The risks and benefits of exercise after a myocardial infarction

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Mats Börjesson

In a new position paper, published in the European Heart Journal, the Sports Cardiology Section of the European Association of Preventive Cardiology (EAPC) outline recommendations for coronary artery disease patients participating in sport (both for leisure and for competitive reasons). In this commentary, the lead author of the paper, Mats Börjesson focuses on the recommendations concerning patients who have had a myocardial infarction. 

Myocardial ischaemia during exercise is caused by a mismatch in oxygen demand-supply. It may be provoked by an increase in heart rate, blood pressure and subsequent workload, exceeding the threshold of ischaemia, during high intensity exercise. Cardiac events may also be triggered by neuro-hormonal activation, plaque rupture and endothelial erosion in patients with underlying coronary artery disease.

While novel cardiac imaging techniques have proven invaluable in detecting coronary artery disease, they do not provide information relative to the coronary flow and reserve—which are vital to assess the risk of sudden cardiac death/sudden cardiac arrest associated with exercise. Therefore, different methods of stress testing (e.g. cycle ergometry or treadmill testing), stress echocardiography/MRI/ single-photon emission computed tomography (SPECT) and positron emission tomography (PET), play a major role. For the evaluation of competitive athletes with suspected coronary artery disease, maximal exercise capacity should be assessed.

When advising patients with coronary artery disease on engagement in competitive sports, the documented benefits of exercise must be balanced with the potential risk for adverse events. In general, leisure time activity is advised and should be recommended individually (i.e., exercise on prescription) to all those with established coronary artery disease.

Risk stratification

For athletes-patients with proven coronary artery disease, as documented by an earlier clinical event such as a myocardial infarction, or by computed tomography (CT) scan or coronary angiography, advice on sport participation should be based on:1

  • The extent of the coronary artery disease on angiography
  • The presence of exercise-induced myocardial ischaemia
  • Any exercise induced arrhythmia
  • Evidence of myocardial dysfunction (echo, MRI)
  • The type and level of sport competition
  • The fitness level of the individual patient and on
  • The cardiovascular risk factor profile.

Specifically, patients are stratified as having a low probability for exercise-induced adverse cardiac events if all of the following apply: absence of critical coronary stenoses (i.e. <70%) of major coronary arteries or <50% of left main stem on coronary angiography; ejection fraction ≥50% on echocardiography, cardiac magnetic resonance (MR) or angiography (and no wall motion abnormalities); normal, age-adjusted exercise capacity; absence of inducible ischaemia (symptoms, abnormal blood pressure response) on maximal exercise testing; and absence of major ventricular tachyarrhythmias (i.e., non-sustained ventricular tachycardia, polymorphic or very frequent ventricular extra beat, at rest and during maximal stress testing).1 Conversely, patients can be stratified as having a high probability for exercise-induced adverse cardiac events if at least one of the above criteria is not fulfilled and/or if having symptoms on exercise.

Recommendations

Patients stratified as low-risk for cardiac events post myocardial infarction can participate in most competitive sports. Restrictions apply on an individual basis for certain sports with the highest cardiovascular demand (e.g. extreme power and endurance disciplines) and for older patients with coronary artery disease, as the risk of sudden cardiac death during endurance events may be considerably higher in men >60-years old.

In patients stratified as at high risk, post myocardial infarction should be restricted from competitive sport and receive appropriate management. In patients with significant ischaemia during exercise, anti-ischaemic therapy needs to be optimised and revascularisation ought to be performed, if ischaemia prevails. If despite adequate treatment ischaemia cannot be completely resolved, the patient should be restricted from competitive sport and advised on leisure-time activities.

According to the cardiac rehabilitation guidelines of the European Society of Cardiology, participation in an exercise programme is recommended for all patients who undergo revascularisation after an acute myocardial infarction. Exercise should be prescribed in a gradual mode, starting with low-intensity exercise of short duration, progressively and step-wise increased to where the patient is able to perform exercise without limitation. Careful attention to the development of new symptoms, are essential. The duration of the progression is dependent upon the extent of myocardial injury and remodelling. In patients with non-ST segment elevation myocardial infarction (NSTEMI) with complete revascularisation and without remaining ischaemia, exercise can be increased faster to previous levels. More intense training and participation in competition should only be considered after a successful, progressive increase in the exercise load.

Conclusion

The recommendation for patients who have had a myocardial infarction/undergoing percutaneous coronary intervention (PCI) and who have a low-probability of further cardiac events is for them to have a minimum of three months’ rehabilitation before they resume participation in competitive sports. If they are receiving dual antiplatelet therapy (DAPT), because of the risk of bleeding, they should be advised to avoid contact sports.

Advice on eligibility to participate in sport must be combined with recommendations to perform proper warm-up and cool-down procedures and ensure adequate hydration. Patients should also be made aware of the need to be mindful of any symptoms occurring during resumed exercise. Continuous long-term cardiac evaluation, at least annually, is then advised. The risk factor profile should be managed pharmacologically and with lifestyle modifications.

Reference

  1. Börjesson et al. Eur Heart J 2018. Epub.

Mats Börjesson is at Department of Neuroscience and Physiology & Sahlgrenska University Hospital, Göteborg, Sweden. 

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