CardioExchange Archive

Dr. Moss, principal investigator of the MADIT-RIT trial, comments on the clinical implications of his study group’s research.

THE STUDY

In a trial funded by implantable cardioverter-defibrillator (ICD) manufacturer Boston Scientific, researchers randomized 1500 patients with a primary indication to receive an ICD programmed in one of three ways:

• high-rate therapy: a 2.5-second delay before therapy initiation at a heart rate of ≥200 bpm
• delayed therapy: a 60-second delay at 170–199 bpm, a 12-second delay at 200–249 bpm, and a 2.5-second delay at ≥250 bpm
• conventional therapy: a 2.5-second delay at 170–199 bpm and a 1-second delay at ≥200 bpm

During a mean follow-up of 1.4 years, both the high-rate and delayed-therapy groups had significantly lower rates of a first occurrence of inappropriate therapy than did the conventionally treated group (4%–5% vs. 20%). The all-cause mortality rate was 7% in the conventionally treated group — significantly higher than in the high-rate group (3%) and nonsignificantly higher than in the delayed-therapy group (4%).

THE EXPERT RESPONDS

Q:  Do the findings from your trial effectively sound the death knell for conventional programming of ICDs? Will clinicians who continue to use conventional programming be considered remiss?

Moss: The findings from the randomized trial are very strong, so it is likely that clinicians involved in implanting and following patients with ICDs will reprogram the ICDs to the safer, more effective mode. That is how medicine is practiced.

Q: Should clinicians simply focus on high-rate programming rather than delayed programming?

Moss: Yes, that would be my recommendation. High-rate therapy was not statistically superior to delayed therapy, but high-rate therapy is much simpler to program. And patients in the trial who received high-rate therapy fared best overall.

Q: Is it time for ICD programming guidelines to be changed? Or do these results need to be confirmed in other trials that test devices made by other manufacturers?

Moss: The programming ICD guidelines need to be updated. We always like confirmation by another randomized trial or equivalent study.

Q: Are we entering an era when expertise and care in programming an ICD will become as important as expertise in implanting it? In effect, do we need to dedicate more clinical focus to the technical details of programming?

Moss: Our findings significantly simplify ICD programming and should result in less focus on the technical details of device programming.

Offer your reflections on the clinical implications of the MADIT-RIT trial. 

For related CardioExchange content, go to our AHA 2012 Headquarters page. For Dr. Mark Link’s perspective on MADIT-RIT, click over to Journal Watch here.