Q: Synchronized electrical cardioversion is targeted to which part of the electrocardiogram (EKG) cycle?
A) P wave
B) PR interval
C) QT interval
D) QRS complex
E) T wave
Cardiac cycle has a vulnerable and a refractory period. The refractory period is during the QRS complex, and the vulnerable period is during the T wave. Application of electrical cardioversion during vulnerable period may induce ventricular fibrillation.
Link, M. Arkins D. 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2010, Volume 122, Issue 18 suppl 3 :: http://circ.ahajournals.org/content/122/18_suppl_3/S706.full#sec-24