title: Long term impact of cardiac contractility modulation on QRS duration.
abstract: OBJECTIVE
  Cardiac contractility modulation (CCM) is an implantable device treatment for heart failure with reduced ejection fraction. CCM therapy improves patient functional status but its effect on intra-ventricular conduction remains unknown.
  
  
  METHODS
  70 patients treated with CCM between 12/2002 and 5/2013 had 12-vector-ECG recordings made at baseline and final follow-up visits. QRS complex duration was measured at each time point.
  
  
  RESULTS
  Mean follow-up was 2.8 years. Mean QRS duration was unchanged from baseline (112.0 ms) to last follow up (112.9 ms, p=n.s.). These results are strikingly different from comparative published data of several studies with heart failure patients without CCM, consistently indicating an increase in QRS duration (6.0-23.4 ms) over a similar time period.
  
  
  CONCLUSIONS
  CCM prevents chronic ventricular depolarization delay that occurs in heart failure and that is associated with poorer outcomes. This supports the safety of long-term CCM therapy and suggests a possible long-term benefit in maintaining QRS duration.
authors.affiliation: Medical Faculty Mannheim of the University of Heidelberg, 1st Department of Medicine, Mannheim, Germany; DZHK (German Centre for Cardiovascular Research) partner site Mannheim, Germany. Electronic address: susanroeger@hotmail.com.
authors.forename: Susanne
authors.initials: S
authors.lastname: Röger
authors.affiliation: Medical Faculty Mannheim of the University of Heidelberg, 1st Department of Medicine, Mannheim, Germany; DZHK (German Centre for Cardiovascular Research) partner site Mannheim, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Michels
authors.affiliation: Medical Faculty Mannheim of the University of Heidelberg, 1st Department of Medicine, Mannheim, Germany; DZHK (German Centre for Cardiovascular Research) partner site Mannheim, Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Heggemann
authors.affiliation: Medical Faculty Mannheim of the University of Heidelberg, 1st Department of Medicine, Mannheim, Germany; DZHK (German Centre for Cardiovascular Research) partner site Mannheim, Germany.
authors.forename: Ksenija
authors.initials: K
authors.lastname: Stach
authors.affiliation: Impulse Dynamics, Hod Hasharon, Israel.
authors.forename: Benny
authors.initials: B
authors.lastname: Rousso
authors.affiliation: Medical Faculty Mannheim of the University of Heidelberg, 1st Department of Medicine, Mannheim, Germany; DZHK (German Centre for Cardiovascular Research) partner site Mannheim, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Borggrefe
authors.affiliation: Medical Faculty Mannheim of the University of Heidelberg, 1st Department of Medicine, Mannheim, Germany; DZHK (German Centre for Cardiovascular Research) partner site Mannheim, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Kuschyk
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000150:complications / Q000175:diagnosis* / Q000517:prevention & control*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000150:complications / Q000175:diagnosis* / Q000517:prevention & control*
keywords: Cardiac contractility modulation; ECG; Heart failure