Cardiac Resynchronization Therapy in Patients with Heart Failure and a QRS Complex <120 ms: the LESSER-EARTH Trial
Background—While the benefits of cardiac resynchronization therapy (CRT) are well established in selected patients with heart failure and a prolonged QRS duration, salutary effects in patients with narrow QRS complexes remain to be demonstrated.
Methods and Results—The LESSER-EARTH trial is a randomized, double-blind, 12-center study that was designed to compare the effects of active versus inactive CRT therapy in patients with severe left ventricular dysfunction and a QRS duration <120 ms. The trial was prematurely interrupted by the Data Safety and Monitoring Board due to futility and safety concerns after 85 patients were randomized. Changes in exercise duration after 12 months were no different in patients with and without active CRT [-0.7 (-2.9, 1.5) minutes versus +0.8 (-1.2, 2.9) minutes, P=0.31]. Similarly, no significant differences were observed in left ventricular end-systolic volumes [-6.4 (-18.8, 5.9) mL versus +3.1 (-9.2, 15.5) mL, P=0.28] and ejection fraction [+3.3% (0.7%, 6.0%) versus +2.1% (-0.5%, 4.8%), P=0.52]. Moreover, CRT was associated with a significant reduction in the 6-minute walk distance [-11.3 (-31.7, 9.7) meters versus +25.3 (6.1, 44.5) meters, P=0.01], an increase in QRS duration [40.2 (34.2, 46.2) ms versus 3.4 (0.6, 6.2) ms, P<0.0001], and a non-significant trend towards an increase in heart failure-related hospitalizations (15 hospitalizations in 5 patients versus 4 hospitalizations in 4 patients).
Conclusions—In patients with a left ventricular ejection fraction ≤35%, symptoms of heart failure, and a QRS duration <120 ms, CRT did not improve clinical outcomes or left ventricular remodelling, and was associated with potential harm.
Clinical Trial Registration Information—ClinicalTrials.gov. Identifier: NCT00900549.
- Received January 9, 2013.
- Accepted January 11, 2013.
- Copyright © 2013, Circulation