Introduction
Primary hyperparathyroidism (PHPT) is an endocrine disease characterized by excessive release of parathyroid hormone (PTH), resulting in dysregulation of calcium (Ca) metabolism (1 ). Although clinical practice focuses more on adverse effects such as renal complications and osteoporosis in hyperparathyroidism, PHPT has been shown to be associated with increased cardiovascular morbidity and mortality (2 ).
Atrial fibrillation (AF) is an important heart rhythm disorder common in clinical practice, which causes hemodynamic disorders, frequent hospitalizations, and thromboembolic events, and affects 1-2% of the general population (3). Although the exact mechanisms causing AF are not fully understood, hypertension, heart failure, diastolic dysfunction, endothelial dysfunction and left ventricular hypertrophy play an important role in the pathogenesis of AF (3, 4 ). Side effects such as hypertension, diastolic dysfunction, endothelial dysfunction, left ventricular hypertrophy can also be seen in PHPT disease (2) . Therefore, these patients may be at increased risk of newly developing AF.
The atrial conduction time (ACT) represents the interval between sinus impulses and atrial mechanical contraction. As an alternative to invasive electrophysiological measurements, it may be measured noninvasively by Tissue Doppler Imaging (TDI) (5 ). The prolongation of intra- and inter-atrial conduction time, called atrial electromechanical delay (EMD), is associated with the frequency and sensitivity of atrial fibrillation (6).
To the best of our knowledge, atrial conduction abnormalities have not been previously evaluated in patients with PHPT. Therefore, we aimed to evaluate the atrial conduction time in PHPT patients with TDI, which is a noninvasive method. In addition, we wanted to investigate whether there is a relationship between atrial conduction time and parathyroid hormone and serum calcium levels.