ABC | Volume 111, Nº5, November 2018

Original Article Sokmen te al Cardiac functions in adrenal incidentaloma Arq Bras Cardiol. 2018; 111(5):656-663 from normal to various degrees of excess daily production rate, and this may not be detectable by standard endocrine work-up. 12 In our study, basal cortisol levels of the groups were similar, but post DST cortisol levels were significantly elevated (not exceeding the cut‑off, 1.8 µg/dl), and DHEAS levels were significantly reduced (not below the cut-off, 40 µg/dl) in nonfunctioning AI group. Additionally, post DST cortisol level was correlated with LV mass index. According to these findings, we speculated that subtle cortisol autonomy of adrenal adenoma might play a role in cardiac hypertrophy. Myocardial performance index is a parameter calculated from tissue Doppler echocardiographic measurements, and predicts both systolic and diastolic ventricular function. In our study, LV MPI was found to be increased in patients with AI indicating impaired global LV function. This impairment may be attributed largely to the impairment of LV diastolic function, because the predictors of LV systolic function such as LV EF and LV Sm were similar in both groups. Considering structural and functional parameters of RV, decreased RV Em/Am ratio might indicate the tendency to impairment of RV diastolic function. PAT was also shortened, indicating increased pulmonary vascular resistance in patients with AI. Atrial fibrillation is the most common arrhythmia encountered in clinical practice, and associated with significant mortality and morbidity due to hemodynamic impairment and thromboembolic events. Impaired atrial conduction is an important step in the pathophysiology of AF. Atrial conduction times can be evaluated by both invasive (electrophysiological study) and noninvasive (P wave dispersion on ECG and EMD on echocardiography) methods. 22 It has been shown that impaired atrial conduction is an independent and strong predictor for development and recurrence of AF, and TDE is a useful and reliable technique to evaluate atrial electromechanical properties. 7-9 Numerous studies demonstrated that atrial conduction time was prolonged in various diseases including obesity, thyroid diseases, chronic obstructive lung diseases, non-alcoholic fatty liver disease, acromegaly and diabetes mellitus (DM). 23-28 Cushing disease is associated with many cardiovascular risk factors, including glucose intolerance, hypertension, LV hypertrophy, central obesity and metabolic syndrome, and may lead to cardiovascular events such as coronary heart disease, heart failure and arrhythmias. 21 So, we hypothesized that AI might be associated with cardiac structural and functional changes, and increased risk of AF. Earlier studies showed increased epicardial fat, increased LV mass and LV diastolic dysfunction in AI similar to our results. 5,12 However, they did not study atrial conduction properties in this patient group. Therefore, this study showed for the first time that both intra- and inter-atrial EMD were impaired in patients with nonfunctioning AI. Moreover, atrial EMD was correlated significantly with post DST cortisol level, ACTH level, LV mass index, LV diastolic dysfunction, age and systolic blood pressure. Post DST cortisol level was an important predictor of intra- atrial EMD, such that 1 µg/dl increase in post DST cortisol level caused the prolongation of intra-atrial EMD by 4.752 msec. We may explain these findings by a few mechanisms. First, subtle cortisol excretion can affect cardiac structure and function as mentioned previously, which in turn is supposed to have detrimental effects on atrial conduction. Secondly, AI and AF share common metabolic risk factors such as increased blood pressure, insulin resistance, endothelial dysfunction and obesity. Lastly, low-level but long-standing subtle cortisol excretion may have direct toxic effect on myocardium by glucocorticoid receptors leading to myocardial fibrosis. 4-6,13,29 Detection of prolonged atrial EMD in these patients may be an earlier sign of atrial dysfunction preceding AF. Study limitations The major limitation of the study was the relatively small number of the subjects in adenoma group, besides the inability to define the length of the disease owing to the lack of overt clinical features. Finally, our study lacks long-term follow-up data, since it is a cross-sectional study. The patients could not be followed for future arrhythmic episodes to see whether the ones with prolonged atrial EMD develop AF. Conclusion Our study revealed that intra- and inter-atrial conduction times were prolonged and LV mass index was increased in patients with nonfunctioning AI. These findings may be markers of subclinical cardiac involvement and tendency to cardiovascular complications. Thus, individuals diagnosed to have nonfunctioning AI should be followed up closely for their increased cardiovascular risk. Author contributions Conception and design of the research and Critical revision of the manuscript for intellectual content: Sokmen G, Gul K; Acquisition of data: Sahin M, Tuzun D, Sokmen A, Bolat H, Oguz A, Nacar H; Analysis and interpretation of the data: Sokmen G, Sahin M, Tuzun D, Sokmen A; Statistical analysis: Doganer A; Writing of the manuscript: Sokmen G, Sahin M. Potential Conflict of Interest No potential conflict of interest relevant to this article was reported. Sources of Funding There were no external funding sources for this study. Study Association This study is not associatedwith any thesis or dissertationwork. Ethics approval and consent to participate This study was approved by the Ethics Committee of the Kahramanmaras Sutcu Imam University under the protocol number 2013/16-02. All the procedures in this study were in accordance with the 1975 Helsinki Declaration, updated in 2013. Informed consent was obtained from all participants included in the study. 661