ECG shows narrow complex tachycardia with HR of approximately 180/min. P waves are absent. RR interval is reduced and regular. ST segment depression is noted in most leads. Diagnosis is PSVT. First line management: Carotid sinus massage. Carotid sinus massage is contraindicated in carotid aery bruit. Known case of ASCVD (Atherosclerotic Cardiovascular Disease)and atherosclerotic narrowing of carotid aery (Carotid aery bruit). If carotid sinus massage is given to this patient it can lead to development of embolic stroke due to physical damage to atherosclerotic plaque in the carotid aery. Adenosine will restore normal sinus rhythm. If it is unsuccessful, DC cardioversion is indicated. Absolute Contraindications to carotid sinus massage include: MI TIA or stroke within the preceding three months. H/O ventricular fibrillation or tachycardia.