I received this e-mail from my Healthcare newsletter. 
It seems like the answer is…….You really need to concentrate on those compressions folks. 
PLEASE READ THIS IN IT’S ENTIRETY.   This study has found some very interesting information.
May 4, 2009 (Kansas City, Missouri) — Survival among adults with bystander-witnessed, out-of-hospital cardiac arrest with an initial rhythm of ventricular fibrillation (VF) [...]