This paper presents our new findings that strong electric-field bursts, which were generated in a high-voltage linear plasma discharge, give rise to impulsive hard x ray fluxes with energies higher than 20 keV detected dominantly from the direction perpendicular to the magnetic field and sometimes from the direction almost parallel to the magnetic field with much lower intensities. Dependence of the angular distribution of electron acceleration on the spectral profile of an originating electric-field burst whose peak frequency is close to the lower hybrid frequency is explained according to the theory of transit time interaction.

Lipoprotein(a) (Lp(a)) has a prothrombotic effect by modulating the fibrinolytic system. The purpose of the present study was to determine whether serum Lp(a) levels are associated with an increased risk of thromboembolism in chronic nonvalvular atrial fibrillation (NVAF). Clinical, laboratory and transesophageal echocardiographic data were collected in 172 consecutive, non-anticoagulated patients with chronic NVAF. Thirty-four patients (thromboembolic group) had a recent (<1 month) embolic event and/or a left atrial thrombus on transesophageal echocardiography. The thromboembolic group had a higher frequency of spontaneous echo contrast (94 vs. 58%, p<0.0001), increased concentrations of Lp(a) (median: 31.5 vs. 15.5 mg/dl, p<0.0001) and fibrinogen (median: 352 vs. 314 mg/dl, p = 0.0015), larger left atrial dimensions (median: 5.1 vs. 4.8cm, p = 0.0078), and reduced left atrial appendage (LAA) flow velocities (median: 9.5 vs. 21.2 cm/s, p<0.0001) than the nonthromboembolic group. Multivariate analysis identified 3 independent predictors of thromboembolism: Lp(a) level > or =30 mg/dl (odds ratio (OR) 9.5, 95% confidence interval (CI) 4.4-20.4, p<0.0001), LAA flow velocity of <20 cm/s (OR 8.7, 95% CI 3.3-23.0, p = 0.0003) and a fibrinogen concentration of <377mg/dl (OR 3.2, 95% CI 1.5-6.9, p = 0.0201). The Lp(a) elevations and reduced LAA flow velocities are independently associated with thromboembolism in chronic NVAF.

Recently we have observed self-excited very large amplitude fluctuations in the electric field (parallel to B) whose mean amplitude was typically 10kV/cm and associated with enhanced anomalous resistivity during the quasistationary current limiting phase of a high-voltage linear plasma discharge. The power spectral density of the.electric field fluctuations shows the peaking around the lower hybrid frequency, and these lower hybrid fluctuations exhibit chaotic behaviors.

A 63-year-old man with left main coronary artery disease underwent aortocoronary bypass surgery using saphenous vein grafts. Less than 1 month later, severe narrowing occurred in the mid-portion of the vein graft to the left anterior descending coronary artery. Preintervention intravascular ultrasonography revealed prominent vein graft shrinkage. Percutaneous transluminal angioplasty failed because the stenotic lesion could not be dilated, even by high-pressure balloon inflation. Saphenous vein graft shrinkage appears to be one of the mechanisms of early saphenous vein graft stenosis, and balloon angioplasty to the vein graft stenosis with prominent shrinkage may be of only limited value.

Background Patients with chronic atrial fibrillation have an increased risk of thromboembolism. Apoprotein(a) has a structural homology with plasminogen, suggesting that lipoprotein(a) [Lp(a)] may produce thrombogenic effects by modulating the fibrinolytic system. However, the role of Lp(a) level in the formation of left atrial thrombus has not been studied. We sought to evaluate whether Lp(a) is a risk factor for left atrial thrombus in patients with chronic atrial fibrillation. Methods and Results The consecutive series of 150 patients (mean age 67 ± 8 years) with chronic atrial fibrillation underwent transesophageal echocardiography. Left atrial thrombus was diagnosed by transesophageal echocardiography. Clinical, biochemical, and echocardiographic variables were prospectively collected. Univariate analysis showed that patients with left atrial thrombus (n = 29, 19%) had higher frequency of spontaneous echo contrast (93% vs 55%, P < .0001) than patients without left atrial thrombus (n = 121). Patients with left atrial thrombus also had a significantly higher serum concentration of Lp(a) (34.5 ± 24.1 vs 17.9 ± 13.5 mg/dL, P < .0001), a larger left atrium (5.4 ± 0.9 vs 4.8 ± 0.7 cm, P < .001), and a lower left atrial appendage peak flow velocity (11.1 ± 5.4 vs 23.5 ± 14.6 cm/s, P < .0001). Multivariate regression analysis showed that the Lp(a) concentration (P < .0001) was a significant positive predictor and the left atrial appendage peak flow velocity (P = .0125) was a significant negative predictor of left atrial thrombus. Left atrial thrombus was present in 16 (48%) of 33 patients with Lp(a) level ≥30 mg/dL. Conclusions Elevated serum levels of Lp(a) are strongly associated with left atrial thrombus. These findings suggest that Lp(a) level may be a novel risk factor for left atrial thrombus in patients with chronic atrial fibrillation. (Am Heart J 1998;136:965-71.)

The patient was a 71-year-old female with Torsade de Pointes (TdP) associated with idiopathic long QT syndrome. TdP and polymorphic nonsustained VT were frequently observed at bedside and an electrophysiologic study was performed. The QT (and QTU) interval was abnormally prolonged, and alteration of the QT interval was also recorded on the electrocardiogram. Monophasic action potential (MAP) from the right ventricle showed a hump on the falling limb of the MAP following a long RR interval of more than 1.0 sec. Intravenous administration of nicorandil (2 mg) resulted in disappearance of the hump, and ventricular arrhythmia was no longer observed. The QT interval at a PP interval of 720 msec was slightly shortened. She was treated with a DDD-pacemaker and given nicorandil. No recurrence of TdP was observed during the follow-up period of 8 months. This drug might be effective in patients with idiopathic long QT syndrome.

A 45-year-old man with a rapidly deteriorating heart condition died suddenly, two hours after admission, after resistance to attempts of cardiac pacing. At autopsy, the heart weighed 600g with asymmetric septal hypertrophy. Histological examination revealed an extensive and diffuse disarray of myocardial fibers in the ventricular septum and in the free wall of both ventricles. Pronounced mononuclear cell infiltrations and interstitial edema were distributed widely in both ventricles. There were few abnormal findings in the other organs. The diagnosis was hypertrophic cardiomyopathy accompanied by Fiedler's myocarditis. Such a case appears to be rare.

An overview is given on some nonlinear phenomena such as electron hole, double layer and turbulent-heating processes which have been observed in a mirror-confined, plasma. Results of computer simulations are also presented to compare with the experimental results.

Mechanisms of spontaneous collapse of double layer (DL) in a linear turbulent heating device are studied. Parameters which may have effect on the life time τD of DL were examined. It is found that the life time of DL depends strongly on the distance between two electrodes and partial pressure of neutral particles, but less on wall materials and size of the wall. It is shown that the empirical law on τD can be best explained by a model which assumes that no ion is supplied from the anode and that ions are reflected at the cathode and stagnate in the cathode-side region of DL. Computer simulation based on this model shows that a pressure inbalance is produced across the DL. Then the DL is pushed toward the anode and vanishes when it reaches the anode.

Appearance of a high potential region whose potential is larger than the externally applied potential difference, has been observed for the first time in a linear turbulent heating device. The positive potential pulse is identified as a strong electron hole. After the decay phase of the hole, a strong double layer is formed. A one-dimensional numerical simulation has been also carried out, showing qualitative agreement with the experimental results.

The Wigner distribution whose usefulness for analyzing non-stationary signals was recently re-discovered, is reviewed and applied to some plasma experimental data. It is shown that better time and frequency resolved spectra can be obtained with the Wigner distribution, when compared to the conventional Fast Fourier Transform (FFT).It is also shown that the pseudo spectra which appear in the Wigner distribution can be suppressed with the aid of FFT.

An empirical law τDIDL =const has been found for the lifetime τD of the double layers (DL) observed in a linear turbulent-heating device NU-II [Phys. Fluids 28, 703 (1985)], where IDL is the current passing through the DL.

Time-dependent asymmetric spectra of the density fluctuations in a linear turbulently heated plasma are measured by far-infrared laser scattering using a newly developed dual homodyne detection system. The low frequency ( < 25 MHz) density fluctuations are found to propagate toward the axis of the cylindrical plasma initially. However, only those propagating outward are observed at a later time. The frequency spectra for various wavenumbers are also shown.

A dual homodyne detection system for measuring scattered radiation from plasmas has been fabricated. The system is operative in the far-infrared regime, and with it the power spectral distribution of the scattered radiation in the upper and lower sidebands with respect to the frequency of the incident wave can be obtained. Theory of operation and experimental results for simulated radiation fields are given.