Influence of chronic volume overload-induced atrial remodeling on electrophysiological responses to cholinergic receptor stimulation in the isolated rat atria

Association of RDW, NLR, and PLR with Atrial Fibrillation in Critical Care Patients: A Retrospective Study Based on Propensity Score Matching

Objective

Previous studies have shown inconsistent results in relation to the red cell distribution width (RDW), neutrophil to lymphocyte ratio (NLR), and platelet to lymphocyte ratio (PLR) of atrial fibrillation (AF). This retrospective study is aimed at detecting the association of RDW, NLR, and PLR with AF.

Methods

A total of 4717 critical care patients were screened from the Medical Information Mart for Intensive Care- (MIMIC-) III database. The patients were separated into the non-AF and AF groups. The imbalances between the groups were reduced using propensity score matching (PSM). ROC curves were generated to detect the diagnostic value of RDW, NLR, and PLR. Logistic regression analysis was used to detect the risk factors for AF.

Results

A total of 991 non-AF patients paired with 991 AF patients were included after PSM in this study. The RDW level in the AF group was significantly higher than that in the non-AF group (15.09 ± 1.93vs. 14.89 ± 1.91, P = 0.017). Neither NLR nor PLR showed any significant difference between the two groups (P > 0.05 for each). According to ROC curve, RDW showed a very low diagnostic value of AF (AUC = 0.5341), and the best cutoff of RDW was 14.1 (ACU = 0.5257, sensitivity = 0.658, specificity = 0.395). Logistic regression analysis showed that an elevated RDW level increased 1.308-fold (95%CI = 1.077-1.588, P = 0.007) risk of AF. Neither elevated NLR nor elevated PLR was a significant risk factor for AF (OR = 0.993, 95%CI = 0.802-1.228, P = 0.945 for NLR; OR = 0.945, 95%CI = 0.763-1.170, P = 0.603 for PLR).

Conclusions

Elevated RDW level but not NLR or PLR levels is associated with AF. RDW > 14.1 is a risk factor for AF, but its diagnostic capacity for AF is not of great value.

Electrophysiological Response to Acehytisine Was Modulated by Aldosterone in Rats with Aorto-Venocaval Shunts

Aldosterone induces cardiac electrical and structural remodeling, which leads to the development of heart failure and/or atrial fibrillation (AF). However, it remains unknown whether aldosterone-induced remodeling may modulate the efficacy of anti-AF drugs. In this study, we aimed to jeopardize the structural and functional remodeling by aldosterone in rats with aorto-venocaval shunts (AVS rats) and evaluate the effect of acehytisine in this model. An AVS operation was performed on rats (n = 6, male) and it was accompanied by the intraperitoneal infusion of aldosterone (AVS + Ald) at 2.0 µg/h for 28 d. The cardiopathy was characterized by echocardiography, electrophysiologic and hemodynamic testing, and morphometric examination in comparison with sham-operated rats (n = 3), sham + Ald (n = 6), and AVS (n = 5). Aldosterone accelerated the progression from asymptomatic heart failure to overt heart failure and induced sustained AF resistant to electrical fibrillation in one out of six rats. In addition, it prolonged PR, QT interval and Wenckebach cycle length. Acehytisine failed to suppress AF in the AVS + Ald rats. In conclusion, aldosterone jeopardized electrical remodeling and blunted the electrophysiological response to acehytisine on AF.

Acehytisine suppresses atrial fibrillation in rats with dilated atria caused by chronic volume overload

Atrial dilation is an independent risk factor for the development of atrial fibrillation (AF) and modulates the efficacy of anti-AF drugs, leading to the unsatisfactory control of AF. Pre-clinical studies showed anti-AF effects of acehytisine, a multi-ion channel inhibitor, in atria without structural and/or electrophysiological abnormalities, but information is limited regarding its anti-AF efficacy in dilated atria. We evaluated anti-AF effects of acehytisine at 4 and 10 mg/kg intravenously infused over 10 min using 8-week-old Wistar rats (n = 5; male) with atrial dilation caused by aorto-venocaval shunt (AVS). Echocardiography showed that atria were enlarged by +26.9% after one month of operation in AVS rats compared with sham-operated rats (n = 4; male). Electrophysiological examinations indicated burst pacing-induced AF reached 206 s. Acehytisine at doses of 4 and 10 mg/kg decreased the duration of burst pacing-induced AF with prolongation of Wenckebach cycle length and P wave duration in a dose-dependent manner. Importantly, the drug effectively terminated the persistent AF that was resistant to multiple programmed electrical stimulations in one rat. Therefore, these results provide in vivo evidence that acehytisine may be beneficial for preventing and terminating persistent AF in dilated atria.