Long Waits for Defibrillators Increase Mortality

Waiting the guideline-mandated three months or nine months required between diagnosis of nonischemic dilated cardiomyopathy (NIDCM) and placement of an implantable cardioverter-defibrillator (ICD) may not be in the best interest of some patients, according to a new study.

Researchers from the Feinberg School of Medicine at Northwestern University (Chicago, IL, USA) analyzed data from the defibrillators in a nonischemic cardiomyopathy treatment evaluation trial that included patients with NIDCM and left ejection fraction of less than 36% and excluded individuals with potentially reversible NIDCM. A total of 458 patients were randomly assigned to standard medical therapy with or without an ICD, regardless of time since diagnosis. The researchers evaluated outcomes as related to time between diagnosis and randomization to ICD treatment or not, with three months and nine months as cut-off points.

When a cut-off point of three months was used, 10.2% of patients with recently diagnosed NIDCM died within the next 2.5 years, whereas among patients who were treated nine months after diagnosis, 11.2% died during the same period. The all-cause mortality rate was 7.3% in those diagnosed within three months of ICD treatment, compared with 15% among those who were treated more than three months after diagnosis. The difference around the nine-month cut-off point was similar: 9.2% mortality before vs 15.6% after. The results were published in the June 20, 2006, issue of the Journal of the American College of Cardiology.

"The primary theoretical reason [for waiting several months] is that there are some people who develop myocarditis who will get better, and because of that concern, people shouldn't get implanted immediately after diagnosis,” said lead author Dr. Alan Kadish. "However, I think this guideline should be reevaluated because, based on the data from this trial and other retrospective studies, there is evidence that some people don't do well if they wait.”

The researchers noted that a task force of experts should develop a list of reversible myopathies for which the need for an ICD would be ruled out, thereby identifying patients who should be treated soon after diagnosis.