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Definition Athlete´s heart means characteristic enlargement /hypertrophy/ of the myocardium in response to repeated exercise stimuli. The Athlete´s Heart. Principle features of athlete´s heart cardiac enlargement to allow for increased maximal stroke volume (SV)
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Definition Athlete´s heart means characteristic enlargement /hypertrophy/ of the myocardium in response to repeated exercise stimuli The Athlete´s Heart • Principle features of athlete´s 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)
Morganroth hypothesis, 1977 M-mode echocardiography-two different morphological forms of athlete´s 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
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
Other limitations in studiesof „Athlete´s 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
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
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
Longitudinal studies in sedentary individuals • Exercise programs in sedentary or untrained individuals result in significant enlargement of LV cavity, increases in LVWT
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