Predictive value of rs2200733 polymorphism for atrial fibrillation recurrence after radiofrequency catheter ablation / 医学研究生学报

Objective The recurrence rate of atrial fibrillation (AF) after radiofrequency catheter ablation (RFCA) remains relatively high. The aim of this study was to investigate the predictive value of rs2200733 polymorphism for AF recurrence after RFCA. Methods Fifty-three AF patients underwent RFCA guided by the magnetic navigation system between July 2015 and September 2016 in Wuxi People’s Hospital. We obtained the baseline data on the patients, conducted genotyping for rs2200733 variants, and followed up the patients for symptoms and complications by electrocardiography (ECG) and dynamic ECG. Using Cox survival analysis, we determined the independent predictors of AF recurrence after RFCA and the sensibility and specificity of predicting AF recurrence at 12 and 24 months post-operatively. Results All the patients were Han Chinese, followed-up for 21.6 ± 9.5 months, and 25 (47.2%) of them experienced AF recurrence at 6.6 ± 5.3 months after RFCA. Kaplan-Meier survival analysis revealed a significant association between rs2200733 polymorphism and AF recurrence in the additive and recessive models (P < 0.001), and multivariate Cox analysis showed the rs2200733 polymorphism (recessive model) to be an independent predictor of post-RFCA AF recurrence (OR = 3.184, 95% CI: 1.378-7.357, P = 0.007). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of rs2200733 TT in predicting AF recurrence at 12 months were 64%, 81%, 70%, 76% and 74%, and those at 24 months were 60%, 82%, 75%, 70%, and 72%, respectively. Conclusion The rs2200733 polymorphism is an independent predictor of AF recurrence after RFCA, and its high specificity indicates that it could be used as a tool for screening Han Chinese patients with AF for RFCA.

The impact of cardiac resynchronization therapy on left ventricular diastolic function evaluated by speckle tracking imaging in patients with dilated cardiomyopathy / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the effects of cardiac resynchronization therapy (CRT) on left ventricular (LV) diastolic function measured by speckle tracking imaging (STI) in patients with dilated cardiomyopathy (DCM).</p><p><b>METHODS</b>CRT was performed in 21 DCM patients [15 male, mean age: 61.2 ± 11.2 (49-82) years].LV synchronization, LV systolic function and LV diastolic function were evaluated with conventional echocardiography, tissue Doppler imaging and STI before and 6 months after CRT.NYHA heart function was also assessed. Clinic Response to CRT was defined as improvement of more than 1 NYHA class.Response to CRT in echocardiography was defined as ≥ 15% reduction in LV end systolic volume at 6 months post CRT.</p><p><b>RESULTS</b>There were 16 responders and 5 non-responders at 6 months post CRT.In terms of diastolic function, conventional echocardiography derived deceleration time was both prolonged in non-responders and responders. At 6 months post CRT, STI derived LV isovolumetric diastolic strain rate [(0.19 ± 0.11) /s vs.(0.14 ± 0.09)/s, P < 0.001] was significantly increased while early diastolic mitral valve blood flow velocity/left ventricular isovolumetric diastolic strain rate (680 ± 600 vs.787 ± 690, P < 0.04) was significantly reduced in responder group while remained unchanged in non-responder group.Furthermore, left ventricular isovolumetric diastolic strain rate negatively correlated with plasma brain natriuretic peptide level (r = -0.68, P < 0.05).</p><p><b>CONCLUSION</b>In CRT responders of DCM patients, LV diastolic function is significantly improved and this change could be detected more effectively by STI derived LV diastolic function parameters.</p>

Changes of open probability of large conductance Ca(2+)-activated K(+) channels in diabetic coronary smooth muscle cells of rats / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the changes of open probability (Po) of large conductance Ca(2+)-activated K(+) channel (BK channel) in diabetic coronary smooth muscle cells and elucidate the underlying cellular electrophysiology mechanisms of coronary dysfunction.</p><p><b>METHODS</b>Rat coronary smooth muscle cells were isolated from control group and diabetic group. BK single channel currents were recorded by patch clamp technique in inside-out configuration. Open probabilities were calculated and compared between two groups. After exposure to DHS-1, a specific BK channel activator, Po at 0.2 and 1 µmol/L free Ca(2+) were compared between control and diabetic groups.</p><p><b>RESULTS</b>In the presence of 0.2 µmol/L free Ca(2+), the Po at baseline was significantly lower in diabetic rats than in control rats (0.0032 ± 0.0012 vs. 0.095 ± 0.036, P < 0.05). Cytoplasmic application of DSH-1 significantly increased the Po to 0.335 ± 0.096 (P < 0.05 vs. baseline) in control rats, whereas DSH-1 had no effect in diabetic rats (Po = 0.022 ± 0.018, P > 0.05 vs. baseline). In the presence of 1 µmol/L free Ca(2+), the Po at baseline was also significantly lower in diabetic rats than in control rats (0.210 ± 0.055 vs. 0.458 ± 0.077, P < 0.05). Cytoplasmic application of DHS-1 further robustly enhanced Po to 0.823 ± 0.019 (P < 0.05 vs. baseline) in control rats and to 0.446 ± 0.098 in diabetic rats (P < 0.05 vs. baseline of diabetic rats; P < 0.05 vs. control rats with DHS-1).</p><p><b>CONCLUSION</b>The decrease of Po of BK single channel in coronary smooth muscle cells may be a potential cause for coronary dysfunction in diabetic rats.</p>

Evaluation of left ventricular function and twist in patients with diabetic cardiovascular autonomic neuropathy by speckle tracking imaging / 中华心血管病杂志

<p><b>OBJECTIVE</b>To evaluate left ventricular (LV) function and twist in patients with diabetic cardiovascular autonomic neuropathy (CAN) by two-dimensional speckle tracking imaging (STI).</p><p><b>METHODS</b>STI was performed in 56 subjects with type 2 diabetes mellitus (DM) (35 with DM only: group A, 21 with CAN: group B) and 34 normal subjects (Control) from LV short-axis view. LV peak systolic, peak early (E') and peak late (A') diastolic circumferential strain in 18 myocardial segments were measured at the levels of mitral annulus, papillary muscle and apex and the rotation at mitral annulus and apex levels were also measured. LV peak systolic and the ratio of E' and A' of global and three levels, twist, untwisting rate and untwisting half-time were calculated.</p><p><b>RESULTS</b>In group A, compared with control group, LV peak systolic radial circumferential strain has no significant difference (P > 0.05), E'/A' was reduced (P < 0.05), twist at aortic valve closure and twist at mitral valve opening were significantly increased (P < 0.05), untwisting rate reduced, and untwisting half time delayed. In group B, compared with control group and group A, circumferential strain parameters [(-12.64 ± 6.49)% vs. (-19.11 ± 9.98)% and (-21.14 ± 10.13)%, P < 0.05] and E'/A' [(0.90 ± 0.35) vs. (1.24 ± 0.47) and (1.98 ± 0.63), P < 0.05] were significantly decreased, twist at aortic valve closure [(19.08 ± 5.62)° vs. (16.57 ± 2.84)° and (14.36 ± 4.06)°, P < 0.05] and twist at mitral valve opening [(13.99 ± 2.31)° vs. (11.36 ± 2.63)° and (9.04 ± 5.63)°, P < 0.05] were significantly increased, untwisting rate [(0.40 ± 0.28)%/ms vs. (0.46 ± 0.14)%/ms and (0.53 ± 0.21)%/ms, P < 0.05] reduced, and untwisting half time [(489.61 ± 97.14) ms vs. (445.21 ± 54.53) ms and (410.60 ± 50.23) ms, P < 0.05] delayed.</p><p><b>CONCLUSION</b>Speckle tracking imaging could be used to evaluate early changes on LV twist deformation and LV systolic function in patients with type 2 diabetes mellitus.</p>

Molecular mechanisms of diabetic coronary dysfunction due to large conductance Ca2⁺-activated K⁺ channel impairment / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Diabetes mellitus is associated with coronary dysfunction, contributing to a 2- to 4-fold increase in the risk of coronary heart diseases. The mechanisms by which diabetes induces vasculopathy involve endothelial-dependent and -independent vascular dysfunction in both type 1 and type 2 diabetes mellitus. The purpose of this study is to determine the role of vascular large conductance Ca(2+)-activated K(+) (BK) channel activities in coronary dysfunction in streptozotocin-induced diabetic rats.</p><p><b>METHODS</b>Using videomicroscopy, immunoblotting, fluorescent assay and patch clamp techniques, we investigated the coronary BK channel activities and BK channel-mediated coronary vasoreactivity in streptozotocin-induced diabetic rats.</p><p><b>RESULTS</b>BK currents (defined as the iberiotoxin-sensitive K(+) component) contribute (65 ± 4)% of the total K(+) currents in freshly isolated coronary smooth muscle cells and > 50% of the contraction of the inner diameter of coronary arteries from normal rats. However, BK current density is remarkably reduced in coronary smooth muscle cells of streptozotocin-induced diabetic rats, leading to an increase in coronary artery tension. BK channel activity in response to free Ca(2+) is impaired in diabetic rats. Moreover, cytoplasmic application of DHS-1 (a specific BK channel b(1) subunit activator) robustly enhanced the open probability of BK channels in coronary smooth muscle cells of normal rats. In diabetic rats, the DHS-1 effect was diminished in the presence of 200 nmol/L Ca(2+) and was significantly attenuated in the presence of high free calcium concentration, i.e., 1 mmol/L Ca(2+). Immunoblotting experiments confirmed that there was a 2-fold decrease in BK-b(1) protein expression in diabetic vessels, without altering the BK channel α-subunit expression. Although the cytosolic Ca(2+) concentration of coronary arterial smooth muscle cells was increased from (103 ± 23) nmol/L (n = 5) of control rats to (193 ± 22) nmol/L (n = 6, P < 0.05) of STZ-induced diabetic rats, reduced BK-b(1) expression made these channels less sensitive to intracellular Ca(2+), which in turn led to enhanced smooth muscle contraction.</p><p><b>CONCLUSIONS</b>Our results indicated that BK channels are the key determinant of coronary arterial tone. Impaired BK channel function in diabetes mellitus is associated with down-regulation of BK-b(1) expression and reduction of the b(1)-mediated BK channel activation in diabetic vessels.</p>

Effects of different pacing algorithms on cumulative ventricular pacing proportion in patients with pacemakers / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>It is well known that increased cumulative ventricular pacing proportion (CumVP%) is one of the most important causes for adverse cardiovascular events. Therefore, how to reduce CumVP% has been a treatment issue in recent years. This study aimed to investigate the effects of different pacing algorithms on CumVP% in patients with pacemakers.</p><p><b>METHODS</b>Pacemakers with three pacing algorithms, i.e., conventional dual chamber rate adaptive pacing (DDDR), search atrioventricular conduction plus (SAV+) and managed ventricular pacing (MVP), were implanted in 42 patients including 41 with bradycardia arrhythmias and one with ventricular tachycardia. Pacemakers were programmed to work in conventional DDDR, SAV+ and MVP during the follow-up periods of the first, the second and the third month. In each pacing algorithm, the time percentages of four pacing and sense status including atrial sense-ventricular sense (AS-VS), atrial sense-ventricular pacing (AS-VP), atrial pacing-ventricular sense (AP-VS) and atrial pacing-ventricular pacing (AP-VP) were calculated. Cumulative ventricular pacing proportions were compared in the three pacing algorithms in the first, the second and the third month postoperatively.</p><p><b>RESULTS</b>In the DDDR algorithm AS-VS, AS-VP, AP-VS and AP-VP were 2.4%, 52.3%, 2.5% and 42.8% respectively, while in SAV+ they were 19.3%, 34.9%, 33.9% and 12.0%, in MVP they were 38.9%, 13.2%, 41.6% and 6.4%. In the above the DDDR, SAV+ and MVP algorithms, cumulative ventricular pacing proportions were 95.1%, 46.9% and 19.6%, respectively (P < 0.05) and the percentages of CumVP% < 40% in patients were 0, 23.8% and 95.2.0% (P < 0.05).</p><p><b>CONCLUSIONS</b>Compared with the conventional DDDR algorithm, both SAV+ and MVP significantly reduced the CumVP%, especially the MVP algorithm. Patients may benefit from MVP algorithm due to reduced CumVP%.</p>

Mechanism related to docosahexaenoic acid induced large conductance calcium-activated potassium channel currents increase in coronary smooth muscle cells / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the mechanism of enhanced large conductance calcium-activated potassium channel currents (BK) in coronary smooth muscle cells (SMCs) by docosahexaenoic acid (DHA).</p><p><b>METHODS</b>Coronary SMCs were isolated by enzyme digestion. Potassium channels in coronary SMCs were identified by applications of different potassium blockers. Effects of DHA and its metabolite 16, 17-epoxydocosapentaenoic acid (16, 17-EDP) on BK channels in the absence and presence of cytochrome P450 epoxygenase inhibitor SKF525A were studied by patch clamp in whole-cell configuration.</p><p><b>RESULTS</b>BK channels were widely distributed in SMCs, and BK currents in normal SMCs accounted for (64.2 ± 2.7)% of total potassium currents (n = 20). DHA could activate BK channels, and its 50% effective concentration (EC(50)) was (0.23 ± 0.03) µmol/L, however, the effect of DHA on BK channels was abolished after SMCs were incubated with cytochrome P450 epoxygenase inhibitor SKF525A. 16, 17-EDP, a metabolite of DHA, could reproduce the effects of DHA on BK channels, and its EC(50) was (19.7 ± 2.8) nmol/L.</p><p><b>CONCLUSION</b>DHA and metabolites can activate BK channels and dilate coronary arteries through activating cytochrome P450 epoxygenase pathway.</p>

Evaluation on left ventricular systolic synchronicity and cardiac function in patients with permanent cardiac pacing by real-time three-dimensional echocardiography / 中华心血管病杂志

<p><b>OBJECTIVE</b>To determine the feasibility on the left ventricular systolic synchronism and cardiac function evaluation in patients with permanent cardiac pacing by real-time three-dimensional echocardiography.</p><p><b>METHODS</b>Fifteen patients with sick sinus syndrome post dual-chamber pacemaker implantation were enrolled in this study. Pacemakers were programmed to AAI, DDD, and VVI respectively. After pacing for 5 minutes in each mode, participants were examined with real-time three-dimensional echocardiography. Images in different pacing modes were obtained and analyzed by the off-line Qlab 4.2 software. Parameters including global and 17-segmental volume-time curves (VTCs), dispersion of time to minimal regional volume for 16, 12, and 6 left ventricular segments (Tmsv16-s, Tmsv12-s, Tmsv6-s), and maximal difference of time to minimal regional volume for l6, 12 and 6 left ventricular segments (Tmsv16-dif, Tmsv12-dif, Tmsv6-dif), end diastolic volume (EDV), end systolic volume (ESV), left ventricular ejection fraction (LVEF) were measured respectively. Parameters of peak filling rate (PFR), regional end diastolic volume (rEDV), regional end systolic volume (rESV), and regional ejection fraction (rEF) were also calculated.</p><p><b>RESULTS</b>Left ventricular systolic synchronism as reflected by VTCs, Tmsv16-s, Tmsv12-s, Tmsv6-s, Tmsv16-dif, Tmsv12-dif and Tmsv6-dif as well as parameters reflecting ventricular function, i.e., LVEF, PFR were significantly better in AAI mode than in DDD and VVI models (all P < 0.05). All above indexes were similar between DDD and VVI models (all P > 0.05). rEFs of left inferior wall in base, septum in base and apex were significantly lower in DDD and VVI models compared that in AAI mode (P < 0.05).</p><p><b>CONCLUSION</b>Real-time three-dimensional echocardiography can objectively and accurately evaluate left ventricular systolic synchronism and cardiac function in patients with permanent cardiac pacing and AAI mode is superior to DDD and VVI models.</p>

ON ANCIENT CHINESE DIET IN HUANG TI'S“NEI CHING SU WEN” / 营养学报

Huang Ti's "Nei Ching Su Wen" is the earliest classical work on medical science in ancient China. It summed up the results of observations made in long years through practice by the ancient Chinese labouring people, accumulating thereby lots of valuable knowledge and experience in different lines of medicine.Some two thousand years ago, Chinese medical scientists in the Chou and the Chin Dynasties already conceived the advanced idea of laying special emphasis on prophylactic measures, and began to adopt diet therapy as a means of medical treatment. Principles of preparing complete diet were worked out by them. And in this connection, it is mentioned in the book "Nei Ching Su Wen" that "five kinds of cereals are the means of subsistence, five kinds of cattle provide beneficial food in the form of meat, five kinds of vegetables can be used for food enrichment, and five kinds of fruits may serve as supplement." These principles point out the necessary sorts of food to constitute a complete diet and their respective positions in it. That is to say, cereals including beans and peas are the staple food and animal meat is of secondary importance, with vegetables to enrich and fruits to supplement the first two. A diet thus prepared will not only consist of all the nutritive elements needed by the human body but also represent an appropriate arrangement of the different kinds of nutrients. Such a diet is, no doubt, in accord with the dietetic theory of modern science.