title: Cardiac resynchronization therapy in patients with heart failure and a QRS complex <120 milliseconds: the Evaluation of Resynchronization Therapy for Heart Failure (LESSER-EARTH) trial.
abstract: BACKGROUND
  Although the benefits of cardiac resynchronization therapy 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.
  
  
  RESULTS
  The Evaluation of Resynchronization Therapy for Heart Failure (LESSER-EARTH) trial is a randomized, double-blind, 12-center study that was designed to compare the effects of active and inactive cardiac resynchronization therapy in patients with severe left ventricular dysfunction and a QRS duration <120 milliseconds. The trial was interrupted prematurely by the Data Safety and Monitoring Board because of 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 cardiac resynchronization therapy (-0.7 minutes [95% confidence interval (CI), -2.9 to 1.5] versus 0.8 minutes [95% CI, -1.2 to 2.9]; P=0.31]. Similarly, no significant differences were observed in left ventricular end-systolic volumes (-6.4 mL [95% CI, -18.8 to 5.9] versus 3.1 mL [95% CI, -9.2 to 15.5]; P=0.28) and ejection fraction (3.3% [95% CI, 0.7-6.0] versus 2.1% [95% CI, -0.5 to 4.8]; P=0.52). Moreover, cardiac resynchronization therapy was associated with a significant reduction in the 6-minute walk distance (-11.3 m [95% CI, -31.7 to 9.7] versus 25.3 m [95% CI, 6.1-44.5]; P=0.01), an increase in QRS duration (40.2 milliseconds [95% CI, 34.2-46.2] versus 3.4 milliseconds [95% CI, 0.6-6.2]; P<0.0001), and a nonsignificant trend toward 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 milliseconds, cardiac resynchronization therapy did not improve clinical outcomes or left ventricular remodeling and was associated with potential harm.
  
  
  BACKGROUND
  URL: http://www.clinicaltrials.gov. Unique identifier: NCT00900549.
authors: Montreal Heart Institute, Université de Montréal, Montreal, QB, Canada. bernard.thibault@umontreal.ca
authors: Bernard
authors: B
authors: Thibault
authors: François
authors: F
authors: Harel
authors: Anique
authors: A
authors: Ducharme
authors: Michel
authors: M
authors: White
authors: Kenneth A
authors: KA
authors: Ellenbogen
authors: Nancy
authors: N
authors: Frasure-Smith
authors: Denis
authors: D
authors: Roy
authors: François
authors: F
authors: Philippon
authors: Paul
authors: P
authors: Dorian
authors: Mario
authors: M
authors: Talajic
authors: Marc
authors: M
authors: Dubuc
authors: Peter G
authors: PG
authors: Guerra
authors: Laurent
authors: L
authors: Macle
authors: Léna
authors: L
authors: Rivard
authors: Jason
authors: J
authors: Andrade
authors: Paul
authors: P
authors: Khairy
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D004311:Double-Blind Method; D005080:Exercise Test / Q000379:methods / Q000523:psychology; D005260:Female; D006333:Heart Failure / Q000503:physiopathology* / Q000523:psychology / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011788:Quality of Life / Q000523:psychology; D016896:Treatment Outcome; D020257:Ventricular Remodeling / Q000502:physiology*