心内非接触式标测技术及应用

对于各种室上性和室性心动过速，因其发生机制及标测诊断、定位标准均已明确，常规标测技术基本上能满足需要。但对于一些房性和室性的难诱发、非持续性、多源性或血流动力学不稳定的心律失常，常规标测往往不能提供有用的信息。某些复杂的心电生理现象，也难以用常规标测技术准确地解释。非接触式标测为这些心律失常提高了新的标测手段。     

导管消融室性心律失常的现状和未来

运用导管消融的方法治疗室性心律失常已经广泛用于临床。术前运用心电图、心脏超声、计算机断层摄影术(CT)和磁共振成像(MRI)等辅助检查手段和起搏标测、激动标测、基质标测、电压标测和起搏拖带等标测方法,对判断室性心律失常的发生机制、起源点位置和制定合理的室性心律失常导管消融策略具有很大的帮助。导管消融治疗特发性室性心律失常,成功率高、风险和并发症发生率低,目前已成为一线治疗。而对于疤痕介导性室性心律失常,导管消融只是药物治疗和植入型心律转复除颤器(ICD)治疗的辅助手段。目前导管消融治疗室性心律失常的临床终点和对患者的临床长期受益,还需要进行前瞻性、随机的多中心研究。     

EnSite Array三维标测系统及临床应用

非接触标测技术试图在一个心动周期中完成对心脏激动的记录与分析,适用于复杂心律失常的标测,而EnSite Array是其中较为成熟的一种方法。EnSite Array系统由Array导管、放大器及工作站组成,Array导管顶端有一多电极阵列,有64个电报,覆于一可充盈的球囊上。利用64个电极感知信号的强弱和角度进行导管电极定位、三维建模和电生理标测。其激动标测及电压标测功能在复杂心律失常如房性心动过速、心房颤动、室性心动过速等,特别是器质性心脏病心律失常中有比较独特的应用价值。     

右室流出道室性心律失常导管消融标测方法

导管消融右室流出道起源的特发性室性心律失常是一种安全有效的治疗方法。右室流出道室性心律失常起源点的标测方法有起搏标测、激动标测、单极电极激动标测、心室局部电压电位标测、双极电极极性反转标测等,综合使用上述方法可提高确定有效消融靶点的精确性,提高导管消融成功率。     

高精密度标测技术在导管消融治疗心律失常中的应用

高精密度标测技术是近年来随着三维电解剖标测技术和导管制造技术的进步而产生的概念。目前高精密度标测技术已经应用于各种心律失常的导管消融,因其更高的标测效率和更高的分辨率,有望缩短手术时间、提高手术成功率。本文就高精密度标测技术在心律失常的导管消融中的应用作一综述。     

特发性右心室流出道室性心律失常心内接触式标测与非接触式标测指导导管射频消融

目的 研究心内接触式标测与心内非接触式标测对特发性右心室流出道室性心律失常射频导管消融术及术后有效性的影响.方法 23例特发性右心室流出道室性心律失常患者(室性早搏14例,室性心动过速9例),平均年龄(38.4±7.7)岁,男性8例,女性15例,采用心内接触式标测指导导管射频消融治疗.12例特发性右心室流出道室性心律失常患者(室性早搏7例,室性心动过速5例),平均年龄(39.2±8.5)岁,男性5例,女性7例,采用EnSite心内非接触式标测指导导管射频消融术治疗.比较心内接触式标测组与心内非接触式标测组心律失常靶点标测时间、X线曝光时间、操作总时间.消融术前、后1、3个月动态心电图检查两组患者24 h室性早搏次数,随访观察右心室流出道室性心律失常复发情况.结果 与心内接触式标测比较,心内非接触式标测指导下,特发性右心室流出道室性心律失常靶点标测时间[(21.8±7.6)min vs(42.4±14.4)min]、X线曝光时间[(17.6±2.9)min vs(36.4±7.5)min]、操作总时间[(88.1±8.8)min vs(108.5±16.9)min]均明显缩短(P《0.01),两组均无并发症发生.术后1个月随访时,心内接触式标测组2例心律失常复发;心内非接触式标测组无复发病例.术后3个月随访时,心内接触式标测组与心内非接触式标测组均无复发病例.结论 与心内接触式标测比较,心内非接触式标测指导下的特发性右心室流出道室性心律失常导管射频消融治疗,心律失常靶点标测时间、X线曝光时间及消融术总时间缩短.并且,EnSite心内非接触式标测深化了特发性右心室流出道室性心律失常的电生理机制研究,制定合理准确的消融策略、降低术后复发率提供了更可靠的指导.     

心脏等时标测

<正> 在心律失常与心电研究中,近年来心电标测技术越来越被重视且得到广泛应用,并成为研究心电生理与病理、心律失常的诊断与治疗以及心肌梗塞定位、面积测量的重要方法之一。心电标测从方法学上分为等电位标测(Isopotential Mapping)和等时标测(Isochronal Mapping)。前者是比较同一时间上的电位正负及其数值,由此确定心肌除极的方向。通常用于体表标测,适于研究心肌梗塞面积、范围和预激综合征(WPW);后者则是比较心肌除极先后顺序及其传导时间。通常用于心内、外膜及心肌标测,适于研究心律失常。从标测图型来分包括:P波标测(适宜研究窦房结和心房除极与传导);QRS波标测(心室肌的除极与传导);S—T段及T波的标测(主要用于研究心室复极)。等时标测通常用于P及QRS波标测。     

心脏电生理学新概念(3)心内多电极标测技术的进展

传统的心内电生理标测技术需要插入多根与心腔内膜相接触的导管电极并对心律失常逐点进行标测,这就意味着对于一些发生于心房或心室的、尤其是非持续性或血液动力学不稳定的心律失常,现有的心内标测技术存在着较大的局限性.除了操作时间和放射照射时间较长之外,其标测定位的准确性及可靠性均不能令人满意,其结果是导致对于这些心律失常射频导管消融治疗的失败率和复发率亦较高.另一方面,传统标测手段所获得的是二维心内电图,与心脏实际的电活动存在较大的差距,这也增大了对复杂心电活动进行准确理解的难度.     

心脏电生理学新概念——心内多电极标测技术的进展

传统的心内电生理标测技术需要插入多根与心腔内膜相接触的导管电极并对心律失常逐点进行标测,这就意味着对于一些发生于心房或心室的、尤其是非持续性或血液动力学不稳定的心律失常,现有的心内标测技术存在着较大的局限性。除了操作时间和放射照射时间较长之外,其标测定位的准确性及可靠性均不能令人满意,其结果是导致对于这些心律失常射频导管消融治疗的失败率和复发率亦较高。另一方面,传统标测手段所获得的是二维心内电图,与心脏实际的电活动存在较大的差距,这也增大了对复杂心电活动进行准确理解的难度。 对于较复杂,尤其是以…     

心外膜标测对心房颤动机制研究的进展

心房颤动（简称房颤）是一种最常见的异位心律，由于一直无根治的药物及手术方法，因而其机制的研究取来愈受到重视，心房心外膜标测在此研究中有着重要的指导作用。心外膜标测是采用心电生理技术在心脏表面对多位点进行电位标记，然后依各位点在激动传导过程中的先后顺序，按心脏解剖结构绘制成图，称心外膜标测图。应用此标测技术还可对心脏各位点的电生理特性进行研究，这种方法常用于阐明心律失常的发生机理、确定心律失常的起源部位及判断疗效。l房四的心房激动形式Moe最早进行房颤的心外膜标测，由于当时标测技术的限制，他只能凭借…     

Simultaneous mapping of endocardium and epicardium from multielectrode intrachamber and intravenous catheters: a computer simulation-based validation

A multielectrode basket-shaped contact catheter (MBC) provides simultaneous recordings of unipolar or bipolar electrograms from within the heart chambers. Another catheter-based mapping approach uses the multielectrode intravenous catheters (MIVCs), which are widely used to diagnose and treat supraventricular arrhythmias. It is also known that mapping techniques are usually limited to one surface at a time. Therefore, an approach that can be used for simultaneous mapping of left and right endocardial surfaces and epicardial surface will be beneficial to characterize and discriminate the endocardial and epicardial sources of the arrhythmias more accurately. In this study, we used statistical estimation method to map the endocardial and epicardial surfaces simultaneously based on combined usage of the MBC and MIVC. The statistical estimation method is based on high-resolution training data set to hypothesize the relationship between catheter measurements and inaccessible sites. To test this approach, we created a high-resolution map database consisting of computer simulation results of Aliev-Panfilov model of cardiac electrical activity on 3-dimensional Auckland canine heart geometry. The simulation database included 2590 maps each paced from a unique endocardial or epicardial site. Fifty or five percent of the database was used as the training data set and the remaining as test data set in the statistical estimation procedure. We selected 64 sites on the left and 64 on the right endocardial surfaces of the model heart geometry and used them as the surrogate MBC measurement sites. Ninety-one sites on the epicardium corresponding to the major coronary veins served as the surrogate MIVC leads. Finally, we tested the success of the method to determine the source of the arrhythmias using the correlation coefficient between the original and estimated activation maps and linear distance between their earliest activated sites. The performance of this approach was promising, such as when MBC on the left endocardium and MIVC were used together, the average linear distance was ∼2.4 mm and mean correlation coefficient was 0.995. It was possible to locate 95% of epicardial arrhythmia cases correctly on the epicardium. Ninety-nine percent of left endocardially originating arrhythmias were correctly located on the left endocardium. The results of this study showed that this approach is feasible and requires further effort.     

Ventricular arrhythmias in heart failure patients

Ventricular arrhythmia represents a significant cause of mortality and morbidity. Its pathophysiologic mechanisms and electroanatomic substrates are slowly being elucidated. Clinical management in patients with heart failure has progressed from antiarrhythmic drugs to device therapy. Catheter ablation is an effective adjunct in the management of ventricular arrhythmia but remains a significant challenge. Advances in robotic and magnetic catheter manipulation may shorten procedural time and increase safety. Incorporation of imaging technologies such as CT, MRI, or ultrasound with electroanatomic mapping can enhance the ability to map and ablate ventricular arrhythmia. Novel imaging modalities may provide rapid characterization of the substrate for ventricular dysfunction and arrhythmia development and the capacity for serial assessment of the disease progression, improving risk stratification for ventricular dysfunction and arrhythmia development and the capacity for serial assessment of the disease progression, improving risk stratification.     

用体表心电标测方法探讨复极离散及空间分布

目的　用体表心电标测时空图法探讨复极离散空间分布和临床价值。方法　采用体表心电标测时空图法及12导联心电图 ,分别测定 6 8例急性心肌梗死 (AMI)患者的QT间期及QT离散度 (QTd) ,并与 5 8例正常对照者进行对比。结果　 (1)在正常人及AMI患者时空图法测得QTd均大于 12导联心电图 ,两种方法均表明AMI后QTd增加。 (2 )正常人时空图分布 :T波呈单群、结束时间相对较一致 ;AMI后时空图分布发生明显变化 :梗死区对应体表部位T波结束延长 ,大致分 3型 ,部分患者可见零线垂直偏斜 ,ST T复极过程中分群现象 ,T波结束离散增大。 (3)AMI患者死亡及合并室性心律失常者时空图法测得QTd较无心律失常者增加、分布主要表现第Ⅰ、Ⅲ型 (18/ 2 1) ,12导联心电图未发现两组间差异。 (4 )时空图尚可展示相邻部位的复极离散和U波分布。结论　时空图法可直观反映QT间期空间分布及离散 ,并能有效鉴别U波 ,可能会成为QTd研究中一项有前途的方法     

Noncontact mapping to guide ablation of right ventricular outflow tract tachycardia

OBJEWCTIVES: The aim of this study was to determine whether noncontact mapping is feasible in the right ventricle and assess its utility in guiding ablation of difficult-to-treat right ventricular outflow tract (RVOT) ventricular tachycardia (VT). BACKGROUND: In patients without inducible arrhythmia, RVOT VT may be difficult to ablate. Noncontact mapping permits ablation guided by a single tachycardia complex, which may facilitate ablation of difficult cases. However, the mapping system may be geometry-dependent, and it has not been validated in the unique geometry of the RVOT. METHODS: Ten patients with left bundle inferior axis VT, no history of myocardial infarction and normal left ventricular function underwent noncontact guided ablation; seven had failed previous ablation and three had received a defibrillator. All noncontact maps were analyzed by a blinded reviewer to determine whether the arrhythmia focus was epicardial and to predict on the basis of the map whether arrhythmia would recur. RESULTS: The procedure was acutely successful in 9 of 10 patients. During a mean follow-up of 11 months, 7 of 9 patients remained arrhythmia-free. Both patients in whom the blinded reviewer predicted failure had arrhythmia recurrence: one due to epicardial origin with multiple endocardial exit sites and one due to discordance between site of lesion placement and earliest activation on noncontact map. CONCLUSIONS: Mechanisms of ablation failure in RVOT VT include absence of sustained arrhythmia, difficulty with substrate localization and epicardial origin of arrhythmia. In this study, noncontact mapping was safely and effectively used to guide ablation of patients with difficult-to-treat RVOT VT.     

'Zero' fluoroscopic exposure for ventricular tachycardia ablation in a patient with situs viscerum inversus totalis

Situs viscerum inversus totalis (SVIT) is a congenital disorder characterized by mirror reversal of the thoracic and abdominal organs. Different studies have shown that the ablation procedure can be performed without fluoroscopy with safety and effectiveness, in the setting of supraventricular tachycardia. We successfully performed an anatomical map and a radiofrequency catheter ablation of ventricular arrhythmia in a patient with SVIT without fluoroscopy.     

A simple method to detect atrial fibrillation using RR intervals

Implantable loop recorders have been developed for long-term monitoring of cardiac arrhythmia, but their accuracy for atrial fibrillation (AF) detection is unsatisfactory. We sought to develop and evaluate a simple method for detecting AF using RR intervals. The new AF detection algorithm is based on a map that plots RR intervals versus change of RR intervals (RdR). The map is divided by a grid with 25-ms resolution in 2 axes and nonempty cells are counted to classify AF and non-AF episodes. We evaluated the performance of the method using 4 PhysioNet databases: MIT-BIH AF database, MIT-BIH arrhythmia database, MIT-BIH normal sinus rhythm (NSR) database, and NSR RR interval database (total 145 patients, 1,826 hours NSR, 96 hours AF, and 11 hours other rhythms). Each record is divided into consecutive windows containing 32, 64, or 128 RR intervals. AF detection is performed for each window and classification results are compared to annotations. A window is labeled true AF if >1/2 of cycles in the window are annotated as AF or non-AF otherwise. The RdR map shows signature patterns corresponding to various heart rhythms. Optimal nonempty cell cut-off threshold for AF detection was determined by receiver operating characteristic curve analysis, which yields excellent sensitivity and specificity for window sizes 32 (94.4% and 92.6%, respectively), 64 (95.8% and 94.3%), and 128 (95.9% and 95.4%). In conclusion, a single metric derived from the RdR map can achieve robust AF detection within as few as 32 heart beats.     

Prognostic importance of T and NK-cells in a consecutive series of newly diagnosed patients with chronic lymphocytic leukaemia

Patients with chronic lymphocytic leukaemia (CLL) have a variable clinical course. The identification of modifiable characteristics related to CLL-specific survival may provide opportunities for therapeutic intervention. The absolute number of T-cell and natural killer (NK)-cells was calculated for 166 consecutive patients with CLL evaluated by flow cytometry at Mayo Clinic < or = 2 months of diagnosis. The size of the T-cell/NK-cell compartment relative to the size of the malignant monoclonal B-cell (MBC) compartment was evaluated by calculating NK:MBC and T:MBC ratios. Patients exhibited substantial variation in the absolute number of T- and NK-cells as well as T:MBC and NK:MBC ratios at diagnosis. Higher T:MBC and NK:MBC ratios were observed among patients with early stage and mutated IGHV genes (all P < or = 0.0003). As continuous variables, both T:MBC ratio (P-value = 0.03) and NK:MBC ratio (P-value = 0.02) were associated with time to treatment (TTT). On multivariate Cox modelling including stage, CD38, absolute MBC count, NK:MBC ratio and T:MBC ratio, the independent predictors of TTT were stage, T:MBC ratio and NK:MBC ratio. These findings suggest that measurable characteristics of the host immune system relate to the rate of disease progression in patients with newly diagnosed CLL. These characteristics can be modified and continued evaluation of immunomodulatory drugs, vaccination strategies and cellular therapies to delay/prevent disease progression are warranted.     

Beat-to-beat interplay of heart rate, ventricular depolarization, and repolarization

To improve malignant arrhythmia risk stratification, the causal and random components of spatiotemporal dynamics of heart rate (RR distances), ventricular depolarization sequence, and repolarization disparity were studied based on body surface potential map records taken for 5 minutes, in resting, supine position on 14 healthy subjects (age range, 20-65 years) and on 6 arrhythmia patients (age range, 59-70 years). Beat-to-beat QRS and QRST integral maps, Karhunen-Loève (KL) coefficients, RR, and nondipolarity index time series were computed. Tight relationship was found between RR and QRS integrals in healthy subjects with less association in arrhythmia patients. Tight KL-domain multiple linear association (r² > 0.72) was found between the QRS and QRST integral dynamics (ie, depolarization sequence and repolarization disparity). Beat-to-beat probability of the generation of significant nondipolarity index spikes was proportional to the QRST KL-component standard deviations (SD_i) and inversely proportional with the mean dipolar KL components (M_i) of the average QRST integral map.     

Putative nuclear triiodothyronine receptors in tadpole liver during metamorphic climax

It has been shown previously that the maximum binding capacity (MBC) of the putative T3 receptors in tadpole red blood cells (RBCs) is increased during development and can be stimulated by treatment with thyroid hormone (TH). The present study was performed to determine if the MBC of tadpole liver nuclei is also increased during development or after treatment with TH. Because of the relatively high levels of endogenous TH in tadpoles during climax, the use of an in vivo saturation assay employing [125I]T3 was not feasible. Thus, MBC was determined by measuring by RIA the amount of T3 bound to the liver nuclei in tadpoles pretreated with sufficient T3 to saturate the receptors. Values were then corrected for the nonsaturable fraction using data obtained in tadpoles given a large dose of T3 (10 nmol). After this dose, essentially all of the T3 in the nucleus was bound to nonsaturable sites. MBC values estimated by this method and by Scatchard analysis were comparable. In contrast to the observations in tadpole RBCs, no significant change in the MBC of liver nuclei occurred as the tadpole progressed from early prometamorphosis to metamorphic climax; in tadpoles at stages XII-XIV and XIX-XXIII, MBC values were 0.308 +/- 0.024 (+/- SE) and 0.260 +/- 0.035 pmol/mg DNA, respectively. Furthermore, treatment of tadpoles with T4 (1 nmol T4; 14 days before study), which resulted in a marked increase in receptor number in RBCs, had no effect on MBC in hepatic nuclei. The amounts of nucleus-bound endogenous T3 in liver and RBCs were also determined. From these data and the MBC values, it was calculated that hepatic and RBC nuclear receptors were, respectively, 80% and more than 90% occupied with T3. These findings indicate that there is tissue specificity in the response of receptor MBC to TH during metamorphosis, and that most of the TH on the receptor during climax is T3.