CPR has saved countless lives, but performing the procedure correctly requires a fair amount of training and practice. One of the most important parts of CPR is matching the rhythm of the heart it give it a kick-start. According to a report from NPR, a recent study has shown that CPR trainers can make good use of a tool commonly used by music instructors – a metronome.

According to pediatric cardiologist Diane Atkins, a spokeswoman for the American heart Association, when performed correctly, CPR is highly effective at increasing survival rate. Anything that can help responders improve their CPR techniques can save lives.

A person performing CPR kneels beside a person in need of aid, and compresses the center of the chest with one hand on top of the other. The CPR performer needs to make 2-inch compressions into the chest cavity to force blood from the heart through the body, manually pumping it.

To give people the best chance of survival, doctors recommend 100 to 120 chest compressions per minute, which is more rapid than the rate at which most people would instinctively compress. Variations from this rate significantly reduce the chances for survival, and it can be hard to maintain in a stressful situation.

The study, published in the journal Pediatrics, examined the use of metronomes to guide CPR for children. Over 150 healthcare professionals performed CPR simulations on pediatric manikins, one to the rhythm of a metronome and one freely. The metronome increased the effectiveness of CPR by 22 percent.

Metronomes aren’t typically kept handy in the toolkits of emergency responders, but Atkins hopes that doctors will take note and create a demand for small, accurate metronomes. There are currently several mobile apps that can help people keep time, but they are generally geared towards musicians.

CPR is typically the response to a person who is unconscious, not breathing, or without a pulse. Trained medical professionals can also apply air into the victim’s lungs, but without training this is not recommended.