42 yrs old man presented with dizziness on standing, SBP falls by 50 mm Hg and HR is 52/min likely cause is -

Cardiac arrest due to bradyarrhythmias or asystole (B/A cardiac arrest) is managed differently. The patient is promptly intubated, CPR is continued, and an attempt is made to control hypoxemia and acidosis. Epinephrine and/or atropine are given intravenously or by an intracardiac route. External pacing devices are used to attempt to establish a regular rhythm. The success rate may be good when B/A arrest is due to ACUTE INFERIOR WALL MYOCARDIAL INFARCTION or to correctable airway obstruction or drug-induced respiratory depression or with prompt resuscitation effos. ref:harrison&;s principles of internal medicine,ed 18,pg no 2245