September 3rd, 2013
For CRT, Let ECG — Not Echo — Be Your Guide
Clyde Yancy, MD and John Ryan, MD
CardioExchange’s John Ryan interviews Clyde Yancy, who co-wrote the NEJM editorial about the EchoCRT Study Group’s randomized trial of echocardiography-guided CRT for patients with NYHA class III–IV heart failure and a narrow QRS complex. The trial was presented at the European Society of Cardiology conference in Amsterdam.
THE STUDY
Ruschitzka and colleagues evaluated the effect of cardiac resynchronization therapy (CRT) in patients with NYHA class III or IV heart failure, an LV ejection fraction ≤35%, a QRS duration <130 msec, and echocardiographic evidence of LV dyssynchrony. Participants from 115 centers underwent device implantation and were randomly assigned to have CRT capability turned on or off. In March 2013, with 809 patients randomized (mean follow-up, 19.4 months), the study was stopped. Incidence of the primary endpoint — a composite of death from any cause or first hospitalization for worsening heart failure — was 28.7% in the CRT group and 25.2% in the control group, a nonsignificant difference. The mortality rate was significantly greater in the CRT group (11.1% vs. 6.4% in the control group).
INTERVIEW WITH THE EDITORIALIST
Ryan: What should a busy practitioner take from this study? Is this just reinforcing existing guidelines, or is anything new?
Yancy: The findings offer several takeaways for the practitioner:
1. We need to focus on the sweet spot of efficacy for CRT, making every effort to optimize device therapy in those with the strongest indications — i.e., wide QRS, LBBB pattern already on optimal guideline directed care.
2. As with so many other proven therapies in heart failure, we remain uncertain about the true markers of benefit for CRT. Arguably, it isn’t truly necessary to discover mechanical dyssynchrony, whereas it is imperative to identify a wide QRS.
3. We are once again reminded of the perils of “indication creep.” Pushing indications for proven therapies into categories that are heuristically reasonable but substantively unproven might be a major therapeutic misstep.
4. Most important, our guidelines and the process used to generate them really work. As we enter an increasingly transparent era of clinical practice with greater practitioner accountability and much more financial risk, having trusted practice templates will serve our community well.
Ryan: Was there anything less than straightforward about the trial — something fellows should notice about how it was done?
Yancy: Clinical trials remain challenging. Those of us who define our skill set as that of “clinical trialists” should beware. An excellent investigatory group conducted this study, yet a substantial number of patients withdrew, were lost to follow-up, or couldn’t be contacted. That’s not sloppy—it’s the reality of the process. All readers, especially fellows, need to appreciate the incredible number of potential permutations and perturbations that can surface when designing and implementing a clinical trial. This isn’t an easy business.
JOIN THE DISCUSSION
What lessons do you take away from the EchoCRT trial? Do you agree with Dr. Yancy?
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