Vagus nerve stimulation: A new approach to reduce heart failure

Autonomic imbalance with increased adrenergic and reduced parasympathetic activity is involved in the development and progress of heart failure (HF). Experimental data have demonstrated that stimulation of the vagus nerve is able to reverse ventricular remodeling of the failing heart. There is also evidence that increasing parasympathetic activity may stimulate the production of nitric oxide, and reduce the devastating inflammatory process involved in HF. Vagus nerve stimulation (VNS) has been successfully applied for many years to treat drug resistant epilepsy. The first study of right vagus stimulation in patients with advance HF has proven the feasibility and safety of this new approach. Long term follow-up of increased vagal tone over 12 months with a specially designed stimulating system (CardioFit, BioControl, Yehud, Israel) has demonstrated that symptoms of HF can be significantly diminished, left ventricular ejection fraction increased, and ventricular volumes reduced. These recently published data are very promising and may offer another approach for patients with advanced HF already treated with optimal medical therapy. A prospective randomized trial with a larger patient cohort is needed to confirm these beneficial results of VNS. (Cardiol J 2010; 17, 6: 638-643

Matrix Models, Argyres-Douglas singularities and double scaling limits

We construct an N=1 theory with gauge group U(nN) and degree n+1 tree level superpotential whose matrix model spectral curve develops an A_{n+1} Argyres-Douglas singularity. We evaluate the coupling constants of the low-energy U(1)^n theory and show that the large N expansion is singular at the Argyres-Douglas points. Nevertheless, it is possible to define appropriate double scaling limits which are conjectured to yield four dimensional non-critical string theories as proposed by Ferrari. In the Argyres-Douglas limit the n-cut spectral curve degenerates into a solution with n/2 cuts for even n and (n+1)/2 cuts for odd n.Comment: 31 pages, 1 figure; the expression of the superpotential has been corrected and the calculation of the coupling constants of the low-energy theory has been adde

Cerebral hemodynamics during atrial fibrillation: computational fluid dynamics (CFD) analysis of lenticulostriate arteries using 7T high-resolution magnetic resonance imaging

Atrial fibrillation (AF) is the most common cardiac arrhythmia, inducing irregular and faster heart beating. Aside from disabling symptoms - such as palpitations, chest discomfort, and reduced exercise capacity - there is growing evidence that AF increases the risk of dementia and cognitive decline, even in the absence of clinical strokes. Among the possible mechanisms, the alteration of deep cerebral hemodynamics during AF is one of the most fascinating and least investigated hypotheses. Lenticulostriate arteries (LSAs) - small perforating arteries perpendicularly departing from the anterior and middle cerebral arteries and supplying blood flow to basal ganglia - are especially involved in silent strokes and cerebral small vessel diseases, which are considered among the main vascular drivers of dementia. We propose for the first time a computational fluid dynamics analysis to investigate the AF effects on the LSAs hemodynamics by using 7 T high-resolution magnetic resonance imaging (MRI). We explored different heart rates (HRs) - from 50 to 130 bpm - in sinus rhythm and AF, exploiting MRI data from a healthy young male and internal carotid artery data from validated 0D cardiovascular-cerebral modeling as inflow condition. Our results reveal that AF induces a marked reduction of wall shear stress and flow velocity fields. This study suggests that AF at higher HR leads to a more hazardous hemodynamic scenario by increasing the atheromatosis and thrombogenesis risks in the LSAs region

QT interval prolongation related to psychoactive drug treatment: a comparison of monotherapy versus polytherapy

BACKGROUND: Several antipsychotic agents are known to prolong the QT interval in a dose dependent manner. Corrected QT interval (QTc) exceeding a threshold value of 450 ms may be associated with an increased risk of life threatening arrhythmias. Antipsychotic agents are often given in combination with other psychotropic drugs, such as antidepressants, that may also contribute to QT prolongation. This observational study compares the effects observed on QT interval between antipsychotic monotherapy and psychoactive polytherapy, which included an additional antidepressant or lithium treatment. METHOD: We examined two groups of hospitalized women with Schizophrenia, Bipolar Disorder and Schizoaffective Disorder in a naturalistic setting. Group 1 was composed of nineteen hospitalized women treated with antipsychotic monotherapy (either haloperidol, olanzapine, risperidone or clozapine) and Group 2 was composed of nineteen hospitalized women treated with an antipsychotic (either haloperidol, olanzapine, risperidone or quetiapine) with an additional antidepressant (citalopram, escitalopram, sertraline, paroxetine, fluvoxamine, mirtazapine, venlafaxine or clomipramine) or lithium. An Electrocardiogram (ECG) was carried out before the beginning of the treatment for both groups and at a second time after four days of therapy at full dosage, when blood was also drawn for determination of serum levels of the antipsychotic. Statistical analysis included repeated measures ANOVA, Fisher Exact Test and Indipendent T Test. RESULTS: Mean QTc intervals significantly increased in Group 2 (24 ± 21 ms) however this was not the case in Group 1 (-1 ± 30 ms) (Repeated measures ANOVA p < 0,01). Furthermore we found a significant difference in the number of patients who exceeded the threshold of borderline QTc interval value (450 ms) between the two groups, with seven patients in Group 2 (38%) compared to one patient in Group 1 (7%) (Fisher Exact Text, p < 0,05). CONCLUSIONS: No significant prolongation of the QT interval was found following monotherapy with an antipsychotic agent, while combination of these drugs with antidepressants caused a significant QT prolongation. Careful monitoring of the QT interval is suggested in patients taking a combined treatment of antipsychotic and antidepressant agents

Invasive versus conservative management in spontaneous coronary artery dissection: A meta-analysis and meta-regression study.

Abstract Background There is a paucity of data regarding the best treatment for spontaneous coronary artery dissection (SCAD). Purpose To compare the prognostic impact of conservative versus invasive treatment in patients with SCAD. Methods We systematically searched the literature for studies evaluating the comparative efficacy and safety of invasive revascularization versus medical therapy for the treatment of SCAD from 1990 to 2019. Random-effect meta-analysis was performed comparing clinical outcomes between the two groups. Results 24 observational studies with 1720 patients were included. After 28±14 months, a conservative approach reduced target vessel revascularization rate compared with invasive treatment (OR=0.50; 95% CI 0.28–0.90; P=0.02). No difference was found regarding all-cause mortality (OR=0.81; 95% CI 0.31–2.08; P=0.66), cardiovascular mortality (OR=0.89; 95% CI 0.15–5.40; P=0.89), myocardial infarction (OR=0.95; 95% CI 0.50–1.81; P=0.87), heart failure (OR 0.96; 95% CI 0.41–2.22; P=0.92) and SCAD recurrence (OR=0.94; 95% CI 0.52–1.72; P=0.85). The meta-regression analysis suggested that male gender, diabetes mellitus, smoking habit, prior coronary artery disease, left main coronary artery involvement and lower ejection fraction at admission are related with higher overall mortality, whereas SCAD recurrence was higher among patients with fibromuscular dysplasia. Conclusion A conservative approach provides similar clinical outcomes and lower target vessel revascularization rates compared to an invasive strategy in the setting of SCAD; therefore, when feasible, it should be preferred in this scenario. Forest plots on the study outcomes Funding Acknowledgement Type of funding source: Non

Drug eluting stents are superior to bare metal stents to reduce clinical outcome and stent-related complications in CKD patients, a systematic review, meta-analysis and network meta-analysis.

AimsTo compare clinical outcome in Chronic kidney disease (CKD) patients receiving coronary stents according to stent type BMS versus DES and 1st generation versus 2nd generation DES.Methods and ResultsPubMed, Cinhal, Cochrane, Embase, and Web of Science were searched for studies including CKD patients. CKD was defined as eGFR < 60 mL/min. We selected n = 35 articles leading to 376 169 patients, of which 76 557 CKD patients receiving BMS n = 35,807, 1st generation DES n = 37,650, or 2nd generation DES n = 3100. Patient receiving DES, compared to BMS, had a 18% lower all‐cause mortality (RR 0.82, 95%CI 0.71‐0.94). The composite of death or myocardial infarction (MI) was lower in DES patients (RR 0.78, 95%CI 0.67‐0.91), as was stent thrombosis (ST) (RR 0.57, 95%CI 0.34‐0.95), target vessel/lesion revascularization (TVR/TLR) (RR 0.69, 95%CI 0.57‐0.84) and death for cardiovascular cause (RR 0.43, 95%CI 0.25‐0.74). We also found a gradient between 1st and 2nd generation DES, through BMS. Second, compared to 1st generation DES, were associated with further relative risk (RR) reduction of −18% in of all‐cause death, and lower incidence of stent‐related clinical events: −39% RR of ST risk; −27 RR of TVR/TLR risk.ConclusionsDES in CKD patients undergoing PCI were superior to BMS in reducing major adverse clinical events. This was possibly explained, by a lower risk of stent‐related events as ST and TVR or TLR. Second, compared to 1st generation DES may furtherly reduce clinical events