Evaluation of Atrial Electromechanical Delay and Diastolic Functions in Patients with Hyperthyroidism Abdullah Sokmen, M.D.,* Gurkan Acar, M.D.,* Gulizar Sokmen, M.D.,* Ahmet Akcay, M.D.,* Murat Akkoyun, M.D.,* Sedat Koroglu, M.D.,† Alper Bugra Nacar, M.D.,‡ and Mesut Ozkaya, M.D.§ *Department of Cardiology, Faculty of Medicine, Kahramanmaras Sutcu Imam University, Kahramanmaras, Turkey; †Cardiology Clinic, Afsin State Hospital, Kahramanmaras, Turkey; ‡Cardiology Clinic, Elbistan State Hospital, Kahramanmaras, Turkey; and §Faculty of Medicine, Department of Endocrinology, Gaziantep University, Gaziantep, Turkey Aim: Hyperthyroidism is a well-known cause of atrial fibrillation (AF) which is associated with increased morbidity and mortality. Atrial electromechanical delay (EMD) is a significant predictor of AF. The aim of this study was to assess the atrial EMD and diastolic functions in subclinical and overt hyperthyroid- ism by using tissue Doppler imaging (TDI). Methods and Results: The study population consisted of 3 groups: group I (30 healthy subjects), group II (38 patients with subclinical hyperthyroidism), and group III (25 patients with overt hyperthyroidism). Atrial electromechanical coupling was measured with TDI. Standard echocardiographic measurements and parameters of diastolic function were obtained by conventional echocardiography and TDI. Intra- and inter-atrial EMD were significantly prolonged in subclinical and overt hyperthyroidism com- pared with control group (P = 0.03 and P < 0.001 for intra-atrial EMD; P < 0.001 for inter-atrial EMD). In groups II and III, mitral A velocity (P = 0.005 and P = 0.001) and mitral E-wave deceleration time (P < 0.001 and P = 0.02) were significantly increased, and mitral E/A ratio (P = 0.005 and P = 0.001) was significantly decreased compared with the control group. The lateral mitral E m /A m ratio in group II and group III was significantly lower than controls (P = 0.001). Mitral E m /A m ratio (b = À0.32, P = 0.002) and thyroid stimulating hormone (TSH) level (b = À0.27, P = 0.009) were negatively and independently correlated with inter-atrial EMD. Conclusion: This study showed that intra- and inter- atrial electromechanical intervals were prolonged and diastolic function was impaired in both overt and subclinical hyperthyroidism. TSH level and mitral E m /A m ratio were found as independent predictors of atrial EMD. (Echocardiography 2013;30:1194-1201) Key words: atrial electromechanical delay, hyperthyroidism, tissue Doppler imaging Hyperthyroidism is a common disorder with prominent cardiovascular effects including sinus tachycardia, systolic hypertension, changes in ventricular systolic and diastolic function, and predisposition to dysrhythmias, especially atrial fibrillation (AF). 1 Thyroid hormones have major effects on cardiac pacemaker function and on myocardial contractility through effects on myo- cardial structural and regulatory gene transcrip- tion. The resulting chronotropic, inotropic, and lusitropic effects of excess thyroid hormone on the heart in overt hyperthyroidism are present to a lesser extent in subclinical hyperthyroidism. 2 In the adult population, AF is the most com- mon type of tachyarrhythmia encountered in clinical practice and is associated with increased morbidity and mortality. 3 It is the most prevalent dysrhythmia after sinus tachycardia in patients with hyperthyroidism. Between 10% and 15% of hyperthyroid patients, clinical or subclinical, develop AF. 4,5 The prolongation of intra- and inter-atrial conduction time and the inhomogeneous prop- agation of sinus impulses are well-known elec- trophysiologic characteristics of the atria prone to fibrillation. Electromechanical delay (EMD) has been defined as the temporal delay between the detected onset of electrical activity and the realization of force in the myocardium. This issue has been evaluated noninvasively by simple electrocardiographic markers such as maximum P-wave duration and P-wave disper- sion as well as by tissue Doppler imaging (TDI). It is well known that increased atrial EMD on TDI is a predictor of the development of AF. 6–11 Address for correspondence and reprint requests: Abdullah Sokmen, M.D., Faculty of Medicine, Department of Cardiol- ogy, Kahramanmaras Sutcu Imam University, 46050 Kahr- amanmaras, Turkey. Fax: +90-344-2217239; E-mail: abdullahs27@yahoo.com 1194 © 2013, Wiley Periodicals, Inc. DOI: 10.1111/echo.12277 Echocardiography