les sportifs, et ensuite?

Exercise tolerance tests in athletes are usually performed to evaluate aerobic exertion capacity and to plan training. They are based on simultaneous measurement of expired gases (determination of ventilation threshold and of VO2max). They can also be used to seek a possible cardiovascular anomaly, particularly in case of clinical symptoms or anomalies on auscultation; findings based on electrocardiography (rhythm, repolarisation, etc.) and on blood pressure readings, however, can lead to suspicion of an early anomaly and direct complementary investigation.

[Rehabilitation modalities as a function of the severity of heart insufficiency]. / Modalités de la réadaptation en fonction de la gravité de l'insuffisance cardiaque.

After a review of the different central and peripherical factors limiting exercise capacity in chronic heart failure, the authors report the mechanisms of these increment with exercise training. The different indications for clinical training techniques of segmental training on a specific bench are discussed; but it appears that both aerobic and repetitive weight programs seem to have short term favorable and complementary effects.

[Significance of exercise induced ST elevation in patient without a history of previous myocardial infarct]. / Signification d'une élévation du segment ST liée à l'effort chez des patients sans antécédent d'infarctus.

UNLABELLED: Between 1980 and 1995, we observed twenty-five patients (22 males, 3 females) at the mean age of 50.6 +/- 13 years, without previous myocardial infarction who presented exercise induced ST elevation on a bicycle stress test. METHODS: Significant ST elevation was defined as a > or = 1 mm change present in > or = 1 lead measured 0.08 sec after the J point and in 3 consecutive beats. All patients have undergone coronary angiography in the days following the exercise test. RESULTS: Most of patients (56%) presented a history of typical angina that was either purely exertional (8 pts) or also occurred at rest (6 pts). Others (36%) had non typical angina or no angina (8%); 78% of pts were smokers. Sixteen patients (group I) had ST elevation during exercise (exercise duration: 7.6 +/- 4 min; peak heart rate: 135.5 +/- 29 batt/min; ST = 3.5 +/- 1.5 mm) and nine (group II) during the recovery phase (exercise duration 16.3 +/- 1.6 min; p < 0.05; peak heart rate 168 +/- 22 batt/min; p < 0.05; ST: 5.8 +/- 3 mm; p < 0.05). In group I, 1 patient had no vessel disease, 12 had one vessel disease, 3 had multivessel disease with 6 cases of hypersevere coronary stenose (> 90%). In group II, 4 patients had normal coronary arteries, there was one vessel coronary artery disease in 4 patients and multivessel in one subject, without hypersevere coronary stenosis. Correlation between anatomic location of stenosis and electrocardiographic ST elevation was excellent, particularly in case of single vessel disease (100%). All patients underwent one or more new exercise tests after therapeutic intervention (surgery n = 3; angioplasty n = 7; medical treatment n = 15), only 2 patients had persistent exercise induced ST elevation. During follow-up (5 +/- 3 years), 3 patients died (2 cardiac deaths) and 3 had recurrent angina controlled by new treatment. CONCLUSION: Exercise-induced ST elevation is a rare phenomenon in patients without prior myocardial infarction. When occurring purely during exercise, coronary lesions are frequent and often servere, in the other hand ST elevation of the recovery phase is frequently associate with normal arteries or less severe lesions. In most cases, revascularisation or medical therapy can abolish clinical and electrocardiographic abnormalities.

[Third degree atrio-ventricular block induced by interferon alpha. Report of a case]. / Apparition d'un bloc auriculo-ventriculaire du troisième degré sous interféron alpha. A propos d'un cas.

Iatrogenic third degree atrioventricular block due to alpha interferon is rare. The authors present a case which occurred with low dosage, regressed when treatment was withdrawn and reappeared when treatment was reintroduced. The physiopathological mechanism of disease of the conduction pathways and its general cardiotoxicity is not yet understood. The secondary effects of this increasingly widely used anti-tumoral and anti-infectious drug should be recognised in order to prevent them. Initial cardiological investigation and follow-up are indicated to ensure this prevention.

Irregular ventricular stimulation in the DDI mode of a dual chamber pacemaker with atrial-based lower rate timing.

This report describes two patients with atrial fibrillation in whom an implanted CHORUS DDD pacemaker programmed to the DDI mode produced an irregular ventricular stimulation rate. The lower rate timing of these devices is atrial-based only when an atrial event opens an AV interval shorter than the programmed AV delay. In the DDI mode, if Api represents the time when an atrial paced event (Ap) would have occurred if it had not been inhibited by a previous atrial sensed event (As), then Api-Vp constitutes the implied AV interval where Vp is a paced ventricular event. Although the As-Vp interval (As-Api + Api-Vp) generates an atrial refractory period during its entire duration, the pacemaker can sense an atrial event (AR) during the implied AV interval. AR cannot start another AV delay, but it can initiate the atrial-based lower rate interval. This timing mechanism can cause irregular prolongation of Vp-Vp intervals to a value longer than the programmed lower interval with a maximal extension equal to the programmed AV delay. Such behavior of the CHORUS pacemaker should not be interpreted as malfunction.

[Preoperative management of patients with high-risk cardiovascular conditions]. / Quels bilans préopératoires chez le patient à risque cardiovascularie?

The growing numbers of elderly and cardiac patients are the consequence of progress in the prevention of the complications of coronary artery and valvular heart disease by surgery and revascularisation and improved treatment of hypertension which delays target organ complications by at least fifteen years. The elderly are particularly exposed to surgical risk: nearly half the patients with ischaemic heart disease die of cancer; a high proportion of elderly people require orthopaedic surgery either as an emergency (fractured femur) or as a standard procedure (knee surgery); nearly a quarter of patients requiring peripheral vascular surgery have coronary artery disease which may be silent. A preoperative consultation with the anaesthetist has been made compulsory, except in emergencies, giving time for preoperative investigations. The decrees of the Court of Cassation have also affected the traditional relationship of trust between patients and their doctors, leading to an increase in the cost of preoperative investigations without an accurate assessment of their benefits with regards to postoperative complications and the cost that they entail. Contrary to present tendencies reflected in the literature, the screening of risks should be simplified: clinical history and examination and resting ECG, often completed by stress testing, are sufficient in the large majority of cases. More importance should be attributed to the functional status than to the lesions. When the cardiac disease is asymptomatic, the chances are that it will remain so during and after surgery.... The main difficulty is not in identifying high risk patients: it is preventing cardiovascular events when surgery is unavoidable. The experience and collaboration between the quartet of anaesthetist, surgeon, cardiologist and general practitioner, are much more useful than the very incomplete bibliographical data concerning this side of the problem.

[Rehabilitation by physical exercise in chronic heart failure]. / Réadaptation par l'exercice physique dans l'insuffisance cardiaque chronique.

The aim of rehabilitation is to improve exercise capacity and, thereby, the autonomy of patients with cardiac failure. For many years, these patients were considered inapt to perform physical exercise and they are in the same situation at the dawn of the year 2000 as patients with myocardial infarction forty years ago. The symptoms of cardiac failure (dyspnoea of effort and muscular fatigue) are not only the consequence of pulmonary hypertension and decreased muscular perfusion. Prolonged interruption of exercise and long stays in bed or in a chair lead to anatomical and functional amyotrophy, which, in turns, incites to further inactivity. Deconditioned respiratory muscles cannot tolerate the increased load of hyperventilation. Neurohormonal changes cause vasoconstriction which reduces muscular perfusion. Physical training can significantly improve these abnormalities, though it does not seem to have a measurable effect on cardiac function; based on segmental work which enables performance of substantial efforts with a minimum of haemodynamic changes, it provides a 20 to 30% gain in capacity, mainly increasing the duration of submaximal exercise rather than maximum performance. Muscular fatigue is the symptom which is the most improved. Unfortunately the organisation, which is more difficult than in the post-infarction period, and the generalisation of the practice of long-term, well adapted physical training remains marginal although hundreds of thousands of patients could benefit; more than the inertia of the official instances concerning anything related to cardiac rehabilitation, it is the lack of interest shown by cardiologists and the absence of flexible structures within the health care organisation for elderly people which are responsible.

[Study of the cardiorespiratory response and chronotropic function after correction of tetralogy of Fallot. Important role of residual pulmonary regurgitation]. / Etude de la réponse cardiorespiratoire et de la fonction chronotrope après correction d'une tétralogie de Fallot. Rôle prépondérant de la régurgitation pulmonaire résiduelle.

Effort tolerance is reduced after correction of Tetralogy of Fallot. This prospective study investigated the cardiorespiratory response and the chronotropic function (mean follow-up 11.1 years) of 70 patients (43 boys and 27 girls) with an average age of 14.9 +/- 7.2 years (group 1) compared with 65 normal, sedentary subjects paired red for age and gender (group 2). All underwent exercise testing (Bruce protocol) with measurement of respiratory gases. Quantification of pulmonary regurgitation was performed by Doppler echocardiography. The chronotropic response to exercise was assessed by calculating the mean of slopes established by chronotropic metabolic relationship of Wilkoff. The cardiorespiratory response to exercise was abnormal in group 1: the duration of exercise (11.3 vs 13.6 min; p = 0.005), peak VO2 (35.5 vs 46 ml/min/kg; p < 0.001) and anareobic threshold (8.3 vs 9.2 min; p = 0.001) were decreased. Maximal heart rate (172 vs 190bpm; p < 0.001) and the mean of the metabolic-chronotropic slopes (0.68 vs 0.83; p < 0.001) were decreased in the patient group, showing abnormal chronotropic response to exercise. The latter seemed to be related to the severity of pulmonary regurgitation. The duration of exercise (10.6 vs 11.5 min; p = 0.001), peak VO2 (33 vs 37 ml/min/kg; p < 0.001), maximal heart rate (161 vs 177 bpm; p = 0.002) and the mean of the slopes of the metabolic-chronotropic relationship (0.59 vs 0.72; p < 0.001) were decreased in patients with moderate to severe pulmonary regurgitation. This study shows that significant pulmonary regurgitation is responsible for a poor cardiorespiratory response to exercise and for an abnormal chronotropic response which seems to be multifactorial but probably related to an adaptation favouring left ventricular filling during exercise.

[Diagnostic value of ST depression corrected for heart rate in the post-exercise recovery period]. / Apport diagnostique du sous-décalage du segment ST rapporté à la fréquence cardiaque en récupération post-effort.

This study assessed the diagnostic value of two new electrocardiographic criteria of coronary artery disease: the ST/HR index and the slope of the linear relationship between ST segment changes and the heart rate during the first three minutes of the post-exercise recovery period. These two criteria were compared to the standard criteria (> or = 1 mm horizontal or descending ST depression or > or = 2 mm ascending ST depression) to Detrano's ST/HR exercise index (> 1.6 microV/bpm in coronary patient), the exercise ST/HR slope (> or = 2.4 microV/bpm in coronary patients) and the exercise recovery loop (clockwise in normal and anticlockwise in coronary patients) in 88 subjects investigated for suspected coronary artery disease who underwent a computerised exercise stress test and coronary angiography (25 single vessel, 21 double vessel, 20 triple vessel disease; 22 with no significant coronary disease). The ROC identified thresholds of abnormality of the ST/HR recovery index at > or = 2.1 microV/bpm and of the ST/HR recovery slope at > or = 2.52 microV/bpm. Global comparison of the areas under the ROC showed the diagnostic superiority of the exercise ST/HR indices (0.96) over the standard criteria (0.92) and recovery indices (0.86) but without statistically significant values (p = 0.65 and p = 0.15 respectively). The ST/HR index and slope during recovery identify coronary disease with a diagnostic accuracy of 80% and 77% respectively which is similar to that (84%) of the standard ST criteria. The exercise-recovery loop was less accurate (64%).