Which of the following is not true about cardiopulmonary resuscitation (CPR)?

Closed chest massage is not as effective as open-chest massage in normalizing blood pressure or perfusion of vital organs, and closed chest massage does generally deliver 5% to 15% of normal coronary and cerebral blood flow. The success rate for out-of-hospital resuscitation has been as high as 30% to 60% when communities are prepared to institute CPR early after a cardiac arrest. Ischemic hea disease is the most common cause of sudden death.