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.     

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.     

Asymptotic theory for gene mapping.

In genetic linkage mapping, the precision of the location estimate depends on both the number of individuals and the number of markers. Convergence rates and limit laws are established for several situations in which the number of markers depends on the sample size. Practical implications of the results are discussed.     

Linkage mapping for hypertension susceptibility genes

Several approaches based on linkage methods have been used to identify susceptibility genes for hypertension. Tests of candidate genes for essential hypertension have generally relied on the combination of linkage and association studies, and have given mostly negative or relatively conflicting results between studies. The detailed exploration of a candidate region, eg, a region of human homology to a principal quantitative trait locus for blood pressure variation in the rat, has led to the identification of linkage to a susceptibility locus for hypertension in humans. Studies of rare Mendelian forms of hypertension have enabled us to identify causative genes in several instances, and to detect mere linkages to chromosomal regions in other instances. Whether molecular variants at these genes are pathophysiologically involved in the common form of hypertension remains to be established. Finally, genome-wide linkage studies for essential hypertension are currently in progress. Confirming linkage to particular regions or genes with a high statistical significance in essential hypertension may prove difficult, therefore, other lines of evidence for a particular gene’s role in hypertension susceptibility, derived from either studies in animal models, studies of Mendelian forms of hypertension, or from association studies, may prove to be crucial.     

三维标测与肺静脉环状标测联合应用于心房颤动导管消融术

目的　探讨左心房三维电解剖标测与肺静脉环状标测联合指导下行心房颤动 (房颤 )导管消融术治疗房颤的可行性。方法　连续 14例药物治疗无效的房颤患者 ,男 10例 ,女 4例 ,平均年龄 5 2 4± 12 8(2 8～ 74 )岁 ,平均左心房内径 4 6 7± 5 4mm。其中阵发性房颤 10例、永久性房颤 3例、持续性房颤 1例。首先在三维标测系统指导下行左心房基质改良术 ,然后在肺静脉环状标测指导下行肺静脉节段性消融术。消融终点包括以下三点 :(1)完成所有预设的左心房消融径线 ;(2 )全部肺静脉均达电隔离 ;(3)阴性诱发结果。结果　 (1) 10例 (71 4 % )阵发性房颤达到消融终点 ;(2 )手术的总操作时间和X线曝光时间分别为 2 92± 4 9min和 5 4± 9min ;(3)随访 5 2± 5 7(1～ 2 3)周 ,7例 (5 0 % )阵发性房颤患者可以无需抗心律失常药物而维持窦性心律 ,3例 (2 1 4 % )阵发性房颤发作显著减少 ,4例 (2 8 6 % )持续性 永久性房颤仍为房颤 ;(4 )术中及随访期无任何操作相关并发症。结论　左心房三维标测与肺静脉环状标测联合应用于房颤的导管消融术安全可行 ,对于左心房增大的阵发性房颤患者具有一定效果     

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,...     

Colored spatial mapping electrocardiography for detecting myocardial infarction

Colored spatial mapping electrocardiography (ECG) was developed for practical use from Frank lead vectorcardiography using a microcomputer system (CERX-CQ3001). Compared to body surface electrocardiography this new device facilitated easy recording and analysis for display on eight-colored spatial mapping electrocardiography at points equivalent to those on a terrestrial globe at intervals of 20 degrees longitude and 10 degrees latitude. In this study, the extent and direction of the Q waves were easily recognized with the aid of a colored display and mapping electrocardiography. To quantitatively evaluate infarct size, the total Q wave area (sigma Aq) was calculated from the mapping electrocardiograms of 12 patients with anteroseptal myocardial infarction, and compared with thallium defect scores obtained by single photon emission CT (SPECT) and the left ventricular ejection fraction (EF). Defect scores were calculated using short-axis images. Sigma Aq was correlated with defect scores and EF (r = 0.83, 0.45, respectively). This new type of colored spatial mapping electrocardiography proved useful for detecting myocardial infarction and for evaluating infarct size.     

High-resolution mapping for essential hypertension using microsatellite markers

During the past decade, considerable efforts and resources have been devoted to elucidating the multiple genetic and environmental determinants responsible for hypertension and its associated cardiovascular diseases. The success of positional cloning, fine mapping, and linkage analysis based on whole-genome screening, however, has been limited in identifying multiple genetic determinants affecting diseases, suggesting that new research strategies for genome-wide typing may be helpful. Disease association (case-control) studies using microsatellite markers, distributed every 150 kb across the human genome, may have some advantages over linkage, candidate, and single nucleotide polymorphism typing methods in terms of statistical power and linkage disequilibrium for finding genomic regions harboring candidate disease genes, although it is not proven. We have carried out genome-wide mapping using 18,977 microsatellite markers in a Japanese population composed of 385 hypertensive patients and 385 normotensive control subjects. Pooled sample analysis was conducted in a 3-stage genomic screen of 3 independent case-control populations, and 54 markers were extracted from the original 18,977 microsatellite markers. As a final step, each single positive marker was confirmed by individual typing, and only 19 markers passed this test. We identified 19 allelic loci that were significantly different between the cases of essential hypertension and the controls.     

Endocardial catheter mapping: wire skeleton technique for representation of computed arrhythmogenic sites compared with intraoperative mapping

Guiding surgical therapy of ventricular tachycardia by preoperative endocardial catheter mapping necessitates improvement of the accuracy of localization of the arrhythmogenic site. We therefore used a new mathematical cineradiographic method during catheter mapping to compute the position of left ventricular arrhythmogenic sites relative to three anatomic reference points: the centers of aortic and mitral valve ostia and the left ventricular apex. To enable the surgeon to identify the position of the computed sites, a wire skeleton (one for each patient) representing a single or multiple arrhythmogenic site(s) relative to the anatomic reference points was constructed. This wire skeleton was inserted into the left ventricular cavity during surgery. Side branches of the device indicated preoperatively localized arrhythmogenic sites. Results in eight consecutive patients were compared with those of intraoperative simultaneous mapping of 64 endocardial sites. Sixteen morphologically distinct monomorphic ventricular tachycardias were mapped by catheter and 15 by intraoperative mapping. In 12 ventricular tachycardias an identical morphology was recorded during both techniques. The distance between arrhythmogenic sites localized with both methods was 1 cm or less in 11 of these 12 ventricular tachycardias and 2 cm in one ventricular tachycardia. These results indicate that endocardial catheter mapping combined with wire skeleton representation of computed positions of arrhythmogenic sites is reliable for guiding surgical therapy of ventricular tachycardia and since some of the ventricular tachycardias were inducible only during either preoperative or intraoperative mapping, both techniques have an additive value. In addition, the wire skeleton proved convenient during surgery by identifying the arrhythmogenic sites.