"Although there are a number of factors that contribute to these findings, this study has significant clinical importance to prevention strategies and treatment of coronary heart disease, ventricular arrhythmias, and sudden death," said Stephen C. Hammill, M.D., president, Heart Rhythm Society. "It is important that we do everything we can to ensure that the cardiac mortality rate continues to decline."

Researchers from the Mayo Clinic examined the incidence rates and trends of patients from Rochester, Minnesota, since 1985 who experienced out-of-hospital cardiac arrest, were treated with an AED by emergency responders, and later received an ICD implant. Twenty-two patients had life-threatening ventricular arrhythmias corrected by their ICD. Termination of potentially fatal arrhythmias increased from 1.1 to 3.5 per 100,000 over the study period, and VF out-of-hospital cardiac arrest declined from 26.3 to 7.7 per 100,000.

"Identifying high-risk individuals is especially important because approximately half of sudden cardiac deaths were not preceded by a diagnosis of coronary heart disease," said Roger D. White, M.D., the study's lead investigator. "Considering recent trial results such as MADIT II, we expect that the number of patients who receive an ICD for primary prevention will increase progressively over the next decade. This trial tells us that we can then also expect the decline in deaths from cardiac arrest to continue."

The journal article is published in the September issue of Heart Rhythm.