(CBS) -- People who suffer cardiac arrests in high-income, white neighborhoods are almost twice as likely to receive cardiopulmonary resuscitation (CPR) than people who live in low-income, black neighborhoods, a new study suggests.
"If you drop in a neighborhood that is 80 percent white with a median income over $40,000 a year, you have a 55 percent chance of getting CPR," study author Dr. Comilla Sasson, an emergency room physician at the University of Colorado Hospital, said in a press release. "If you drop in a poor, black neighborhood you have a 35 percent chance," she said.
The study, published Oct. 25 in the New England Journal of Medicine, looked at data from 14,225 patients who had cardiac arrests in 29 cities from 2005 to 2009. Researchers then overlaid the findings onto U.S. census data, to show which neighborhood the person suffered the event in. Low income neighborhoods were designated as places where households made at or below $40,000 a year.
The researchers found a "direct relationship" between household income and racial composition of the neighborhood, where the odds of having a bystander perform CPR were 50 percent lower in low-income black neighborhoods than high-income non-black neighborhoods.
"Life or death can literally be determined by what side of the street you drop on," Sasson said.
But not all the disparities could be attributed to the neighborhood.
Regardless of the neighborhood where cardiac arrests occurred, blacks and Hispanics were found to be 30 percent less likely than whites to receive CPR from a bystander. Also, people who were living in wealthy black neighborhoods were 23 percent less likely to receive CPR than those living in high-income non-black neighborhoods, the study found.
"This suggests that, neighborhood effects, though important, do not fully account for observed racial differences," the study said.
Sasson, who worked at a level one trauma center in Atlanta as a doctor, said she observed the discrepancies for herself.
"I would see African-Americans coming in and dying from cardiac arrests after having laid there for 10 minutes with no one delivering CPR," she said. "There is no reason in 2012 that this kind of disparity exists - that you live or die depending on what side of the street you drop on. It is simply unacceptable."
Sudden cardiac arrest occurs when electrical impulses in the heart cause it to beat too fast or chaotically, which then stops the heart from beating, according to the American Heart Association (AHA). It is not the same as a heart attack, which occurs when the blood supply to the heart is cut off for some reason.
About 383,000 out-of-hospital sudden cardiac arrests happen each year, and 88 percent -- about four out of five -- take place at home, according to AHA. Many of those people are otherwise healthy and have no heart disease or other risk factors. The study authors believe that survival rates range from 0.2 percent in Detroit to 16 percent in Seattle.
They also believe for every 20 people who are administered CPR, one person will be saved.
"So you are talking about thousands of lives being saved here," Sasson explained.
Researchers believe that part of the reason is that CPR costs a lot to learn, which takes away money from low-income families who need it for other things.
"If they paid $250 for a CPR class you are talking about 15 percent of their salary," Sasson said. "When you look at the competing economic interests - am I going to eat tonight or attend a CPR class? - the answer is obvious."
Dr. Gordon Tomaselli, chief of the division of cardiology at Johns Hopkins University and a former president of the American Heart Association, said to HealthDay, that the study brings light to an important issue.
"There's always been some concern that underserved, poor, racial and ethnic minority areas are places where you don't want to have a cardiac arrest," Tomaselli said. He was not involved in the study. "I think this is an important study in that it has brought forth, in one large data repository, something we thought was the case from multiple smaller studies."