title: Right ventricular apical pacing-induced left ventricular dyssynchrony is associated with a subsequent decline in ejection fraction.
abstract: BACKGROUND
  In patients with normal left ventricular (LV) ejection fraction (EF), the interposition of chronic, high-dose right ventricular apical (RVA) pacing may produce late EF decline.
  
  
  OBJECTIVE
  To test the hypothesis that LV dyssynchrony, defined echocardiographically and apparent early after interposition of pacing, would be greater in patients who subsequently demonstrated EF decline.
  
  
  METHODS
  Ninety-one patients with normal prepacing EF who underwent atrioventricular node ablation and subsequent high-dose RVA pacing were studied. Transthoracic echocardiograms were performed early (median 4 months) and late (median 28 months) after interposition of pacing, with a significant decline in EF between these studies defined as ≥5%. Speckle-tracking longitudinal strain analysis of the early echocardiogram was performed to quantify dyssynchrony. In addition to standard dyssynchrony indices, a novel index of apex-to-base mechanical propagation delay (MPD) was used.
  
  
  RESULTS
  Multivariable analysis determined that MPD of the septum correlated with a significant decline in EF, independent of all other dyssynchrony, clinical, or pacing variables. A septal MPD value exceeding 50 ms was associated with EF decline at 81% sensitivity and 88% specificity.
  
  
  CONCLUSIONS
  Dyssynchrony, in particular septal MPD, measured early after interposition of high-dose RVA pacing predicted a significant late decline in EF in patients who had normal prepacing EF.
authors: Heart, Lung and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors: Mohamed
authors: M
authors: Ahmed
authors: Heart, Lung and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors: John
authors: J
authors: Gorcsan
authors: Heart, Lung and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors: Josef
authors: J
authors: Marek
authors: Heart, Lung and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors: Keiko
authors: K
authors: Ryo
authors: Heart, Lung and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors: Kristina
authors: K
authors: Haugaa
authors: Heart, Lung and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors: Daniel
authors: D
authors: R Ludwig
authors: Heart, Lung and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania. Electronic address: schwartzmand@upmc.edu.
authors: David
authors: D
authors: Schwartzman
mesh_terms: D000368:Aged; D002304:Cardiac Pacing, Artificial; D017115:Catheter Ablation; D004452:Echocardiography; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D013318:Stroke Volume / Q000502:physiology*; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology*
keywords: Atrial fibrillation; Dyssynchrony; Echocardiography; Heart failure; Pacemakers