[Biologist's view on diastolic dysfunction].
Modern biology provides satisfactory explanations for the abnormalities of the different phases of relaxation and diastole. Ventricular filling depends on three factors: active relaxation; the only factor is the concentration of ATP which has to re-increase. This requires elimination of the cytoplasmic calcium which activates ATP-ase by the Ca2+ ATPase of the sarcoplasmic reticulum and the Na+/Ca2+ pump. In hypertrophy, the concentration of the first and the activity of the second are decreased; passive wall compliance, which depends on the quantity and quality of parietal collagen. This factor is partially regulated in the myocardium by the concentration of aldosterone and angiotensin II; atrial contraction, which depends on the size of the atria and their isomyosine content. This changes in atrial overload to a slow form of myosine, one of the mechanisms of adaptation.
Swynghedauw
B
B
U 127, INSERM, hôpital Lariboisière, Paris.
D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D003187:Compliance; D003971:Diastole / Q000502:physiology; D006321:Heart / Q000502:physiology; D006801:Humans; D009200:Myocardial Contraction; D009206:Myocardium / Q000201:enzymology; D009218:Myosins / Q000378:metabolism
D009218:Myosins; D000252:Calcium-Transporting ATPases; D002118:Calcium
Le dysfonctionnement diastolique vu par le biologiste.