RESUMO
BACKGROUND: Previous large animal heart failure models led to inhomogeneous results. Therefore, we developed a novel model combining rapid pacing with forced ventricular desynchronization. METHODS: Heart failure was induced in 20 pigs during a pacing period of 21 days. Group A (n = 10) received one right ventricular lead (220 bpm). In group B (n = 10), two leads were implanted in different right ventricular regions with beat-to-beat alternation of activation sites (each lead 110 bpm). Sham-operated pigs (n = 6) served as controls. Hemodynamics were invasively evaluated and tissue was analyzed by immunohistochemistry and zymography. RESULTS: Hemodynamics were significantly more impaired in group B with an increase of pulmonary capillary wedge and central venous pressure and a reduction of cardiac index (control 4.3 +/- 0.1 l/min/m (2); A 3.6 +/- 0.2; B 2.9 +/- 0.2, P < 0.05). Heart-to-body weight ratio was significantly higher in group B. Histological analyses showed a significant increase of cell diameters and interstitial fibrosis with significantly higher collagen contents in group B. CONCLUSION: The new model with a combination of rapid pacing and forced desynchronization of the ventricular contraction is superior to traditional heart failure models induced solely by rapid pacing.