Identification of a novel Scn3b mutation in a Chinese Brugada syndrome pedigree: implications for Nav1.5 electrophysiological properties and intracellular distribution of Nav1.5 and Navß3.

Background: The Scn3b gene encodes for Navß3, a pivotal regulatory subunit of the fast sodium channel in cardiomyocytes. However, its mutation status in the Chinese population suffering from Brugada Syndrome (BrS) has not been characterized, and the contributory pathophysiological mechanisms to disease pathology remain undefined. Methods and Results: A Scn3b (c.260C>T, p.P87l) mutation was identified in a patient with BrS of Chinese descent. Functional analyses demonstrated that sodium channel activation for the wild type, mutant samples, and co-expression of both commenced at -55 mv and peaked at -25 mv. The mutant group exhibited a notable reduction, approximately 60%, in peak sodium channel activation current (INa) at -25 mv. The parameters for half-maximal activation voltages (V1/2) and slope factors (k) showed no significant differences when comparing wild type, mutant, and combined expression groups (P = 0.98 and P = 0.65, respectively). Additionally, no significant disparities were evident in terms of the steady-state sodium channel inactivation parameters V1/2 and k (with P-values of 0.85 and 0.25, respectively), nor were there significant differences in the activation time constant τ (P = 0.59) and late sodium current density (P = 0.23) across the wild-type, mutant, and co-expressed groups. Confocal imaging and Western blot analysis demonstrated decreased plasma membrane localization of SCN3B and SCN5A in the P87l group. Computational simulations of cardiac action potentials suggested that SCN3B P87l can alter the morphology of the action potentials within the endocardium and epicardium while reducing the peak of depolarization. Conclusions: The pathogenic impact of the Scn3b P87l mutation predominantly originates from a reduction in peak INa activation current coupled with decreased cell surface expression of Nav1.5 and Navß3. These alterations may influence cardiac action potential configurations and contribute to the risk of ventricular arrhythmias in individuals with BrS.

The Effect of Female Sex on Short-Term Outcomes of Patients Undergoing Off-Pump Versus On-Pump Coronary Artery Bypass Grafting

ABSTRACT Introduction: According to the American Heart Association guideline for coronary artery bypass grafting (CABG), female patients undergoing on-pump CABG (ONCAB) are at higher risk of short-term adverse outcomes than male patients. However, whether off-pump CABG (OPCAB) can improve the short-term outcome of female patients compared to ONCAB remains unclear. Methods: We conducted a meta-analysis to study the effect of the female sex on short-term outcomes of OPCAB vs. ONCAB. A total of 31,115 patients were enrolled in 12 studies, including 20,245 females who underwent ONCAB and 10,910 females who underwent OPCAB. Results: The in-hospital mortality in female patients who underwent OPCAB was significantly lower than in those in the ONCAB group with (2.7% vs. 3.4%; odds ratio [OR] 0.76; 95% confidence interval [CI] 0.65-0.89) and without (OR 0.68; 95% CI 0.52-0.89) adjustment for cardiovascular risk factor. The incidence of postoperative stroke in female patients who underwent OPCAB was lower than in those in the ONCAB group (1.2% vs. 2.1%; OR 0.59; 95% CI 0.48-0.73) before cardiovascular risk factor adjustment but was not significant (OR 0.87; 95% CI 0,66-1.16) after adjustment. There was no significant difference in the incidence of postoperative myocardial infarction between women who underwent OPCAB and those in the ONCAB group (1.3% vs. 2.3%; OR 0.88; 95% CI 0.54-1.43). Conclusion: In contrast to the American Heart Association CABG guideline, female patients who had OPCAB don't have unfavorable outcomes compared with the ONCAB group.

The Effect of Female Sex on Short-Term Outcomes of Patients Undergoing Off-Pump Versus On-Pump Coronary Artery Bypass Grafting.

INTRODUCTION: According to the American Heart Association guideline for coronary artery bypass grafting (CABG), female patients undergoing on-pump CABG (ONCAB) are at higher risk of short-term adverse outcomes than male patients. However, whether off-pump CABG (OPCAB) can improve the short-term outcome of female patients compared to ONCAB remains unclear. METHODS: We conducted a meta-analysis to study the effect of the female sex on short-term outcomes of OPCAB vs. ONCAB. A total of 31,115 patients were enrolled in 12 studies, including 20,245 females who underwent ONCAB and 10,910 females who underwent OPCAB. RESULTS: The in-hospital mortality in female patients who underwent OPCAB was significantly lower than in those in the ONCAB group with (2.7% vs. 3.4%; odds ratio [OR] 0.76; 95% confidence interval [CI] 0.65-0.89) and without (OR 0.68; 95% CI 0.52-0.89) adjustment for cardiovascular risk factor. The incidence of postoperative stroke in female patients who underwent OPCAB was lower than in those in the ONCAB group (1.2% vs. 2.1%; OR 0.59; 95% CI 0.48-0.73) before cardiovascular risk factor adjustment but was not significant (OR 0.87; 95% CI 0,66-1.16) after adjustment. There was no significant difference in the incidence of postoperative myocardial infarction between women who underwent OPCAB and those in the ONCAB group (1.3% vs. 2.3%; OR 0.88; 95% CI 0.54-1.43). CONCLUSION: In contrast to the American Heart Association CABG guideline, female patients who had OPCAB don't have unfavorable outcomes compared with the ONCAB group.