T Ohta

Shimane University, Matsue-shi, Shimane-ken, Japan

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Publications (7)25.67 Total impact

  • Article: Drop in plasma brain natriuretic peptide levels after successful direct current cardioversion in chronic atrial fibrillation.
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    ABSTRACT: According to previous reports, plasma atrial natriuretic peptide levels increase in atrial fibrillation (AF) and decrease after successful direct current (DC) cardioversion, but there have been no reports on plasma brain natriuretic peptide (BNP). To determine whether plasma BNP levels decrease after successful direct DC cardioversion in patients with chronic AF. Twenty patients who remained in sinus rhythm for at least seven days after cardioversion, and 20 normal control subjects, were studied. Group A consisted of 10 patients with underlying heart disease, including dilated cardiomyopathy (n=2), hypertrophic cardiomyopathy (n=1), mitral valve disease (n=3), hypertensive heart disease (n=3) and status after atrial septal closure (n=1). Group B consisted of 10 patients with just AF. Group C (serving as controls) comprised 20 subjects with normal sinus rhythm and no risk factors. Before cardioversion, plasma BNP levels were higher in group A (176.7+/-128.1 ng/mL) and in group B (96.8+/-51.7 ng/ml) than in group C (6.3+/-3.8 ng/ml) (P<0.01 for all). After successful cardioversion, mean plasma BNP levels in groups A and B decreased from 136.8+/-105.5 ng/mL to 46.4+/-44.2 ng/mL (P<0.01). In group A, plasma BNP levels decreased from 176.7+/-128.1 ng/mL to 62.5+/-54.6 ng/mL (P<0.01), and in group B, plasma BNP levels decreased from 96.8+/-51.7 ng/mL to 30.3+/-23.8 ng/mL (P<0.01). Lone AF raises plasma BNP levels, which is more marked if there is underlying structural heart disease present, and cardioversion reduces plasma BNP levels. Therefore, high plasma BNP levels in patients with chronic AF are likely to be caused by AF and reflect cardiac overloading associated with, although contributed to in part by, underlying heart diseases.
    The Canadian journal of cardiology 05/2001; 17(4):415-20. · 3.36 Impact Factor
  • Article: Effects of supine and lateral recumbent positions on pulmonary venous flow in healthy subjects evaluated by transesophageal Doppler echocardiography.
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    ABSTRACT: This study attempted to evaluate the effects of supine and lateral recumbent positions on pulmonary venous flow by transesophageal Doppler echocardiography in healthy subjects. Although transesophageal echocardiographic examination is usually performed with the patient lying in the left lateral decubitus or supine position, little attention has been paid to the effects of these positions on pulmonary venous flow. We performed pulsed Doppler transesophageal echocardiography of the left and right pulmonary veins in 16 normal subjects as they lay in the left and right lateral decubitus and supine positions. Data are reported as mean value +/- SD. Adequate recordings were obtained in 12 subjects (75%). In the left pulmonary vein, peak systolic velocity and time-velocity integral of systolic flow increased significantly in the left compared with the right lateral decubitus position (56 +/- 12 vs. 44 +/- 13 cm/s, p < 0.05, and 15 +/- 4 vs. 9 +/- 4 cm, p < 0.05, respectively). In the right pulmonary vein, peak systolic velocity and time-velocity integral of systolic flow decreased significantly in the left compared with the right lateral decubitus position (38 +/- 10 vs. 48 +/- 9 cm/s, p < 0.05, and 9 +/- 2 vs. 12 +/- 2 cm, p < 0.05, respectively). There were no significant differences between positions in peak diastolic flow velocity, time-velocity integral of diastolic flow or peak velocity of flow reversal at atrial contraction. Pulmonary venous systolic peak velocities and time-velocity integrals of systolic flow increase when the pulmonary venous recording is from the recumbent subject's lower side. Therefore, the effects of position should be considered in evaluating left ventricular diastolic function by transesophageal Doppler echocardiography.
    Journal of the American College of Cardiology 11/1994; 24(6):1552-7. · 14.16 Impact Factor
  • Article: Phasic venous return abnormality in chronic pulmonary diseases: pulsed Doppler echocardiography study.
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    ABSTRACT: Features of venous return in chronic pulmonary diseases and factors determining such features were studied by analysis of respiration-related variation in the superior vena cava flow on pulsed Doppler echocardiography. Subjects of this study were 85 patients with chronic pulmonary diseases; 54 healthy subjects served as normal controls. In the healthy subjects, the velocity of the S and D waves increased during inspiration (type I pattern), and the velocity of the A wave increased during expiration. In the patients with pulmonary diseases, the pattern of the superior vena cava flow was either type I or type II (disappearance of the D wave or disappearance of both the D and S waves). The incidence of the type II pattern was significantly higher in the patients showing a reduction of both FEV1.0% and % VC. The respiration-related variation in the superior vena cava flow pattern was found to be determined by the pressure fall between right atrium and subclavian vein. A type II pattern was attributed to the elevation of right atrial pressure caused by positive pleural pressure. The velocity of the A wave increased during expiration, showing a good correlation with pulmonary vascular resistance. Venous return in the presence of chronic pulmonary disease was found to be affected by the type of ventilatory disturbance and intensity of pulmonary vascular resistance.
    Internal Medicine 07/1994; 33(6):326-33. · 0.94 Impact Factor
  • Article: Effect of left and right lateral decubitus positions on mitral flow pattern by Doppler echocardiography in congestive heart failure.
    The American Journal of Cardiology 04/1993; 71(8):751-3. · 3.37 Impact Factor
  • Article: [Venous return disturbances in chronic pulmonary disease: a study using pulsed Doppler echocardiography].
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    ABSTRACT: Pulsed Doppler echocardiography was used for investigation of respiratory changes of superior vena caval flow in chronic pulmonary disease to analyze the mode of venous return and its regulating factors. The subjects consisted of 55 patients with various pulmonary diseases and 44 healthy controls. 1. In the controls, the velocities of the S and D waves increased during the inspiratory phase. 2. Patients with pulmonary diseases were categorized into 2 groups. One with the mode of the healthy subjects (normal pattern), and the other with disappearance of the D wave or both the S and D waves (abnormal pattern) in the expiratory phase. All patients with restricted ventilation exhibited the normal patterns, while the abnormal patterns were observed in some of the patients with obstructive ventilation, and most of the patients with combined ventilation. 3. The respiratory patterns of the pressure gradients between the right atrium and subclavian vein reflected patterns of the superior vena caval flow well. In cases with abnormal patterns, the right atrial pressure exceeded the subclavian vein pressure in the expiratory phase. 4. The velocity of the A wave at the expiratory phase correlated significantly with pulmonary vascular resistance and with the mean pulmonary artery pressure. In conclusion, the mode of venous return in patients with pulmonary disease varies depending on the mode of the ventilation disturbance and the presence of right ventricular pressure overload, which is most likely caused by the intrathoracic pressure and by right ventricular filling abnormalities.
    Journal of Cardiology 02/1991; 21(4):1009-15. · 1.28 Impact Factor
  • Article: [Factors regulating venous return: analysis based on the respiratory variations of superior vena caval flow].
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    ABSTRACT: Characteristics of venous return and its determining factors were observed using pulsed Doppler echocardiography. Superior vena caval (SVC) flow was regarded as representing venous return. Ten healthy subjects and 23 patients with chronic pulmonary disease were studied. 1. In the healthy subjects, the forward flow was biphasic with dominant systolic (S) wave. Among 23 patients, 18 had normal SVC flow patterns (Group I), while in the remaining 5, SVC flow showed disappearance of the diastolic (D) wave, or both the D and S waves (Group II). 2. The healthy subjects and Group I patients had negative pleural pressures during inspiration and expiration. Consistent findings in Group II patients included positive pleural pressures during expiration and reduction in FEV1.0%. In the normal subjects and Group I patients, right atrial (RA) pressure was less than the pressure of the subclavian vein (ScV) during an entire respiratory phase. However, in Group II, RA pressure was equal to or greater than ScV pressure during expiration, resulting in disappearance or reversal of the S and D waves. 3. Respiratory variation in pleural pressure correlated significantly with that of the S wave (r = 0.77) (p < 0.005), D wave (r = 0.80) (p < 0.005), x descent of RA pressure (r = 0.77) (p < 0.005), and y descent of RA pressure (r = 0.82) (p < 0.005). The present study clearly confirmed that the superior vena caval flow patterns were closely correlated with right heart hemodynamics and truly reflected the effects of pleural pressure.
    Journal of Cardiology 01/1991; 21(4):1001-8. · 1.28 Impact Factor
  • Article: [Contrast echocardiographic detection of pulmonary arteriovenous shunt in a hypoxemic patient with liver cirrhosis].
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    ABSTRACT: A 62-year-old man with liver cirrhosis and hypoxemia was admitted to evaluate the etiology of hypoxemia. The patient had noticed exertional dyspnea for three years. Physical examination, laboratory tests, ultrasonography and liver scintigraphy revealed liver cirrhosis. The arterial blood gas test showed hypoxemia (PO2 46.3 mmHg). Chest roentgenogram showed old pulmonary tuberculosis and the pulmonary function test demonstrated decreased FEV 1.0% and %DLco, which did not account for the marked hypoxemia. Contrast echocardiography was performed by injecting hand-agitated saline into the antecubital vein. Three seconds after the right ventricle was opacified, the contrast echoes appeared in the left atrium and then the left ventricle. Pulmonary arteriography revealed no pulmonary arteriovenous fistula. Hemodynamic data showed low pulmonary vascular resistance. Contrast echocardiography by injecting hand-agitated saline from the catheter tip was performed at both pulmonary arteries and the left atrium was opacified by each injection. The hypoxemia was mainly attributed to a intrapulmonary arteriovenous shunt. Although the etiology of hypoxemia in liver cirrhosis seems to be multifactorial, the intrapulmonary arteriovenous shunt is the most important factor. Contrast echocardiography was useful for detecting this shunt.
    Journal of Cardiology 24(2):155-60. · 1.28 Impact Factor