The change of cardiac axis deviation in catheter ablation of verapamil-sensitive idiopathic left ventricular tachycardia.

BACKGROUND: The underlying mechanism of verapamil-sensitive idiopathic left ventricular tachycardia (ILVT) has been postulated to be reentrant activation in the Purkinje fiber network of the left posterior fascicle or the left anterior fascicle (LAF). However, changing of cardiac axis deviation in sinus rhythm (SR) or during ILVT after radiofrequency catheter ablation (RFCA) has been rarely analyzed. METHODS: Of the 232 patients with sustained ILVT induced and surface electrocardiogram (ECG) in SR recorded before and after RFCA, the changes of ECG morphology in SR and during ILVT were analyzed. RESULTS: The surface ECG in SR changed in 114 (49.1%) patients after RFCA. ILVT could still be induced in 27 (23.7%) patients. In comparison with the original ILVT, three forms of ECG morphology were observed. In eight patients, the ILVT morphology was unchanged. In the 13 patients with ILVT axis deviation conversion after ablation, the successful target was more proximal. In the six patients with ILVT morphology change but without axis deviation conversion after ablation, the successful ablation site was more distal. Among 15 patients with recurrent ILVT during follow-up, seven patients had previous axis deviation changes in SR after RFCA, the changes maintained in four patients and recovered in three patients. CONCLUSIONS: The morphology changes on surface ECG in SR after RFCA would not be a necessary prerequisite or a good endpoint for ILVT ablation. To analyze ILVT morphology changes after ablation would help to further clarify an appropriate approach for catheter ablation of ILVT.

Purkinje Fibers in Canine False Tendons: New Anatomical and Electrophysiological Findings.

INTRODUCTION: Purkinje system and false tendons (FTs) are related to ventricular arrhythmia, but the association between Purkinje fibers and FTs is not clear. This study investigated the associations of anatomical and electrophysiological characteristics between Purkinje fibers and FTs. METHODS AND RESULTS: We optimized the protocol of Lugol's iodine solution staining of Purkinje fibers to study the anatomical structure and originated a novel electrophysiological mapping method, named the direct visual mapping (DVM) method, to study the electrophysiological characteristics. By using the above-mentioned innovations in 12 dogs, we found the following. (1) There was no Purkinje fiber found 0.5 cm-1.0 cm below the valve annulus or on the leaflets or chordae tendineae of the mitral valve or adjacent to the top 1/3 of the papillary muscle. (2) Purkinje fibers existed in all FTs, including smaller and tiny FTs. (3) The Purkinje fibers contained in the FTs extended from the proximal to the distal end, and their electrophysiological characteristics were similar to the fibers on the endocardium, including anterograde, retrograde, and decremental conduction and automaticity. CONCLUSIONS: Purkinje fibers are commonly found in FTs. The electrophysiological characteristics of the Purkinje fibers contained in FTs are similar to the fibers on the endocardium. FTs might have an anatomical and electrophysiological basis for ventricular arrhythmia.

Different Approaches for Catheter Ablation of Para-Hisian Accessory Pathways: Implications for Mapping and Ablation.

BACKGROUND: Catheter ablation of para-Hisian accessory pathways (APs) can be challenging because of adjacent conduction tissue. Some different approaches for ablation, including the inferior vena cava approach (IVC-A), the noncoronary cusp approach (NCC-A), or the superior vena cava approach (SVC-A), have been reported. However, when should para-Hisian APs be mapped and ablated by the IVC-A, NCC-A, or SVC-A is not well established. METHODS AND RESULTS: This study included 55 consecutive patients (mean age, 53±11 years, 36 males) with para-Hisian APs. On the basis of the approach resulting in successful ablation, patients were divided into IVC-A, NCC-A, and SVC-A groups. The clinical characteristics, surface ECG, intracardiac electrogram findings, and response to ablation were analyzed. Para-Hisian APs were eliminated by IVC-A in 48 of the 55 (87%) patients. The rates of para-Hisian APs requiring NCC-A (4/55 patients, 7%) and SVC-A (3/55 patients, 6%) were relatively low. During mapping at the para-Hisian region, the local ventricular and atrial potentials were well fused during retrograde AP conduction in 45 of the 48 patients in IVC-A group, 0 of the 4 patients in NCC-A group, and 1 of the 3 patients in SVC-A group, respectively. There was no significant difference in the preexcitation characteristics among the 3 groups. CONCLUSION: Most para-Hisian APs can be safely and effectively ablated by IVC-A, and ablation in the NCC is not an initial or a preferred approach. The degree of local ventriculoatrial fusion in the para-Hisian region during retrograde AP conduction can differentiate or predict the successful ablation site.

Cellular repressor of E1A-stimulated genes inhibits inflammation to decrease atherosclerosis in ApoE(-/-) mice.

AIMS: Macrophage inflammation response is important in the pathogenesis of atherosclerosis. We investigated the role and mechanism of cellular repressor of E1A-stimulated genes (CREG) in regulating TNF-α induced inflammation response in macrophages and explore whether CREG might be a therapeutic target for atherosclerosis. METHOD AND RESULTS: Immunostaining and western blotting showed that expression of CREG was reduced in human atherosclerotic coronary artery. In vivo experiments demonstrated that supplementation of recombinant CREG protein to ApoE(-/-) mice fed with high fat diet alleviated aortic atherosclerosis development and inflammation. In vitro, macrophage from ApoE(-/-) mice fed with high fat diet had lower level of CREG compared to control mice fed with normal diet. Immunohistochemical staining and western blotting further confirmed that CREG inhibited inflammatory response of macrophages induced by TNF-α. Supplementation of exogenous recombinant CREG protein or CREG gene silencing showed that CREG promoted autophagy in TNF-α treated macrophages. The use of autophagy inhibitors, 3-methyladenine and bafilomycin A, identified that CREG attenuated TNF-α induced inflammation by activate autophagy. In addition, supplementation of exogenous CREG protein stimulated expression and maturity of cathepsin B and cathepsin L and induced lysosome formation, whereas CREG deficiency reduced lysosomal formation. CONCLUSION: CREG inhibits inflammation and promotes autophagy mediated by lysosome formation; it might be a potential therapeutic target in atherosclerosis.

Focal atrial tachycardia surrounding the anterior septum: strategy for mapping and catheter ablation.

BACKGROUND: Focal atrial tachycardias (ATs) surrounding the anterior atrial septum (AAS) have been successfully ablated from the right atrial septum (RAS), the aortic cusps, and the aortic mitral junction. However, the strategy for mapping and ablation of AAS-ATs has not been well defined. METHODS AND RESULTS: Of 227 consecutive patients with AT, 47 (20.7%; mean age, 56.3±11.6 years) with AAS-ATs were studied; among them, initial ablation was successful at RAS in only 5 of 14 patients and at noncoronary cusp (NCC) in 28 of 33 patients. In 45 of the 47 patients, the 46 of 48 AAS-ATs were eliminated at RAS in 8 patients, NCC in 35 patients (earliest activation time at NCC was later than that at RAS by 5-10 ms in 6 patients), and aortic mitral junction in 3 patients (all with negative P wave in lead aVL and positive P wave in the inferior leads), including 1 patient whose 2 ATs were eliminated separately from the NCC and the aortic mitral junction. CONCLUSIONS: Most of the ATs surrounding the AAS can be eliminated from within the NCC, which is usually the preferential ablation site. Ablation at the RAS and aortic mitral junction should be considered when supported by P-wave morphologies on surface ECG and results of activation mapping and ablation.

Purification and functional assessment of smooth muscle cells derived from mouse embryonic stem cells.

OBJECTIVE: To obtain a pure population of smooth muscle cells (SMC) derived from mouse embryonic stem cells (ESC) and further assess their functions. METHODS: A vector, expressing both puromycin resistance gene (puro(r) ) and enhanced green fluorescent protein (EGFP) gene driven by smooth muscle 22α (SM22α) promoter, named pSM22α-puro(r)-IRES2-EGFP was constructed and used to transfect ESC. Transgenic ESC (Tg-ESC) clones were selected by G418 and identified by PCR amplification of puro(r) gene. The characteristics of Tg-ESC were detected by alkaline phosphatase (ALP) staining, SSEA-1 immunofluorescence and teratoma formation test in vivo. After induction of SMC differentiation by all-trans retinoic acid, differentiated Tg-ESC were treated with 10 µg/mL puromycin for three days to obtain purified SMC (P-SMC). Percentage of EGFP(+) cells in P-SMC was assessed by flow cytometer. Expressions of smooth muscle specific markers were detected by immunostaining and Western blotting. Proliferation, migration and contractility of P-SMC were analyzed by growth curve, trans-well migration assay, and carbachol treatment, respectively. Finally, both P-SMC and unpurified SMC (unP-SMC) were injected into syngeneic mouse to see teratoma development. RESULTS: Tg-ESC clone was successfully established and confirmed by PCR detection of puro(r) gene in its genomic DNA. The Tg-ESC was positive for ALP staining, SSEA-1 staining and formed teratoma containing tissues derived from three germ layers. After retinoic acid induction, large amount of EGFP positive cells outgrew from differentiated Tg-ESC. Three days of puromycin treatment produced a population of P-SMC with an EGFP(+) percentage as high as 98.2% in contrast to 29.47% of unP-SMC. Compared with primary mouse vascular smooth muscle cells (VSMC), P-SMC displayed positive, but lowered expression of SMC-specific markers including SM α-actin and myosin heavy chain (SM-MHC) detected either, by immunostaining, or immunoblotting, accelerated proliferation, improved migration (99.33 ± 2.04 vs. 44.00 ± 2.08 migrated cells/field, P < 0.05), and decreased contractility in response to carbachol (7.75 ± 1.19 % vs. 16.50 ± 3.76 % in cell area reduction, P < 0.05). In vivo injection of unP-SMC developed apparent teratoma while P-SMC did not. CONCLUSIONS: We obtained a pure population of ESC derived SMC with less mature (differentiated) phenotypes, which will be of great use in research of vascular diseases and in bio-engineered vascular grafts for regenerative medicine.

Cellular repressor of E1A stimulated genes enhances endothelial monolayer integrity.

Cellular repressor of E1A stimulated genes (CREG) is a novel modulator that maintains the homeostasis of vascular cells. The present study aimed to investigate the effects of CREG on tumor necrosis factor (TNF)-α-mediated inflammatory injury of vascular endothelial cells. Human umbilical vein endothelial cells (HUVECs) were cultured and CREG overexpressing (VC), knockdown (VS) and mock-transfected (VE) HUVECs were challenged with TNF-α. We demonstrated that TNF-α prompted robust intercellular filamentous actin (F-actin) stress fiber formation as examined by rhodamin-phalloidin staining. Transwell assay and rhodamine B isothiocyanate-dextran staining indicated that TNF-α induced intercellular hyperpermeability of the HUVEC monolayers. These effects were attenuated in VC cells with forced CREG overexpression but significantly potentiated in VS cells with CREG silencing. After TNF-α stimulation, interleukin (IL)-6 and IL-8 secretions in VE cells were markedly increased and inducible nitric oxidase (iNOS) expression substantially elevated, whereas these effects were pronouncedly damped in VC cells. Conversely, in VS cells, the increase in inflammatory markers was substantially potentiated. Immunofluorescence staining demonstrated that nuclear factor κB (NF-κB) slowly and transiently translocated into the nuclei of VC cells upon TNF-α stimulation. However, a more swift and sustained nuclear translocation was observed in VS as compared to VE cells. Corresponding changes in the pattern of its protein expression was also observed. These data suggested that CREG can inhibit NF-κB activation, TNF-α-induced inflammatory responses and the hyperpermeability of endothelial cells, and may therefore represent a potential therapeutic target for pathological vascular injury.

Long-term clinical effects of programmer-guided atrioventricular and interventricular delay optimization: Intracardiac electrography versus echocardiography for cardiac resynchronization therapy in patients with heart failure.

OBJECTIVES: To compare the haemodynamic results and long-term clinical outcomes of intracardiac electrography (QuickOpt®; St Jude Medical, St Paul, MN, USA) and echocardiography for optimization of atrioventricular (AV) and interventricular (VV) delays in cardiac resynchronization therapy (CRT). METHODS: Patients with CRT devices were prospectively enrolled; AV/VV delays were optimized by either QuickOpt® or echocardiography. Patients in the QuickOpt® group underwent both echocardiography and QuickOpt® optimization, and QuickOpt® AV/VV delays were used to program the CRT. All patients were followed-up for 12 months. RESULTS: In total, 44 patients were enrolled. There was good correlation between AV/VV delays determined by QuickOpt® (n = 20) and echocardiography (n = 24). QuickOpt® was significantly faster than echocardiography-guided optimization. Cardiac function, 6-min walking distance and left ventricular ejection fraction were significantly and similarly improved in both groups at 6 and 12 months compared with baseline. In the QuickOpt® group, left ventricular end diastolic diameters were significantly smaller at 6 and 12 months compared with baseline. CONCLUSIONS: QuickOpt® is a quick, convenient and easy to perform method for optimization of AV and VV delays, with a similar long-term clinical outcome to echocardiography-guided optimization.

Pattern of expression of the CREG gene and CREG protein in the mouse embryo.

The cellular repressor of E1A-stimulated genes (CREG) is a secreted glycoprotein that inhibits cell proliferation and/or enhances differentiation. CREG is widely expressed in adult tissues such as the brain, heart, lungs, liver, intestines and kidneys in mice. We investigated the level of CREG expression during mouse embryogenesis and its distribution at 18.5 days post coitus (dpc) using immunohistochemical staining with diaminobenzidine, western blotting and reverse transcription-polymerase chain reaction. CREG expression was first detected in mouse embryos at 4.5 dpc. It was expressed at almost all stages up to 18.5 dpc. The level of CREG was found to increase gradually and was highest at 18.5 dpc. Western blotting showed that the CREG protein was expressed at higher levels in the brain, heart, intestines and kidneys than in the lungs and liver at 18.5 dpc. In 9.5 dpc embryos, CREG was expressed only in the endothelial cells of blood vessels, after the vascular lumen had formed. With advanced differentiation, vascular smooth muscle cells developed in the embryonic vascular structures; the expression of smooth muscle α-actin protein and CREG were positive and increased gradually in 10.5 dpc embryonic vessels. CREG expression in the embryonic blood vessels peaked at 15.5 dpc and was reduced slightly at 18.5 dpc. These results indicate that CREG is expressed during mouse embryogenesis and might participate in the differentiation of these organs during embryogenesis.

Elective percutaneous intervention for unprotected left main coronary artery stenosis complicated with left anterior descending artery chronic total occlusive lesions.

BACKGROUND: The patients with unprotected left main coronary artery (ULMCA) stenosis and chronic total occlusion (CTO) lesions at the left anterior descending (LAD) artery are often recommended for bypass surgery. However, some of these patients are deemed inoperable or are at high risk for surgery. In this study, we explored strategies and evaluated the efficacy of percutaneous coronary intervention for the treatment of ULMCA stenosis complicated by LAD CTO. METHODS: From November 2001 to July 2009, 78 patients with ULMCA stenosis and LAD CTO lesions were selectively treated with stenting. Six patients (7.7%) refused surgery due to their young age (< or = 40 years), and the other 72 patients (92.3%) were unsuitable for surgery. Reasons for poor surgical candidacy included advanced age (> 80 years), chronic obstructive pulmonary, unsuitable distal target vessels for bypass, EuroSCORE > or = 6, and so on. Four different strategies were applied based on the degree of left main stenosis and the ostial diameter and involvement of the left circumflex. RESULTS: Total procedural success was achieved in 94.9%, there were no deaths or thromboses. Five patients (6.4%) experienced non-Q-wave myocardial infarction in hospital. At long-term follow-up ((52 +/- 28) months), there were 3 cardiac deaths (3.8%) and 4 (5.1%) nonfatal myocardial infarctions. Angiographic follow-up was performed in 50 patients (64.1%), and target vessel revascularizations were required in 10 patients (12.8%), among which 4 nonfatal myocardial infarction patients included. The rate of major adverse cardiac events was 16.7% (13/78). CONCLUSIONS: This study indicates that percutaneous intervention can be performed safely in high risk surgical patients with ULMCA and LAD CTO lesions based on individual therapeutic strategies. It may be feasible to apply this technique in selected patients mentioned above.

[Effects of cilostazol on long-term clinical outcomes after coronary stenting].

OBJECTIVE: To evaluate the effects of cilostazol on long-term clinical outcomes in patients underwent coronary stent implantation. METHODS: One hundred patients who underwent coronary stenting were randomly assigned to receive cilostazol 200 mg/d for 6 months (n = 50) or ticlopidine 500 mg/d for 1 month (n = 50). Aspirin 100 mg/d was administrated concomitantly with cilostazol or ticlopidine. Angiographic follow-up was carried out at 6 months and clinical follow-up for 3 years after stenting. RESULTS: Angiographic restenosis occurred in 5 of 34 patients (14.7%) in cilostazol group and 10 of 37 patients (27.0%) in ticlopidine group (P = 0.204). At the end of three-year follow-up, the incidence of major adverse cardiac and cerebral events (MACCE) was greatly reduced in cilostazol group compared with ticlopidine group (16% vs 36%, P = 0.023). Changes of Seattle angina questionnaire (SAQ) physical limitation score showed no significant difference between two groups (21.8 +/- 12.3 vs 16.8 +/- 15.9, P = 0.086). However, changes the improvement of angina frequency score much more was significant in cilostazol group (22.6 +/- 12.7) compared with that in ticlopidine group (16.1 +/- 13.3, P = 0.015). Recurrent angina occurred in 38% of patients in cilostazol group and 54% in ticlopidine group, respectively (P = 0.105). Readmission due to cardiac and cerebral vascular diseases was much less in cilostazol group than that in ticlopidine group (20% vs 40%, P = 0.029). CONCLUSIONS: Cilostazol treatment significantly reduced MACCE and improved the quality of life pf patients in three-year clinical follow-up after coronary stenting.