Cardiac arrest, when the heart suddenly stops beating, leads to death if not treated within minutes with cardiopulmonary resuscitation or defibrillation.

The new study, which used data from a cardiac arrest registry in Georgia, analyzed by census tract more than 1,100 incidents of cardiac arrest in three years ending in November 2008. It found that some areas had consistently higher rates of cardiac arrest — as well as lower rates of bystanders’ doing CPR — than others.

While the average census tract had 2.2 cardiac arrests per year, some tracts had two to three times that rate. The study identified 14 neighborhoods with the highest rates of cardiac arrest and the lowest rates of bystander CPR. Researchers say they will use this information to focus on these high-need communities, training residents to do CPR and teaching them about heart disease.

“We know that CPR makes a difference and saves lives,” said Dr. Comilla Sasson, a clinical lecturer in emergency medicine at the University of Michigan and the lead author of the study, released early by The Annals of Internal Medicine.