Slow pathway catheter ablation of atrioventricular nodal re-entrant tachycardia guided by electroanatomical mapping: a randomized comparison to the conventional approach.

BACKGROUND: Electroanatomical mapping may be expected to improve safety, efficiency and efficacy of selective slow pathway ablation for atrioventricular nodal re-entrant tachycardia (AVNRT). The goal of this prospective randomized study was to compare the efficiency of conventional fluoroscopic and electroanatomical mapping in guiding catheter ablation of AVNRT. METHODS AND RESULTS: Following induction of typical AVNRT, 20 consecutive patients were randomized to either conventional fluoroscopic or electroanatomical (CARTO) mapping to guide slow pathway ablation using a 4mm electrode. Endpoints for ablation were non-inducibility and no more than a single AV nodal echo on aggressive retesting. Acute procedural success was 100% in both groups, with no complications. Although there were no differences in time taken for pre- and post-ablation electrophysiological evaluations, in the electroanatomical group the ablation portion of the procedure showed a substantial reduction in duration (12.6+/-6.8 vs 35.9+/-18.3 min; P< 0.001) and fluoroscopic exposure (0.7+/-0.5 vs 9.6+/-5.0 min; P< 0.001) compared with the fluoroscopic group, reflected in reduced total procedure time (83.6+/-23.6 vs 114+/-19.3 min; P=0.008) and total fluoroscopic exposure (4.2+/-1.4 vs 15.9+/-6.4 min; P< 0.001). Electroanatomical mapping was associated with a lower number (2.7+/-1.6 vs 5+/-2.8; P=0.018), duration (165.3+/-181.6 vs 341+/-177.7s; P=0.013), and total energy delivery (24.3+/-3.1 vs 28.7+/-4.5 watts; P=0.042) of RF applications. There were no acute or long-term (8.9+/-2.2 month) complications or arrhythmia recurrence in either group. CONCLUSIONS: While both conventional and non-fluoroscopic electroanatomical mapping are associated with excellent results in guiding ablation of typical AVNRT, the latter offers significantly shorter procedure and fluoroscopy times, improving the efficiency of the procedure and reducing X-ray exposure.     

Biofeedback benefits only patients with outlet dysfunction, not patients with isolated slow transit constipation

BACKGROUND & AIMS: Biofeedback is reported to be as effective for slow transit constipation as for pelvic floor dyssynergia and no more effective than education. We aimed to test the hypothesis that biofeedback benefits only patients with pelvic floor dyssynergia, describe the physiologic mechanism of treatment, and identify predictors of success. METHODS: Fifty-two patients (49 women; average age, 35 years), all with delayed whole gut transit, included 34 with pelvic floor dyssynergia, 12 with slow transit only, and 6 who met only 1 of 2 criteria for pelvic floor dyssynergia. All received 5 weekly biofeedback sessions directed at increasing rectal pressure and relaxing pelvic floor muscles during straining plus practice defecating a balloon. Patients were retested by questionnaire; symptom diary; balloon defecation; transit study at 1, 6, 12, and 24 months; and anorectal manometry at 1 and 6 months. RESULTS: At 6 months, greater improvements were seen in pelvic floor dyssynergia compared with slow transit only; 71% versus 8% reported satisfaction ( P = .001), and 76% versus 8% reported >/=3 bowel movements per week ( P < .001). Improvements were maintained at 24 months of follow-up. Biofeedback eliminated dyssynergia in 91% and enabled 85% to defecate the balloon. Satisfaction was correlated with improved ability to defecate the balloon (rho = .73; P < .001), reductions in dyssynergia (rho = .69; P < .001), and increased rectal pressure during straining (rho = .36; P < .01). Success was predicted by pelvic floor dyssynergia, milder constipation, and less frequent abdominal pain at baseline. CONCLUSIONS: Biofeedback is an effective treatment for pelvic floor dyssynergia but not slow transit constipation.     

正向低频长脉冲对逆向刺激模拟胃异位起搏点诱发胃电过速的治疗作用

目的探讨正向低频长脉冲胃电刺激对逆向高频长脉冲模拟胃异位起搏点诱发胃电过速的治疗作用。方法7条纯种雌性比格犬，依次沿胃大弯前壁浆膜层植入4对心脏起搏电极。通过距离幽门最近的1对电极输入高频长脉冲电信号诱导内源性胃肌电活动发生胃电过速，刺激参数为0．3mA、300ms、9cpm。刺激10min后，通过距离口端最近的1对电极输入不同振幅的低频长脉冲，直至纠正胃电过速，从而获得正向控制胃电过速的最小能量。观察电刺激前、刺激中和刺激后消化不良症状并进行评分。结果正向低频长脉冲能够完全控制逆向高频长脉冲模拟异位起搏点诱发的胃电过速，最小刺激振幅为（5．0±0．93）mA，最小刺激能量为（1500±277．75）（ms×mA）。获得完全控制的正向低频长脉冲与逆向高频长脉冲相比，正常胃慢波百分率升高（95．61％±3．78％ vs42．68％±19．74％，P=0．001），胃电过速百分率降低（3．58％±0．85％ vs40．29％±19．68％，P=0．001），主频降低（6．35±0．66 vs5．60±0．85，P=0．031），主功升高（-9．67±5．08 vs-2．26±1．03，P=0．001）。胃慢波基线期、高频长脉冲（RG-ES）期、完全控制的低频长脉冲（FGES＋RGES）期的消化不良症状评分均为1分，无明显差异。结论正向低频长脉冲能够完全纠正由高频逆向长脉冲模拟人工 异位起搏点引发的胃电过速，并恢复由此降低的胃动力。     

绝经后女性冠状动脉慢血流现象的相关因素分析

目的探讨可能与绝经后女性冠状动脉慢血流（slow coronary flow,SCF）现象相关的危险因素。方法回顾性分析2005年8月至2010年12月在新疆医科大学第一附属医院心脏中心行冠状动脉造影,显示心外膜主要冠状动脉无明显病变的患者186例,其中绝经后女性52例的临床资料。把冠状动脉血流仅为心肌梗死溶栓试验（thrombolysis in myocalrdial infarction,TIMI）血流2级或以下的患者定义为SCF。将绝经后女性患者分为绝经后女性SCF组（n=24）和绝经后女性对照组（n=28）。结果绝经后女性SCF组与绝经后女性对照组年龄、原发性高血压和糖尿病所占比例、血小板计数和血清空腹血糖、甘油三酯、总胆固醇、高密度脂蛋白胆固醇、低密度脂蛋白胆固醇、血尿酸浓度比较,差异无统计学意义（P〉0．05）;而绝经后女性SCF组的自细胞计数[（6．279±1．828）×10^9/Lvs.（5．241±1．527）×10^9g／L,P〈0．05]、中性粒细胞计数[（6．688±1．705）×10^9／Lvs.（3．763±1．573）×10^9／L,P〈0．05]、左心室质量指数（left ventricular mass index,LVMI）[（110．530±30．936）g／m^2 vs.（93．815±20．141）g／m^2,P〈0．05]均高于对照组,差异有统计学意义。Logistic分析表明,绝经女性SCF与LVMI（OR=1．028,95％CI：1．002-1．055,P=0．037）、白细胞计数（OR=1．501,95％CI：0．011-2．229,P=0．044）相关。结论白细胞计数、中性粒细胞计数、LVMI增高可能参与了绝经女性SCF的发生、发展。LVMI、白细胞计数增高可能是绝经女性SCF患者的危险因素。     

冠状动脉介入术后血流与靶血管直径相关

目的:评价冠状动脉支架术后血流与血管直径的相关性。方法:对192例行冠状动脉介入(PCI)治疗患者的224支靶血管进行定量冠状动脉造影(QCA)分析和术前术后TIMI帧数分析。术前术后TIMI帧数差值进行三分位数分组,≤2为"慢血流组",3~9为"正常血流组",≥10为"快血流组"。同时根据参考血管直径分成大血管组(≥4 mm)、正常血管组(2.76~4.0 mm)、小血管组(≤2.75 mm)。对3组的冠状动脉病变特征和基线资料进行比较。比较不同直径血管的病变特征。对术后血流的相关危险因素进行多元线性回归分析。结果:慢血流组、正常血流组和快血流组患者靶血管参考血管直径分别为(3.4±0.7)mm、(3.2±0.7)mm和(3.2±0.7)mm,P0.05。大血管在慢血流组、正常血流组和快血流组的比率分别为29%(23/78)、10%(8/80)和14%(9/66),P0.01。≥4 mm血管组和4 mm血管组的斑块面积分别为(23±11)mm2和(15±8)mm2,P0.01。多元回归分析PCI术后血流状态的危险因素为年龄(P0.05)和参考血管直径(P0.01)。结论:PCI术后血流与冠状动脉血管直径相关。血管直径越大发生介入术后慢血流的几率越高。     

Sex differences in circadian timing systems: Implications for disease

Virtually every eukaryotic cell has an endogenous circadian clock and a biological sex. These cell-based clocks have been conceptualized as oscillators whose phase can be reset by internal signals such as hormones, and external cues such as light. The present review highlights the inter-relationship between circadian clocks and sex differences. In mammals, the suprachiasmatic nucleus (SCN) serves as a master clock synchronizing the phase of clocks throughout the body. Gonadal steroid receptors are expressed in almost every site that receives direct SCN input. Here we review sex differences in the circadian timing system in the hypothalamic–pituitary–gonadal axis (HPG), the hypothalamic–adrenal–pituitary (HPA) axis, and sleep–arousal systems. We also point to ways in which disruption of circadian rhythms within these systems differs in the sexes and is associated with dysfunction and disease. Understanding sex differentiated circadian timing systems can lead to improved treatment strategies for these conditions.     

Ideal glass transitions by random pinning

We study the effect of freezing the positions of a fraction c of particles from an equilibrium configuration of a supercooled liquid at a temperature T. We show that within the random first-order transition theory pinning particles leads to an ideal glass transition for a critical fraction c = c_K(T) even for moderate supercooling; e.g., close to the Mode-Coupling transition temperature. First we derive the phase diagram in the T - c plane by mean field approximations. Then, by applying a real-space renormalization group method, we obtain the critical properties for |c - c_K(T)| → 0, in particular the divergence of length and time scales, which are dominated by two zero-temperature fixed points. We also show that for c = c_K(T) the typical distance between frozen particles is related to the static point-to-set length scale of the unconstrained liquid. We discuss what are the main differences when particles are frozen in other geometries and not from an equilibrium configuration. Finally, we explain why the glass transition induced by freezing particles provides a new and very promising avenue of research to probe the glassy state and ascertain, or disprove, the validity of the theories of the glass transition.     

On relaxations and aging of various glasses

Slow relaxation occurs in many physical and biological systems. "Creep" is an example from everyday life. When stretching a rubber band, for example, the recovery to its equilibrium length is not, as one might think, exponential: The relaxation is slow, in many cases logarithmic, and can still be observed after many hours. The form of the relaxation also depends on the duration of the stretching, the "waiting time." This ubiquitous phenomenon is called aging, and is abundant both in natural and technological applications. Here, we suggest a general mechanism for slow relaxations and aging, which predicts logarithmic relaxations, and a particular aging dependence on the waiting time. We demonstrate the generality of the approach by comparing our predictions to experimental data on a diverse range of physical phenomena, from conductance in granular metals to disordered insulators and dirty semiconductors, to the low temperature dielectric properties of glasses.