Impact of high-power short-duration atrial fibrillation ablation technique on the incidence of silent cerebral embolism: a prospective randomized controlled study.

BACKGROUND: High-power short-duration (HPSD) ablation strategy has emerged as a popular approach for treating atrial fibrillation (AF), with shorter ablation time. The utilized Smart Touch Surround Flow (STSF) catheter, with 56 holes around the electrode, lowers electrode-tissue temperature and thrombus risk. Thus, we conducted this prospective, randomized study to investigate if the HPSD strategy with STSF catheter in AF ablation procedures reduces the silent cerebral embolism (SCE) risk compared to the conventional approach with the Smart Touch (ST) catheter. METHODS: From June 2020 to September 2021, 100 AF patients were randomized 1:1 to the HPSD group using the STSF catheter (power set at 50 W) or the conventional group using the ST catheter (power set at 30 to 35 W). Pulmonary vein isolation was performed in all patients, with additional lesions at operator's discretion. High-resolution cerebral diffusion-weighted magnetic resonance imaging (hDWI) with slice thickness of 1 mm was performed before and 24-72 h after ablation. The incidence of new periprocedural SCE was defined as the primary outcome. Cognitive performance was assessed using the Montreal Cognitive Assessment (MoCA) test. RESULTS: All enrolled AF patients (median age 63, 60% male, 59% paroxysmal AF) underwent successful ablation. Post-procedural hDWI identified 106 lesions in 42 enrolled patients (42%), with 55 lesions in 22 patients (44%) in the HPSD group and 51 lesions in 20 patients (40%) in the conventional group (p = 0.685). No significant differences were observed between two groups regarding the average number of lesions (p = 0.751), maximum lesion diameter (p = 0.405), and total lesion volume per patient (p = 0.669). Persistent AF and CHA2DS2-VASc score were identified as SCE determinants during AF ablation procedure by multivariable regression analysis. No significant differences in MoCA scores were observed between patients with SCE and those without, both immediately post-procedure (p = 0.572) and at the 3-month follow-up (p = 0.743). CONCLUSIONS: Involving a small sample size of 100 AF patients, this study reveals a similar incidence of SCE in AF ablation procedures, comparing the HPSD strategy using the STSF catheter to the conventional approach with the ST catheter. TRIAL REGISTRATION: Clinicaltrials.gov: NCT04408716. AF = Atrial fibrillation, DWI = Diffusion-weighted magnetic resonance imaging, HPSD = High-power short-duration, ST = Smart Touch, STSF = Smart Touch Surround Flow.

Extracardiac Vagal Stimulation-Assisted Cardioneuroablation: Dynamically Evaluating the Impact of Sequential Ganglionated Plexus Ablation on Vagal Control of SAN and AVN in Patients with Sinoatrial Node Dysfunction.

Cardioneuroablation (CNA) is proposed as a promising therapy for patients with sinoatrial node dysfunction (SND) that is mediated by excessive vagal tone. However, a series of urgent questions about CNA remain unanswered. From December 2020 to March 2022, six patients with symptomatic SND who underwent CNA were summarized in this report. Sequential CNA targeting Ao-SVC GP, PMLGP, RAGP, and LSGP was performed in patients, guided by fractionated intracardiac electrograms and dynamically evaluated by extracardiac vagal stimulation (ECVS). The results showed that Ao-SVC GP ablation led to a significant increase in heart rate (HR) and the elimination of sinus arrest evoked by ECVS, while the vagal responses of atrial ventricular block were eliminated by the ablation of PMLGP and LSGP. Post-procedure HR increased up to 64-86% of the maximum HR of an atropine test at baseline. The median HR from Holter monitoring increased from 52.8 ± 2.1 bpm at baseline to 73.0 ± 10.4 bpm after the procedure (p = 0.012) and to 71.3 ± 10.1 bpm at the six-month follow-up (p = 0.011). Bradycardia-related symptoms disappeared in all patients at the six-month follow-up. This case series reveals the feasibility of using the ECVS-assisted sequential CNA technique and indicates the critical role of ECVS in dynamically evaluating the impact of sequential CNA on the vagal control of SAN and AVN.

[Effect of total flavonoids of astragalus on endoplasmic reticulum chaperone, calumenin and connecxin 43 in suckling mouse myocardium with myocarditis caused by coxsackievirus B3].

OBJECTIVE: To investigate the effect of total flavonoids of astragalus on the expression of endoplasmic reticulum chaperone, calumenin and connecxin 43 (CX43) in suckling mouse myocardium with myocarditis caused by coxsackievirus B3 (CVB3). METHODS: The primary culture of suckling mouse myocardium cells were randomly divided into control group, CVB3 infected group and total flavonoids of astragalus group. Firstly, to confirm the identity of the suckling mouse myocardium, α-SMA was monitored by immunohistochemistry method. Then the protein expression changes of endoplasmic reticulum chaperone-glucose regulatory protein 78 ( GRP78), calumenin and CX43 were detected by Western blot. RESULTS: (1) Compared with that of the control group, the GRP78 expression level in CVB3 infected group was improved, the expression levels of calumenin and CX43 were all reduced. (2) Compared with that of CVB3 infected group, GRP78 expression level was decreased, and the expression levels of calumenin and CX43 were increased in total flavonoids of astragalus group. CONCLUSION: CVB3 infection may cause endoplasmic reticulum stress of rat myocardium cells by increasing the expression of GRP78 and decreasing the expression of calumenin and CX43. On the other hand, total flavonoids of astragalus can reduce the expression of GRP78 and increase the expression of calumenin and CX43.The results of this experiment may be closely related to the effects of anti-arrhythmia with viral myocarditis caused by CVB3.

Total Flavonoids of Astragalus Plays a Cardioprotective Role in Viral Myocarditis.

BACKGROUND: Viral myocarditis is initiated by viral infection of myocardial tissue leading to dilated cardiomyopathy and congestive heart failure. Recent studies have linked viral myocarditis with dysfunctions in endoplasmic reticulum (ER) mediated Ca(2+) homeostasis and the unfolded protein response (UPR). Currently there are no effective treatments for this viral infection. METHODS: We employed the use of a well-characterized pathogen coxsackievirus B3 (CVB3) to induce mouse viral myocarditis. After intraperitoneal administration of total flavonoids of Astragalus (TFA), we examined the protective effect of TFA on CVB3-induced heart function impairment and decreased calumenin mRNA levels. Furthermore, calumenin protein level was studied in vivo and in vitro with CVB3 infection in the presence or absence of TFA. The interaction between calumenin and the sarco/endoplasmic reticulum Ca(2+)-ATPase 2 (SERCA2) was also tested in HL-1 cells. RESULTS: Whereas customarily we would expect that CVB3 infection would decrease mRNA and protein levels of the Ca(2+) binding ER chaperone calumenin, here TFA treatment prevented this decline in both CVB3 infected mice and in an in vitro system of infected HL-1 cardiomyocytes. CVB3 infection in HL-1 cells prevented the association of calumenin with the calcium mobilizing protein SERCA2, and TFA treatment rescued this interaction. CONCLUSIONS: This study identified that CVB3 infection promotes cardiomyocyte dysfunction by effecting expression levels and activity of the cardio protective ER chaperone calumenin. For the first time, TFA was shown to prevent loss of mRNA and protein levels of calumenin and also rescued the association of this protein with SERCA2. KEY WORDS: Calumenin; Sarco/endoplasmic reticulum Ca(2+)-ATPase; Total flavonoids of Astragalus; Viral myocarditis.

[Effects of Mongolian new medicine-â ¡ on cardiac functions, endoplasmic reticulum stress and apoptosis in congestive heart failure rats with dilated cardiomyopathy].

OBJECTIVE: To investigate the effects of Mongolian new medicine-Ⅱ oncardiac functions, myocardial pathology, endoplasmic reticulum stress and myocardial apoptosis in congestive heart failure with dilated cardiomyopathy in rats. METHODS: Thirty SD male rats were randomly dividedinto 3 groups(n=10):control group, dilated cardiomyopathy group (intraperitoneal injection of adriamycin 2 mg/kg body weight, 1 time/week, 4 weeks after treatment were observed for 4 weeks), Mongolian new medicine-Ⅱ group(intraperitoneal injection of adriamycin 2 mg/kg body weight, 1 time/week, 4 weeks after treatment, 30 mg/(kg·d)was given Mongolian new medicine-Ⅱ orally for 4 weeks). During the experiment, general conditions of rats were observed. After 8 weeks, these rats were killed after measurement of the cardiac function indexes by high frequency echocardiography. The morphological changes of myocardial tissues were observed by using HEstaining, VG staining and electron microscopic. The myocardial apoptosis was detected by TUNEL method and the expressions of endoplasmic reticulum chaperone GRP78, GRP94, pro-apoptotic factor CHOP and caspase-3 were monitored by Western blot. RESULTS: ① Compared with dilated cardiomyopathy group, the cardiac systolic and diastolic functions were significantly increased in Mongolian new medicine-Ⅱ group, which were reflected in that left ventricular contraction diameter(LVIDs) and left ventricular end-diastolic diameter(LVIDd) were decreased, and left ventricular shortening fraction(FS) and ejection fraction(EF) were increased. The hemodynamic parameters of rats were improved significantly in Mongolian new medicine-Ⅱ group. ②Compared with dilated cardiomyopathy group, the myocardial lesion score was decreased and fibrosis of tissue space was relieved in Mongolian new medicine-Ⅱ group. ③Compared with dilated cardiomyopathy group, the apoptosis of myocardial cells was decreased. ④The expressions of endoplasmic reticulum chaperone GRP78, GRP94, pro-apoptotic factor chop and caspase-3 were decreased in Mongolian new medicine-Ⅱ group. CONCLUSIONS: Mongolian new medicine-Ⅱ could improve the pathologic alterations of cardiac cells and cardiac functions, decrease endoplasmic reticulum stress, the degree of fibrosis and myocardial apoptosis. The experimental results may be one of the mechanisms of treatment function of Mongolian new medicine-Ⅱ on dilated cardiomyopathy.

[The effect of astragalus injection on the expression of endoplasmic reticulum stress chaperonin GRP78 and GRP94 mRNA in adriamycin-injured cardiomyocytes with calumenin silencing by shRNA].

OBJECTIVE: To investigate the effect of astragalus injection on the endoplasmic reticulum stress in adriamycin(ADR)-injured cardiomyocytes with calumenin silencing by shRNA. METHODS: Firstly, the stable lentiviral calumenin shRNAvector was constructed. Secondly, in vitro cultured neonatal rat cardiac myocytes were randomly divided into control group、normal group (3 mg/L ADR), lentivirus infection group (lentivirus infection+3 mg/L ADR), Astragalus group 1 (3 mg/L ADR+Astragalus), Astragalus group 2 (lentivirus infection+3 mg/L ADR+Astragalus). The mRNA epression level of calumenin expression and reticulum stress chaperone in GRP78, GRP94 of each group was monitored by real-time PCR. RESULTS: ①Compared with that of the control group, the calumenin mRNA expression in the normal group was reduced(P<0.05), yet its mRNA level in lentivirus the infection group and the Astragalus group 2 was further reduced(P<0.01). Compared with that of the normal group, the mRNA contents of calumenin in the Astragalus group 1 was increased(P<0.05). The expression of calumenin in Astragalus group 2 was increased comparing with lentivirus infection group (P<0.01). ②Compared with that in the control group, the expression of reticulum stress chaperone in GRP78, GRP 94 in lentivirus infection group and normal group was significantly increased (P<0.01); Compared with that in the normal group, the expression of reticulum stress chaperone in GRP78, GRP94 in Astragalus group 1 was reduced(P<0.01); Compared with that in the lentivirus infection group, the expression of reticulum stress chaperone in GRP78, GRP94 in the Astragalus group 2 was obviously decreased(P<0.01). CONCLUSIONS: ①Calumenin can alleviate endoplasmic reticulum stress induced by ADR-injured myocardial cells. ②Astragalus injection can restrain the endoplasmic reticulum stress induced by adriamycin, which may be achieved by the calumenin protein.