Resumen en español

The main purpose of this paper is to relate cellular cardiac electrical activity with the cardiac electrical activity measured in only one electrocardiogram (ECG) lead, through a cellular action potential (AP) parametrical model. This is performed by relating known dynamics, which can be mathematically modeled, existing at a cardiac cell level, to dynamics which can be obtained from a standard ECG recording. The main cellular dynamic used for relating with the ECG is the one known as three dimensional cellular restitution curve, which relates the action potential duration (APD) with its preceding diastolic interval and with the APD of the preceding cardiac cycle. Similar restitution curves were found in ECG signals recorded under the isometric handgrip test by relating the QT interval with its preceding TQ interval and with the QT interval of the preceding cardiac cycle. Following this similarity, a parametrical restitution curve, derived from a three ionic current cellular AP model was fitted to the ECG restitution relation for AP model parameter estimation. This model is finally simulated by stimulating it with an impulse train of frequency similar to the heart rate of the tested subject. The results show that the restitution curve experimentally obtained from the ECG is similar to the one obtained from de AP model simulation. Moreover the simulated APD follows satisfactorily the QT interval time variation of the tested subject. This opens new perspectives for the analysis of cellular cardiac electrical activity from standard ECG recordings.