Electrophysiologic Spectrum of Atrioventricular Nodal Behavior in Patients with Atrioventricular Nodal Reentrant Tachycardia Undergoing Selective Fast or Slow Pathway Ablation

AV Nodal Behavior After Ablation. Introduction; The objective of this report is to delineate the atrioventricular (AV) nodal electrophysiologic behavior in patients undergoing fast or slow pathway ablation for control of their AV nodal reentrant tachycardia (AVNRT).
Methods and Results: One hundred sixteen consecutive patients with symptomatic AVNRT were included. Twenty-two patients underwent fast pathway ablation with complete abolition of AVNRT in all and development of complete AV block in five patients. Of 17 patients with intact AV conduction postablation, 12 had demonstrated antegrade dual pathway physiology during baseline study, which was maintained in three and lost in nine patients postablation. Two patients with successful fast pathway ablation developed uncommon AVNRT necessitating a slow pathway ablation. Twenty-one patients demonstrated both common and uncommon forms of AV nodal reentry during baseline study. The earliest site of atrial activation was close to the His-bundle recording site (anterior interatrial septum) during common variety and the coronary sinus ostium (posterior interatrial septum) during the uncommon AV nodal reentry in all 21 patients. Ninety-six patients underwent successful slow pathway ablation. Among these, the antegrade dual pathway physiology demonstrable during baseline study (60 patients) was maintained in 25 and lost in 35 patients postablation.
Conclusion: These data suggest that: (1) dual pathway physiology may persist after successful ablation, which might be a reflection of multiple reentrant pathways in patients with AVNRT: and (2) the retrograde pathways during common and uncommon AVNRT have anatomically separate atrial breakthroughs. These findings have important electrophysiologic implications regarding the prevailing concept of the AV nodal physiology in patients with AVNRT.     

基于单中心的冠状动脉慢血流危险因素分析及其与炎症反应的相关性

目的：探讨冠状动脉慢血流（coronary slow flow, CSF）现象的临床危险因素及炎症反应在其发病机制中的可能作用。方法：采用校正的心肌梗死溶栓治疗（thrombolysis in myocardial infarction, TIMI）临床试验血流帧数（corrected TIMI frame count, CTFC）评价冠状动脉血流情况。入选我院2016年1月至2016年12月择期行冠状动脉造影（coronary angiography, CAG）并证实CSF的患者96例为CSF组,入选同期行CAG证实血流完全正常的患者106例为非慢血流（non-CSF, NCSF）组。比较两组患者的临床特点、生化指标及相关炎症因子（包括外周静脉血及冠状动脉血）之间的差异,炎症因子包括：白细胞介素-6（interleukin-6, IL-6）、超敏C反应蛋白（hypersensitive C reactive protein, hsCRP）、基质金属蛋白酶-9（matrix metalloproteinase-9, MMP-9）。同时进行单因素及多因素Logistic回归分析,分析CSF的危险因素及其与炎症反应的相关性。结果：CSF组冠状动脉三分支的CTFC值均显著高于NCSF组（前降支：32.3±3.7 vs 17.8±2.1;回旋支：34.5±3.9 vs 23.1±2.8;右冠状动脉：34.9±4.3 vs 21.4±3.2,P均<0.01）,且右冠状动脉为CSF最常见的受累冠脉（83.3%）。单因素分析发现：CSF组患者体质指数,糖尿病比例,尿酸,冠状动脉血IL-6、hsCRP,外周静脉血及冠状动脉血MMP-9均显著高于NCSF组（P<0.05或0.01）。Logistic回归分析发现：体质指数（OR=1.313, 95%CI 1.026~1.654, P=0.034）、糖尿病（OR=1.604, 95%CI 1.198~2.466, P=0.006）、高尿酸水平（OR=1.036, 95%CI 1.006~1.102, P=0.027）、外周静脉血MMP-9（OR=2.279, 95%CI 1.478~4.022, P=0.004）、受累冠状动脉血MMP-9（OR=3.145, 95%CI 2.011~5.023, P=0.000）是发生CSF的独立危险因素。结论：体质指数、糖尿病、尿酸是CSF发生的独立危险因素;与全身炎症反应相比,受累冠脉局部炎症反应与CSF更相关;炎症因子MMP-9在CSF的病理生理过程中发挥重要作用。     

冠状动脉慢血流现象临床危险因素及形态学研究

目的探寻冠状动脉慢血流现象(CSFP)的临床危险因素,了解冠状动脉形态对心肌梗死溶栓治疗试验(TIMI)血流的影响,推测CSFP的发病机制。方法回顾性收集2017年1月至2019年7月于兰州大学第一医院心脏中心行冠状动脉造影无狭窄病变的患者256例,根据TIMI血流帧数将其中血流减慢的患者设为CSFP组(100例),将血流正常患者设为对照组(156例),按年龄和性别匹配。收集患者临床数据和冠状动脉造影数据,采用二元logistic回归模型分析CSFP的危险因素,并采用Pearson相关分析检验冠状动脉形态学参数与平均校正的TIMI帧数(cTFC)的相关性。结果CSFP组同型半胱氨酸[(22.07±7.27)mmol/L比(18.16±6.63)mmol/L]、中性粒细胞百分比[(44.40±15.60)%比(35.43±12.49)%]、淋巴细胞百分比[3.65%(1.32%,24.65%)比1.80%(1.02%,6.22%)]、平均血小板体积(MPV)[(13.17±1.82)fl比(12.20±1.57)fl]、血小板分布宽度(PDW)[(14.17±2.17)f l比(13.21±2.42)f l]与对照组相比更高,三酰甘油[(3.05±1.37)mmol/L比(3.44±1.36)mmol/L]、纤维蛋白原[(2.65±0.68)g/L比(2.86±0.66)g/L]与对照组相比更低,术中血压更低,冠状动脉平均直径更大,平均远端分支数更少,差异均有统计学意义(均P<0.05)。二元logistic回归模型拟合显示:同型半胱氨酸(OR 1.077,95%CI 1.034~1.123,P<0.001)、中性粒细胞百分比(OR 1.064,95%CI 1.032~1.097,P<0.001)、PDW(OR 1.194,95%CI 1.051~1.356,P=0.006)、MPV(OR 1.338,95%CI 1.127~1.588,P=0.001)是预测CSFP的独立危险因素。相关性分析显示,冠状动脉平均直径与平均cTFC呈显著正相关(r=0.583,P<0.05);冠状动脉平均远端分支数与平均cTFC呈显著负相关(r=-0.508,P<0.05)。结论同型半胱氨酸、中性粒细胞百分比、PDW和MPV是预测CSPF的独立危险因素。冠状动脉平均直径和远端分支数均与冠状动脉平均cTFC密切相关。炎症可能是CSFP发生的关键机制。     

Mechanism of ventricular tachycardia in a patient with double-outlet left ventricle

We report the case of ventricular tachycardia (VT) ablation procedure in a patient with history of surgically repaired double-outlet left ventricle. The electrophysiology procedure revealed a re-entry pattern between the right-ventricle to main-pulmonary-artery conduit and the tricuspid annulus. The re-entrant mechanism was most likely promoted by a fibrous remodeling of this area, related to the surgical repair. This case is the first to describe a re-entry mechanism between fixed anatomical barriers in a repaired right ventricle of a double-outlet left ventricle. A pace mapping technique was used to highlight the VT isthmus.     

冠状动脉慢血流与血管内皮的相关性研究及药物干预

目的探讨冠状动脉慢血流与血管内皮的相关性及应用麝香通心滴丸进行药物干预的作用。方法选取2016年12月至2017年12月于沈阳医学院附属中心医院循环内科因胸痛、胸闷就诊的患者共59例,分为试验组(28例,慢血流患者)及对照组(31例,血流正常的患者),检测两组低密度脂蛋白胆固醇(LDL-C)、尿酸、同型半胱氨酸、NO、ET-1指标水平。试验组术中测量应用药物前后校正的TIMI及应用麝香通心滴丸1个月后低密度脂蛋白、尿酸、同型半胱氨酸、NO、ET-1水平,并进行相关性分析。结果试验组同型半胱氨酸、低密度脂蛋白、尿酸、ET-1水平高于对照组(P<0.05,P<0.01),而NOS低于对照组(P<0.05)。试验组患者用药后CTFC(校正的TIMI)显著降低(P<0.05),用药前与用药后1个月的LDL-C、尿酸、ET-1水平比较差异有统计学意义(P<0.05,P<0.01)结论冠状动脉慢血流的患者内皮功能存在受损,麝香通心滴丸可以改善血流速度及改善内皮功能。     

Inertial flywheel vs heavy slow resistance training among athletes with patellar tendinopathy: A randomised trial

ObjectivesTo compare the efficacy of inertial flywheel and heavy slow resistance training in reducing pain and improving function in patellar tendinopathy.DesignRandomised clinical trial.MethodsFourty two participants (1 woman, 41 men) with longstanding (>3 months) patellar tendinopathy were randomised into inertial flywheel resistance (N = 21) or heavy slow resistance (N = 21) group. Both programmes consisted of three supervised inertial flywheel or heavy slow resistance exercise sessions per week in a fitness center during 12 weeks. Primary outcome was pain and function, assessed by the Spanish Victorian Institute of Sport Assessment for Patella (VISA-P) score at 6 and 12 weeks. Secondary outcomes were activity limitation using Patient Specific Functional Scale (PSFS), health status (EuroQol-5D), patient impression of change on pain and function, adherence, adverse events, pain provocation test for the patellar tendon (numerical rating score of pain between 0 and 10), physical test, patellar tendon thickness and doppler signal on ultrasound. Secondary outcomes were taken at 0 and 12 weeks.ResultsBoth groups showed significant improvements in VISA-P scores from 0 to 12 weeks but there was not statistically significant between-group difference (P = 0.506). No adverse events or side effects occurred in any of the groups during the intervention period.ConclusionsInertial flywheel resistance three times a week during 12 weeks resulted in similar pain and function benefit at 12 weeks compared with the heavy slow resistance training among people with patellar tendinopathy. Flywheel training is another exercise option for managing people with patellar tendinopathy.ClinicalTrials.gov RegistryNCT03917849.     

Sex differences in objective measures of sleep in post‐traumatic stress disorder and healthy control subjects

A growing literature shows prominent sex effects for risk for post‐traumatic stress disorder and associated medical comorbid burden. Previous research indicates that post‐traumatic stress disorder is associated with reduced slow wave sleep, which may have implications for overall health, and abnormalities in rapid eye movement sleep, which have been implicated in specific post‐traumatic stress disorder symptoms, but most research has been conducted in male subjects. We therefore sought to compare objective measures of sleep in male and female post‐traumatic stress disorder subjects with age‐ and sex‐matched control subjects. We used a cross‐sectional, 2 × 2 design (post‐traumatic stress disorder/control × female/male) involving83 medically healthy, non‐medicated adults aged 19–39 years in the inpatient sleep laboratory. Visual electroencephalographic analysis demonstrated that post‐traumatic stress disorder was associated with lower slow wave sleep duration (F_(3,82) = 7.63, P = 0.007) and slow wave sleep percentage (F_(3,82) = 6.11, P = 0.016). There was also a group × sex interaction effect for rapid eye movement sleep duration (F_(3,82) = 4.08, P = 0.047) and rapid eye movement sleep percentage (F_(3,82) = 4.30, P = 0.041), explained by greater rapid eye movement sleep in post‐traumatic stress disorder females compared to control females, a difference not seen in male subjects. Quantitative electroencephalography analysis demonstrated that post‐traumatic stress disorder was associated with lower energy in the delta spectrum (F_(3,82) = 6.79, P = 0.011) in non‐rapid eye movement sleep. Slow wave sleep and delta findings were more pronounced in males. Removal of post‐traumatic stress disorder subjects with comorbid major depressive disorder, who had greater post‐traumatic stress disorder severity, strengthened delta effects but reduced rapid eye movement effects to non‐significance. These findings support previous evidence that post‐traumatic stress disorder is associated with impairment in the homeostatic function of sleep, especially in men with the disorder. These findings suggest that group × sex interaction effects on rapid eye movement may occur with more severe post‐traumatic stress disorder or with post‐traumatic stress disorder comorbid with major depressive disorder.     

Cyclic adenosine monophosphate modulation of contractility via slow Ca2+ channels in chick heart

The catecholamines exert a positive inotropic effect associated with elevated tissue cyclic AMP levels and possibly with increase in the number of membrane slow cationic channels available for voltage activation. In the present study, catecholamines (isoproterenol, dopamine and dobutamine) were tested for their ability to affect the maximum upstroke velocity (+ V_max) of the slow action potentials, the first derivative ($\text{d}\text{T}\text{d}\text{t}$) of developed tension accompanying the slow responses, and the tissue cyclic AMP levels in the ventricular myocardium of isolated perfused chick hearts. To study the slow channels exclusively, the fast Na⁺ channels were voltage inactivated by elevated (25 mm) K⁺. In this condition of functional removal of the fast channels, the heart could not be excited by intense electrical stimulation. It was found that these catecholamines induced slow action potentials accompanied by contractions. Elevation of the concentration of these agents produced increases in + V_max, $\text{d}\text{T}\text{d}\text{t}$, and cyclic AMP in a dose-dependent fashion; a close correlation was obtained between the cyclic AMP level, + V_max and $\text{d}\text{T}\text{d}\text{t}$. These results support the hypothesis that the increases in + V_max of the slow action potentials and in contraction are explained by increase in the number of available slow channels mediated by intracellular cyclic AMP levels, and the resulting increase in the Ca²⁺ influx.     

GOLDART--Gold Alloy Versus Platinum-Iridium Electrode for Ablation of AVNRT

Introduction: Radiofrequency (RF) catheter ablation targeting the slow pathway is currently the most effective treatment for patients with atrioventricular nodal reciprocating tachycardia (AVNRT). Gold exhibits a more than four times greater thermal conductivity than platinum, and the creation of deeper lesions was demonstrated in ex vivo animal experiments. The current clinical trial was initiated to compare gold catheters with standard platinum–iridium (Pt–Ir) material and to analyze differences in the increase of power or temperature as a function of time during RF ablation.
Methods: A prospective, randomized multicenter study design was used to compare RF deliveries at the slow pathway with standard Pt–Ir tip catheters (128 patients), as well as gold alloy tip electrodes (124 patients) during AVNRT ablation.
Results: Although there was a trend towards higher power delivery in the gold group (4.96 vs. 4.28 W/s), this trend was not statistically significant. Likewise, cumulative duration of all RF ablations, total procedure time, and power delivered at other time points were not significantly different between the groups. Also, the occurrence of AV-block and sensations of pain were similar in both treatment groups. However, charring on the catheter tip after the intervention was observed eightfold more frequently in the Pt–Ir group.
Conclusion: In conclusion, power delivery cannot be significantly increased by RF ablation of AVNRT with gold electrodes. But the electrode material seems to be safe and well-tolerated and specifically did not increase the risk of AV-block. The significant reduction of coagulum formation on gold tips suggests a possible advantage of this material beyond its better conduction properties.