Muscular Subaortic Stenosis: The Effect of Peripheral Vasodilatation

Amyl nitrite was administered on two occasions to a patient with muscular subaortic stenosis, to ascertain if selective peripheral vasodilatation would affect the degree of obstruction to left ventricular outflow in this condition. On each occasion there was a marked increase in the systolic pressure gradient across the left ventricular outflow tract prior to the onset of reflex tachycardia. Following the second amyl nitrite inhalation, the systolic cross-sectional area of the left ventricular outflow tract decreased to 1.0 sq. cm., from the control value of 2.6 sq. cm. It is believed that the increased degree of muscular subaortic stenosis, following peripheral vasodilatation, could be secondary to a decrease in the systolic size of the whole left ventricle, or to a selective decrease in the physical size of the left ventricular outflow tract.     

Verapamil Sensitive Ventricular Tachycardia Associated With A Cardiac Hemangioma In The Right Ventricular Outflow Tract

Primary tumors of the heart are rare, but they are often associated with refractory arrhythmias. Vascular tumors of the heart comprise a small minority of primary cardiac tumors. In patients with structurally normal hearts, ventricular tachycardia (VT) originating from the right ventricular outflow tract (RVOT) can be sensitive to adenosine, vagal maneuvers, and calcium channel blockers. In this report, we describe a case of ventricular tachycardia originating from within a hemangioma in the RVOT that was ultimately controlled with verapamil.     

Radiofrequency Catheter Ablation of Idiopathic Right Ventricular Outflow Tract Arrhythmias

Idiopathic ventricular arrhythmias (VA) consist of various subtypes of VA that occur in the absence of clinically apparent structural heart disease. Affected patients account for approximately 10% of all patients referred for evaluation of ventricular tachycardia (VT). Arrhythmias arising from the outflow tract (OT) are the most common subtype of idiopathic VA and more than 70–80% of idiopathic VTs or premature ventricular contractions (PVCs) originate from the right ventricular (RV) OT. Idiopathic OT arrhythmias are thought to be caused by adenosine-sensitive, cyclic adenosine monophosphate (cAMP) mediated triggered activity and, in general, manifest at a relatively early age. Usually they present as salvos of paroxysmal ventricular ectopic beats and are rarely life-threatening. When highly symptomatic and refractory to antiarrhythmic therapy or causative for ventricular dysfunction, ablation is a recommended treatment with a high success rate and a low risk of complications.     

心电图左心室劳损和左心室肥厚对主动脉瓣狭窄患者预后的影响

目的:探讨心电图左心室劳损(LV)和左心室肥厚(LVH)对无症状主动脉瓣狭窄患者预后的影响。方法:到我院治疗的主动脉瓣狭窄患者766例,心电图左心室劳损和左心室肥厚的预测值用Sokolow-Lyon(SL)电压标准和Cornell电压-时间(CVDP)标准评估,通过对其他预后协变量调整并进行评价。结果:心电图左心室劳损患者的心肌梗死的累计发生率显著高于非心电图劳损的患者(HR=2.7,95%CI:1.4-5.3,P=0.006)。与非心电图左心室肥厚的患者比较,SL标准与CVDP标准联用诊断的左心室肥厚患者心力衰竭的风险显著增加(95%CI:4.7-26.4,P0.001);行主动脉瓣置换术风险显著增加(95%CI:1.6-3.2,P0.001);非致死性梗死、心力衰竭或心血管死亡的复合终点风险也显著增加(95%CI:1.2-3.7,P0.05)。结论:心电图LV和LVH是无症状主动脉瓣狭窄患者预后不良的独立预测因子。     

右室流出道室性心动过速的发生机制研究进展

右心室流出道室性心律失常是临床上常见的特发性心律失常,占特发性室速的60%~70%,绝大多数右心室流出道室速为腺苷敏感性,其发病机制为儿茶酚胺介导的延迟后除极和触发活动。其发生机制一直是电生理领域研究的热点问题,新近研究表明,L型钙通道的改变与特发性右心室流出道室性心动过速的发生密切相关,提示L型钙通道可能会成为特发性右心室流出道室性心动过速治疗的新靶点。     

应用同种带瓣管道重建右室流出道的危险因素分析

目的:评价采用同种带瓣管道行右室流出道重建术的临床效果,探讨影响手术效果及临床预后的因素。方法:回顾2002年11月至2010年11月期间应用同种带瓣管道行右室流出道重建患者的临床资料,分析患者手术前后的一般信息、血流动力学表现与临床预后的关系。结果:行右室流出道重建术后49例痊愈出院,5例死亡,存活率90.7%,死亡率9.3%。手术前后比较右室流出道内径较术前明显增加,右室-左室收缩压比值、右室-肺动脉压差较术前明显降低,三尖瓣反流、肺动脉瓣反流较术前加重,肺动脉瓣狭窄较术前减轻。统计分析表明患者死亡的危险因素有术后右室平均压、术后肺动脉-主动脉收缩压比值、术后二尖瓣反流。术后心胸比、术后肺动脉收缩压、术后肺动脉-主动脉收缩压比值、术后三尖瓣反流可能和术后患者ICU时间延长有关。McGoon指数、术后心胸比、术后肺动脉收缩压、术后右室平均压、术后肺动脉-主动脉收缩压比值、合并动脉导管未闭、术后三尖瓣反流可能和术后患者呼吸机时间延长有关。结论:复杂先天性心脏病患者采用同种带瓣管道重建右室流出道可以取得较满意的临床效果,术后流出道梗阻矫正满意,可以防止肺动脉返流导致的心脏损害。     

应用同种带瓣管道重建右室流出道的危险因素分析

目的：评价采用同种带瓣管道行右室流出道重建术的临床效果,探讨影响手术效果及临床预后的因素。方法：回顾2002年11月至2010年11月期间应用同种带瓣管道行右室流出道重建患者的临床资料,分析患者手术前后的一般信息、血流动力学表现与临床预后的关系。结果：行右室流出道重建术后49例痊愈出院,5例死亡,存活率90．7％,死亡率9-3％。手术前后比较右室流出道内径较术前明显增加,右室一左室收缩压比值、右室-肺动脉压差较术前明显降低,三尖瓣反流、肺动脉瓣反流较术前加重,肺动脉瓣狭窄较术前减轻。统计分析表明患者死亡的危险因素有术后右室平均压、术后肺动脉-主动脉收缩压比值、术后二尖瓣反流。术后心胸比、术后肺动脉收缩压、术后肺动脉一主动脉收缩压比值、术后三尖瓣反流可能和术后患者ICU时间延长有关。McGoon指数、术后心胸比、术后肺动脉收缩压、术后右室平均压、术后肺动脉一主动脉收缩压比值、合并动脉导管未闭、术后三尖瓣反流可能和术后患者呼吸机时间延长有关。结论：复杂先天性心脏病患者采用同种带瓣管道重建右室流出道可以取得较满意的临床效果,术后流出道梗阻矫正满意,可以防止肺动脉返流导致的心脏损害。     

Anatomic Guidance For Ablation: Atrial Flutter,Fibrillation, and Outflow Tract Ventricular Tachycardia

After initial documentation of excellent efficacy with radiofrequency ablation, this procedure is being performed increasingly in more complex situations and for more difficult arrhythmia. In these circumstances, an accurate knowledge of the anatomic basis for the ablation procedure will help maintain this efficacy and improve safety. In this review, we discuss the relevant anatomy for electrophysiology interventions for typical right atrial flutter, atrial fibrillation, and outflow tract ventricular tachycardia. In the pediatric population, maintaining safety is a greater challenge, and here again, knowing the neighboring and regional anatomy of the arrhythmogenic substrate for these arrhythmias may go a long way in preventing complications.     

法乐氏四联症右室流出道心肌间质胶原表达改变

摘要：探讨法乐氏四联症患者右室流出道I、Ⅲ型胶原蛋白mRNA与蛋白质合成的表达改变,以期进一步阐明法乐氏四联症的发病机制．用RT—PCR方法检测32例法乐氏四联症患者与同期17例小室缺患者右室流出道Ⅰ、Ⅲ型胶原mRNA的表达差异,并分析了不同氧饱和度对法乐氏四联症胶原蛋白mRNA表达的影响．同时应用免疫组化图像分析及Western blot检测右室流出道Ⅰ、Ⅲ型胶原蛋白含量并作对比分析．研究发现法乐氏四联症患者右室流出道Ⅰ、Ⅲ型胶原蛋白mRNA与蛋白质合成均较对照组增高并且出现胶原比值改变,缺氧程度与胶原合成关系密切．     

Extensive Preferential Pathway Ablation for the Elimination of Premature Ventricular Contractions Arising from the Right Ventricular Outflow Tract

A 76 y/o women presented with 2 different types of premature ventricular contractions (VPCs 1 and 2) arising from the right ventricular outflow tract (RVOT). Catheter ablation (CA) eliminated PVC1 at the earliest activation site (EAS), but thereafter another PVC morphology (PVC3) appeared. Small potentials preceding the local potential were broadly exhibited from the RVOT’s supero-anterior region to the EAS during PVC3. Point CA targeting such prepotentials failed. Transverse-linear CA with a line connecting sites with such pre-potentials eliminated both PVCs 3 and 2. In cases with broadly spreading preferential pathways, extensive CA might be needed to eliminate the PVCs.     

Left Ventricular Geometry and Blood Pressure as Predictors of Adverse Progression of Fabry Cardiomyopathy

Background

In spite of several research studies help to describe the heart in Fabry disease (FD), the cardiomyopathy is not entirely understood. In addition, the impact of blood pressure and alterations in geometry have not been systematically evaluated.

Methods

In 74 FD patients (mean age 36±12 years; 45 females) the extent of myocardial fibrosis and its progression were quantified using cardiac magnetic-resonance-imaging with late enhancement technique (LE). Results were compared to standard echocardiography complemented by 2D-speckle-tracking, 3D-sphericity-index (SI) and standardized blood pressure measurement. At baseline, no patient received enzyme replacement therapy (ERT). After 51±24 months, a follow-up examination was performed.

Results

Systolic blood pressure (SBP) was higher in patients with vs. without LE: 123±17 mmHg vs. 115±13 mmHg; P = 0.04. A positive correlation was found between SI and the amount of LE-positive myocardium (r = 0.51; P<0.001) indicating an association of higher SI in more advanced stages of the cardiomyopathy. SI at baseline was positively associated with the increase of LE-positive myocardium during follow-up. The highest SBP (125±19 mmHg) and also the highest SI (0.32±0.05) was found in the subgroup with a rapidly increasing LE (ie, ≥0.2% per year; n = 16; P = 0.04). Multivariate logistic regression analysis including SI, SBP, EF, left ventricular volumes, wall thickness and NT-proBNP adjusted for age and sex showed SI as the most powerful parameter to detect rapid progression of LE (AUC = 0.785; P<0.05).

Conclusions

LV geometry as assessed by the sphericity index is altered in relation to the stage of the Fabry cardiomyopathy. Although patients with FD are not hypertensive, the SBP has a clear impact on the progression of the cardiomyopathy.     

The Different Substrate Characteristics of Arrhythmogenic Triggers in Idiopathic Right Ventricular Outflow Tract Tachycardia and Arrhythmogenic Right Ventricular Dysplasia: New Insight from Noncontact Mapping

BackgroundThe aim of this study was to investigate the different substrate characteristics of repetitive premature ventricular complexed (PVC) trigger sites by the non-contact mapping (NCM).MethodsThirty-five consecutive patients, including 14 with arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC) and 21 with idiopathic right ventricular outflow tract tachycardia (RVOT VT), were enrolled for electrophysiological study and catheter ablation guided by the NCM. Substrate and electrogram (Eg) characteristics of the earliest activation (EA) and breakout (BO) sites of PVCs were investigated, and these were confirmed by successful PVC elimination.ResultsOverall 35 dominant focal PVCs were identified. PVCs arose from the focal origins with preferential conduction, breakout, and spread to the whole right ventricle. The conduction time and distance from EA to BO site were both longer in the ARVC than the RVOT group. The conduction velocity was similar between the 2 groups. The negative deflection of local unipolar Eg at the EA site (EA slope_3,5,10ms values) was steeper in the RVOT, compared to ARVC patients. The PVCs of ARVC occurred in the diseased substrate in the ARVC patients. More radiofrequency applications were required to eliminate the triggers in ARVC patients.Conclusions/InterpretationThe substrate characteristics of PVC trigger may help to differentiate between idiopathic RVOT VT and ARVC. The slowing and slurred QS unipolar electrograms and longer distance from EA to BO in RVOT endocardium suggest that the triggers of ARVC may originate from mid- or sub-epicardial myocardium. More extensive ablation to the trigger site was required in order to create deeper lesions for a successful outcome.     

The Homeostatic Chemokine CCL21 Predicts Mortality in Aortic Stenosis Patients and Modulates Left Ventricular Remodeling

Background

CCL21 acting through CCR7, is termed a homeostatic chemokine. Based on its role in concerting immunological responses and its proposed involvement in tissue remodeling, we hypothesized that this chemokine could play a role in myocardial remodeling during left ventricular (LV) pressure overload.

Methods and Results

Our main findings were: (i) Serum levels of CCL21 were markedly raised in patients with symptomatic aortic stenosis (AS, n = 136) as compared with healthy controls (n = 20). (ii) A CCL21 level in the highest tertile was independently associated with all-cause mortality in these patients. (iii) Immunostaining suggested the presence of CCR7 on macrophages, endothelial cells and fibroblasts within calcified human aortic valves. (iv). Mice exposed to LV pressure overload showed enhanced myocardial expression of CCL21 and CCR7 mRNA, and increased CCL21 protein levels. (v) CCR7^−/− mice subjected to three weeks of LV pressure overload had similar heart weights compared to wild type mice, but increased LV dilatation and reduced wall thickness.

Conclusions

Our studies, combining experiments in clinical and experimental LV pressure overload, suggest that CCL21/CCR7 interactions might be involved in the response to pressure overload secondary to AS.     

Circulating Level of miR-378 Predicts Left Ventricular Hypertrophy in Patients with Aortic Stenosis

Aims

Excessively high left ventricle mass is an independent predictor of adverse prognosis. MicroRNAs (miRs) play crucial roles in the regulation of left ventricle hypertrophy (LVH). However, few circulating miRs have been established as predictors of LVH in aortic stenosis (AS) patients. In this study, we aimed to investigate whether circulating levels of miR-1, miR-133, and miR-378 predict LVH in patients with AS.

Methods and Results

One-hundred twelve patients with moderate to severe AS and 40 healthy controls were included in the study. Levels of miR-1, miR-133, and miR-378 in the plasma were measured by qPCR. Compared with healthy controls, AS patients had significantly lower circulating levels of miR-1, miR-133, and miR-378. AS patients with LVH had significantly lower miR-378 but not miR-1 and miR-133 compared with those without LVH. Linear regression analysis showed circulating miR-378 had strong correlation with left ventricular mass index (r = 0.283, p = 0.002) and logistic regression showed that lower miR-378 was an independent predictor for LVH in patients with AS (p = 0.037, OR 4.110, 95% CI 1.086 to 15.558).

Conclusion

Circulating levels of miR-1, miR-133 and miR-378 were decreased in AS patients, and miR-378 predicts LVH independent of the pressure gradient. Further prospective investigations are needed to elucidate whether these circulating miRs affect clinical outcome.     

A Method for the Investigation of Fast Water Inflow and Outflow by Changes in the External Osmotic Pressure

An original noninvasive method for monitoring water relations in plant roots is described. The gravimetric method was combined with the continuous recording of the photoelectric signal. According to this method, an intact plant was attached to the arm of a sensitive weighing beam and balanced. The root system was exposed to the air and continuously sprinkled with a solution flowing at a constant rate, in order to preserve the plant intact and to continue recording after the solution was changed. When the equilibrium was upset as a result of a change in plant weight, the movement of the beam's shutter cut off the flow of light incident on the photoelectric cell. The photocurrent was measured using a highly sensitive recording microampermeter. The method was tested with the seedlings of sunflower (Helianthus annuus L.) and tomato (Lycopersicon esculentum L.), when their roots were treated with salt solutions of various concentrations. NaCl solutions at the plasmolytic concentration induced a severe salt stress (200 mM) and brought about a significant loss of water in the plant. A similar response was observed at a lower salt concentration (10 mM) that induced neither plasmolysis nor salt stress. In both cases, the response was reversible and essentially devoid of any lag period. The method is notable for a high sensitivity (1–10 l) and a short lag time (its resolution is one second). It ensures the continuous automatic recording of even small changes in water content in intact plants. The method may be used for the investigation of immediate stress-induced water loss with an accurate estimation of short lag periods of this response.     

Population and Single-Cell Analysis of Human Cardiogenesis Reveals Unique LGR5 Ventricular Progenitors in Embryonic Outflow Tract

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The Relationship between Adiponectin and Left Ventricular Mass Index Varies with the Risk of Left Ventricular Hypertrophy

Background

Adiponectin directly protects against cardiac remodeling. Despite this beneficial effect, most epidemiological studies have reported a negative relationship between adiponectin level and left ventricular mass index (LVMI). However, a positive relationship has also been reported in subjects at high risk of left ventricular hypertrophy (LVH). Based on these conflicting results, we hypothesized that the relationship between serum adiponectin level and LVMI varies with the risk of LVH.

Methods

A community-based, cross-sectional study was performed on 1414 subjects. LVMI was measured by echocardiography. Log-transformed adiponectin levels (Log-ADPN) were used for the analysis.

Results

Serum adiponectin level had a biphasic distribution (an increase after a decrease) with increasing LVMI. Although Log-ADPN did not correlate with LVMI, Log-ADPN was modestly associated with LVMI in the multivariate analysis (β = 0.079, p = 0.001). The relationship between adiponectin level and LVMI was bidirectional according to the risk of LVH. In normotensive subjects younger than 50 years, Log-ADPN negatively correlated with LVMI (r = −0.204, p = 0.005); however, Log-ADPN positively correlated with LVMI in ≥50-year-old obese subjects with high arterial stiffness (r = 0.189, p = 0.030). The correlation coefficient between Log-ADPN and LVMI gradually changed from negative to positive with increasing risk factors for LVH. The risk of LVH significantly interacted with the relationship between Log-ADPN and LVMI. In the multivariate analysis, Log-ADPN was associated with LVMI in the subjects at risk of LVH; however, Log-ADPN was either not associated or negatively associated with LVMI in subjects at low risk of LVH.

Conclusion

Adiponectin level and LVMI are negatively associated in subjects at low risk of LVH and are positively associated in subjects at high risk of LVH. Therefore, the relationship between adiponectin and LVMI varies with the risk of LVH.     

感觉神经损伤性盐敏感性高血压大鼠左心室肥厚与血压的关系

目的研究感觉神经损伤性盐敏感性高血压大鼠左心室肥厚与血压的关系。方法建立感觉神经损伤性盐敏感性高血压大鼠模型,计算左心室相对重量,观察左心室组织病理学形态特点。结果感觉神经损伤性盐敏感性高血压大鼠CAP-HS组收缩压明显升高,左心室明显增重,心肌细胞肥大,肌纤维排列紊乱,心肌间质纤维化,其左心室重量指数明显升高（P〈0.01）;CON-HS组大鼠左心室重量指数也有升高（P〈0.05）。结论感觉神经损伤性盐敏感性高血压大鼠左心室增重,心肌组织病理学改变与血压升高和摄入高盐有关。