Search

A 40-year-old female presented at our hospital because of heart palpitations. During an electrophysiological study, atrioventricular (AV) conduction showed dual AV nodal physiology. Three types of supraventricular tachycardia (SVT) were induced. The initiation of SVT was reproducibility dependent on a critical A-H interval prolongation. An early premature atrial contraction during SVT repeatedly advanced the immediate His potential with termination of the tachycardia, indicating AV node reentrant tachycardia (AVNRT). However, after atrial overdrive pacing during SVT without termination of the tachycardia, the first return electrogram resulted in an AHHA response, consistent with junctional tachycardia. The mechanism of paradoxical responses to pacing maneuvers differentiating AVNRT and junctional tachycardia was discussed. [ABSTRACT FROM AUTHOR]

A 57-year-old male with persistent atrial fibrillation (AF) was referred for catheter ablation. Multidetector computed tomography (MDCT) revealed that a membrane divided the left atrium into two chambers, thus indicating the presence of cor triatriatum sinister. A 3D image reconstructed by MDCT showed that the accessory atrium received the left common and the right side PVs, as if it were a total common trunk, and this then flowed into the main atrium. After isolation of the pulmonary vein and posterior wall from the left atrium, AF could not be induced by any programmed pacing. The patient has remained free from AF during the 1 year of follow-up. [ABSTRACT FROM AUTHOR]

We investigate how to find generic and globally rigid realizations of graphs in R d based on elementary geometric observations. Our arguments lead to new proofs of a combinatorial characterization of the global rigidity of graphs in R 2 by Jackson and Jordán and that of body-bar graphs in R d recently shown by Connelly, Jordán, and Whiteley. We also extend the 1-extension theorem and Connelly's composition theorem, which are main tools for generating globally rigid graphs in R d . In particular we show that any vertex-redundantly rigid graph in R d is globally rigid in R d , where a graph G = ( V , E ) is called vertex-redundantly rigid if G − v is rigid for any v ∈ V . [ABSTRACT FROM AUTHOR]

For a function $f:2^{V} \to \mathbb {Z}_{+}$ on a finite set V with f(∅)= f( V)=0, a digraph D=( V, A) is called f-connected if it satisfies the f-cut condition, that is, δ( X)≥ f( X) for any X⊆ V, where δ( X) is the number of arcs from X to V∖ X. We show that, for any crossing supermodular function f, the f-connectivity can be tested with a constant number of queries in the general digraph model with average degree bound. As immediate corollaries, we obtain constant-time testers for k-edge-connectivity, rooted-( k, l)-edge-connectivity, and the property of having k arc-disjoint arborescences. We also give a corresponding result for the undirected case. [ABSTRACT FROM AUTHOR]

Purpose: Although catheter ablation targeting the pulmonary vein (PV) is a well-known therapy for patients with paroxysmal atrial fibrillation (PAF), ectopic firings from the superior vena cava (SVC) can initiate PAF. The purpose of this study was to investigate predictors of SVC firing. Methods: The subjects included 336 consecutive PAF patients (278 males, age 56.1 ± 10.8 years) undergoing atrial fibrillation (AF) ablation. The appearance of SVC firing was monitored throughout the procedure using a decapolar catheter with multiple electrodes to record electrograms of the coronary sinus and SVC. In addition to PV isolation, SVC isolation was performed only in patients with documented SVC firing. Results: SVC firing was observed in 43/336 (12.8 %) of the patients, among whom complete isolation of the SVC was achieved in 40/43 (93 %) patients. A lower body mass index (BMI) (22.8 ± 2.8 vs 24.1 ± 3.1 kg/m, p = 0.007) and higher prevalence of prior ablation procedures (58 vs 18 %, p = 0.0001) were related to the presence of SVC firing. In a multivariate analysis, a lower BMI ( p = 0.012; odds ratio 0.83, 95 % CI 0.72 to 0.96) and history of prior ablation procedures ( p < 0.0001; odds ratio 5.37, 95 % CI 2.71 to 10.63) were found to be independent predictors of the occurrence of SVC firing. Among 96 patients undergoing repeat ablation procedures, less PV-left atrial re-conduction was observed in patients with SVC firing than in those without (2.7 ± 1.2 vs 3.2 ± 0.8, p = 0.02). Conclusions: The presence of SVC firing in patients with PAF is associated with a history of repeat ablation procedures and lower BMI values. [ABSTRACT FROM AUTHOR]

This paper deals with online graph exploration problems by multiple searchers. The information on the graph is given online. As the exploration proceeds, searchers gain more information on the graph. Assuming an appropriate communication model among searchers, searchers can share the information about the environment. Thus, a searcher must decide which vertex to visit next based on the partial information on the graph gained so far by searchers. We assume that all searchers initially start the exploration at the origin vertex, and the goal is that each vertex is visited by at least one searcher and all searchers finally return to the origin vertex. The objective is to minimize the time when the goal is achieved. We study the case of cycles and trees. For the former, we give an optimal online exploration algorithm in terms of competitive ratio, and for the latter, we also give an online exploration algorithm which is optimal among greedy algorithms. [ABSTRACT FROM AUTHOR]

Abstract: Huber, Krokhin, and Powell (2013) introduced a concept of skew bisubmodularity, as a generalization of bisubmodularity, in their complexity dichotomy theorem for valued constraint satisfaction problems over the three-value domain. In this paper we consider a natural generalization of the concept of skew bisubmodularity and show a connection between the generalized skew bisubmodularity and a convex extension over rectangles. We also analyze the dual polyhedra, called skew bisubmodular polyhedra, associated with generalized skew bisubmodular functions and derive a min–max theorem that characterizes the minimum value of a generalized skew bisubmodular function in terms of a minimum-norm point in the associated skew bisubmodular polyhedron. [Copyright &y& Elsevier]

Plasma B-type natriuretic peptide (BNP) is finely regulated by the cardiac function and several extracardiac factors. Therefore, the relationship between the plasma BNP levels and the severity of heart failure sometimes seems inconsistent. The purpose of the present study was to investigate the plasma BNP levels in patients with cardiac tamponade and their changes after pericardial drainage. This study included 14 patients with cardiac tamponade who underwent pericardiocentesis. The cardiac tamponade was due to malignant diseases in 13 patients and uremia in 1 patient. The plasma BNP levels were measured before and 24-48 h after drainage. Although the patients reported severe symptoms of heart failure, their plasma BNP levels were only 71.2 ± 11.1 pg/ml before drainage. After appropriate drainage, the plasma BNP levels increased to 186.0 ± 22.5 pg/ml, which was significantly higher than that before drainage ( P = 0.0002). In patients with cardiac tamponade, the plasma BNP levels were low, probably because of impaired ventricular stretching, and the levels significantly increased in response to the primary condition after drainage. This study demonstrates an additional condition that affects the relationship between the plasma BNP levels and cardiac function. If inconsistency is seen in the relationship between the plasma BNP levels and clinical signs of heart failure, the presence of cardiac tamponade should therefore be considered. [ABSTRACT FROM AUTHOR]

We herein present the case of a 60-year-old male with narrow QRS tachycardia who had a remarkable PR prolongation during sinus rhythm. The tachycardia was diagnosed as a slow-fast atrioventricular nodal reentry tachycardia. Slow pathway ablation was performed after the confirmation of the presence of an antegrade fast pathway. Following the elimination of the slow pathway, the PR and atrio-His intervals became shortened from 470 and 420 to 170 and 120 ms, respectively. Moreover, the improvement of atrioventricular conduction after the slow pathway ablation lasted for at least 34 months. [ABSTRACT FROM AUTHOR]

Abstract: A simple undirected graph is a rigidity circuit if and for every with , where denotes the set of edges connecting vertices in . It is known that a rigidity circuit can be decomposed into two edge-disjoint spanning trees. Graver et al. (1993) asked if any rigidity circuit with maximum degree 4 can be decomposed into two edge-disjoint Hamiltonian paths. This paper presents infinitely many counterexamples for the question. Counterexamples are constructed based on a new characterization of a 3-connected plane graph in terms of the sparsity of its medial graph and a sufficient condition for the connectivity of medial graphs. [Copyright &y& Elsevier]

A rooted-forest is the union of vertex-disjoint rooted-trees. Suppose we are given a graph G=( V, E), a collection { R,..., R} of k root-sets (i.e., vertex-sets), and a positive integer d. We prove a necessary and sufficient condition for G to contain k edge-disjoint rooted-forests F,..., F with root-sets R,..., R such that each vertex is spanned by exactly d of F,..., F. [ABSTRACT FROM AUTHOR]

A 47-year-old male with both atrial tachycardia and atrial fibrillation underwent catheter ablation. During the procedure, rapid administration of adenosine triphosphate induced atrial tachycardia. A non-contact mapping system revealed a focal atrial tachycardia originating from the lateral right atrium, which was successfully ablated. Following the ablation of tachycardia, atrial fibrillation was induced by the injection of adenosine along with multiple extra pulmonary vein foci, which were eliminated by the application of radiofrequency under the guidance of a non-contact mapping system. [ABSTRACT FROM AUTHOR]

Given n points, called terminals, in the plane ℝ and a positive integer k, the bottleneck Steiner tree problem is to find k Steiner points from ℝ and a spanning tree on the n+ k points that minimizes its longest edge length. Edge length is measured by an underlying distance function on ℝ, usually, the Euclidean or the L metric. This problem is known to be NP-hard. In this paper, we study this problem in the L metric for any 1≤ p≤∞, and aim to find an exact algorithm which is efficient for small fixed k. We present the first fixed-parameter tractable algorithm running in f( k)⋅ nlog n time for the L and the L metrics, and the first exact algorithm for the L metric for any fixed rational p with 1< p<∞ whose time complexity is f( k)⋅( n+ nlog n), where f( k) is a function dependent only on k. Note that prior to this paper there was no known exact algorithm even for the L metric. [ABSTRACT FROM AUTHOR]

Pulmonary vein (PV) isolation was performed in atrial fibrillation (AF) patients whose cardiac rhythm was dominated by the ectopic beats originating from the PV. We herein report two cases with dominant PV ectopic rhythm that underwent catheter ablation for the treatment of paroxysmal AF. In one case, a permanent pacemaker implantation was required to treat a symptomatic long sinus pause after the isolation of all four PVs, while no AF was documented during the 5-year period after ablation. However, the isolation of all four PVs except for a PV with a dominant ectopic rhythm was performed in the other case. The latter case was free from both AF and symptomatic bradycardia following the procedure without the implantation of a pacemaker. Selective PV isolation therefore appears to be an effective therapy to both achieve the successful treatment of AF and to prevent the manifestation of sick sinus syndrome. [ABSTRACT FROM AUTHOR]

Background: Although pulmonary vein (PV)–left atrium (LA) reconnection is associated with recurrence of atrial fibrillation (AF) in patients who undergo pulmonary vein isolation (PVI), no noninvasive method for evaluating PV reconnection has yet been established. Objective: The purpose of this study was to examine whether PV–LA reconnection could be detected noninvasively by analyzing the change of P-loop configuration by vectorcardiography (VCG). Methods: The study included 80 patients with paroxysmal AF (8 female; mean age 58 ± 10 years) who underwent PVI. VCG was prospectively analyzed by recording during the procedure (before and after PVI) and 1 year after the procedure to noninvasively evaluate PV–LA reconnection. Results: All patients showed a significant antero-leftward shift in the middle portion of the P loop on the horizontal plane of VCG, with an increase of the area within the P loop after the initial PVI (2.4 ± 1.7 vs 4.6 ± 2.7 × 103 mV2, P <.001). Sixty-three (78.8%) patients without AF recurrence demonstrated no remarkable change in the P-loop area after 16 ± 11 months of follow-up (4.4 ± 2.7 vs 4.1 ± 2.5 × 103 mV2, P = .51), whereas 17 (21.2%) patients with AF recurrence demonstrated P-loop reversion to the preprocedural P-loop morphology, with a decrease of P-loop area (5.6 ± 2.7 vs 3.2 ± 1.7 × 103 mV2, P <.001). Conclusion: Change of the P loop on VCG was associated with subsequent PV–LA reconnection. VCG is helpful as a noninvasive method for detecting PV–LA reconnection after PVI for paroxysmal AF. [ABSTRACT FROM AUTHOR]

We prove the Molecular Conjecture posed by Tay and Whiteley. This implies that a graph G can be realized as an infinitesimally rigid panel-hinge framework in ℝ by mapping each vertex to a rigid panel and each edge to a hinge if and only if $\bigl({d+1 \choose 2}-1\bigr)G$ contains ${d+1\choose2}$ edge-disjoint spanning trees, where $\bigl({d+1 \choose2}-1\bigr)G$ is the graph obtained from G by replacing each edge by $\bigl({d+1\choose2}-1\bigr)$ parallel edges. [ABSTRACT FROM AUTHOR]

Background: Intravenous administration of adenosine triphosphate (ATP) is used to induce transient pulmonary vein (PV) reconduction (dormant PV conduction) following PV isolation. This study investigated the detailed characteristics of dormant PV conduction in patients with atrial fibrillation (AF) who underwent catheter ablation. Methods: Two hundred sixty consecutive patients (235 men; mean age, 54 ± 10 years) who underwent catheter ablation of their AF were included in this study. ATP was injected following PV isolation to induce dormant PV conduction, which was then eliminated by radiofrequency application. Results: Dormant PV conduction was induced by ATP in 60.4% (157/260) of the patients and in 25.3% (258/1,021) of the isolated PVs. This transient PV reconduction was more frequently observed in the left superior PV in comparison with other PVs (P < .0001). There was no significant difference in the prevalence of the dormant PV conduction among patients with paroxysmal AF, persistent AF, and long-lasting AF (62%, 66%, and 48%, respectively; P = .13). During the follow-up period, repeat AF ablation was performed in 70 patients with recurrent AF. The dormant PV conduction was less frequently induced in the repeat procedure than in the initial procedure (60.4% vs 31.4%, P < .0001). Conclusions: Dormant PV conduction was evenly induced among AF types. The repeat PV isolation led to the decrease in incidence of the ATP-induced acute transient pharmacological PV reconduction. [Copyright &y& Elsevier]

Background: The elimination of transient pulmonary vein (PV) reconduction (dormant PV conduction) revealed by adenosine in addition to PV isolation reduced the atrial fibrillation (AF) recurrence after catheter ablation. The dormant PV conduction is induced in approximately half of the AF patients that undergo PV isolation. The present study compared the clinical outcome of AF ablation in patients whose dormant PV conduction was eliminated by additional radiofrequency applications with the outcome in patients without dormant conduction. Methods: A total of 233 consecutive patients (206 male, 54.2 ± 10.1 years) that underwent AF ablation were included in the present study. Dormant PV conduction was induced by the administration of adenosine triphosphate after PV isolation and was eliminated by supplemental radiofrequency application. All patients were followed up for >12 months (mean 903 days) after the first ablation. Results: Following PV isolation, dormant PV conduction was induced in 139 (59.7%) of 233 patients and was successfully eliminated in 98% (223/228) of those in the first ablation procedure. After the first procedure, 63.9% (149/233) of patients were free from AF recurrence events. The success rates of a single or final AF ablation in patients with the appearance of the dormant PV conduction were similar to those of patients without dormant conduction (P = .69 and P = .69, respectively). Conclusions: Dormant PV conduction was induced in over half of the patients with AF. After the elimination of adenosine triphosphate–induced reconnection, the clinical outcome of patients with the dormant PV conduction was equivalent to that of patients without conduction. [ABSTRACT FROM AUTHOR]