By delivering a small shock that gets the heart beating regularly again, implantable cardioverter-defibrillator or ICDs can save the lives of patients with heart conditions. However, new research indicates that this benefit may not extend to patients who’ve had a recent heart attack.

ICD use after a heart attack does reduce deaths caused by abnormal heartbeats, but because this is matched by an increase in deaths from other causes, no drop in the overall death rate occurs, the report shows.

In the current study, Dr. Stefan H. Hohnloser, from J. W. Goethe University in Frankfurt, Germany, and colleagues assessed the outcomes of 674 patients who had an ICD implanted or not within 40 days of experiencing a heart attack.

To be included in the study, the subjects needed to have evidence that the heart was not pumping as well as it should be. On average, the patients were followed for 30 months.

As noted, the overall death rate was not affected by ICD use; 62 patients died in the ICD group compared with 58 in the comparison group, according to the report in The New England Journal of Medicine.

Just 12 abnormal heartbeat-related deaths occurred in the ICD group compared with 29 in the comparison group, a reduction in risk of 58 percent.

For other types of deaths, however, the numbers were reversed, with the ICD and comparison groups experiencing 50 and 29, respectively. Thus, ICD-treated patients were 75 percent more likely to die from other causes than were comparison subjects.

The reason for this increase in other causes of death is unclear, the authors state. “The most likely explanation is that the patients ‘saved’ from a (heartbeat)-related death by ICD therapy are also at high risk for death from other cardiac causes.”

In a related editorial, Dr. Anne M. Gillis, from the University of Calgary in Canada, comments that based on the current findings and others, “routine implantation of an ICD cannot be recommended for all patients” with decreased heart function after a heart attack.

She suggests that “therapy needs to be individualized according to the patient’s risk of sudden cardiac death and the competing risk of death from other causes.”

SOURCE: The New England Journal of Medicine, December 9, 2004.