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Speech-induced atrial tachycardia (AT) with presyncope is extremely rare. A 52-year-old woman employed at a supermarket reported recurrent presyncope while speaking out loud at her job. Holter electrocardiography revealed AT while swallowing without presyncope. The patient's blood pressure decreased during AT, and she experienced presyncope while saying "IRASSHAIMASE" loudly during a tilt table test. Accordingly, bisoprolol 1.25 mg was prescribed, and the patient did not experience episodes of presyncope with recurrence of AT for 2 years. This case suggests that provocation of arrhythmia in the tilting position may be useful for demonstrating a relationship between arrhythmia and presyncope and/or syncope.

We herein report a 34-year-old man who presented with recurrent palpitations that occurred while swallowing solid food. Holter monitoring revealed atrial tachycardia (AT) while eating. In addition, chest computed tomography (CT) showed a small nodule in the front of the ascending aorta. Thoracoscopic surgery was performed to remove the nodule; a pathological examination revealed that the nodule was a thymic cyst. The AT disappeared postoperatively. This case demonstrates that a mediastinal nodule can cause swallowing-induced AT.

Syncope is defined as the transient loss of consciousness due to cerebral hypoperfusion. Reflex syncope (neurally mediated syncope) is among all syncope, vasovagal syncope is among reflex syncope in addition. We frequently treated several patients with vasovagal syncope in our clinical situation. We report here the mechanisms and treatments of vasovagal syncope. Although this syncope has a low risk, the diagnosis and the treatments are complicated. Therefore, invasive treatments are necessary in selected patients. This article discusses the management procedures of syncope according to the guidelines and our clinical experience.

Ventricular tachycardia induced by tilt table testing.

We herein report the case of a 20-year-old man with a history of epilepsy who presented with frequent transient loss of consciousness (T-LOC) and polymorphic ventricular tachycardia (VT) with QT interval prolongation. Blood investigations revealed panhypopituitarism. Following a biopsy, he was diagnosed with brain germinoma. During the biopsy, he had an episode of polymorphous VT with QT prolongation. There was no recurrence of T-LOC following chemotherapy and hormone replacement therapy. This case indicates the importance of checking the QT interval in patients with T-LOC, including those with seizures and brain tumors, to ensure appropriate treatment.

Introduction: Atrial arrhythmia (AA) and left ventricular systolic dysfunction (LVSD) frequently co-exist, which loom as burgeoning public health problems. It is difficult to determine whether a tachycardia is the indicator or consequence of LVSD in patients with tachycardia and LVSD. Tachycardia mediated cardiomyopathy (TCM) raises a “chicken or egg” question. Regardless of the etiology, the patients with severe LVSD are considered as the candidate for the implantation of cardioverter defibrillator as primary prevention. It is well known that the LVSD improves after the successful treatment of AA in TCM population. However, enlarged left ventricular end-diastolic dimension (LVDd) is considered as a parameter of irreversible LVSD. Hypothesis: Enlarged LVDd could not be a predictor for irreversible LVSD in patients with AA. Methods: We assessed patients with persistent AA and heart failure (Ejection Fraction (EF) Results: Twenty-five patients with persistent AA and LVSD (23 men; mean age 63.8±9.3 years) were enrolled in this study. After restored and maintained SR, EF and left ventricular end-systolic volume (ESV) and BNP were improved in all patients respectively (EF 30.7±10.7 to 54.0±7.3%, ESV; 82.1±32.4 to 50.6±24.1ml, BNP; 379.2±237.9 to 48.0±29.7pg/ml P60mm were observed in 5 patients (25%) before the treatment. EF was normalized in patients with severe LVSD (EF Conclusions: The unnecessary device implantation could be avoided in patients with AA and severe LVSD with aggressive rhythm control therapy. Even in the patients with severe LVSD and enlarged LVDd, LVSD is reversible when AA exists.

Background Computed tomography is the best noninvasive imaging modality for evaluating valve leaflet calcification. Objective To evaluate the association of aortic valve leaflet calcification with instantaneous valve opening and closing using dynamic multidetector computed tomography (MDCT). Methods We retrospectively evaluated 58 consecutive patients who underwent dynamic MDCT imaging. Aortic valve calcification (AVC) was quantified using the Agatston method. The aortic valve area (AVA) tracking curves were derived by planimetry during the cardiac cycle using all 20 phases (5% reconstruction). da/dt in cm 2 /s was calculated as the rate of change of AVA during opening (positive) or closing (negative). Patients were divided into 3 three groups according to Agatston score quartile: no AVC (Q2, Score 0, n = 18), mild AVC (Q3, Score 1–2254, n = 24), and severe AVC (Q4 Score >2254, n = 14). Results In multivariable linear regression, compared to the non AVC group, the mild and severe AVC groups had lower maximum AVA (by −1.71 cm 2 and −2.25 cm 2 , respectively), lower peak positive da/dt (by −21.88 cm 2 /s and −26.65 cm 2 /s, respectively), and higher peak negative da/dt (by 13.78 cm 2 /s and 18.11 cm 2 /s, respectively) (p Conclusions AVA and its opening and closing were influenced by leaflet calcification. The present study demonstrates the ability of dynamic MDCT imaging to assess quantitative aortic valve motion in a clinical setting.

BACKGROUND An adaptive cardiac resynchronization therapy (aCRT) algorithm has been described for synchronized left ventricular (LV) pacing and continuous optimization of cardiac resynchronization therapy (CRT). However, there are few algorithmic data on the effect of changes during exercise.Methods and Results:We enrolled 27 patients with availability of the aCRT algorithm. Eligible patients were manually programmed to optimal atrioventricular (AV) and interventricular (VV) delays by using echocardiograms at rest or during 2 stages of supine bicycle exercise. We compared the maximum cardiac output between manual echo-optimization and aCRT-on during each phase. After initiating exercise, the optimal AV delay progressively shortened (P

We report an autopsy-proven case of a 33-year-old man who died of intimal sarcoma of the pulmonary artery. A large mass (5×4 cm) occluded the main and bilateral pulmonary arteries. Tumor cell morphology was consistent with that of undifferentiated pleomorphic sarcoma. Comprehensive histological observation of 18 pulmonary arteries from proximal to distal revealed continuous extension of the tumor from the main to the subsegmental arteries along the intima, forming an arteriosclerosis-like intimal thickening. Distal small arteries were also affected by eccentric intimal thickening or recanalization. Lung parenchyma was not involved, although there were two wedge-shaped small pulmonary infarctions caused by tumorous obstruction of the associated arteries. Histological results indicated that the intimal sarcoma in the pulmonary artery, which appeared occlusive with growth limited to the proximal artery, had in fact already spread more peripherally than expected. Both the proximal lesions and the distal small arteries were affected by peripheral tumor emboli or by pulmonary hypertension induced by the proximal tumor. However, as seen in this case, most of the occlusive tumor was located locally and intraluminally, in the proximal artery, and removing the proximal tumor by pulmonary endarterectomy was considered effective for symptomatic improvement.

Long-Term Observation with ILR. Introduction: In the literature, the average diagnostic yield of the implantable loop recorder (ILR) is reported to be 35% over an observation period generally less than 18 months. The aim of this study was to evaluate the diagnostic value of ILR during very prolonged observation. Methods and Results: Consecutive patients who had received one or more (in the case of battery exhaustion before diagnosis) ILR (Reveal/plus/DX, Medtronic Inc.) from 2001 to 2010 were included. The diagnostic ECG was classified according to the ISSUE classification. We analyzed 157 patients (87 males, 69 ± 14 years): 70 of these were followed up for ≥18 months. The estimated cumulative diagnostic rates were 30%, 43%, 52%, and 80% at 1, 2, 3, and 4 years, respectively; 26% of diagnoses were made after 18 months. The diagnostic yield was independent of structural heart disease, bundle branch block, number of syncopes, age, and gender; the median time to diagnosis of ISSUE type 1 patients was shorter than that of the others (4 [2;10] vs. 16 [6;23] months; P = 0.003). During the observation period, 3 patients (1.9%) died and none suffered arrhythmic death. Conclusions: Prolonging observation up to 4 years increased the diagnostic value of ILR in syncopal patients and was safe. A quarter of patients diagnosed needed more than 18 months of follow-up. As consequence, when a strategy of prolonging monitoring is chosen, monitoring should be maintained even for several years until diagnosis is established. (J Cardiovasc Electrophysiol, Vol. 23, pp. 67-71, January 2012)

Desorption of thiolate self-assembled monolayers (SAMs) seriously limits the fabrication of thiol-based devices. Here we demonstrate that nanoporous Au produced by dealloying Au-Ag alloys exhibits high electrochemical stability against thiolate desorption. Nanoporous Au has many defective sites, lattice strain and residual Ag on the ligament surface. First-principles calculations indicate that these surface aspects increase the binding energy between a SAM and the surface of nanoporous Au.

Recently, the remote transmission of data detected by implantable loop recorders (ILRs) has become available. The aim of this study was to evaluate effectiveness and acceptance of remote monitoring in the clinical management of syncope and palpitations in patients with ILR. Methods and results Consecutive patients implanted with ILR (Reveal DX/XT Medtronic, Inc.) and followed up by means of remote moni- toring (CareLink w ) were included. The patients were requested to transmit the data stored in the ILR every week, via the CareLink system, or more frequently during the first period. Patient acceptance of ILR was evaluated by means of a questionnaire concerning physical and mental components. Forty-seven patients (27 males, average age 64+ 19 years) were enrolled and followed up for 20+ 13 weeks. Thirty-two patients (68%) had at least one ECG recording of a true relevant event. The mean time from ILR implantation to the first true relevant ECG was 28+ 49 days, which was 71+ 17 days less than in the clinical practice of 3-monthly in-office follow-up examinations. Thirty- eight patients (81%) had at least one false arrhythmic event, mainly false asystole and false fast ventricular tachycardia. In the absence of Carelink transmission, at least one episode of memory saturation of ILR would have occurred in 21 patients (45%) that would have limited the diagnostic yield. Patient compliance was good even though one- fifth had some minor psychological concern regarding the ILR implant. CareLink was well accepted and judged easy to use. Conclusion Remote monitoring enhances the diagnostic effectiveness of Reveal, limiting the risk of memory saturation due to the high number of false detections and reducing the time to diagnosis. Both ILR and CareLink were well accepted and well tolerated by the patients, as they were considered useful.

Hydrogen absorption/desorption properties of nanoporous Pt fabricated by dealloying were investigated. At high pressure (> 1:3MPa), the nanoporous Pt released hydrogen during hydrogen pressurization; in contrast, it absorbed hydrogen up to 3.5 atom% during hydrogen depressurization, which have not been seen in current metal/hydride systems including nanoparticles. First-principles calculations suggested that the abnormal hydrogen absorption/desorption properties are due to the relaxation/preservation of the lattice strain in Pt hydride. [doi:10.2320/matertrans.M2010403]

Distinctive Electrogram and Aortography of Coronary Cusp. Background: The coronary cusps have recently become target sites for radiofrequency catheter ablation of both outflow tract ventricular arrhythmias originating near the coronary cusps (CC-VA) and atrial tachyarrhythmias such as focal atrial tachycardia originating near the noncoronary cusp (NCC-AT). However, the relation between local electrograms recorded at each CC during sinus rhythm and their anatomical position as assessed by aortography has not yet been systematically described. Methods and Results: In 28 patients undergoing RFCA for CC-VA or NCC-AT, amplitudes of the atrial and ventricular potentials at the CCs were measured during sinus rhythm, and the atrial/ventricular (A/V) potential ratio was computed. Relative positions of the CCs were assessed by aortography in 2 X-ray projections. In the right (RCC) and left coronary cusps (LCC), amplitudes of the ventricular potential were larger than those of the atrial potential, leading to an A/V ratio

Aims We thought to evaluate feasibility of continuous non-invasive blood pressure monitoring during procedures of interventional electrophysiology. Methods and results We evaluated continuous non-invasive finger blood pressure (BP) monitoring by means of the Nexfin device in 22 patients (mean age 70 ± 24 years), undergoing procedures of interventional electrophysiology, in critical situations of hypotension caused by tachyarrhythmias or by intermittent incremental ventricular temporary pacing till to the maximum tolerated systolic BP fall (mean 61 ± 14 mmHg per patient at a rate of 195 ± 37 bpm). In all patients, Nexfin was able to detect immediately, at the onset of tachyarrythmia, the changes in BP and recorded reliable waveforms. The quality of the signal was arbitrarily classified as excellent in 11 cases, good in 10 cases, and sufficient in 1 case. In basal conditions, calibrations of the signal occurred every 49.2 ± 24.3 s and accounted for 4% of total monitoring time; during tachyarrhythmias their frequency increased to one every 12.7 s and accounted for 19% of total recording duration. A linear correlation for a range of BP values from 41 to 190 mmHg was found between non-invasive and intra-arterial BP among a total of 1055 beats from three patients who underwent simultaneous recordings with both methods (coefficient of correlation of 0.81, P < 0.0001). Conclusion In conclusion, continuous non-invasive BP monitoring is feasible in the clinical practise of an interventional electrophysiology laboratory without the need of utilization of an intra-arterial BP line.

Nanoporous Ni specimens with ligament lengths of 10–210 nm and specific surface areas of 0.03–0.58 nm−1 were fabricated by the dealloying of Ni0.25Mn0.75 alloy and annealing at 473–873 K, and saturation magnetization investigated in terms of their size dependence. Saturation magnetization decreased with decreasing ligament length or increasing specific surface area. This trend is the same as that for nanoparticle Ni. However, the saturation magnetization of nanoporous Ni tends to be lower than that of the nanoparticle Ni when their specific surface areas are the same. It is suggested, therefore, that the surface effect due to a noncollinear arrangement is enhanced by the surface defects in the nanoporous Ni.

The hydrogen storage properties of nanoporous Pd fabricated by dealloying a Pd0.2Co0.8 alloy were investigated by measuring pressure−composition isotherms (PCTs). The hydrogen storage behaviors of ...

For the purpose of discriminating between cases of nephrotic syndrome with and without corticosteroid effect, a linear discriminant function was applied in attempt to predict the effect of corticosteroid by the use of a computer. The parameters used were 15-min values of the PSP test, urinary protein, serum cholesterol, renal biospy findings, the number of red cells in the urinary sediment and immunoglobulin clearance ratio. The rate of correct prediction using the function with immunoglobulin clearance ratio was 87.0 %.

Since photovoltaic generators (PV) have been mainly introduced in residential areas, it is necessary to consider the consequences of setting up large numbers of PVs locally. In such a situation, it will be difficult to manage the voltage in distribution lines, because the reverse power supplied from the PV raises the voltage of the power lines. In this study, a large PV system was connected to a distribution system, and for every inverter the authors used simulations to verify the appraisal of systematic voltage and the electric power generation. As a result, the authors verified that power factor control is more effective than output control. In addition, the authors verified that with each user the power generation becomes more unequal. In the future, when a large PV system is connected to a distribution system, the problem of unsatisfactory equalization of demand for home appliance usage may arise. A method for determining the set value for the inverter for each user was proposed in order to solve this problem, and the effectiveness of the proposed technique was verified through simulations. © 2009 Wiley Periodicals, Inc. Electron Comm Jpn, 91(10): 46– 58, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10166

In recent years, distributed resources such as photovoltaic power generation system or wind-turbine generator system are increased, therefore the distributed resources which connect to distribution networks are increased gradually. Under the situation there are several problems such as expansion of the voltage fluctuation, increase of the short circuit current, increase of harmonics phenomenon which we have to consider, and the problems make us difficult to examine the effect of interconnection and to design the distribution system. However, analysis support system to evaluate the influence to connect distributed resources to low voltage distribution system has not developed.Therefore We have developed the analysis system for low voltage for low voltage distribution systems. We can evaluate the influence of distributed resources accurately, examine the interconnection and design the configuration of distribution networks by using the analysis system. In this paper, the concept of the analysis system, the load flow method for unbalanced V-connection 3-phase 4-line distribution system and the calculation method for the connectable capacity of distributed resources. Outline of the man/machine interface and examples of calculation results for sample network are also described.

This paper describes a load dispatch method which minimizes power cost—[fuel cost]/[electric output]—for a power system with thermal plants and energy storage facilities. The proposed method employs fractional programming to convert a minimization problem with fractional objective function to a series of quadratic minimization problems, and semidefinite programming to solve converted problems. The method provides the optimum time-dependent power output/input and storage level of energy storage facilities as well as time-dependent power output of thermal plants. The method has been applied to a power system with five thermal plants, two energy storage facilities of various performances, and five load demands. The optimum load scheme of four time mesh points is obtained for the thermal plants and energy storage facilities. The fractional programming successfully converges the optimal scheme through a few iterations. The semidefinite programming deals with a variable matrix of 164 dimensions, and 185 inequality constraints. © 2001 Scripta Technica, Electr Eng Jpn, 138(2): 49–58, 2002

A multivariate analysis of CAMPAS-PX2 can increase its diagnostic accuracy in differential diagnosis of pancreatic cancer from benign pancreatic or extrapancreatic disease, when compared with CA19-9 alone. However, the improvement in diagnostic accuracy is still not satisfactory in spite of an elaborate combination of serum markers in diagnosis for pancreatic cancer. Optimal combination of a sensitive serum marker and another diagnostic modality, such as ultrasonography, can be a practical way to improve important diagnostic and cost-effectiveness in diagnosis for pancreatic cancer.No specific biological test has yet been developed for diagnosis of pancreatic cancer, although increasing numbers of tumor markers become available. For improvement in the diagnostic and cost effectiveness, it is important to select optimal combination of several serum markers relatively independent of each other.A new model of discriminant function, computer-aided multivariate and pattern analysis system for pancreatic cancer examination 2 (CAMPAS-PX2), was developed based on the data of the 23 serum tumor markers from the first prospective trial (1) to differentiate between pancreatic cancer and benign pancreatobiliary disease by logistic regression analysis using a stepwise selection method. In 243 patients suspected of having pancreatic pancreatic cancer by a multicenter prospective study, the diagnostic value of the multivariate analysis, CAMPAS-PX2, was compared with the 23 markers.Pancreatic cancer was subsequently identified in 27 patients. Positive in disease, negative in health, and area under receiver operating characteristic curve were significantly higher by CAMPAS-PX2 (89, 87, 91%) than by CA 19-9 (78, 82, 84%), the most sensitive marker among the 23 markers.

We designed an osmotic pump, using a semipermeable membrane which changes its volume according to the concentration of an outside solution. No energy supply or regulation system are required. This pump directly converts chemical potential to mechanical action without an intermediary like an electrical apparatus, called a mechanochemical actuator. This mechanism was applied to an insulin pump that works by changing the glucose concentration. We demonstrated that this pump may possibly be used in the treatment of diabetes mellitus patients.

The effect of clinical triggers on tilt-table testing (TTT) responses has not been systematically evaluated. In the present study, we evaluated the effect of clinical triggers on positive responses to TTT potentiated with nitroglycerin (which acts mainly through peripheral dilation) or clomipramine (which acts mainly through a central serotoninergic mechanism). We enrolled 380 consecutive adult patients. In 66 patients, syncope was triggered by emotional distress (central trigger), in 161 by specific situations or prolonged standing (peripheral trigger), and in 153 syncope occurred in the absence of any detectable trigger. Nitroglycerin TTT, performed in 252 patients, consisted of a passive phase of 20 minutes followed, if negative, by sublingual administration of 400 μg nitroglycerin spray and continuation of tilting for 15 minutes. Clomipramine TTT, performed in 128 patients, consisted of 20 minutes of tilting with intravenous administration of 5 mg clomipramine during the first 5 minutes. The positivity of nitroglycerin TTT was greater in patients with clinical triggers (71% central and 75% peripheral) than in those without (36%). With clomipramine TTT, the positivity rate was greater in patients with central triggers (92%) than in those with peripheral triggers (45%) or no triggers (30%). The cardioinhibitory form was more frequent in patients with a central trigger than in the other 2 groups (34% vs 12% and 7%) and with clomipramine TTT than with nitroglycerin TTT (19% vs 11%, respectively). In contrast, mixed or vasodepressor forms were more frequently induced by nitroglycerin TTT (41% vs 24%). In conclusion, the presence of clinical triggers increased the positivity of TTT and influenced the type of response. We found some specificity of nitroglycerin and clomipramine for peripheral and central mechanisms.

Endothelin-1 (ET-1), a 21-amino acid vasoconstrictive peptide, increases intracellular Ca2+ level and has hypertrophic action on ventricular myocytes. To elucidate a possible role of Ca2+ entry through sarcolemmal Ca2+ channels on this ET-1 action, we examined effects of ET-1 on L-type (ICa,L) and T-type (ICa,T) Ca2+ currents in cultured neonatal rat ventricular myocytes using the patch-clamp technique. ET-1 at a concentration of 10 nM increased the maximum current density of ICa,T from -3.0 +/- 1.4 microA/cm2 in the control condition to -4.4 +/- 1.6 microA/cm2 (p < 0.01). Although the peak amplitude of ICa,L was decreased during ET-1 application (from -9.7 +/- 1.9 microA/cm2 in the control condition to -5.0 +/- 1.4 microA/cm2 [p < 0.01]), this magnitude of decrease in ICa,T (52 +/- 19%) was comparable to that of spontaneous "run-down" of ICa,L (47 +/- 26%). The enhancement of ICa,T by ET-1 was dose dependent; it was initiated as low as 0.32 nM, and the maximal response was attained at approximately 10 nM, with a half-maximal dose of 1.26 nM. The enhancement of ICa,T by ET-1 was antagonized by protein kinase C inhibitors staurosporine (0.2 microM) and 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7, 20 microM) applied to the pipette solution. Extracellular application of tumor-promoting phorbol esters, phorbol 12,13-dibutyrate (PDBu) and 4 beta-phorbol 12-myristate 13-acetate, augmented ICa,T. PDBu (0.2 microM) increased the maximal current density of ICa,T from -4.2 +/- 0.5 microA/cm2 in the control condition to -5.5 +/- 1.0 microA/cm2 (p < 0.01). In the presence of H-7 (20 microM) in the pipette solution, PDBu failed to enhance ICa,T, and an inactive isomer of PDBu (4 alpha-phorbol 12,13-dibutyrate, 0.2 microM) did not augment ICa,T. Thus, ET-1 enhances Ca2+ entry through the sarcolemmal T-type Ca2+ channel, possibly through a pathway involving activation of protein kinase C. This ET-1 action may be involved in the rise of the intracellular Ca2+ level and may contribute to the induction of cardiac hypertrophy by ET-1.

We attempt a microrobotic drug delivery system (DDS) in which drug carriers of air-filled microcapsules are recognized with echography and are controlled using resonant ultrasound. We have confirmed the physical possibility of resonance design for drug carriers depending on the shell structure of the microcapsule. In addition, we have developed a novel echographic imaging system to locate microrobots precisely. Path lines of microrobots in blood flow could be clearly visualized.

Background: The role of autonomic effects in the occurrence and maintenance of atrial fibrillation (AF) has undergone little investigation in the remodeling heart. Methods and Results: In the present study, 2 groups were studied: those with complete atrioventricular block (AVB) produced by radiofrequency current application (AVB dogs, n=17) and those not undergoing AVB (sham dogs, n=5). Eight weeks after creation of AVB, electrophysiologic study, including pulmonary vein (PV) pacing for AF induction, was performed under vagal nerve stimulation (VNS) and sympathetic stimulation (SS) in both groups. After 8 weeks, atrial dimensions and the percentage of fibrosis in the atria were significantly greater in the AVB dogs. In AVB dogs, atrial and PV effective refractory periods were shorter (P

Aims The purpose of this retrospective study was to assess characteristics of patients who had suffered atrial flutter (AFL) with 1:1 atrioventricular (AV) conduction (1:1 AFL). Methods and results Subjects were 8 patients (61 ± 14 years) with documented 1:1 AFL, and 101 AFL patients without a history of 1:1 AFL (control patients). 1:1 AFL occurred during physical activity with a ventricular rate of 218 ± 18 bpm. Antiarrhythmic agents were administered to all eight 1:1 AFL patients, whereas AV nodal conduction-suppressing agents were administered to four. The maximum ventricular rate at which 1:1 AV conduction occurred was significantly lower than when spontaneous 1:1 AFL occurred (164 vs. 218 bpm, P < 0.05). The 1:1 AFL patients had a significantly longer AFL cycle length (CL) (292 vs. 258 ms, P < 0.05) and more rapid AV nodal conduction time (maximum 1:1 AV conduction: 375 vs. 464 ms, P < 0.05) than did control. Arrhythmia had occurred in patients with an AFL CL ≥ 250 ms and a CL of maximum 1:1 AV conduction ≤400 ms. Conclusion Clinicians should be aware of the potential for 1:1 AV conduction in AFL patients, especially in those with remarkable prolongation of the CL in addition to enhanced AV conduction.

Introduction: The role of the autonomic nervous system in inducing pulmonary vein (PV)-triggered atrial fibrillation (AF) and the termination mechanism of the AF are unknown. The purpose of this study was to elucidate the mechanism of the conversion of a tachycardia within a PV into AF under autonomic stimulation and the termination mechanism of the AF in normal canine hearts. Methods and Results: In open-chest dogs, the electrophysiologic parameters were measured under vagal stimulation (VS) or an isoproterenol administration. The effects of the VS or isoproterenol on the PV tachycardias (PVTs), which were created by burst pacing from a PV or the application of aconitine onto the PV, were evaluated. Pilsicainide, a Na channel blocker, was administered during the induced AF. VS and isoproterenol shortened the atrial and PV effective refractory periods. In the pacing model, the VS converted the PV rapid activations into sustained AF in 9 of 12 dogs during pacing cycle lengths ≤120 msec, but the isoproterenol did not cause any sustained AF. In the aconitine model, the VS increased the rate of the aconitine-induced PVTs and transformed them into sustained AF in all 14 dogs, whereas the isoproterenol did not induce AF, and decreased the PVT rate. In all 14 dogs the sustained AF was terminated by pilsicainide, which had suppressive effects on the PVT as well as atria and PV-atrial junction. Conclusions: These findings indicate that the vagal effects affecting the PVT and atria facilitate the onset and maintenance of PV-triggered AF in normal canine hearts.

Echo enhancers in blood flow appear as particles in ultrasonic B-mode images. Moving particles in blood flow are different in size and speed from solid parts of major structures. Using these differences, echoic particles are extracted from the original B-mode images. Path lines of blood flow are demonstrated by overlapping the extracted particles. Superimposing the path lines on the original B-mode image with different color provides blood flow information and structure information on one plane. Based on this algorithm, a new method is developed to visualize path lines of blood flow, i.e. two-dimensional moving target indication (2D-MTI). >