Comparison of propagation of atrial excitation with the cardiopotential distribution on the body surface of hypertensive rats.

Objective: Arterial hypertension is associated with the risk of developing atrial arrhythmia. This research was aimed at studying the sequence of depolarization along the atrial epicardium and formation of the cardioelectric field on the body surface of hypertensive rats.

Methods: The study was carried out on eleven ISIAH rats (with hereditary stress-induced hypertension). We analyzed spatial-temporal characteristics of body surface potential map (BSPM), time characteristics of electrocardiogram during atrial depolarization, sequence of atrial epicardial depolarization of rats. Statistical analysis was performed using independent samples t-test.

Results: The results indicated that in 27% of hypertensive rats in the pulmonary vein (PV) sleeves, early excitation areas are formed 2.0 ± 0.5 ms after the beginning of depolarization of the sino-atrial node area, in 73% of animals, the area of the PV sleeves is excited 6.5 ± 0.4 ms after the beginning of depolarization. In experimental animals, the beginning of inversion of areas of positive and negative cardioelectric potentials on BSPM does not differ. In 73% of rats, duration of inversion on BSPM was 7.7 ± 1.9 ms, and in 27% - 3.9 ± 0.1 ms (p=0.011). The formation of early activation zones in PV of rats with arterial hypertension testifies to possible wandering focus in the myocardium of PV sleeves. Stress-induced hypertension results in actual risk of atrial arrhythmias, which originate at the base of the PV.

Conclusion: In rats with arterial hypertension, two early depolarization zones are revealed in the sinus node area and in the PV return to the left atrium, projected on BSPM by mutual positions of negative and positive potential zones.