Exercise-induced Changes in Cardiac Function & Morphology
Condition: Myocardial Ischemia; Exercise; Myocardial Contraction; Myocardial Stunning; Heart Failure
MeSH terms: Myocardial Ischemia; Myocardial Stunning; Ischemia
Study type: Interventional

Summary: 
      Until now it has been assumed that regular endurance training has a positive influence on
      cardiac function and that the positive effect increases with increasing intensity. However,
      little is known about the effects of intense endurance stress on the heart. According to
      current knowledge repeated exposure to strenuous endurance activity may lead to minor but
      possibly irreversible damage to the heart with resultant scarring of the heart's muscle.

      Within this study we attempt to find out by different analytical methods - in particular
      magnetic resonance imaging (MRI) and ultrasound of the heart - to what extent the heart
      muscle is affected by an intense endurance exercise, i.e. the "Jungfrau-Marathon", and which
      changes can possibly be found. Due to repeated measurements we will obtain further
      information on the short-term course of possible changes.

      Hypotheses: A single bout of prolonged strenuous exercise (PSE) leads to transient alteration
      in cardiac function accompanied by the appearance of biomarkers for myocardial damage.
    

Detailed description: 
      Background

      Despite the well documented cardio-protective effects of aerobic exercise of moderate
      intensity, short- and long-term consequences of strenuous exercise are less clear. There is
      increasing evidence that maintaining a high cardiac workload over a prolonged duration may
      result in transient impairment of cardiac function. Recent studies have also reported a
      transient increase in cardiac biomarkers after prolonged strenuous exercise. While in
      patients with cardiac disease the presence of cardiac dysfunction and increased cardiac
      biomarkers generally reflects myocardial damage, the impact of these observations in athletes
      is ill defined. It is a matter of concern whether in athletes such findings simply reflect a
      reversible response or whether repetitive events may lead to an accumulative cardiac damage.
      Traditional echocardiographic methods used to determine potential cardiac changes in
      morphology or function are investigator-dependent and may be subject to interference by
      cardiac pre- and afterload. Cardiac magnetic resonance imaging provides an
      investigator-independent and objective method to quantify cardiac dimensions and function.
      Delayed contrast enhancement MR imaging is a highly reproducible cardiovascular magnetic
      resonance imaging technique to directly visualize myocardial edema, necrosis and fibrosis.

      Objective

      To use cardiac and delayed contrast enhancement magnetic resonance imaging in combination
      with echocardiographic methods to quantify cardiac dysfunction after a single competitive PSE
      event and to study post-exercise changes in morphology and function as well as the
      post-exercise dynamics of specific markers of myocardial damage.

      Methods

      Cardiac and delayed contrast enhancement magnetic resonance imaging will be used in
      combination with echocardiographic methods to repetitively investigate post-exercise cardiac
      function and morphology in 10 elite athletes finishing the "Jungfrau Marathon". Biomarkers of
      myocardial damage are assessed simultaneously.

      Post-exercise dynamics of the outcome parameters are followed over a minimum of 7 days after
      the exercise.
    

Intervention name(s): Strenuous Endurance exercise
Intervention type(s): Other
Intervention description(s): "Jungfraumarathon": Mountain-Marathon with a length of 42km and a altitude-difference of approximately 1830meters.
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Basic Science