BETHESDA, Md., April 4 (UPI) -- Antiarrhythmic drugs can benefit patients who experience cardiac arrest outside the hospital but do not respond to electric shock treatment, according to a recent study.
When paramedics use the drugs amiodarone and lidocane with out-of-hospital sudden cardiac arrest patients, the number of patients who survived to leave the hospital improved slightly, researchers at the University of Washington report.
While the researchers make clear the difference is small -- about 3 to 5 percent more patients survived to be discharged from the hospital -- the improvement is still worth noting and further exploring, especially considering adverse effects from the drugs were infrequent.
Sudden cardiac arrest, when the heart stops beating unexpectedly, affects about 300,000 people outside the hospital per year, according to the National Heart, Lung and Blood Institute. About 10 percent of people who have them survive these events.
"We can and should strive to improve our treatments for this all-to-common event," Dr. Peter Kudenchuck, a cardiac electrophysiologist at the University of Washington Medical Center, in a press release, adding that while the effects of the drug were not statistically significant, "we believe this study is a significant step in that direction."
For the study, published in the New England Journal of Medicine, 3,026 patients at 10 North American hospitals were treated by paramedics with either amiodarone, lidocaine or placebo by paramedics after cardiac arrest outside the hospital.
Among the three treatment groups, 24.4 percent of patients given amiodarone, 23.7 percent of patients treated with lidocaine and 21 percent of patients receiving a placebo survived their heart attack. While there was a 0.7 percent difference in survival between patients receiving amiodarone instead of lidocaine, 3.2 percent more patients treated with either drug survived than those given a placebo.
Among those treated with either drug, survival to discharge increased from 23 percent to 28 percent when their cardiac arrest was witnessed by a bystander, researchers report, suggesting using the drugs as soon as possible after they collapse could save even more lives.
Though modest, Kudenchuk said the 3 to 5 percent increase in survival seen during the study could mean 1,800 more people per year survive sudden heart failure, which is significant.
"This trial shows that amiodarone and lidocaine offer hope for bringing patients back to life and into the hospital after cardiac arrest," Kudenchuk said. "While the overall increase in survival to hospital discharge of about 3 percent with amiodarone was not statistically significant, it came very close. Importantly, there was a significant improvement in survival to hospital discharge with either drug when the cardiac arrest was bystander-witnessed."