Both obesity and heart failure (HF) are associated with sudden cardiac death. The current study aimed to investigate the effects of overweight and HF on the substrate for ventricular fibrillation (VF), and whether renal denervation (RDN) can protect the heart from sympathetic activation and cardiac remodelling in HF rabbits fed with high-fat diet (HFD).Twenty-four rabbits randomized into control group fed with regular diet (Control), HFD, HFD-HF, and HFD-HF-RDN groups. Rapid ventricular pacing of 400 b.p.m. for 4 weeks was applied in HFD-HF and HFD-HF-RDN. Surgical and chemical RDNs were approached through bilateral retroperitoneal flank incisions in HFD-HF-RDN. All rabbits received electrophysiological study and a VF inducibility test. The ventricular myocardium was harvested for trichrome stain. After 3 months, mean body weight was heavier in HFD, compared with control (3.5 ± 0.1 kg vs. 2.6 ± 0.1 kg, P < 0.01). No differences in body weight among the three groups fed with HFD were observed. The ventricular refractory periods were longer in HFD-HF and HFD-HF-RDN than in control. An extension of ventricular fibrosis was observed in HFD and HFD-HF compared with control, and the degree of ventricular fibrosis was suppressed in HFD-HF-RDN compared with HFD-HF. The level of tyrosine hydroxylase staining was reduced in HFD-HF-RDN compared with HFD and HFD-HF. Importantly, VF inducibility was lower in HFD-RDN-HF (10 ± 4%), when compared with those in HFD-HF (58 ± 10%, P < 0.01) and HFD (42 ± 5%, P < 0.05), respectively.Our results suggest that overweight and HF increase sympathetic activity, structural remodelling, and VF inducibility, but RDN prevents them.
