Myocardial collagen metabolism in failing hearts before and during cardiac resynchronization therapy

In patients with heart failure cardiac resynchronization therapy (CRT) leads to reverse ventricular remodelling.

To evaluate whether myocardial collagen metabolism in patients with heart failure is implicated in adverse ventricular remodelling and response to CRT.

Collagen synthesis and degradation were assessed from the concentrations of aminoterminal propeptides of type I and type III collagen (PINP and PIIINP) and carboxyterminal telopeptide of type I collagen (ICTP), respectively, in serum of 64 patients with heart failure before and after 6 months of CRT. Forty-six patients (72%) showed a > 10% reduction in LV end-systolic volume at follow-up and were classified as responders to CRT, the other 18 patients (28%) were classified as non-responders.

Responders demonstrated a mean (+/-SEM) increase of serum PINP and PIIINP during follow-up, from 32.9+/-2.2 to 46.7+/-4.0 microg/L (p < 0.001) and from 4.59+/-0.24 to 5.13+/-0.36 microg/L (p < 0.05), respectively. In non-responders, serum PINP and PIIINP remained unchanged during follow-up. At baseline, responders had significantly lower serum PINP than non-responders (32.9+/-2.2 vs. 41.8+/-4.3 microg/L; p < 0.05). ICTP levels of responders at baseline tended to be higher than in non-responders (3.54+/-0.56 vs. 2.08+/-0.37 microg/L, p = ns), and in both groups ICTP levels did not change upon CRT.

Reverse LV remodelling following CRT is associated with increased collagen synthesis rate in the first 6 months of follow-up.