title: The Relationship of Myocardial Collagen Metabolism and Reverse Remodeling after Cardiac Resynchronization Therapy.
abstract: BACKGROUND
  In the majority of patients with a wide QRS complex and heart failure resistant to optimal medical therapy, cardiac resynchronization therapy (CRT) leads to reverse ventricular remodeling and possibly to changes in cardiac collagen synthesis and degradation. We investigated the relationship of biomarkers of myocardial collagen metabolism and volumetric response to CRT.
  
  
  METHODS
  We prospectively studied 46 heart failure patients (mean age 61±9 years, 87% male) who underwent CRT implantation. Plasma concentrations of amino-terminal propeptide type I (PINP), a marker of collagen synthesis, and carboxy-terminal collagen telopeptide (CITP), a marker of collagen degradation, were measured before and 6 months after CRT. Response to CRT was defined as 15% or greater reduction in left ventricular end-systolic volume at 6-month follow-up.
  
  
  RESULTS
  Baseline PINP levels showed a negative correlation with both left ventricular end-diastolic volume (r=-0.51; p=0.032), and end-systolic diameter (r=-0.47; p=0.049). After 6 months of device implantation, 28 patients (61%) responded to CRT. No significant differences in the baseline levels of PINP and CITP between responders and nonresponders were observed (p>0.05 for both). During follow-up, responders demonstrated a significant increase in serum PINP level from 31.37±18.40 to 39.2±19.19 μg/L (p=0.049), whereas in non-responders serum PINP levels did not significantly change (from 28.12±21.55 to 34.47± 18.64 μg/L; p=0.125). There were no significant changes in CITP levels in both responders and non-responders (p>0.05).
  
  
  CONCLUSIONS
  Left ventricular reverse remodeling induced by CRT is associated with an increased collagen synthesis in the first 6 months of CRT implantation.
authors.affiliation: School of Medicine, University of Belgrade, Belgrade, Serbia.
authors.forename: Ivana
authors.initials: I
authors.lastname: Petrovic
authors.affiliation: Department of Cardiology, University Clinical Hospital Centre Zemun, Belgrade, Serbia.
authors.forename: Ivan
authors.initials: I
authors.lastname: Stankovic
authors.affiliation: School of Medicine, University of Belgrade, Belgrade, Serbia; Pacemaker Center, Clinical Center of Serbia, Medical Faculty, University of Belgrade, Belgrade, Serbia.
authors.forename: Goran
authors.initials: G
authors.lastname: Milasinovic
authors.affiliation: Pacemaker Center, Clinical Center of Serbia, Medical Faculty, University of Belgrade, Belgrade, Serbia.
authors.forename: Gabrijela
authors.initials: G
authors.lastname: Nikcevic
authors.affiliation: Pacemaker Center, Clinical Center of Serbia, Medical Faculty, University of Belgrade, Belgrade, Serbia.
authors.forename: Bratislav
authors.initials: B
authors.lastname: Kircanski
authors.affiliation: Pacemaker Center, Clinical Center of Serbia, Medical Faculty, University of Belgrade, Belgrade, Serbia.
authors.forename: Velibor
authors.initials: V
authors.lastname: Jovanovic
authors.affiliation: Pacemaker Center, Clinical Center of Serbia, Medical Faculty, University of Belgrade, Belgrade, Serbia.
authors.forename: Srdjan
authors.initials: S
authors.lastname: Raspopovic
authors.affiliation: Pacemaker Center, Clinical Center of Serbia, Medical Faculty, University of Belgrade, Belgrade, Serbia.
authors.forename: Nikola
authors.initials: N
authors.lastname: Radovanovic
authors.affiliation: School of Medicine, University of Belgrade, Belgrade, Serbia; Pacemaker Center, Clinical Center of Serbia, Medical Faculty, University of Belgrade, Belgrade, Serbia.
authors.forename: Sinisa U
authors.initials: SU
authors.lastname: Pavlovic
keywords: cardiac resynchronization therapy; collagen metabolism; reverse remodeling