Statins to prevent pacing-induced cardiomyopathy: Evidence from the bench applied to clinical studies

Background: Pacing-induced cardiomyopathy is an undesired outcome in patients with atrioventricular block (AVB), and our animal model showed lipotoxic cardiomyopathy after pacing. Objectives: The purpose of this study was to explore the mechanisms and clinical outcomes of statins in AVB patients receiving pacing. Methods: Rat ventricular cardiomyocytes were treated with atorvastatin, liver X receptor (LXR) agonist, and LXR antagonist during pacing. Pigs were divided into 3 groups: right ventricular pacing, pacing with concomitant atorvastatin treatment, and sham control. Clinically, we enrolled 1717 AVB patients who had received a permanent pacemaker from Chang Gung Memorial Hospital Medical database. The primary outcome (cardiovascular death or heart failure [HF] hospitalization) and individual outcome were compared between statin and nonstatin groups after inverse probability of treatment weighting. Results: Lipid accumulation in rat cardiomyocytes by pacing was significantly reduced by treatment with LXR agonist and atorvastatin, whereas LXR antagonist counteracted the atorvastatin effect on lipid expression. Left ventricular ejection fraction (LVEF) was significantly lower in the AVB pig pacing group compared to the group concomitantly treated with atorvastatin. Moreover, lipid accumulation and fibronectin expression were significantly ameliorated by concomitant treatment with atorvastatin. In the clinical study, the statin group had a significantly lower risk of the primary outcome event (hazard ratio [HR] 0.69; 95% confidence interval [CI] 0.56–0.84), less HF hospitalization (HR 0.45; 95% CI 0.30–0.67), and higher LVEF than the nonstatin group. Conclusion: In experimental models, atorvastatin ameliorated lipid accumulation in cardiomyocytes and fibrosis in left ventricular myocardium induced by pacing. Clinically, treatment with statins was associated with less HF hospitalization and cardiovascular death in AVB patients receiving pacemaker therapy.