The potential benefits of treatment of sleep apnea in heart failure

At least half of patients with heart failure (HF) suffer from sleep apnea. Growing evidence suggests that there may be a strong pathophysiological link between chronic HF and sleep apnea due to nocturnal oxygen desaturation and sympathetic activation. It seems that sleep apnea contributes to systolic and diastolic HF, reduced left and right ventricular function, and arrhythmia (e.g. atrial fibrillation, bradycardia, or ventricular ectopy). Therefore, treatment of sleep apnea might alleviate cardiac symptoms and improve cardiac function. Nevertheless, the exact role of long-term treatment of sleep apnea in HF patients remains to be elucidated, as important clinical endpoints (e.g mortality) have been assessed in only a few studies. Heart Fail Monit 2008;5(4):106-11.     

心脏自主神经重构与心肌梗死后室性心律失常

心肌梗死后心脏不同区域出现不同程度的去迷走神经支配、去交感神经支配以及交感神经过度再生。这种心脏自主神经的不均一重构加重了心肌梗死后心肌的电生理异质性,导致了室性心律失常易感性增加。多种针对自主神经重构的治疗手段可以有效预防及治疗心肌梗死后患者的室性心律失常,具有较大的临床应用前景。     

Inducibility of Atrial Fibrillation After GP Ablations and “Autonomic Blockade”: Evidence for the Pathophysiological Role of the Nonadrenergic and Noncholinergic Neurotransmitters

Autonomic Blockade and Atrial Fibrillation . Background: Recent clinical reports that used cholinergic and adrenergic blockade (CAB) as an alternative to ganglionated plexi (GP) ablation to terminate atrial fibrillation (AF) showed mixed results. We investigated the role of other neurotransmitters in AF inducibility. Methods: In 23 pentobarbital anesthetized dogs, a left and right thoracotomy allowed the attachment of electrode catheters to the left and right pulmonary veins and atrial appendages (AA). Programmed stimulation was used to determine the effective refractory periods (ERP) and AF inducibility, measured by the window of vulnerability (WOV). AF duration in response to acetylcholine (Ach; 100 mM) applied to the AA was measured before and after GP ablation + CAB and with vagus nerve stimulation (VNS). After GP ablation + CAB, Ach induced AF duration was determined in response to vasoactive intestinal peptide (VIP) and its specific antagonist ([Ac‐Tyr1,D‐phe2]‐VIP). Results: GP ablation + CAB significantly prolonged ERP, eliminated WOV, and suppressed the duration of Ach induced AF (P ≤ 0.01 for all). Also slowing of the heart rate by VNS was essentially blocked; however, with Ach 100 mM applied to the AA, VNS, and VIP applied to the AA markedly prolonged AF duration. This effect was blocked by the VIP antagonist. Conclusions: Neither GP ablation nor CAB can fully suppress AF inducibility arising from the atrial neural network. Our findings suggest that other neurotransmitters, such as VIP released during VNS, can promote sustained AF despite GP ablation and “autonomic blockade,” which may further define the substrate for AF outside the pulmonary vein‐atrial junctions. (J Cardiovasc Electrophysiol, Vol. 24, pp. 188‐195, February 2013)     

人类染色体17p13.3位点新克隆基因HC56,HC71 和HC90在白血病细胞的表达

为研究人类染色体17p13．3位点新克隆的基因HC56，HC71和HC90在白血病细胞中的表达，应用同位素标记的、以βM2基因作为内参的半定量RT—PcR法，检测35例急性白血病和4株白血病细胞系的Hc56，Hc70和HC90基因的表达。结果显示，急性淋巴系白血病病人的HC90基因和T淋巴系白血病细胞系Jurkat细胞HC90基因表达水平降低。急性髓系白血病病人HC71基因表达水平降低。HC56基因表达在急性白血病和正常对照间未见显差异。结论：在人类白血病有HC70和HC90的基因表达异常。     

A Prospective,Randomized Comparison of Modified Pulmonary Vein Isolation Versus Conventional Pulmonary Vein Isolation in Patients with Paroxysmal Atrial Fibrillation

Modified Pulmonary Vein Isolation in AF Ablation. Introduction: Pulmonary vein isolation (PVI) is the primary ablation therapy in patients with atrial fibrillation (AF). We hypothesized that high dominant frequency (DF) sites (AF nests during sinus rhythm [SR]) adjacent to the PV ostia are associated with the atrial substrate that maintains AF, and PVI incorporating the high‐frequency AF nests may have a higher efficacy. Methods and Results: In a prospective and randomized comparison, 126 symptomatic paroxysmal AF patients that underwent PVI were enrolled. We compared the efficacy of a modified PVI (ablation line: 1.0–1.5 cm from the PV ostium with encircling the AF nests [spectral analysis with DF >70 Hz during SR, Group II]) versus the anatomy‐guided conventional PVI (Group I). In Group II, the DF value along the PV ostium was lower than 70 Hz after the PVI. The primary endpoint was the freedom from symptomatic atrial arrhythmias after a single procedure. We also followed the autonomic function by a time‐domain analysis of the heart rate variability. In both groups, AF nests were observed and electric isolation was successfully obtained in all patients. With a mean duration of 16 ± 6.1 months of follow‐up, Group II had a higher single procedure efficacy without drugs (78.7% vs 66.1%, log‐rank test: P = 0.02), and fewer repeat procedures (6.6% vs 23%; P = 0.04), as compared to Group I. Conclusion: PVI incorporating the high frequency AF nests adjacent to the PV ostia had a better single procedure efficacy. (J Cardiovasc Electrophysiol, Vol. 23, pp. 1155–1162, November 2012)     

Intracoronary autologous bone marrow cell transplantation beneficially modulates heart rate variability

Antegrade femoral artery access is commonly used for percutaneous transluminal revascularization of ipsilateral lower limbs in patients with critical limb ischemia. While hemostasis at the end of the procedure can be achieved by manual compression, this may lead to an increase in local vascular complications. Femoral artery closure devices, such as the Angioseal collagen plug and anchor device, have been approved and shown of benefit after retrograde femoral artery catheterization. To date, there are however no data on the use of such arteriotomy closure device after antegrade femoral access. We hereby report a case series of five patients in whom Angioseal was successfully used after antegrade femoral puncture and below-the-knee percutaneous transluminal angioplasty. In all cases the device enabled immediate and complete hemostasis without major complications, despite the intense antithrombotic regimen, including heparin, aspirin, and clopidogrel in all patients, as well as glycoprotein IIb/IIIa inhibitors (in two patients) and fibrinolytic therapy (in one).     

Ablation ektoper rechtsatrialer Tachykardien unter Verwendung eines 20-poligen Mapping-Katheters

INTRODUCTION : Ectopic atrial tachycardia (EAT) are frequently unresponsive to pharmacological antiarrhythmic therapy. Radiofrequency ablation seems to be a safe approach to treat those arrhythmias. In the present study we report our results of radiofrequency ablation of EAT with a new mapping system (Stablemapr, Medtronic). METHODS : Thirty consecutive patients with right atrial tachycardia were included in the study. In 15 patients (G1) the 20-polar Stablemapr was used for localization of the arrhythmia foci. Data were compared with a control group (G2, n=15), in which mapping was performed conventionally. The demographic characteristics and the distribution of the different cardiac diseases were comparable in both groups. In group 1 the identification of the EAT was facilitated by the placement of the 20-pole mapping catheter in the right atrium. In group 2 point by point measurements were performed to find the earliest local atrial activation compared to a reference electrode in the high right atrium (activation mapping), or foci were identified by analysis of the P-wave morphology during stimulation (pacemapping). RESULTS : It was possible to successfully ablate all atrial tachycardias. The distribution of the foci was similar in both groups (G1/G2): near to the superior (3/5) and inferior (1/0) caval vene ostium, on the free wall (3/3), at the coronary sinus ostium (3/3) and on the interatrial septum (5/4). The mean procedure (G1: 88+/-33 vs G2: 151+/-61 min; p= or <0.05) and fluoroscopic times (G1: 19+/-9 vs G2: 38+/-28 min; p= or <0.05) were significantly shorter in group 1. Moreover, the mean number of radiofrequency applications was reduced significantly by using the new mapping system (G1: 10+/-10 vs G2: 16+/-13; p= or <0.05). CONCLUSION : Radiofrequency ablation of EAT with right atrial focus can be performed safely and successfully using a 20-pole mapping catheter. The greatest advantages compared to conventional mapping and ablation strategies lies in the shortened investigation and fluoroscopic time.     

Upregulation of antithrombotic ectonucleotidases by aspirin in human endothelial cells in-vitro

Abstract— Ecto ATP-diphosphohydrolase (apyrase) activity of human endothelial cells following aspirin treatment has been studied in-vitro. It was shown by HPLC analysis of supernatant samples that pre-incubation of the cultures with aspirin resulted in a significantly increased turnover of supplemented ATP into its degradation products (ADP and AMP). Enhanced expression of ectoenzyme after aspirin treatment could be observed as demonstrated by immunofluorescence-staining with monoclonal anti-apyrase antibodies. This suggests enhancement of endothelial ATP-diphosphohydrolase activity induced by aspirin. The present data obtained in human vascular cells in-vitro are in line with results from previous animal studies in-vivo, suggesting a novel cyclo-oxygenase-independent antithrombotic activity of aspirin.     

Prevalence of paroxysmal atrial fibrillation depending on the regression of left ventricular hypertrophy in arterial hypertension.

Arterial hypertension (HTN) represents one of the major causes of atrial fibrillation, a cardiac arrhythmia with high prevalence and comorbidity. The aim of this study was to investigate whether paroxysmal atrial fibrillation can be treated by the regression of left ventricular hypertrophy achieved by antihypertensive therapy. Included in the present study were 104 patients who had had HTN for more than 1 year. None of them suffered from coronary heart disease. All patients were investigated by 24-h Holter ECG and echocardiography at baseline and after a mean of 24 months. Patients were divided into two groups: group A consisted of those (53.8%) who showed a regression of the left ventricular muscle mass index (LVMMI) during the follow-up (154.9+/-5.1 vs. 123.5+/-2.8 g/m(2)), and group B those (45.2%) who showed a progression of LVMMI (122.2+/-3.2 vs. 143.2+/-3.2 g/m(2)). In group A the prevalence of atrial fibrillation decreased from 12.5% to 1.8% (p<0.05), while it was increased in group B from 8.5% to 17.0%. The left atrial diameter was reduced following antihypertensive therapy in group A from 39.1+/-5.3 mm to 37.4+/-4.6 mm (p<0.01) and increased in group B from 37.0+/-0.7 mm to 39.0+/-0.9 mm (p<0.01). We conclude that a regression of the left ventricular muscle mass leads to a reduction of left atrial diameter and consecutively to a decrease in the prevalence of intermittent atrial fibrillation. This may be explained by a better left ventricular diastolic function following decreased vascular and extravascular resistance of the coronary arteries. This relation shows the benefits of causal antihypertensive therapy for the treatment of paroxysmal atrial fibrillation.     

In vitro proliferation of hematopoietic stem cells in the absence of an adherent monolayer

Experiments on long-term murine bone marrow cultures indicate that the production and maintenance of the hematopoietic stem cell is dependent on the establishment of an adherent monolayer and a secondary repopulation of the culture with fresh marrow. In contrast, we have found that bone marrow cultures derived from the Syrian hamster do not require a repopulation step and produce stem cells that proliferate and differentiate for more than 12 wk in the absence of an adherent layer. Stem cells were grown in Fisher's medium (pH 7.0-7.2) containing 20% horse serum in a fully humidified atmosphere of 5% CO2 in air at 37 degrees C. Cultures were fed twice weekly by removal of half of the medium and supernatant cells and replacement with an equal volume of fresh medium. No hormones or exogenous growth factors were required for the maintenance of myeloid cells, monocytes, and megakaryocytes in either the adherent or suspension cells cultures.