Abstract 5881: Influence Of Cardiac Inflammation And Extracellular Matrix Regulation On Diastolic Dysfunction In Patients With Heart Failure With Normal Ejection Fraction
Aims: One of the hemodynamic mechanisms underlying heart failure with normal EF (HFNEF) is increased LV stiffness. In order to clarify the pathological changes leading to increased stiffness we investigated the left ventricular (LV) function using pressure-volume loops under basal conditions and during atrial pacing and investigated endomyocardial biopsies of patients with HFNEF.
Methods: In 36 patients with HFNEF and 8 controls pressure volume loops were measured under basal conditions and during atrial pacing. Furthermore, endomyocardial biopsies were analyzed for changes in the extracellular matrix regulation, cardiac inflammation and changes in the titin isoforms.
Results: Patients with HFNEF had an increased LV diastolic stiffness (+350%) compared to controls. During atrial pacing, stroke volume decreased (−35%) due to a leftward shift of the PV loops. This was associated with increased collagen content in cardiac biopsies (+380%), which blunted their cardiac output response to enhanced cardiac demand. This may explain the exercise intolerance in HFNEF patients. The total collagen correlated with cardiac stiffness in the HFNEF group (r2=0.69). This was associated with increased mRNA levels of the pro fibrotic TGF-b. Furthermore, the collagenase matrix metalloproteinases (MMP) 1 was not changed while TIMP-1 was increased (+150%), which supposes a decrease in collagen degradation in HFNEF. Nevertheless, MMP 2 was increased (+160%). This MMP is also associated with inflammation, and coherently, we investigated cardiac inflammation. We documented increased cardiac inflammation by an increment of adhesion molecules (ICAM +55%) and invading cells (CD11b cells +250%) in the cardiac tissue of HFNEF patients compared to controls. Interestingly, there was no change in titin isoforms between both groups.
Conclusion: Patients with HFNEF have increased diastolic stiffness leading to an impairment of the Frank-Starling mechanism during atrial pacing. Since increased stiffness correlated with the cardiac collagen content, changes in the ECM regulation might be important for the development of HFNEF and invading cells triggering cardiac inflammation might further participate in this pathophysiology.