Usually occur during the initial 24-72 hours, but may occur later on also. The causes may be ventricular irritability due to manipulations of heart during cardiac surgery, hyper or hypokalemia, hypotension leading to decreased blood supply to the coronary arteries causing myocardial ischemia/hypoxia. The common dysrhythmias occurring may be bradycardias, ventricular standstill, VF or VT, or over riding tachydsrhythmias. Treatment is as for dysrhythinias or connecting the pacing wires inserted to temporary pacemaker as needed. Rarely, patients may need permanent pacemaker.