Association of serotonin levels in patients of vasovagal syncope and postural tachycardia syndrome.

Objective: To determine the level of serotonin in patients of vasovagal syncope and postural tachycardia syndrome after head-up tilt test.

Methods: The cross-sectional analytical study was conducted at the Islamic International Medical College and the Department of Electrophysiology, Armed Forces Institute of Cardiology, Rawalpindi, from April 2017 to March 2018. Group A comprised cases of vasovagal syncope, group B had patients of postural tachycardia syndrome, and group C had healthy controls.