Kaitoku seamount and the mystery cloud of 9 april 1984.

On 9 April 1984, commercial airlines enroute from Tokyo, Japan, to Anchorage, Alaska, reported an unusual mushroom-shaped cloud at about 38.5 degrees N, 146.0 degrees E. On 8 and 9 April the intensity of volcanism from Kaitoku Seamount (26.0 degrees N, 140.8 degrees E), as indicated by T-phase recordings on an array of ocean bottom hydrophones, reached a maximum level and then declined rapidly. An examination was made of the possible relation of the cloud to eruptions of Kaitoku through an analysis of pilot depositions, satellite photos, wind charts, signal strengths and spectra of known man-made underwater explosions, as well as ascent rates of volcanic plumes and cumulonimbus clouds.

Spectral analyses of high-frequency pn and sn phases observed at great distances in the Western pacific.

Both P(n), and S(n), phases recorded at distances greater than 3000 kilometers in the western Pacific have substantial amounts of energy at high frequencies, in sorne instances as high as 12 hertz for P(n) and 15 hertz for S(n), A comparison of P(n) and S(n) spectra reveals generally higher energy levels and higher proportions of high-frequency to low-frequency energy for S(n) than for P(n). Estimates of the effective quality factor, Q, indicate that the efficiency of S(n) propagation may be two or three times that of P(n). First arrivals of Pn and Sn have apparent velocities in agreement with values for the uppermost mantle, whereas maximum-energy arrivals have apparent velocities in agreement with values for the lower crust.

Doppler echocardiographic detection of left ventricular diastolic dysfunction in patients with pulmonary sarcoidosis.

STUDY OBJECTIVE: To determine the prevalence of left ventricular diastolic dysfunction in patients with biopsy specimen-proved pulmonary sarcoidosis without clinical evidence of cardiac disease. DESIGN: A cross-sectional study. SETTING: A large tertiary care university teaching hospital. PATIENTS AND CONTROL SUBJECTS: Fifty consecutive subjects had biopsy specimen-proved pulmonary sarcoidosis without suspected cardiac involvement. Those with other conditions known to affect diastolic function were excluded. The control group comprised 30 healthy hospital workers. INTERVENTIONS: Clinical examination, 12-lead ECG, and combined echocardiographic/phonocardiographic examination. MEASUREMENTS: Indexes of left ventricular diastolic function, including isovolumic relaxation time, peak velocity of early (E) and late (A) ventricular filling, deceleration rate of early diastolic flow, and the sum of the time velocity integrals of E and A were obtained in each patient and control subject. Systolic function was determined using a modification of Simpson's rule. RESULTS: Diastolic dysfunction was present in 7 (14%) patients, 6 of whom had normal systolic function and normal two-dimensional echocardiographic examination. Those with diastolic dysfunction had a longer duration of illness (15 +/- 7 vs 6 +/- 5 years; p = 0.0004), were significantly older (52 +/- 11 vs 38 +/- 9 years; p = 0.0009), and had higher systolic BP (130 +/- 13 vs 117 +/- 12 mm Hg; p = 0.01) than the sarcoid patients with normal diastolic function. CONCLUSIONS: These results demonstrate a significant prevalence of left ventricular diastolic dysfunction in patients with pulmonary sarcoidosis. The cause of this abnormality may be a subclinical sarcoid cardiomyopathy.

Real-time 3-dimensional echocardiography imaging for right ventricular endomyocardial biopsy: a comparison with fluoroscopy.

Real-time 3-dimensional (RT3D) echocardiography has the potential to precisely identify the position of an object in 3-dimensional space. Therefore, we hypothesized that RT3D echocardiography could rapidly facilitate accurate placement of a bioptome within the right ventricle and may offer advantages over a fluoroscopically guided approach. During 63 routine right ventricular biopsy procedures (total of 315 biopsy attempts) in 33 cardiac allograft recipients, the bioptome was initially guided against the intraventricular septum with the use of biplane fluoroscopy. Bioptome position was then evaluated by RT3D echocardiography by using the Volumetrics Model 1 with the transducer placed at the apex. Multiple long-axis and short-axis planes were simultaneously visualized and customized to identify the tip of the bioptome. Bioptome placement was prospectively classified as septal, free wall/septal junction, or free wall. Of the 36 patients studied, 33 (91%) had adequate RT3D images. Of 315 bioptome placements visualized by RT3D echocardiography after fluoroscopic placement, bioptome position against the septum was confirmed in 113 (36%), against the septal/free wall (anterior or posterior) junction in 140 (44%), against the free wall in 60 (19%), and in the coronary sinus in 2 (1%). RT3D echocardiography is readily feasible for use in the majority of transplant patients undergoing right ventricular endomyocardial biopsy. Visualization of the bioptome in multiple simultaneous planes allows accurate localization of the biopsy site. The potential for improved localization of the bioptome tip in the right ventricle may have important clinical implications for augmenting the efficacy of this procedure.

Plasma atrial natriuretic peptide is elevated in patients with hypertrophic cardiomyopathy.

STUDY OBJECTIVES: To determine if plasma levels of atrial natriuretic peptide are elevated in patients with hypertrophic cardiomyopathy and to determine the relationship of atrial natriuretic peptide to symptoms and echocardiographic indices of left ventricular structure and diastolic function in these patients. DESIGN: A prospective study in which atrial natriuretic peptide was measured in peripheral venous plasma in 14 patients (age 44 +/- 14 years) with hypertrophic cardiomyopathy and 17 healthy controls. Echocardiography was performed in all cases and 30 controls to examine indices of left heart structure and function. All patients underwent clinical evaluation. RESULTS: The concentration of atrial natriuretic peptide was significantly higher in patients with hypertrophic cardiomyopathy than controls, (17.86 +/- 8.72 vs. 6.22 +/- 3.26 pmol/l, P = 0.0001). Diastolic dysfunction was observed in 11 of 14 patients with hypertrophic cardiomyopathy. No correlation was demonstrated between atrial natriuretic peptide levels and the degree of diastolic dysfunction, septal or free wall thickness, left atrial size, degree of mitral regurgitation or New York Heart Association functional class. CONCLUSIONS: Plasma levels of atrial natriuretic peptide are elevated in patients with hypertrophic cardiomyopathy but do not correlate with symptoms or echocardiographically-derived indices of left ventricular structure or diastolic function.

The factor structure of "schizotypal' traits: a large replication study.

The heterogeneity of schizotypal traits, suggested in previous research, was further investigated in a sample of subjects (N = 1095) administered a composite questionnaire consisting of a large number of published scales the majority of which were designed to measure psychotic characteristics. Factor analysis confirmed the four components previously indicated in our work with the same instrument; namely, "aberrant perceptions and beliefs', "cognitive disorganization', "introvertive anhedonia' and "asocial behaviour'. This structure was maintained regardless of whether or not the analysis included scales from the Eysenck Personality Questionnaire, which might otherwise have been held to explain the variance. "Aberrant perceptions and beliefs'-reminiscent of the positive symptoms of schizophrenia-was the strongest component; but, given the multidimensional nature of the data, together with the pattern of factor loadings and intercorrelations for the scales involved, it was concluded that the broader term "psychosis-proneness' or "psychoticism' (in a non-Eysenckian sense) might be a better descriptor of the clinical and personality domain sampled.

Giant coronary aneurysm in adult Kawasaki disease: angiographic, 64-slice coronary MDCT and cardiac MRI appearances.

BACKGROUND: Kawasaki disease is a small-to-medium-vessel vasculitis that preferentially affects infants and young children. This condition is rare in adults, and therefore the diagnosis can easily be missed in a patient presenting to a primary care clinic. We report an unusual case of a patient who presented with ventricular fibrillation on a background of adult Kawasaki disease. OBJECTIVES: To identify the advantages of using coronary multidetector computed tomography (MDCT) and cardiac magnetic resonance imaging (MRI) in diagnosing adult Kawasaki disease. METHODS: We studied a 52-year-old patient with Kawasaki disease using coronary angiography, cardiac MDCT and MRI. RESULTS: Invasive coronary angiography demonstrated an occluded right coronary artery (RCA) and appearances suspicious for a calcified giant RCA aneurysm. The full extent of the aneurismal RCA was depicted with MDCT. Cardiac MRI revealed a chronic inferior segment myocardial infarction representing an arrhythmia substrate. DISCUSSION: Our case highlights the increasing utility of contrast-enhanced cardiac MRI and MDCT in the diagnosis of this rare condition in adults.

Role of respiratory sleep disorders in the pathogenesis of nocturnal angina and arrhythmias.

This report documents how respiratory sleep disorders can adversely effect ischaemic heart disease. Three male patients (aged 60-67 years) with proven ischaemic heart disease are described. They illustrate a spectrum of nocturnal cardiac dysfunction, two with nocturnal angina and one with nocturnal arrhythmias. Full sleep studies were performed in a dedicated sleep laboratory on all patients, and one patient had 48 hours of continuous Holter monitoring. Two patients were found to have obstructive sleep apnoea with apnoea/hypopnoea indices of 57 and 36 per hour, respectively, the former with nocturnal arrhythmias and the latter with nocturnal angina. In both cases, nasal continuous positive airways pressure successfully treated the sleep apnoea, with an associated improvement in nocturnal arrhythmias and angina. The third patient who presented with nocturnal angina, did not demonstrate obstructive sleep apnoea (apnoea/hypopnoea index = 7.2) but had significant oxygen desaturation during rapid eye movement (REM) sleep. This patient responded to a combination of nocturnal oxygen and protriptyline, an agent known to suppress REM sleep, and had no further nocturnal angina. All patients were considered to be an optimum cardiac medication and successful symptom resolution only occurred with the addition of specific therapy aimed at their sleep-related respiratory problem. We conclude that all patients with nocturnal angina or arrhythmias should have respiratory sleep abnormalities considered in their assessment.

Haemodynamic effects of nasal continuous positive airway pressure in severe congestive heart failure.

Nasal continuous positive airway pressure (NCPAP) during sleep may be a useful adjunct to medical therapy in patients with stable severe congestive heart failure (CHF), particularly when there is a coexisting respiratory sleep disorder. However, the direct haemodynamic effects of NCPAP in patients with severe stable CHF have not yet been adequately assessed. Right heart catheter studies were performed in seven awake males (aged 51-75 yrs) with stable CHF, before, during and after the application of 5 cmH2O NCPAP over 3 h. All patients had left ventricular ejection fractions < or = 30% and baseline pulmonary capillary wedge pressures > 12 mmHg, and six patients were in atrial fibrillation. Cardiac index fell from baseline in all patients whilst on NCPAP, with the greatest fall at 2 h (from 3.3 +/- 0.3 (mean +/- SEM) at baseline to 2.8 +/- 0.2 l.min-1.m-2) and rose back to baseline after NCPAP withdrawal. Systemic vascular resistance (SVR) increased during NCPAP application (1,268 +/- 108 to 1,560 +/- 82 dyn.s-1.cm5), with baseline SVR showing a significant negative correlation vs percentage fall in cardiac index (CI) at 2 h on multiple linear regression analysis (r2 = 0.8). These data indicate that domiciliary nocturnal NCPAP should not be prescribed as part of the therapy in severe CHF without first determining the individual patient's cardiac response to such therapy.

Global alterations in mechanical function in healed reperfused first anterior myocardial infarction.

Two-dimensional analysis techniques were applied to breathhold magnetic resonance (MR) tagged images in humans to better understand left ventricular (LV) mechanics 8 weeks after large reperfused first anterior myocardial infarction (MI). Eighteen patients (aged 51 +/- 13 yr, 15 men) were studied 8 +/- 1 weeks after first anterior MI as were 9 volunteers, (aged 30 +/- 3, 7 men). Breathhold MR myocardial tagging was performed with short-axis images spanning the LV from apex to base. Myocardial deformation was analyzed from apical, mid-LV, and basal slices using two-dimensional analytic techniques and expressed as L1 (greatest systolic lengthening), L2 (greatest systolic shortening), and beta (angular deviation of L1 from the radial direction). LV ejection fraction (EF) by MR imaging in the patients after MI was 45 +/- 15%. The apex and midventricle in patients demonstrated reduced L1 and L2 and increased beta compared with normal subjects with the greatest abnormalities at the apex, as expected in anterior infarction. However, in addition, basal L1 was lower than normal subjects (10 +/- 6% versus 19 +/- 7%, p < 0.0001) as was L2 (14 +/- 7% versus 17 +/- 6%, p < 0.04). Beta was greater than normal at the base (23 +/- 20 degrees and 14 +/- 10 degrees, p < 0.02). L2 correlated significantly with EF in the patient group (EF = 2.6 x L2 + 7, r = 0.68, p < 0.002). After healing of reperfused first anterior MI, maximal lengthening and maximal shortening and the orientation of maximal strains are abnormal throughout the left ventricle, including mild abnormalities at the base. This suggests more diffuse abnormalities in regional mechanical function than simply within the zone of healed infarction.

Regional myocardial strain before and after mitral valve repair for severe mitral regurgitation.

Magnetic resonance tagging (MRI) can be used to study intramyocardial trains in human in vivo. We wished to determine whether patients with severe mitral regurgitation demonstrate subtle myocardial contractile dysfunction despite normal left ventricular (LV) ejection fraction (EF) and how, mitral valve repair (MVR) may preserve EF in such patients. MRI was performed on seven patients with severe mitral regurgitation (mean age +/- SD, 65+/-13 years) and normal EF day 1 (range, 0-8 days) before (Pre) and week 8+/-3 after (Post) MVR and on nine normal volunteers (mean age, 32+/-4). LV mass index (LVMI), end-diastolic and end systolic volume, mass/volume ratio, EF, and sphericity index were measured Pre and Post. Two-dimensional strain analysis of MR tagged images was performed and expressed as L1 (greatest systolic lengthening, radial in normal subjects), L2 (greatest systolic shortening, circumferential in normals), and beta (angular deviation of L1 from the radial direction). LVMI fell from 142+/-38 g/m2 Pre to 117+/-44 g/m2 Post (p < or = 0.008) as did LV end-diastolic volume (117+/-26 to 69+/-12 ml, p < or = 0.003), whereas EF remained unchanged (59+/-7% at both time points). LV mass/volume ratio increasedfrom 2.2+/-0.3 g/ml Pre to 3.1+/-0.4 g/ml Post (p < or = 0.02) and sphericity index fell from 0.86+/-0.10 to 0.71+/-0.13 (p = 0.02). In the short axis, L1 was greater in patients with mitral regurgitation than normal subjects (19+/-9% vs 16+/-6%, p < or = 0.003) and tended to increase further after MVR (21+/-8%, p < or = 0.06 vs. Pre). Beta was abnormal in mitral regurgitation (19+/-8 vs. 12+/-8 degrees in control subjects, p < 0.0001) and remained abnormal after MVR (19+/-9 degrees). L2 in the short axis was depressed in mitral regurgitation compared with control subjects (12+/-6% vs. 21+/-6%, p < or = 0.001) and was further depressed after MVR (9+/-7%, p < 0.001 vs. Pre). As detected by MRI, regional myocardial strains are abnormal in severe mitral regurgitation despite normal EF, characterized by increased short-axis systolic lengthening that is abnormally directed and by reduced shortening. After MVR, the further increase in short-axis lengthening may preserve EF despite its abnormal direction and a fall in shortening. The increase in short-axis lengthening may be due in part to the reduction in LV sphericity after MVR.