The Athletes Heart

1
The Athletes Heart
Definition Athletes heart means characteristic
enlargement /hypertrophy/ of the myocardium in
response to repeated exercise stimuli

• Principle features of athletes heart
• cardiac enlargement to allow for increased
  maximal stroke volume (SV)
• and cardiac output (Q) adaptations that drive
  the increase in oxygen delivery in the trained
  state since no training effect is evident in
  maximal heart rate (HR max)

2
Morganroth hypothesis, 1977

• M-mode echocardiography-two different
• morphological forms of athletes heart
• eccecentric LV hypertrophy - increase in LV
  cavity dimensions,proportional increase in left
  ventricle wall thickeness /LVWT/ to normalise
  myocardial strain, typically in pure
  aerobic,endurance sports
• concentric LV hypertrophy - increase in LVWT
  to normalise increased wall tension
  with rise in pressure, typically in resistance or
  strength training athletes

3
Critical evaluation of cardiac morphology
measurement

• Echocardiographic imaging
• large methodological error range in measuring
  LVID, LVWT
• Magnetic resonance imaging (MRI)
• highly accurate and reproducible technique for
  determining LVM and cardiac dimensions
• drawback- expensive,limited availibility
• MRI x Echocardiography (DeCastro, 2006)
• 18 male, elite-level rowers,12 untrained
  sedentary subjects
• echocardiography underestimation LVIDd and LVM
  relative to MRI

4
Other limitations in studies
of Athletes Heart

• No normalisations of LV dimensions for body size
  and composition (BSA, FFM)
• Cross sectional studies
  - cardiac
  dimensions during active (competitive)
  
  season x nonathletic sedentary groups
• Few studies comparing endurance trained
  (isotonic) with resistance (isometric) trained
  athletes

5
(No Transcript)
6
Evidence regarding impact of training duration
and intensity on remodelling

• Training in mixed aerobic and resistance sports
  (rowing, paddling)
  - associated with morphological
  changes
• Training at least 3 hours per week required to
  induce changes in LVM

7
Longitudinal studies of exercise training and
cardiac morphology in athletes

• LVIDd can be further augmented with training
  mainly with endurance training in elite athletes
  despite preexisting increase in cardiac internal
  dimensions

8
Longitudinal studies in sedentary individuals

• Exercise programs in sedentary or untrained
  individuals result in significant enlargement of
  LV cavity, increases in LVWT

9
Conclusions

• Athletes exhibit significant cardiac adaptations
  with absolute LVM increase in both endurance and
  strength trained athletes compared with
  controls
• LVM and LVMi are larger in endurance-trained
  athletes compared with strengths-trained athletes
• Volume of training influences the degree of
  increase in LVM in endurance athletes

10
(No Transcript)