Energetic metabolism during acute stretch-related atrial fibrillation.
METHODS
Perturbations in energetic metabolism and impaired atrial contractility may play an important role in the pathogenesis of atrial fibrillation (AF). Besides, atrial stretch is commonly associated with AF. However, the atrial energetics of stretch-related AF are poorly understood. Here, we measured indicators of energy metabolism during acute stretch-related AF. PCr, adenine nucleotides, and derivatives concentrations as well as the activity of the F(0)F(1)-ATPase and Na,K-ATPase were obtained after 1 h of stretch and/or AF in isolated rabbit hearts and compared to control hearts without stretch and AF.


RESULTS
After 1 h of stretch-related AF, the total adenine nucleotides' pool was significantly lower (42.2 +/- 2.6 vs. 63.7 +/- 8.3 micromol/g protein in control group, P < 0.05) and the PCr/ATP ratio significantly higher (2.3 +/- 0.3 vs. 1.1 +/- 0.1 in control group P < 0.05), because of ATP, ADP, and AMP decrease and PCr increase. The sum of high-energy phosphate compounds did not change. There were no significant differences in F(0)F(1)-ATPase nor Na,K-ATPase activity between the groups.


CONCLUSIONS
Results show that in this experimental model, acute stretch-related AF induces specific modifications of atrial myocytes energetics that may play a pivotal role in the perpetuation of the arrhythmia.
Kalifa
Jérôme
J
Centre de Résonance Magnétique Biologique et Médicale (CRMBM), CNRS UMR n degrees 6612, Faculté de Médecine de Marseille, Université de la Méditerranée, 27 Bd Jean Moulin, 13385, Marseille Cedex 5, France.
Maixent
Jean-Michel
JM
Chalvidan
Thierry
T
Dalmasso
Christiane
C
Colin
David
D
Cozma
Dragos
D
Laurent
Pierre
P
Deharo
Jean-Claude
JC
Djiane
Pierre
P
Cozzone
Patrick
P
Bernard
Monique
M
D000818:Animals; D001281:Atrial Fibrillation / Q000201:enzymology / Q000378:metabolism* / Q000503:physiopathology; D004734:Energy Metabolism; D066298:In Vitro Techniques; D008928:Mitochondria / Q000201:enzymology; D010710:Phosphates / Q000378:metabolism; D010725:Phosphocreatine / Q000378:metabolism; D006180:Proton-Translocating ATPases / Q000378:metabolism; D011817:Rabbits; D012032:Refractory Period, Electrophysiological; D012508:Sarcolemma / Q000201:enzymology; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013314:Stress, Mechanical
D010710:Phosphates; D010725:Phosphocreatine; D006180:Proton-Translocating ATPases; D000254:Sodium-Potassium-Exchanging ATPase