Effects of short-term rapid atrial pacing on electrophysiological characteristics of atrium in hyperthyroidism

Abstract

To investigate the effects of short-term rapid atrial pacing on the electrophysiological characteristics of atrium in hyperthyroidism. Forty-six adult rabbits were randomly divided into 4 groups: normal control group (n=10), pacing group (n=10), hyperthyroidism group (n=14), hyperthyroidism/pacing group (n=12). Baseline AERP and AERPs after pacing 2, 4, 6 h were determined in all groups at driver cycle length (DCL) of 200 ms, 150 ms and 130 ms. In pacing group, AERPs at different DCL (200 ms, 150 ms and 130 ms) were shortened after rapid pacing 2, 4, 6 h when compared with before pacing and control group (P<0.01). AERPs (at DCL of 200 ms, 150 ms and 130 ms) in hyperthyroidism group were shorter than those in control group at all time points (P<0.01). AERPs (at DCL of 200 ms, 150 ms and 130 ms) in hyperthyroidism/pacing group after rapid pacing 2, 4, 6 h were shorter than those in pacing 0 h (P<0.01) and hyperthyroidism group (P<0.05). AERP200-150 and AERP200-130 in pacing group after rapid pacing 2, 4, 6 h were significantly different from at pacing 0 h and control group (P<0.01). AERP200-150 and AERP200-130 in hyperthyroidism and hyperthyroidism/pacing group were significantly different from control group at all time points (P<0.01). No differences were observed in AERP200-150 and AERP200-130 between hyperthyroidism group and hyperthyroidism/pacing group. Hyperthyroidism and short-term atrial pacing in the presence of hyperthyroidism can lead to remodeling of atrial electrophysiology.