3, 4-Benzopyrene (Bap) aggravated abdominal aortic aneurysm formation by targeting pyroptosis in smooth muscle cells through ET-1 mediated NLRP3-inflammasome activation

According to epidemiological studies, smoking is one of the leading causes of the high incidence of abdominal aortic aneurysms (AAA).3,4-Benzopyrene (Bap) is a by-product of coal tar and tobacco combustion produced by the incomplete combustion of organic fuels. It is an essential component of both automobile exhaust and tobacco smoke, it is also an important member of the air pollutants. However, the exact mechanism by which Bap can worsen the condition of patients with AAA and increase the mortality of patients with AAA remains unknown. This research aims to investigate the role of Bap in inducing pyroptosis in AAA. In vitro experiments, we revealed that pyroptosis-Gasdermin D (GSDMD) increased when Bap was used. Additionally, the release of inflammatory factors, such as IL-1β and IL-18 were also rising. An mRNA sequencing analysis revealed that macrophages expressed a high level of the endothelin gene when cells were stimulated by Bap. It seemed that smooth muscle cells pyroptosis was related to macrophages. Experiments revealed that endothelin could increase the calcium ion concentration in smooth muscle cells, resulting in a large amount of ROS and activation of NLRP3 inflammasomes. We discovered that treatment with endothelin receptor antagonist (ABT-546) in vivo and calcium ion chelator (BAPTA) in vitro decreased AAA diameter, downregulated NLRP3 inflammasomes and ROS, and significantly reduced the number of activated GSDMD. Inflammatory mediators were released at a lower level. These findings suggest that Bap-induced pyroptosis may be mediated by the ET-1-Ca2+-inflammasome pathway, providing a new way to reduce mortality in AAA patients.

The safety of catheter ablation for premature ventricular contractions in patients without structural heart disease

Background

Patients with frequent premature ventricular contractions (PVCs) are often symptomatic. Catheter ablation was usually indicated to eliminate symptoms in patients with PVCs-induced cardiomyopathy. Currently, PVCs-ablation is also applied for patients with PVCs and no structural heart diseases (SHD); however, the safety and efficacy of ablation in these patients remains unclear.

Methods

In this retrospective study, data from patients who underwent ablation for PVCs from January 2010 to December 2016 at our hospital was retrieved. Predictors of complications and acute procedural success were evaluated.

Results

A total of 1231 patients (mean age 47.8 ± 16.8 years, 59% female) were included. The overall complication rate was 2.7%, and the most common complication was hydropericardium. Two ablation-related mortalities occurred. One patient died of coronary artery injury during the procedure and the other died from infectious endocarditis. Location (left ventricle and epicardium) was the main predictor of complications, with right ventricular outflow tract (RVOT) predicting fewer complications. The acute procedural success rate was 94.1% in all patients. The main predictor of acute procedural success was RVOT origin, while an epicardial origin was a predictor of procedural failure.

Conclusion

Locations of left ventricle and epicardium were predictors of procedural complications for patients with PVCs. Therefore, ablation is not recommended in these patients. For other origins of PVCs, particularly RVOT origin, ablation is a safety and effective treatment.

[Electrocardiogram characteristics of patients with ventricular arrhythmia originating from the distal great cardiac vein]

Objective: To explore the electrocardiographic characteristics of patients with idiopathic ventricular arrhythmias (VAs) originating from different portions of distal great cardiac veins (DGCV). Methods: The study included 49 patients underwent successful RFCA of premature ventricular complex(PVCs)/ventricular tachycardia(VT) from different portions of the DGCV in our department from July 2009 to March 2016. The surface 12-lead electrocardiogram (ECG) and intraventricular ablation mapping features were analyzed. Patients were divided into four groups according to the mapping and ablation results: DGCV1(10 patients), DGCV2 (13 patients), proximalanterior interventricular vein (PAIV, 17 patients)and extend distal great cardiac vein (EDGCV, 9 patients). We analyzed the similarities and differences between surface 12-lead ECG of patients with PVCs/VT from different portions of DGCV, and compared with random chosen 290 patients with PVCs/VT from ventricular outflow tract and adjacent structure. Results: A positive R wave in inferior leads, a negative QS morphology in lead aVL and aVR were found among all groups. The different characteristics of surface 12-lead ECG of VAs originating from DGCV were as follows: (1)EDGCV patients demonstrated a positive R or r wave on lead Ⅰ(6/9) while a negative rS or qr wave was evidenced in other three groups (39/40). (2)A positive R pattern on lead V(1), V(5)-V(6) (11/13) was presented in patients of DGCV2 group; R (without S or s) wave on V(1) (9/10), RS or Rs wave on V(5)-V(6) were found in DGCV1 group; RS or rS wave was seen on lead V(1), R(without S)wave in lead V(5)-V(6) (25/26) were found in EDGCV and PAIV group and the amplification of R wave in EDGCV was higher than V(1) of PAIV group.(3)Precordial lead transition zone was in front of V(1) for DGCV1 and DGCV2 groups (23/23), within V(1)-V(3) for EDGCV group, but on V(2) or within V(2)-V(3) for PAIV group.(4)Patients of DGCV1 and DGCV2 demonstrated a longer Pseudo delta wave time(PdW), intrinsicoid deflection time (IDT), significantly larger maximum deflection index (MDI) than those in PAIV and EDGCV groups (P<0.001). (5)The different characteristics of surface 12-lead ECG between VAs originating from DGCV and those from ventricular outflow tract and adjacent structure were as follows: ① The ECG features were similar between PVIA and LCC group, both demonstrated a rs wave on the lead Ⅰ, rS wave on V(1)-V(2) and R wave on V(5)-V(6); ②The ECG features were similar betweenEDGCV and RCC group, both presented with R or r wave on the lead Ⅰ, the QRS wave of precordial leads was similar as PAIV and LCC groups; ③A R wave on the lead V(1), V(5)-V(6) was found in group DGCV2, and ILCC; ④Similar to the group Endo-MAA, patients in DGCV1 group also demonstrated a R wave on the lead V(1) and a Rs wave on V(5)-V(6). Conclusion: A positive R wave in inferior leads, a negative QS morphology in lead aVL and aVR are seen in all patients, but different electrocardiographic characteristics of PVC/VT originating from the different portions of the DGCV are presented on lead Ⅰ and V(1)-V(6).

Electrocardiogram features of premature ventricular contractions/ventricular tachycardia originating from the left ventricular outflow tract and the treatment outcome of radiofrequency catheter ablation

BACKGROUND

Radiofrequency catheter ablation (RFCA) has been used for the ablation of premature ventricular contractions (PVCs) or ventricular tachycardia (VT). To date, the mapping and catheter ablation of the arrhythmias originating from the left ventricular outflow tract (LVOT) has not been specified. This study investigates the electrocardiogram (ECG) feature of PVCs or VT originating from the LVOT. Moreover, the treatment outcome of RFCA is analyzed.

METHODS

Mapping and ablation were performed on the supravalvular or subvalvular aorta in 52 cases with PVCs/VT originating from the LVOT. The data were compared with those from 104 patients with PVCs/VT originating from the right ventricular outflow tract (RVOT). A differential procedure was prepared based on the comparison of the ECG features of PVCs/VT originating from the RVOT, LVOT, and their different parts.

RESULTS

Among 52 cases with PVCs originating from the LVOT, 47 were successfully treated by RFCA, with a success rate of 90.38%. Several differences among the 12-lead ECG features were observed from the RVOT and LVOT in the left and right coronary sinus groups, as well as under the left coronary sinus group (left fibrous trigone): (1) If the precordial leads transition <V3 plus the precordial leads transitional index >0 are considered as the diagnostic parameters of PVCs/VT originating from the LVOT, then the sensitivity, specificity, as well as positive and negative predictive values are 94.12%, 93.00%, 87.27%, and 96.88%, respectively; (2) The analysis of different subgroups of the LVOT are as follows: (a) A mainly positive wave of r or m pattern was recorded in the lead I in 72.73% of patients in the right coronary sinus group, versus 12.90% of patients in the left coronary sinus group, and 0% in the under left coronary sinus group. (b) All patients in the right coronary sinus group presented waves of RII>RIII and QSaVR>QSaVL, whereas most patients in the other two groups showed waves of RIII>RII and QSaVL>QSaVR. (c) Most patients in the under left coronary sinus group in lead V1 had a mainly positive wave (R) (77.78%), whereas those in the right (81.82%) and left (62.50%) coronary sinus groups had mainly negative waves (rS).

CONCLUSIONS

RFCA is a safe and effective curative therapy for PVCs/VT originating from the LVOT. The 12-lead ECG features of the LVOT from different origins exhibit certain distinctions.