Open-window mapping of accessory pathways utilizing high-density mapping

Journal of Interventional Cardiac Electrophysiology - Accessory pathway (AP) mapping is currently based on point-by-point mapping and identifying if a local electrogram’s origin is atrial,...     

Phylogenetic fate mapping

Cell fate maps describe how the sequence of cell division, migration, and apoptosis transform a zygote into an adult. Yet, it is only in Caenorhabditis elegans where microscopic observation of each cell division has allowed for construction of a complete fate map. More complex, and opaque, animals prove less yielding. DNA replication, however, generates somatic mutations. Consequently, multicellular organisms comprise mosaics where most cells acquire unique genomes that are potentially capable of delineating their ancestry. Here we take a phylogenetic approach to passively retrace embryonic relationships by deducing the order in which mutations have arisen during development. We show that polyguanine repeat DNA sequences are particularly useful genetic markers, because they frequently change length during mitosis. To demonstrate feasibility, we phylogenetically reconstruct the lineage of cultured mouse NIH 3T3 cells based on mutations affecting the length of polyguanine markers. We then employ whole genome amplification to genotype polyguanine markers in single cells taken from a mouse and use phylogenetics to infer the developmental relationships of the sampled tissues. The result is consistent with the present understanding of embryogenesis and demonstrates the large scale potential of this method for producing a complete mammalian cell fate at the resolution of a single cell.     

Epicardial isopotential mapping from body surface isopotential mapping in myocardial infarction

It is useful to construct the epicardial isopotential mapping (the Ep Map) from the body surface isopotential mapping (the Body Map) for clinical diagnosis of cardiac disease, even though there are many unsolved problems in using the inverse solution. Yamashita et al. carried out this solution by using the finite element technique. In the present study, the clinical value of that method has been investigated in cases of myocardial infarction. The Ep Maps at 20, 25 and 30 msec. from the beginning of the QRS complex were obtained from the Body Map at the same time by using that method; the infarcted areas on the Ep Map were determined by using Toyama's method which was reported in a previous study. The infarcted area at 30 msec. on the Ep Map was located at the anterior wall along the ventricular septum in anterior infarction and at the posterior wall of the left ventricle in inferoposterior infarction. Patients were independently examined with the scintigram with thallium-201 and the infarcted area was coincident to the location of the abnormal findings of the scintigram. Moreover, the size of the infarcted area on the Ep Map and the size of the abnormal findings of the scintigram were parallel in most cases except one.     

非接触球囊导管标测系统指导心律失常的心内膜标测和导航消融

目的:观察非接触球囊导管标测系统指导疑难心律失常的标测与射频消融的有效性与优越性。方法:6例患者,男5例,女1例,年龄28~50(36.2±12.3)岁。电生理检查为右室特发性室性期前收缩1例,左房房性心动过速1例,右房房性心动过速2例,左房心房颤动2例。其中3例常规电生理标测消融未获成功。经股静脉置入64极球囊电极和射频消融导管至同一心腔,计算机标测系统首先构建心腔几何构型,然后建立心动过速的腔内等电势图,分析心动过速的起源点及关键峡部,利用计算机导航系统指导消融导管至拟定靶点处进行消融。结果:1例起源于右室流出道偏间隔的室性期前收缩患者行片状消融获得成功,1例左房房性心动过速标测其心动过速起源于右肺下静脉间隔部,并指引消融导管行右肺下静脉至二尖瓣之间线性消融获得成功,2例右房房性心动过速中1例标测其最早激动点位于下腔静脉口,此处行环状消融获得成功,另1例位于上腔静脉后方穿过界嵴中部线性消融获得成功。2例左房心房颤动患者,1例在窦性心律下其致心房颤动房性期前收缩起源于左右上肺静脉之间,行线性消融成功;另1例在心房颤动持续发作下行左上下肺静脉环状消融及左右上肺静脉间线性消融成功。6例患者术中、术后均无并发症发生,随访4~13个月,无一例复发。结论:非接触球囊导管标测指导心律失常的心内膜标测与消融是安全有效的,对复杂、难治性心律失常的电生理机制的阐明和指导消融具有较好的临床应用价值。     

Body surface isopotential mapping system by colored spatial mapping electrocardiography]

We developed a new body surface isopotential mapping system using a colored spatial mapping electrocardiographic technique based on Frank's vectorcardiography to be used with CERX CQ-3011 and NEC PC-100 computers. We assessed its usefulness in comparison with the conventional body surface mapping technique in 12 patients with old myocardial infarction (6 with anterior and 6 with inferior infarction), and in 10 healthy subjects. All distributions of positive and negative zones presented on body surface isopotential maps were obtained with this new technique, which corresponded well with the distribution of zones on conventional body surface isopotential maps. Although the maximum and minimum positions of the 2 maps did not coincide with one another, this new map aided in diagnosing anterior and inferior infarction from the minimum position determined 20 msec after the onset of QRS. This new mapping system allows a clear spatial representation of vectorcardiograms and requires less complicated procedure compared with the conventional body surface mapping technique. Thus, this body surface isopotential mapping system should be clinically useful.     

Body surface potential mapping for mapping and treatment of persistent atrial fibrillation

Techniques facilitating individual mapping and ablation of arrhythmogenic substrates are desired to enhance our understanding of persistent atrial fibrillation (persAF) mechanisms as a prerequisite to increasing the success rates of single procedure persAF catheter ablation. The technique of body surface potential mapping (BSM) involves the use of multiple electrodes to collect the potentials over a large body surface area and, with the use of a computed tomography scan, it facilitates their correlation to a 3D model of the atrial structures. During AF,the visualization and localization of AF driver activity, both reentrant and focal wavefronts, is possible with this technique. The ECVUE system from CardioInsight was examined for this indication in clinical studies and showed a termination rate of persAF of 63?% in a large multicenter trial (AFACART) with a promising low recurrence rate during follow-up. From our initial experience, the system appears to be effective in persAF patients who have continuous AF for less than ?1 year. However, the utility of the system for highly challenging cases like long-standing persistent AF and patients with very short AF cycle length remains to be explored. Further studies are needed to confirm these data and answer the multitude of open questions in this field.     

Endocardial mapping of right ventricular outflow tract tachycardia using noncontact activation mapping

INTRODUCTION: Activation mapping and pace mapping identify successful ablation sites for catheter ablation of right ventricular outflow tract (RVOT) tachycardia. These methods are limited in patients with nonsustained tachycardia or isolated ventricular ectopic beats. We investigated the feasibility of using noncontact mapping to guide the ablation of RVOT arrhythmias. METHODS AND RESULTS: Nine patients with RVOT tachycardia and three patients with ectopic beats were studied using noncontact mapping. A multielectrode array catheter was introduced into the RVOT and tachycardia was analyzed using a virtual geometry. The earliest endocardial activation estimated by virtual electrograms was displayed on an isopotential color map and measured 33 +/- 13 msec before onset of QRS. Virtual unipolar electrograms at this site demonstrated QS morphology. Guided by a locator signal, ablation was performed with a mean of 6.9 +/- 2.2 radiofrequency deliveries. Acute success was achieved in all patients. During follow-up, one patient had a recurrence of RVOT tachycardia. Compared with patients (n = 21) who underwent catheter ablation using a conventional approach, a higher success rate was achieved by noncontact mapping. Procedure time was significantly longer in the noncontact mapping group. Fluoroscopy time was not significantly different in the two groups. CONCLUSION: Noncontact mapping can be used as a reliable tool to identify the site of earliest endocardial activation and to guide the ablation procedure in patients with RVOT tachycardia and in patients with ectopic beats originating from the RVOT.     

Information-based functional brain mapping

The development of high-resolution neuroimaging and multielectrode electrophysiological recording provides neuroscientists with huge amounts of multivariate data. The complexity of the data creates a need for statistical summary, but the local averaging standardly applied to this end may obscure the effects of greatest neuroscientific interest. In neuroimaging, for example, brain mapping analysis has focused on the discovery of activation, i.e., of extended brain regions whose average activity changes across experimental conditions. Here we propose to ask a more general question of the data: Where in the brain does the activity pattern contain information about the experimental condition? To address this question, we propose scanning the imaged volume with a "searchlight," whose contents are analyzed multivariately at each location in the brain.     

Functional connectivity density mapping

Brain networks with energy-efficient hubs might support the high cognitive performance of humans and a better understanding of their organization is likely of relevance for studying not only brain development and plasticity but also neuropsychiatric disorders. However, the distribution of hubs in the human brain is largely unknown due to the high computational demands of comprehensive analytical methods. Here we propose a 10³ times faster method to map the distribution of the local functional connectivity density (lFCD) in the human brain. The robustness of this method was tested in 979 subjects from a large repository of MRI time series collected in resting conditions. Consistently across research sites, a region located in the posterior cingulate/ventral precuneus (BA 23/31) was the area with the highest lFCD, which suggest that this is the most prominent functional hub in the brain. In addition, regions located in the inferior parietal cortex (BA 18) and cuneus (BA 18) had high lFCD. The variability of this pattern across subjects was <36% and within subjects was 12%. The power scaling of the lFCD was consistent across research centers, suggesting that that brain networks have a “scale-free” organization.     

Radiation hybrid mapping.

A theory is developed to predict marker retention and conditional retention or loss in radiation hybrids. Applied to multiple pairwise analysis of a human chromosome 21 data set, this theory fits much better than proposed alternatives and gives a physical map consistent with other evidence and robust with respect to errors to typing. Radiation hybrids have great promise to provide order and physical location at two levels of resolution, spanning the techniques of linkage and restriction fragments and not limited to polymorphic loci.     

Degree of mapping for nonlinear mappings of monotone type: Densely defined mapping

The classical degree function constructed earlier for pseudomonotone mappings has been used to develop a broader degree theory of classical type for the sum of a maximal monotone map from a reflexive Banach space to its dual together with a bounded pseudomonotone map. The proof uses the generalized Yosida approximation of the maximal monotone mapping.     

Degree of mapping for nonlinear mappings of monotone type: Strongly nonlinear mapping

The classical degree function constructed earlier for pseudomonotone mappings has been used to develop a broader degree theory of classical type for the sum of a maximal monotone map from a reflexive Banach space to its dual together with a bounded pseudomonotone map. The proof uses the generalized Yosida approximation of the maximal monotone mapping.     

应用非接触球囊导管标测系统指导心动过速的心内膜标测与消融

目的观察非接触球囊导管标测系统指导难治性室性心动过速的标测与射频消融的有效性和优越性。方法5例患者均为男性，平均年龄33.2岁。经股静脉或股动脉置入64极球囊电极和射频消融导管至同一心室，计算机标测系统首先构建心腔的几何构型，然后建立心动过速的腔内等电势图，分析心动过速的最早起源点及折返激动的关键峡部，最终利用计算机导航系统指导消融导管至拟定靶点处进行环状或线形消融。结果5例患者共诱发出6种心动过速，心动过速平均周期为（336.6±42.7）ms。2例特发性左室室性心动过速及1例隐匿性束室纤维患者均消融成功。1例扩张型心肌病患者共有两种心动过速，一种起源于右室流出道，另一种起源于左室间隔部，前者消融成功，后者因导管操作致心动过速持续发作伴血流动力学不稳定而终止手术。1例致心律失常性右室心肌病患者于最早激动点处做环状消融，未获成功。5例患者术中和术后均无并发症发生。随访4个月，所有消融成功患者均未再有心动过速发作。结论非接触性球囊导管标测系统指导心律失常的心内膜标测与消融是安全、有效的，与常规的标测和消融方法比较，该系统有一定的优越性，尤其适用于复杂病例、血流动力学不稳定和非持续性室性心律失常的标测及指导射频消融。     

Comparison between three-dimensional electro-anatomical mapping and conventional mapping in the ablation of atrial tachycardias

In atrial tachycardias, catheter ablation using conventional mapping system is associated with high immediate success and low recurrence. Three-dimensional electroanatomical mapping system combined to catheter ablation of atrial tachycardias has reached, in small uncontroled series, success rates of 100%. However, limited data are available about rates of recurrence or complication using this approach. In order to compare both mapping systems, we have conducted a study of 65 consecutive patients (36 women and 29 men) that underwent both electrophysiologic study and catheter ablation for suspected atrial tachycardias. Pre-existing heart disease was noted in 43%, hypertension in 32% and a history of atrial fibrillation of flutter in 52%. Catheter ablation guided by conventional mapping was undertaken in 44 patients and by three-dimensional electroanatomical mapping in 21. Successful ablation was performed in 68% of patients with conventional mapping and in 90% with three-dimensional electroanatomical mapping. No complication and recurrence were observed with the latter approach, while 5 patients had a recurrence and 2 had immediate complication with conventional mapping. Catheter ablation of atrial tachycardias combined with three-dimensional electroanatomical mapping appeared to be effective and safe, however, conventional mapping system still remains a reliable approach that must be considered as the first choice for atrial tachycardias ablation.     

非接触球囊导管标测系统指导心房扑动消融的初步经验

目的　评价非接触球囊导管标测系统在心房扑动 (房扑 )标测和射频消融中的临床应用。方法　 7例房扑患者 ,年龄 (6 0± 10 )岁 ,男 4例 ,女 3例。其中 1例为房间隔缺损修补术后 ,2例为采用常规方法消融典型房扑后复发患者。应用非接触球囊导管标测系统构建右房三维几何模型 ,标测心动过速的折返激动顺序和关键峡部 ,并利用其导航系统指导峡部的线性消融。消融后分别于峡部两侧起搏判断峡部阻滞情况。结果　 6例患者诱发出房扑 ,心动过速周长 (2 16± 2 2 )ms。6例房扑均为峡部依赖型 ,2例呈逆钟向传导 ,4例呈顺钟向传导 ;4例房扑呈双环折返激动 ;7例消融均成功 ,房扑不再诱发 ,峡部呈完全双向传导阻滞 ;手术时间 (30 0± 12 9)min ,X线曝光时间 (2 5 0± 6 5 )min ,放电次数 (2 5 7± 12 1)次。无手术并发症。随访 3～ 14个月无复发病例。结论　在房扑标测和消融中应用非接触球囊导管标测系统是安全有效的 ,不仅能确定折返环路 (特别是双环折返激动 )的顺序和关键峡部 ,而且能准确判断线性损伤的连续性 ,同时可减少X线曝光时间。