title: Scar tissue-guided left ventricular lead placement for cardiac resynchronization therapy in patients with ischemic cardiomyopathy: an acute pressure-volume loop study.
abstract: BACKGROUND
  Response to cardiac resynchronization therapy (CRT) is hampered by the extent and location of left ventricular (LV) scar tissue. It is commonly advised to avoid scar tissue while placing the LV lead. However, whether individual patients benefit from this strategy remains unclear.
  
  
  METHODS
  Thirty-two CRT candidates with ischemic cardiomyopathy were enrolled from 2 successive clinical trials (TBS and E-pot study). Magnetic resonance imaging with late contrast enhancement was performed to assess location, degree and transmurality of LV scar tissue. Patients underwent invasive pressure-volume loop measurements to assess acute LV pump function changes during pacing at posterolateral (PL) and anterolateral LV sites.
  
  
  RESULTS
  In the study population (26 [81%] men, ejection fraction [EF] 22% ± 8%, QRS 149 ± 20 milliseconds), baseline mean stroke work (SW) and dP/dtmax were 4.4 ± 2.2 L∙mmHg and 849 ± 212 mmHg/s, respectively. The extent of scar tissue was inversely related to the acute increase in SW during pacing (R = -0.53, P = .002). Stimulating PL scar tissue resulted in deterioration of pump function (∆SW -17% ± 17%, P = .018), whereas pacing PL viable tissue led to an increase in pump function (∆SW +62% ± 51%, P < .001). Switching from pacing at the location of scar tissue, irrespective of the scar location, to viable tissue showed a significant increase in SW (-8% ± 20% vs +20 ± 40, P = .004).
  
  
  CONCLUSIONS
  The extent of LV scar tissue is inversely related to acute pump function improvement during CRT. Pacing at the location of (transmural) scar tissue at any site of the LV will generally deteriorate LV pump function. Placing the LV lead over viable myocardium significantly improves pump function as compared with pacing at the location of scar tissue in patients with ischemic cardiomyopathy.
authors.affiliation: Department of Cardiology, and Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, Amsterdam, The Netherlands. Electronic address: gj.deroest@vumc.nl.
authors.forename: Gerben Jan
authors.initials: GJ
authors.lastname: de Roest
authors.affiliation: Department of Cardiology, and Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: LiNa
authors.initials: L
authors.lastname: Wu
authors.affiliation: Department of Cardiology, and Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Carel C
authors.initials: CC
authors.lastname: de Cock
authors.affiliation: Department of Cardiology, and Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Matthijs L
authors.initials: ML
authors.lastname: Hendriks
authors.affiliation: Department of Cardiology, Isala klinieken, Zwolle, The Netherlands.
authors.forename: Peter Paul H M
authors.initials: PP
authors.lastname: Delnoy
authors.affiliation: Department of Cardiology, and Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, Amsterdam, The Netherlands; Interuniversity Cardiology Institute of the Netherlands (ICIN), Utrecht, The Netherlands.
authors.forename: Albert C
authors.initials: AC
authors.lastname: van Rossum
authors.affiliation: Department of Cardiology, and Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Cornelis P
authors.initials: CP
authors.lastname: Allaart
mesh_terms: D000368:Aged; D002306:Cardiac Volume / Q000502:physiology*; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006352:Heart Ventricles; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D017202:Myocardial Ischemia / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D010138:Pacemaker, Artificial; D025321:Surgery, Computer-Assisted / Q000379:methods*; D016896:Treatment Outcome; D016277:Ventricular Function, Left / Q000502:physiology*; D017725:Ventricular Pressure / Q000502:physiology*