Increased P wave dispersion in hypothyroidism: a sign of risk of atrial fibrillation

Aim: As in hyperthyroidism, cardiac arrhythmias can be seen in hypothyroidism. In this study, we measured P wave dispersion among hypothyroid patients to evaluate atrial fibrillation risk. Methods: 75 patients who received first time diagnosis of hypothyroidism and 40 normal control patients were included in this study. Each patient had echocardiographic and electrocardiographic studies were carried out. Groups were compared for statistically significant difference in P wave dispersion, minimum P wave duration and maximum P wave duration. Results: The groups were similar in echocardiographic and electrocardiograpic features. P wave dispersion was significantly higher in the hypothyroid group compared to normal controls (31.9±9.3 ms vs. 26.5±9.4 ms, P = 0.003). Minimum P wave duration was significantly shorter in the hypothyroid group compared to controls (63.8±9.2 ms vs 68 ± 9.2ms, P = 0.026). Maximum P wave duration was not significantly different between groups (95.4±12.3 ms vs. 94.7±8.7 ms, p.0, 74). Conclusion: P wave dispersion was increased in the first time diagnosed clinical hypothyroid patients. This is the first study to evaluate P wave dispersion in clinical hypothyroid patients. We believe that our findings have clinically important implications and provide insight into possible mechanisms of this morbid condition.