Radiofrequency catheter ablation of atrioventricular nodal reentrant tachycardia guided by magnetic navigation system: a prospective randomized comparison with conventional procedure / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Atrioventricular nodal reentrant tachycardia (AVNRT) is one of the most common paroxysmal supraventricular tachyarrhythmias. The aim of the study was to prospectively compare the characteristics of radiofrequency catheter ablation of AVNRT guided by a magnetic navigation system with the conventional procedure.</p><p><b>METHODS</b>Patients with AVNRT diagnosed by electrophysiological tests were randomized into two groups. In the conventional technique group (CMT), a common 4-mm-tip quadrapolar temperature-controlled ablation catheter was used. In the magnetic navigation system guidance group (MNS), a magnetic 4-mm-tip quadrapolar temperature-controlled ablation catheter was used. The following parameters were collected and compared between the two groups: ablation procedure time, patient fluoroscopy time, operator fluoroscopy time, energy delivery numbers, maximal energy per deployment, success rate, complication rate and operative cost.</p><p><b>RESULTS</b>Forty patients were enrolled and randomized into CMT and MNS groups. The age, gender, tachycardia history and basic cardiovascular diseases of the two groups were comparable (P > 0.05). All procedures were conducted successfully without complications. No tachycardia recurred during the follow-up period of (9.3 ± 2.6) months. In the MNS group, the patient and operator fluoroscopy times ((11.5 ± 4.3) min, (4.2 ± 1.5) min), energy delivery numbers (3.2 ± 0.9), and maximal energy per deployment ((16.9 ± 3.4) W) were shorter or lower than those of the CMT group ((14.3 ± 6.2) min, (13.6 ± 3.5) min, 6.3 ± 2.1, (23.7 ± 1.3) W, respectively) (P < 0.05). But the operative cost for the MNS group was higher than that of the CMT group (P < 0.01).</p><p><b>CONCLUSION</b>Magnetic navigation system guided radiofrequency catheter ablation of AVNRT has the advantages of shorter fluoroscopy time and lower energy delivery numbers and maximal energy per deployment compared to the present conventional ablation technique.</p>

Extremely low warfarin dose in patients with genotypes of CYP2C9*3/*3 and VKORC1-1639A/A / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Patients with the genotypes of both CYP2C9*3/*3 and VKORC1-1639 A/A are expected to require the lowest dose of warfarin, and to have a greatly increased risk of bleeding. The experience for the dosing of warfarin in such extremely rare cases has been seldom reported.</p><p><b>METHODS</b>Demographic and clinical data from two cases with stable low dose of warfarin in China were studied by resequencing the corresponding gene segments in their whole blood DNA. The potential clinical value of the pharmacogenetic algorithm for them was evaluated by calculating the stable dose of warfarin in pharmacogenetic algorithm developed by International Warfarin Pharmacogenetics Consortium.</p><p><b>RESULTS</b>Both cases (68-year-old female and 50-year-old male) were diagnosed as chronic nonvalvular atrial fibrillation needing warfarin treatment, with target international normalized ratio (INR) 2 to 3. Case 1 had stable warfarin dose of 0.625 mg/d and case 2 1.25 mg/d. They needed more than 1 month to stabilize their anticoagulation. Exceeding INR values were recorded for them when the dose of warfarin was no more than 2 mg/d. Hemorrhagic complication appeared in case 1 when the dose was titrated from 2.5 to 1.25 mg/d. No concomitant medicine to increase or decrease the INR value was recorded for them. Genotyping CYP2C9 and VKORC1 showed both patients were the carriers of the homozygous alleles -CYP2C9*3/*3 and VKORC1-1639 A/A. Their stable doses of warfarin calculated by the pharmacogenetic dose algorithm (0.672 mg/d for case 1 and 1.16 mg/d for case 2) were comparable with their actual stable therapeutic doses.</p><p><b>CONCLUSIONS</b>Two Chinese with the rare genotypes of both CYP2C9*3/*3 and VKORC1-1639 A/A were found to require the extremely low dose of warfarin. The pharmacogenetic algorithm incorporating the variances of VKORC1 and CYP2C9 genotypes, as well as the non-genetic factors could predict their stable dose of warfarin with high accuracy.</p>

Effect of phosphatase PHLPP1 gene transfer on the proliferation of human umbilical vein endothelial cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the constituent expression of PH domain leucine-rich repeat protein phosphatase 1 (PHLPP1) in human umbilical vein endothelial cells (HUVECs) and the effect of PHLPP1 gene transfer on the proliferation of the cells in vitro.</p><p><b>METHODS</b>Cultured HUVECs were transfected with pcDNA3-GFP or pcDNA3HA-PHLPP1 via lipofectamine 2000. The cell proliferation ability was determined by cell counting and MTT colorimetric assay, and Western blotting was used to detect the protein expression of PHLPP1 in the cells.</p><p><b>RESULTS</b>No PHLPP1 protein was detected in the non-transfected cells or pcDNA3-GFP-transfected cells. pcDNA3HA-PHLPP1 gene transfection significantly increased PHLPP1 expression in the HUVECs (P<0.01), but the cell proliferation status remained unchanged (P>0.05). The absorbance of the cells measured by MTT assay was 0.134-/+0.0152, 0133-/+0.014 and 0.137-/+0.016, with cell counts of (8.293-/+0.962)x10(5), (7.937-/+0.101)x10(5) and (8.127-/+0.112)x10(5), respectively, showing no significant differences between the 3 groups (P>0.05).</p><p><b>CONCLUSIONS</b>Phosphatase PHLPP1 may not be the most important signal protein in the regulation of HUVEC proliferation.</p>

Influence of cyclosporine A on atrial L-type calcium channel alpha1c subunit in a canine model of atrial fibrillation / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the impact of cyclosporine A (CsA) on atrial expression change of L-type calcium channel alpha1c subunit in a canine model of atrial fibrillation (AF).</p><p><b>METHODS</b>AF was induced by rapid atrial pacing (400 beats/min) for 8 weeks in adult male dogs and placebo (n = 6) or CsA (5 mg x kg(-1) x d(-1), n = 6) were orally administered to these animals. Sham operated animals served as normal controls (n = 6). The atrial electrophysiological parameters including P wave duration, atrial effective refractory period (AERP) were recorded and analyzed at baseline and 8 weeks later. Animals were scarified at 8 weeks post final electrophysiological examinations and atrial expressions of L-type calcium channel alpha1c subunit were determined by Western blot.</p><p><b>RESULTS</b>Compared to sham group, the P wave duration was significantly prolonged while AERP was significantly decreased in AF and CsA groups (all P < 0.05). AERP was significantly longer in CsA group than that in AF group (P < 0.05). L-type calcium channel alpha1c subunit expression was significantly downregulated in AF group compared to sham group (P < 0.05) and CsA significantly attenuated this downregulation (P < 0.01 vs. AF group).</p><p><b>CONCLUSION</b>CsA could attenuate the downregulation of the L-type calcium channel alpha1c subunit expression and improve the atrial electrophysiological remodeling in this canine model of AF.</p>

Safety and efficacy comparison between rapamycin-eluting stent with biodegradable polymer or permanent polymer in patients with coronary artery disease / 中华心血管病杂志

<p><b>OBJECTIVE</b>To evaluate the safety and efficacy of rapamycin-eluting stent with biodegradable polymer (EXCEL) or permanent polymer (Cypher) in patients with coronary artery disease (CAD).</p><p><b>METHODS</b>In this prospective, non-random and comparative study, 60 patients with CAD were divided into EXCEL group (n = 32) and Cypher group (n = 28). The coronary angiography (CAG) and stenting procedure were identical. The safety and efficacy of EXCEL stent was evaluated by major adverse cardiac events (MACE), restenosis rate and percent diameter stenosis rate as well as late luminal loss (LLL) at six months post stenting.</p><p><b>RESULTS</b>During follow-up (mean: 6.04 +/- 2.12 months), there was no MACE in the two groups. Quantitative coronary angiography (QCA) data at 6.0 +/- 2.1 months post stenting were available in 27 patients (84.38%) in EXCEL group and 10 patients (35.71%) in Cypher group. Restenosis rate was zero in both groups. Percent diameter stenosis rate (5.98% +/- 5.52% vs. 5.21% +/- 6.3%) and LLL (-0.02 +/- 0.09 mm vs. -0.01 +/- 0.07 mm) were similar between the 2 groups.</p><p><b>CONCLUSIONS</b>EXCEL stent was safe for the treatment of CAD and comparable as Cypher stent in preventing MACE and restenosis at 6 months post stenting.</p>