Amiodarone Versus Propafenone to Treat Atrial Fibrillation after Coronary Artery Bypass Grafting: A Randomized Double Blind Controlled Trial

Association between amiodarone use and risk of cataract: a population-based active-comparator study

BACKGROUND

Despite previous concerns about ocular side effects related to amiodarone, the relationship between amiodarone and cataract remains uncertain. Therefore, this study aimed to assess the potential association between amiodarone use and the subsequent risk of cataract, taking into account potential confounders.

METHODS

This population-based, active comparator-controlled cohort study utilized the data from the Taiwan National Health Insurance program and involved adults over 40 years old between 2001 and 2013. We analyzed 12 055 new amiodarone users and contrasted them with a propafenone user cohort. The primary outcome was the incidence of cataract. Inverse-probability treatment-weighting (IPTW) was further used to eliminate the potential confounding effects, and Cox proportional-hazard regression analyses were performed to calculate the risk of cataract. Serial subgroup analyses were also performed.

RESULTS

In the main analysis, amiodarone users did not exhibit a significant causal relationship in both full cohort [adjusted hazard ratio (aHR): 0.994, 95% confidence interval (CI): 0.913-1.082] and IPTW cohort (IPTW-aHR 0.977, 95% CI: 0.900-1.060). Furthermore, it is important to highlight a significantly reduced risk of cataract among patients with heart failure (IPTW-aHR 0.708, 95% CI: 0.554-0.905) and during the 2-year follow-up period (IPTW-aHR 0.889, 95% CI: 0.794-0.996), implying potential advantages linked to the use of amiodarone.

CONCLUSIONS

The study found no increased risk of cataract with amiodarone, one of the most frequently used antiarrhythmic medications, compared to the use of propafenone. Future research is recommended to explore potential mechanisms and their implications for clinical practice.

Amiodarone but not propafenone impairs bioenergetics and autophagy of human myocardial cells

Cardiac and extra-cardiac side effects of common antiarrhythmic agents might be related to drug-induced mitochondrial dysfunction. Supratherapeutic doses of amiodarone have been shown to impair mitochondria in animal studies, whilst influence of propafenone on cellular bioenergetics is unknown. We aimed to assess effects of protracted exposure to pharmacologically relevant doses of amiodarone and propafenone on cellular bioenergetics and mitochondrial biology of human and mouse cardiomyocytes. In this study, HL-1 mouse atrial cardiomyocytes and primary human cardiomyocytes derived from the ventricles of the adult heart were exposed to 2 and 7 μg/mL of either amiodarone or propafenone. After 24 h, extracellular flux analysis and confocal laser scanning microscopy were used to measure mitochondrial functions. Autophagy was assessed by western blots and live-cell imaging of lysosomes. In human cardiomyocytes, amiodarone significantly reduced mitochondrial membrane potential and ATP production, in association with an inhibition of fatty acid oxidation and impaired complex I- and II-linked respiration in the electron transport chain. Expectedly, this led to increased anaerobic glycolysis. Amiodarone increased the production of reactive oxygen species and autophagy was also markedly affected. In contrast, propafenone-exposed cardiomyocytes did not exert any impairment of cellular bioenergetics. Similar changes after amiodarone treatment were observed during identical experiments performed on HL-1 mouse cardiomyocytes, suggesting a comparable pharmacodynamics of amiodarone among mammalian species. In conclusion, amiodarone but not propafenone in near-therapeutic concentrations causes a pattern of mitochondrial dysfunction with affected autophagy and metabolic switch from oxidative metabolism to anaerobic glycolysis in human cardiomyocytes.

The effect of nanocurcumin on the incidence of atrial fibrillation, and markers of inflammation and oxidative stress level after coronary artery bypass graft surgery: A randomized, double-blind, placebo-controlled clinical study

Objective

Postoperative atrial fibrillation (POAF) is the most frequent dysrhythmias observed following coronary artery bypass graft (CABG) surgery. Several studies have shown the beneficial effects of curcumin on cardiovascular diseases; however, there is no clinical trial to examine its effect on POAF. This randomized, double-blind, placebo-controlled clinical study was designed to evaluate the prophylactic effects of a nano-formulation of curcumin (SinaCurcumin™) versus placebo on POAF and levels of biomarkers of inflammation and oxidative stress in patients undergoing CABG surgery.

Materials and Methods

A total of 234 eligible patients were randomized to receive 240 mg curcumin nano-formulation or placebo three days prior to the surgery and on the first four postoperative days. The occurrence of POAF was monitored for at least 96 hr after the surgery. Also, C-reactive protein (hs-CRP), malondialdehyde (MDA) and glutathione (GSH) levels were assessed at baseline and the end of the study.

Results

Analyses were done in the intention-to-treat population. No significant difference was observed in the occurrence of POAF between the treatment (9.5%) and placebo (11.5%) groups. Also, curcumin intervention did not alter serum concentration of the hs-CRP, MDA, or GSH in comparison with placebo.

Conclusion

In conclusion, it seems that perioperative treatment with SinaCurcumin™ did not prevent POAF after CABG surgery.