"Successful resuscitation from cardiac arrest was optimized at 100–120 compressions/minute."
A recent study appearing in the Journal of Emergency Medical Services ("Study Determines Optimal Chest Compression Rate") examined results of rescuer CPR for optimal blood flow and best patient survival to hospital discharge. The study largely confirmed the belief that rates of compression over 100 per minute were best but also established that rates of compression over 120 per minute decreased victim survival rate.