Myocardial adaptation to exercise training: a view through positron emission tomography.
Myocardial adaptation to exercise training includes changes in morphology, energy metabolism and autonomic control. Positron emission tomography (PET) provides a tool for investigating tissue perfusion, metabolism and neurotransmission in vivo. Combined with echocardiography, magnetic resonance imaging and assessment of cardiovascular autonomic nervous function, this technology allows us to study the effects of exercise training on cardiac physiology in a noninvasive way. For example, exercise-induced increases in coronary blood flow have been quantified in myocardial segments supplied by angiographically normal as well as diseased vessels. Recent studies have shown that adaptive changes of energy substrate utilization occur in the athlete's heart. Simulation of physical exercise by dobutamine infusion has been used to study demand-induced changes in cardiac energetics and efficiency. Studies on the dysfunctionally hibernating myocardium have outlined the consequences of exercise-induced ischaemia, whereas in heart failure exercise training may normalize myocardial hypoperfusion and sympathetic denervation. In conclusion, PET has matured to a very informative clinical research tool which, particularly in combination with other imaging modalities, has brought into attention previously unaccessible features of cardiovascular physiology.
Voipio-Pulkki
L M
LM
Department of Medicine, University of Turku, Turku University Central Hospital, Finland. liisa-maria.voipio-pulkki@utu.fi
D000222:Adaptation, Physiological; D003326:Coronary Circulation / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D006801:Humans; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D010806:Physical Education and Training; D012680:Sensitivity and Specificity; D014055:Tomography, Emission-Computed