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Severe and Early Alteration of Action Potential During Acute Cardiac Rejection in Rats
Author(s) -
BABUTY DOMINIQUE,
OJEDA CARLOS,
MACHET MARIECHRISTINE,
AUPART MICHEL,
COSNAY PIERRE,
FAUCHIER JEANPAUL,
GARNIER DIDIER
Publication year - 1998
Publication title -
journal of cardiovascular electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.193
H-Index - 138
eISSN - 1540-8167
pISSN - 1045-3873
DOI - 10.1111/j.1540-8167.1998.tb00885.x
Subject(s) - medicine , ventricle , repolarization , cardiology , cardiac action potential , atrial action potential , electrophysiology , heart transplantation , ventricular action potential , transplantation
Alteration of Cardiac Action Potential . Introduction: Alteration of cardiac action potential and its adaptation to heart rate could contribute to cardiac dysfunction and arrhythmias during acute cardiac rejection. Methods and Results: Heterotopic heart transplantation was performed in allogeneic and syngeneic rats in which the action potentials of right and left ventricles were measured at 1, 2.5, 3.3, and 5.7 Hz successively using standard microelectrode techniques and compared with nontransplanted hearts. For each frequency, we measured action potential amplitude, action potential duration, transmembrane resting potential, and Vmax. In the right ventricle, at 1 Hz in the presence of rejection (n = 40), a significant increase was observed in action potential duration at 20%, 50%, and 70% repolarization (82.5%, 75.6%, and 70.8%, respectively) and in action potential amplitude (+17.9 mV), and the resting potential was decreased (‐5.3 mV). A lack of adaptation of action potential duration to the driving frequency was observed in the rejecting heart group in contrast to controls (n = 20) and nourejecting hearts (n = 13). Similar results were observed in the left ventricle and surprisingly in the native hearts (n = 11) of recipients with allografted rejecting hearts in the abdominal position. Conclusion: Action potential and its adaptation to the driving frequency is considerably altered during acute rejection. A humoral factor could contribute to cardiac dysfunction.