Timing the shock to the R wave prevents the delivery of the shock during the vulnerable period (or relative refractory period) of the cardiac cycle, which could induce ventricular fibrillation. If the patient is conscious, various drugs are often used to help sedate the patient and make the procedure more tolerable. However, if the patient is hemodynamically unstable or unconscious, the shock is given immediately upon confirmation of the arrhythmia. When synchronized electrical cardioversion is performed as an elective procedure, the shocks can be performed in conjunction with drug therapy until sinus rhythm is attained. After the procedure, the patient is monitored to ensure stability of the sinus rhythm.
timing the shock to the r wave prevents the delivery of the shock during the vulnerable period (or relative refractory period) of the cardiac cycle which could induce ventricular fibrillation if the patient is conscious various drugs are often used to help sedate the patient and make the procedure more tolerable however if the patient is hemodynamically unstable or unconscious the shock is given immediately upon confirmation of the arrhythmia when synchronized electrical cardioversion is performed as an elective procedure the shocks can be performed in conjunction with drug therapy until sinus rhythm is attained after the procedure the patient is monitored to ensure stability of the sinus rhythm