P Wave Duration and P Wave Dispersion in Hyperthyroidism: Effect of Antithyroid Treatment [Turk Kardiyol Dern Ars]
Turk Kardiyol Dern Ars. 2004; 32(8): 556-563

P Wave Duration and P Wave Dispersion in Hyperthyroidism: Effect of Antithyroid Treatment

Yeşim GÜRAY1, Ümit GÜRAY1, M.Birhan YILMAZ1, Hakan ALTAY1, Halil KISACIK1, Serdar GÜLER2, Şule KORKMAZ1

Atrial fibrillation is frequently encountered in patients with hyperthyroidism. Previously, it was shown that prolonged maximum P wave duration and increased P wave dispersion on 12-lead surface electrocardiograms (ECG) are closely related to the development of paroxysmal atrial fibrillation (PAF). In this study, these P wave parameters were measured from 12-lead surface ECG in hyperthyroid patients with or without PAF during sinus rhythm and compared to euthyroid controls. In addition, influence of pharmacologic antithyroid therapy on these P wave parameters was investigated. Fifty-two hyperthyroid patients were included in the study. All patients underwent 24-hour Holter recordings and then, patients were divided into two groups according to the presence (PAF+; n=29) or absence (PAF-; n=23) of PAF. Maximum P wave duration (P max), minimum P wave duration (P min) were measured from the 12-lead surface ECG and P dispersion (PWD=P max-P min) values were then calculated. P max values were found to be significantly longer in both PAF+ (114.8±11.6 ms) and PAF- (105.6±11ms) patient groups as compared to controls (91±7.6 ms; p<0.001 for both comparisons). PWD values of both PAF+ and PAF- groups were also significantly higher than the controls (53.3±12 ms, 43.6±10 ms and 31.2±5 ms, respectively; p<0.001 for both comparisons). Age-adjusted PWD were significatly associated with the prevalans of PAF. Moreover P max and PWD values were significantly higher in PAF+ group as compared to PAF- group (p=0.006 for P max, p=0.003 for PWD). There were no significant differences in P min among groups. After restoration of euthyroidism by antithyroid therapy, P max (106±10ms, p<0.001) and PWD (42.2±6.4 ms, p<0.001) were found to be significantly decreased in PAF+ group as compared to baseline. In PAF- patients, P max (97.7±14 ms, p=0.001) and PWD (34.5±6.4 ms, p<0.001) were also decreased. In both groups, no significant changes were detected in P min values between baseline and after treatment. It is concluded that prolongation of P max and PWD in hyperthyroid patients could reflect a propensity to develop atrial fibrillation. However, significant decline in both of these P wave parameters after management of hyperthyroidism is thought to be the result of decreased unfavorable effects of circulating thyroid hormones on atrial electrophysiology. (Türk Kardiyol Dern Arş 2004; 32: 556-563)

Keywords: Antithyroid therapy, hyperthyroidism, paroxysmal atrial fibrillation, P wave dispersion, P wave duration

How to cite this article
Yeşim GÜRAY, Ümit GÜRAY, M.Birhan YILMAZ, Hakan ALTAY, Halil KISACIK, Serdar GÜLER, Şule KORKMAZ. P Wave Duration and P Wave Dispersion in Hyperthyroidism: Effect of Antithyroid Treatment. Turk Kardiyol Dern Ars. 2004; 32(8): 556-563
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