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Biomedical subjects

N Ohte

Publications and source records attributed to N Ohte.

11 recordsLinked to original sources
PubMed1992

Noninvasive evaluation of left ventricular performance by the shortest distance between mitral leaflets coaptation and interventricular septum at end-systole.

We attempted to evaluate left ventricular performance from the shortest distance between the mitral leaflets coaptation and the interventricular septum at end-systole (MVC-IVS distance). The subjects were 37 patients with coronary artery disease (CAD) with prior myocardial infarction (MI), 8 with CAD without prior MI, 22 with atypical chest pain, and 4 with aortic regurgitation. The MVC-IVS distance was measured on a two-dimensional echocardiogram obtained from the parasternal or apical long-axis view and frozen at end-systole. Left ventricular end-systolic volume and end-diastolic volume were obtained by left ventriculography, and the left ventricular ejection fraction was calculated. A significant positive correlation was observed between the MVC-IVS distance and the end-systolic volume (r = 0.83, p less than 0.001); a close correlation was observed between the MVC-IVS distance end-systolic volume and ejection fraction by monoexponential fitting (r = -0.91, p less than 0.001). Thus, a significant negative correlation was observed between the MVC-IVS distance and the left ventricular ejection fraction (LVEF) (r = -0.83, p less than 0.001). An MVC-IVS distance of greater than or equal to 30 mm suggests diagnosis of left ventricular dysfunction (LVEF less than 50%) with high sensitivity (94.4%) and specificity (90.6%), while a value less than 30 mm suggests that the left ventricular performance is likely to be normal. Thus one can easily evaluate the left ventricular performance noninvasively using this new index.

Adult↗
PubMed1992

Evaluation of a new systolic time interval, the Q-V peak: effects of heart rate, contractile state, and loading conditions in dogs.

The authors investigated the effects of alterations in heart rate, contractility, and loading conditions on a newly defined systolic time interval, the Q-V peak, in 46 anesthetized dogs. The Q-V peak was measured as the time from the beginning of the electrocardiographic Q wave to the moment at which the blood flow rate reached its peak in the ascending aorta as determined with an electromagnetic flowmeter. The Q-V peak did not change significantly as the heart rate was varied by atrial pacing between 70 and 110 beats/minute. The Q-V peak shortened when the contractility was augmented with dobutamine (p = 0.0001) and was prolonged when it was depressed with propranolol (p = 0.0001). However, the Q-V peak did not change significantly when the left ventricular end-diastolic pressure or the mean aortic blood pressure was increased to 130% or decreased to 70% of the baseline values. These findings suggest that one may also evaluate left ventricular performance by measuring the time to systole, which the authors define as the Q-V peak.

Animals↗
PubMed1992

[Differentiation between "pseudonormal" from normal transmitral flow velocity waveforms by evaluating isovolumic relaxation time].

We tried to differentiate "pseudonormal" from normal transmitral flow velocity waveforms by evaluating isovolumic relaxation times (IRT) in patients with old myocardial infarction. Forty-three healthy volunteers and 54 patients with old myocardial infarction were studied. Transmitral flow velocity waveforms were obtained by pulsed Doppler echocardiography with a phonocardiogram. Early peak filling velocity (E) and late peak filling velocity (A) were measured, and the E/A ratio was calculated. The time from the beginning of the IIA sound to the onset of transmitral flow was defined as IRT. We observed a significantly positive correlation between IRT and age in the healthy volunteers (r = 0.56, p < 0.01). Based on these results, we selected age-matched healthy subjects (control group, n = 23) older than 35 years from the healthy volunteers. We divided the patients into 2 groups; those with a mean pulmonary capillary wedge pressure (mPCWP) of > or = 16 mmHg (H group, n = 9) and those with an mPCWP of < 16 mmHg (L group, n = 45). E, E/A, IRT, mean blood pressure (mBP), and heart rate were compared among the H, L, and control groups. There was no significant difference in mBP or heart rate between these 3 groups. Both E and E/A were significantly lower in the L group than in the control group (p < 0.05), however, no significant difference was observed in E and E/A between the H and control groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Severity of coronary atherosclerosis correlates with the respiratory component of heart rate variability.

Decreased vagal activity is frequently observed in coronary artery disease, but the mechanism of this association is unknown. We investigated cardiac autonomic function by relating heart rate spectral components to clinical and angiographic findings in 80 patients who were undergoing coronary angiography. The age- and sex-adjusted magnitude of the respiratory spectral component, which is an index of cardiac vagal tone, showed a significant negative correlation with the extent of coronary atheromatosis (r = -0.43, p less than 0.0001) and a less significant negative correlation with the severity of coronary stenosis (r = -0.30, p = 0.0070). These relationships were independent of previous myocardial infarction and of left ventricular function. Stepwise regression analysis showed that the respiratory spectral component contributed to atheromatosis independently of established coronary risk factors (partial R2 = 9.4%, p = 0.002), but not to stenosis. Our results support the hypothesis that decreased cardiac vagal activity is associated with an increased risk of coronary atherosclerosis.

Adult↗
PubMed1991

Continuous-wave Doppler echocardiography for evaluating left ventricular performance--clinical significance of a new systolic time interval.

Left ventricular performance was evaluated in 51 patients with acute myocardial infarction and angina pectoris using parameters derived from the flow velocity waveform at the ascending aorta. Flow velocity waveforms were obtained from the suprasternal notch by continuous-wave Doppler echocardiography and were recorded on a line-scan recorder at a paper speed of 100 mm/sec with lead II ECG. The peak flow velocity and the systolic time interval from the beginning of ECG Q wave to the peak flow velocity (Q-V peak interval) were measured. Relationships were investigated between these parameters and the left ventricular ejection fraction (LVEF) obtained from multigated equilibrium blood pool imaging with 99mTc-pertechnetate. The peak flow velocity did not correlate with LVEF (r = 0.27). However, a highly significant negative correlation was observed between the systolic time interval Q-V peak and LVEF (r = -0.84, p less than 0.001). The regression equation was LVEF = -0.46 X (Q-V peak) + 142. We conclude that left ventricular performance can be evaluated in patients with coronary artery disease at the bedside using the Q-V peak interval measured from simultaneous recording of the velocity waveform at the ascending aorta and the ECG.

Adult↗
PubMed1991

[Determinants of mitral inflow velocity profiles in relation to left ventricular volume change: evaluations by pulsed Doppler echocardiography and left ventriculography].

We evaluated relationships between pulsed Doppler echocardiographic (PDE) parameters of flow velocity profiles across the mitral orifice and left ventriculographic (LVG) parameters of left ventricular volume changes. Subjects consisted of 19 patients with coronary artery disease and 12 patients with chest pain syndrome. Peak flow velocities at the rapid filling (E) and atrial contraction (A) were measured by PDE. Time constant of left ventricular relaxation (T), left ventricular minimum pressure (LVPmin), LV end-diastolic pressure (LVEDP) and pulmonary capillary wedge V wave pressure (PCW-V) were measured during cardiac catheterization. From the analysis of LVG, the rapid filling fraction (RFF), and the atrial filling fraction (AFF) were obtained. The left ventricular chamber stiffness (K) was identified by the analysis of the pressure-volume relationship of the left ventricle. We investigated the relationship between A/E and AFF/RFF by univariate linear regression analysis. We then performed stepwise multivariate linear regression analysis to predict E, A, A/E, RFF, AFF and AFF/RFF by the variables of left ventricular filling, i.e., T, LVPmin, LVEDP, PCW-V, K, heart rate (at the examination of PDE or LVG), mean arterial blood pressure (at PDE or LVG) and age. The A/E correlated significantly with AFF/RFF (r = 0.50, p < 0.01). The results of the multivariate linear regression analyses were as follows: [sequence: see text] The correlation of A/E and AFF/RFF were explained by some variables, except the variable T. The results of uni- and multivariate linear regression analyses showed that factors affecting the flow velocity profile across the mitral orifice did not account for the left ventricular volume changes. We also observed that, even in subjects with coronary heart disease, aging is a main factor that influences peak flow velocity at atrial contraction (A).

Adult↗
PubMed1990

Decreased magnitude of heart rate spectral components in coronary artery disease. Its relation to angiographic severity.

We analyzed the spectral components of RR interval variability under controlled respiration (15 breaths/min) in 56 patients (age range, 35-73 years) referred for coronary angiography; 14 patients had multivessel disease (group M), 21 had one-vessel disease (group S), and 21 had nonsignificant disease or normal coronary artery (group N). There were 43 healthy controls (age range, 36-71 years) (group C). The patients had no clinical evidence of heart failure, hypertension, diabetes mellitus, or acute stage of infarction and had taken no medication for 3 days. The autoregressive power spectral density of RR interval variability contains two major components, respiratory sinus arrhythmia (RSA) (0.25 Hz) and Mayer wave-like sinus arrhythmia (MWSA) (0.04-0.15 Hz), which have magnitudes that are quantitative markers of cardiac vagal activity and sympathetic activity with vagal modulation, respectively. We represented the magnitudes by the coefficient of component variance (CCV), which provided the amplitude relative to the mean RR interval. The age- and sex-adjusted mean of CCVRSA significantly decreased with advancing angiographic severity (1.64 +/- 0.09%, 1.66 +/- 0.12%, 1.22 +/- 0.13%, and 0.81 +/- 0.16% for groups C, N, S, and M, respectively) (p = 0.0001). The CCVRSA was unrelated to left ventricular function, previous myocardial infarction, or stenosis of any specific artery including the sinoatrial and atrioventricular node arteries. The CCVMWSA decreased only in group M (p = 0.0462). These results indicate that coronary artery disease is associated with vagal dominant impairment in autonomic cardiac function and that reduction in the vagal cardiac function correlates with the angiographic severity.

Adult↗
PubMed1990

[Noninvasive evaluation of left ventricular function using new systolic time intervals obtained from continuous-wave Doppler echocardiography].

Left ventricular function was evaluated using parameters derived from the flow velocity waveforms at the ascending aorta as obtained at the suprasternal notch by continuous-wave Doppler echocardiography in 39 patients; 12 with chest pain but without coronary stenosis, eight with angina pectoris; and 19 with myocardial infarction. Peak flow velocity and the time interval from the beginning of the Q wave of lead II of the ECG to peak flow velocity (Q-V peak) correlated with specific invasive hemodynamic parameters, such as max dp/dt and (max dp/dt)/IP (IP: total left ventricular pressure at the same instant) during isometric contraction of the left ventricle measured with a catheter tip manometer, and left ventricular ejection fraction (LVEF) obtained by bi-plane cineangiography (using the area-length method). There was no correlation between the peak flow velocity and the invasive hemodynamic parameters. However, significant negative correlations were observed between the Q-V peak time and max dp/dt, with r = 0.40 (p less than 0.05), and between the Q-V peak time and (max dp/dt)/IP with r = -0.61 (p less than 0.01). A negative correlation was obtained between the Q-V peak time and LVEF (r = -0.75, p less than 0.01). The regression equation was LVEF = -0.67 x (Q-V peak) + 176. To compare the effectiveness for predicting LVEF between the Q-V peak and the established systolic time intervals as PEP and PEP/ET, these time intervals were measured from flow velocity waveforms invasively obtained with a catheter-type electromagnetic flowmeter inserted into the ascending aorta in 14 patients selected from the original subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[A case of chronic recurrent pulmonary embolism treated by pulmonary embolectomy and Günther vena caval filter implantation].

A case report of chronic recurrent pulmonary embolism treated by embolectomy and Günther vena caval filter. A 62-year-old man had suffered from dyspnea on effort for 4 years, and his feeling of dyspnea had gradually increased during the past 3 months. On the day of admission he was in a preshock state, and his pulmonary artery pressure was very high at 90/30 mmHg. Pulmonary blood perfusion scintigraphy showed multiple defects of isotope uptake. Immediately after the scintigraphy, pulmonary embolectomy was performed while using extracorporeal circulation. The operation was successful and his physical activity was markedly improved. After the operation, anti-coagulant and anti-platelet therapies were continued, but recurrence of pulmonary emboli was detected by scintigraphy, and some thrombi were found by venography in deep veins of the lower parts of both legs. To prevent recurrent pulmonary embolism, a Günther vena caval filter was inserted into the inferior vena cava. We considered this case as an acute worsening of chronic recurrent pulmonary embolism and we had the impression that pulmonary embolectomy is a very effective therapeutic method for serious pulmonary embolism, and that insertion of the Günther vena caval filter is a very easy and safe procedure.

Chronic Disease↗
PubMedDate not supplied

Coronary risk factors in angiographically defined patients with chest pain.

Coronary risk factors were assessed in 186 consecutive patients who received coronary angiography. The severity of coronary luminal narrowing was scored as the coronary sclerosis index (CSI). Patients were divided into normal coronary arteries (N, n = 72), coronary sclerosis without infarction (C, n = 73) and previous myocardial infarction (MI, n = 41). The CSI increased with age. A significant difference in serum triglycerides, HDL cholesterol and atherogenic index was observed between Groups C or MI and N. Multivariate analysis revealed that CSI had correlated with total- and HDL-cholesterol, uric acid and age in subjects under 55 years; and with age, blood sugar, factor H and HDL cholesterol in those of 55 years or over. When patients were classified by their total and LDL cholesterol level, a significantly different CSI was found between the desirable and high cholesterol levels in subjects under the age of 55, but it was not significant in those over 55. Therefore, disorders in lipid metabolism should be corrected in early middle age.

Adult↗