March 30th, 2014
Long-Term Follow-Up from MADIT-CRT: Guideline Implications
Arthur J. Moss, MD
CardioExchange’s John Ryan interviews Arthur J. Moss about his research group’s study of long-term survival for patients who received cardiac resynchronization therapy with a defibrillator (CRT-D) in the MADIT-CRT trial. The findings were presented at ACC.14 and published simultaneously in The New England Journal of Medicine.
Seven-year follow-up in the MADIT-CRT trial was tracked, on an intention-to-treat basis, for all 1691 surviving participants and, subsequently, for 854 participants who were enrolled in post-trial registries. The cumulative all-cause mortality rate among patients with left bundle-branch block (LBBB) was significantly lower in the CRT-D group than in the defibrillator-alone group (18% vs. 29%). However, in patients without LBBB, CRT-D had no benefit and showed possible harm.
Ryan: Your results are very impressive. Will they compel us to change our practice and offer CRT-D to patients who have asymptomatic or mild congestive heart failure?
Moss: On the basis of data from our prior studies and publications (N Engl J Med 2010; 363:2385; MADIT-CRT), CRT-D is already approved for patients with asymptomatic or mild heart failure, a reduced LV ejection fraction, and a left bundle-branch block (LBBB) conduction disturbance. The current findings published in the NEJM strengthen the guideline indications, given the significant reduction in all-cause mortality during long-term (7-year) follow-up with CRT-D treatment in these patients.
Ryan: The 2013 heart failure guidelines list CRT as a class IIa recommendation for patients who have a “non-LBBB pattern with a QRS duration of >150 msec.” Given your findings, should this recommendation be revisited?
Moss: The 2013 heart failure guidelines should be revised because our original trial results from 2010 showed no benefit of CRT-D in reducing the incidence of heart failure in patients with a non-LBBB pattern even with a wide QRS duration >150 msec. Findings from our current trial show no evidence of mortality reduction during long-term follow-up.
Share your thoughts on Dr. Moss’ analysis of the long-term results from MADIT-CRT.
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Realizing your trial only included new implants, how do feel these data can be applied in the situation of a device upgrade.
Consider the case of a 60 yo male chronic ICD patient, perhaps implanted with a primary prevention ICD prior to MADIT CRT or REVERSE trials. This patient has a dilated nonischemic cardiomyopathy with LVEF 25%, LBBB, QRS 152 msec and stable class II on appropriate optimized medical therapy. His left side dual chamber ICD is RV pacing <0.1% and he's in the office for a routine visit 5 years after the implant. His leads are not under advisory. He's had a good year with no new complaints and his ICD check is favorable with no hardware abnormalities and no new therapies. He has an anticipated 3 years left until device ERI. On exam, you see venous collaterals over the left chest and a modest asymmetric JVP elevation of the left IJ.
Do you recommend CRT upgrade?
What if he had no venous collaterals on exam?
Would you consider performing left subclavian vein angiograpy prior to making a recommendation?
What if his device is due for ERI in 6 months?
As a busy clinical electrophysiologist, I see similar scenarios commonly. Do you think the new mortality data affects your approach in this decision process.
Thanks in advance for your thoughts.
Edward J Schloss MD FACC FHRS
Medical Director, Cardiac Electrophysiology
The Christ Hospital
The whole lbbb, ivcd and rbbb division is difficult. The definitions are not widely understood and were not directly specified in much of the original trials. Is there a difference between ivcd and rbbb. And patien with rbbb and a very broad qrs often have conduction delay in the left ventricle. I’m struggling with what to do advise in a patient with severe heart failure, Ef 20% and rbbb qrs 180ms, bearing in mind the guidelines and the data!
Thanks for your question regarding your interesting patient. If it weren’t for the probable left-sided venous occlusion (? left upper sublcavian or innominate vein), we would probably upgrade his ICD to a CRT-D. However, the venous problem will increase the likelihood of a procedure complication so my recommendation is simply to replace the ICD at ERI. If your patient were having active symptoms or evidence of increasing dyssynchrony or heart failure, then the risk/benefit considerations might favor an upgrade to CRT-D. If CRT-D becomes indicated then a venous angiogram before device upgrade would be appropriate.
I hope this helps. From your questions, I am sure you came to the same conclusions.