Study Participants and Methods
We included 84 healthy subjects, aged between 30 and 50, in our study. After an announcement in our hospital, this group was recruited from medical students, medical residents, and clinical and non-clinical hospital personnel. Each person signed a detailed written informed consent before enrollment in the investigation. The study was in accordance with the Declaration of Helsinki. After comprehensive history taking and physical examination, an electrocardiography (ECG) was acquired and detailed echocardiography was performed based on the latest guidelines for performing a comprehensive transthoracic echocardiographic examination in adults1. Exclusion criteria were any of the coronary artery disease risk factors including : diabetes, hyperlipidemia, hypertension, cigarette smoking), history of cardiac or pulmonary diseases, any signs or symptoms in favor of cardiac, pulmonary, or thyroid diseases, ECG abnormalities (including bradycardia, tachycardia, axis deviation or bundle branch blocks and any ST-T changes) or any echocardiographic abnormalities in chamber sizes or function and cardiac valves. Participants with mild valvular regurgitations in echocardiography were not excluded.
Echocardiography was done in the left lateral decubitus position with the ”Vivid S5 GE” vendor. All echocardiographic measurements were done in offline mode by an expert echocardiography fellowship. In the RV-focused view, the M-mode cursor was aligned with the lateral tricuspid annulus. The distance between early systole and end-systolic excursion of RV free wall was measured in centimeters (cm). Color-coded M-mode was used to better delineate the peak systole of the RV free wall. Systolic time (TAPSE-t) was also measured in the exact tracing by measuring the time from the initial QRS to the maximum systolic excursion (Figure A, B)