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Biomedical subjects

K Manabe

Publications and source records attributed to K Manabe.

At least 55 records · Page 3Linked to original sources
PubMed1997

Concealed left ventricular hypertrophy and diastolic dysfunction in hypertrophic cardiomyopathy in the presence of acute left ventricular volume overload. A case report.

We report a patient in whom hypertrophic cardiomyopathy, with both left ventricular hypertrophy and diastolic dysfunction, was masked by acute severe aortic regurgitation and marked left ventricular dilation. Upon admission, 1) two-dimensional echocardiogram of the left ventricle revealed a dynamic and flail vegetation on the aortic right coronary cusp and marked left ventricular dilation, 2) a massive aortic regurgitant signal was recorded by color Doppler flow imaging, and 3) transmitral flow velocity by pulsed Doppler echocardiogram revealed a pseudonormalization. However, symmetric hypertrophy of the left ventricular wall, a decrease in early diastolic wave and a compensatory increase in atrial systolic wave of the transmitral flow velocity appeared after successful aortic valve replacement.

Aortic Valve↗
PubMed1997

Transesophageal echocardiographic prediction of initially successful electrical cardioversion of isolated atrial fibrillation. Effects of left atrial appendage function.

Left atrial appendage (LAA) flow velocities prior to electrical cardioversion were recorded using transesophageal pulsed Doppler echocardiography to predict initially successful cardioversion of isolated atrial fibrillation (AF). Patients with AF were placed into either a success group (19 patients) in which sinus rhythm was maintained for at least 2 days or a failure group (12 patients). The duration of AF was shorter in the success group. The maximum left atrial diameter was the same for the two groups. The maximum LAA area was smaller in the success group. The maximum forward and backward LAA velocities were greater in the success group, as were the mean forward and backward LAA velocities. In the patients with mean LAA flow velocities greater than 19 cm/sec, the success of cardioversion could be predicted with high sensitivity (80%) and specificity (88%). We conclude that the duration of AF, the maximum LAA area, and LAA flow velocities prior to cardioversion predict the initial recovery of sinus rhythm for isolated AF.

Adult↗
PubMed1997

The 'sail sound' and tricuspid regurgitation in Ebstein's anomaly: the value of echocardiography in evaluating their mechanisms.

We describe a patient with Ebstein's anomaly in whom Doppler echocardiography was used to clarify the mechanism responsible for 'sail sound' and tricuspid regurgitation associated with this condition. Phonocardiography revealed an additional early systolic heart sound, consisting of a first low-amplitude component (T1) and a second high-amplitude component (T2, 'sail sound'). In simultaneous recordings of the tricuspid valve motion using M mode echocardiography and phonocardiography, the closing of the tricuspid valve occurred with T1 which originated at the tip of the tricuspid leaflets, while T2 originated from the body of the tricuspid leaflets. Using color Doppler imaging, the tricuspid regurgitant signal was detected during pansystole, indicating a blue signal during the phase corresponding to T1 and a mosaic signal during the phase corresponding to T2 at end-systole. Thus, 'sail sound' in patients with Ebstein's anomaly is not simply a closing sound of the tricuspid valve, but a complex closing sound which includes a sudden stopping sound after the anterior and/or other tricuspid leaflets balloon out at systole.

Diagnosis, Differential↗
PubMed1997

[Response rates and non-response bias in a health-related mailed survey].

A health-related mailed survey was conducted to investigate the effect of follow-up mailings to response rates. In addition, the answer distributions among early and late respondents were compared to check non-response bias. Approximately 3,000 persons aged 40-64 were randomized into two groups; a questionnaire with four pages (twenty-two questions) was assigned to the first group, and a questionnaire with eight pages (thirty-five questions) to the second group. Both questionnaires contained questions of current health status, health-related practice, smoking status, etc. Follow-up mailings were sent twice to non-respondents. Response rates were increased from 38% to 62% by the first follow-up mail, and to 71% by the second follow-up mail. Although the length of the questionnaire did not affect response rates, response rates among the older subjects was higher than the younger subjects. Positive response to current smoking status was 10% lower among early respondents than late respondents, collected after the second follow-up mailing, and response to regular participation in physical/medical checkup was 15% higher among early respondents, whereas there were few differences for answers to other questions. Odds ratios between current health status and several health-related questions may not be biased by late response. However, increased response rates are needed to prevent non-response bias, because there were some differences in responses from follow-up mailings.

Adult↗
PubMed1996

Changes in left ventricular inflow and pulmonary venous flow velocities during preload alteration in dilated heart.

The aim of the present study was to assess the changes of left ventricular inflow (LVIF) and pulmonary venous flow (PVF) velocities during preload alteration in 30 patients with dilated heart (LV end-diastolic dimension > or = 6.0 cm) and impaired LV systolic function (% fractional shortening of the LV < or = 25%). We performed transesophageal pulsed Doppler echocardiography during lower body negative (LBNP, -40 mmHg) and positive pressure (LBPP, +40 mmHg) in 10 patients with dilated cardiomyopathy, in 20 with old myocardial infarction, and in 22 healthy controls. Eight of the patients showed a pseudonormalization (compliance failure) pattern, and 22 showed a decreased early diastolic wave and compensatorily increased atrial systolic wave (relaxation failure) pattern of LVIF in the control state. Mean pulmonary capillary wedge pressure (PCWP) was greater in the compliance failure group than in the relaxation failure group in the control state. LVIF in 6 of the 22 patients with the relaxation failure pattern changed to the compliance failure pattern during LBPP, and that in 3 of 8 patients in the compliance failure group changed to the relaxation failure pattern during LBNP. The 6 patients with a change from the relaxation failure to the compliance failure pattern showed significantly higher peak diastolic and atrial systolic PVFs during LBPP than in the control state, and significantly higher PCWPs in the control state than the 16 patients with no change in LVIF. These findings suggest that the compliance failure and relaxation failure patterns of LVIF are readily interchangeable in various hemodynamic conditions, and that pattern analysis of LVIF and PVF during preload alteration is useful for understanding the hemodynamic severity and for evaluating preload reduction therapy in the dilated heart.

Blood Flow Velocity↗
PubMed1996

Clinical significance of the apical late systolic ejection murmur: a new phonocardiographic sign indicating dynamic mid-left ventricular obstruction.

Systolic ejection murmurs of the left heart usually have their peak during early to mid-systole. Few reports have addressed ejection murmurs with their peak at late systole. We evaluated the clinical significance of an apical systolic ejection murmur with a peak intensity during late systole using Doppler and two-dimensional (2-D) echocardiography and phonocardiography. The apical late systolic ejection murmur was observed in 9 of 13 consecutive patients with mid-left ventricular obstruction. We investigated the ejection flow velocity and the timing of maximum velocity at the three different sites of the left ventricle, the left ventricular cavity shape, and the timing of the peak murmur intensity in these nine patients (late-murmur group). The same parameters were also examined in 8 consecutive patients with mid-systolic ejection murmurs (mid-murmur group), 10 with early systolic ejection murmurs (early-murmur group), and 7 controls without murmurs. Patients with aortic stenosis were excluded. The mid-ventricular ejection flow velocity was significantly higher in the late-murmur group than in the other three groups; that of the outflow tract was markedly higher in the mid-murmur group. The ejection flow velocity at the aortic orifice of patients in the early-murmur group was significantly high compared with that of the controls. The timing of the peak murmur intensity in each group correlated with that of the peak flow signal at the corresponding site with maximum velocity. In all patients in the late-murmur group, 2-D echocardiography revealed a systolic narrowing of the cavity at the mid-ventricle. Amyl nitrite inhalation induced a marked increase in the intensity of the murmur without evidence of appearing or increasing mitral regurgitation. It was concluded that the apical ejection murmur with a late systolic peak intensity is a new phonocardiographic sign indicative of dynamic, mid-left ventricular obstruction. This murmur should be differentiated from the mitral regurgitant murmur.

Adult↗
PubMed1996

Possible mechanisms of mitral regurgitation in dilated hearts: a study using transesophageal echocardiography.

HYPOTHESIS: This study was undertaken to clarify the mechanisms of mitral regurgitation (MR) in dilated hearts. METHODS: In all, 68 patients with dilated heart and MR, including 26 patients with dilated cardiomyopathy (DCM), 24 with prior anterior myocardial infarction (A-MI), and 18 with prior posteroinferior myocardial infarction (I-MI), as well as 25 normal subjects were examined by transesophageal two-dimensional and color Doppler echocardiography. RESULTS: The maximum area of the MR signal in the DCM group correlated positively with the anteroposterior diameter of the mitral annulus at late systole. Although the coaptation edge length of the anterior and posterior mitral leaflets appeared shorter in dilated hearts than in the hearts of controls, a significant difference did not exist. The length of the coaptation edge correlated negatively with the maximum area of the MR signal in all dilated hearts, and characteristic systolic displacement of the coaptation point of both mitral leaflets occurred. The MI groups demonstrated anterior and posterior displacement in the direction of the short axis of the left ventricle in the A-MI and I-MI groups, respectively. However, the DCM group demonstrated inferior displacement toward the long axis of the left ventricle; its magnitude correlated positively with the maximum area of the MR signal. CONCLUSION: A major cause of MR in dilated hearts is mitral malcoaptation due to displacement of the coaptation point of the mitral leaflets along the long or short axis of the left ventricle. This is caused by left ventricular enlargement and/or asynergy of the left ventricular wall, rather than by a decrease in mitral coaptation edge length due to mitral annular dilation.

Adult↗
PubMed1996

Changes in transmitral and pulmonary venous flow velocity patterns after cardioversion of atrial fibrillation.

To examine the recovery time of left atrial mechanical function after electrical cardioversion of atrial fibrillation, we recorded transmitral flow, pulmonary venous flow velocities, and interatrial septal motion during atrial systole within 24 hours (16 +/- 5 hours) and 10 days after cardioversion in 25 patients with atrial fibrillation, including 6 patients with hypertension, 4 with ischemic heart disease, 2 with alcoholic heart disease, 5 with dilated cardiomyopathy, and 8 with no evidence of underlying heart disease. With the exception of the five patients with dilated cardiomyopathy, the peak atrial systolic transmitral and pulmonary venous flow velocities, peak first systolic velocity of pulmonary venous flow, duration of both atrial systolic waves, and amplitude of the interatrial septal motion during atrial systole decreased markedly within 24 hours after cardioversion and increased 10 days after cardioversion. These results suggest that active atrial systolic and relaxant variables obtained from transmitral and pulmonary venous flow velocities may reflect left atrial mechanical function after cardioversion of atrial fibrillation.

Atrial Fibrillation↗
PubMed1996

Evidence that the HLA DQA1*03 allele confers protection from chronic HCV-infection in Northern European Caucasoids.

In the search for factors which may influence susceptibility to and outcome from chronic hepatitis C virus (HCV) infection, few studies have considered the influence of host genes. In the present investigation we have performed HLA DRB1, DQA1, DQB1, and DPB1 genotyping on 104 northern European patients with chronic HCV infection and 177 racially and geographically matched controls. Three HLA class II alleles, DRB1*0403, DQA1*03, and DQB1*0302 were present at a significantly lower frequency in patients compared with controls (4.9% vs. 13%, 20.7% vs. 41.2%, and 11.4% vs. 30.5%, respectively) though only two DQB1*0302 and DQA1*03 were significant after correction for multiple testing (pc = 0.038, and pc = 0.046, respectively). No further HLA associations with chronic HCV infection were observed and there was no correlation between stage of disease and HLA genotype. These data provide the first suggestion that susceptibility to chronic HCV infection may be influenced by the hosts' HLA DQ alleles.

Alleles↗
PubMed1996

Relationship between the angiotensin converting enzyme gene polymorphism and the effects of enalapril on left ventricular hypertrophy and impaired diastolic filling in essential hypertension: M-mode and pulsed Doppler echocardiographic studies.

OBJECTIVE: To investigate the relationship between the angiotensin converting enzyme (ACE) gene polymorphism and the effects of the ACE inhibitor enalapril on left ventricular hypertrophy and impaired diastolic filling. DESIGN AND METHODS: Enalapril (5-10 mg/day) was administered for 12 months to 60 previously untreated patients with essential hypertension. M-mode and pulsed Doppler echocardiography were performed before and after treatment, and changes in various parameters after treatment with enalapril were examined. ACE gene polymorphism was examined by the polymerase chain reaction method and the patients were classified as having the 190 bp deletion homozygous (DD) genotype, the 490 bp insertion homozygous (II) genotype or the 490 bp insertion 190 bp deletion heterozygous (ID) genotype. RESULTS: The DD genotype was observed in 10 patients (17%), the ID genotype in 24 patients (40%) and the II genotype in 26 patients (43%). Plasma ACE activity before treatment with enalapril was significantly higher in seven patients with DD genotype than it was in 18 patients with ID genotype and in 14 patients with II genotype. In all of the 60 patients, the left ventricular mass index, the peak atrial systolic velocity:early diastolic velocity ratio and the deceleration time from the peak of the early diastolic wave to the baseline in transmitral flow velocity were decreased significantly after treatment with enalapril. The changes in left ventricular mass index and atrial systolic velocity:early diastolic velocity ratio after enalapril administration were significantly greater in the DD genotype group than they were in the other two genotype groups. CONCLUSION: Enalapril-induced regression of left ventricular hypertrophy and improvement in left ventricular impaired diastolic filling were significantly greater in the DD genotype group than they were in the ID and II genotype groups, suggesting that the circulating and tissue renin-angiotensin systems, particularly the former system, are most active in hypertensive patients with the DD genotype.

Adult↗
PubMed1996

Assessment of left atrial pressure and volume changes during atrial systole with transesophageal pulsed Doppler echocardiography of transmitral and pulmonary venous flow velocities.

To determine whether transmitral and pulmonary venous flow velocity patterns can be used to evaluate left atrial pressure and volume changes during atrial systole, we performed transesophageal pulsed Doppler echocardiography and right heart catheterization in 85 patients (20 with hypertrophic cardiomyopathy, 20 with dilated cardiomyopathy, 30 with prior myocardial infarction, and 15 with mitral regurgitation), and 35 normal subjects. Pulsed Doppler variables from transmitral and pulmonary venous flow velocities during atrial systole were compared with mean pulmonary capillary wedge pressure (mean PCWP), pressure rise during atrial systole (PCWP-A), and left atrial volume change during atrial systole (delta LAV). The mean PCWP correlated significantly with the peak atrial systolic transmitral flow (r = -0.38, p < 0.05) and pulmonary venous flow (r = 0.40, p < 0.05) velocities in all patients. The PCWP-A correlated significantly with the peak atrial systolic transmitral flow (r = -0.39, p < 0.05) and pulmonary venous flow (r = 0.68, p < 0.0001) velocities in all patients. There was a particularly close correlation between the PCWP-A and the peak atrial systolic pulmonary venous flow velocities. The sum of the time-velocity integral of the atrial systolic transmitral and pulmonary venous flow velocities (TAI) correlated closely with the delta LAV (r = 0.70, p < 0.0001) in all patients. Thus, the peak atrial systolic pulmonary venous flow velocity correlated well with left atrial pressure changes during atrial systole. Furthermore, the sum of the time-velocity integral of the atrial systolic transmitral and pulmonary venous flow velocities correlated well with left atrial volume changes during atrial systole. Therefore, transesophageal echocardiographic measurements of atrial systolic transmitral and pulmonary venous flow velocities are reasonable indicators of left atrial pressure and volume changes during atrial systole.

Adult↗
PubMed1996

[Usefulness of reaction times in high-cortical recognition tasks].

We compared reaction times for high-cortical recognition tasks with kana-searching test in a group of 46 normal individuals aged 21 to 83 who gain a full score in Mini-Mental State. The following tasks of reaction time were used; simple reaction time (SRT), choice reaction time (CRT), memory scanning time (MST), and visual searching time (VST). The results were consistent and demonstrated that mean reaction time of 46 individuals increased in difficult tasks such as MST or VST. All reaction times increased depending on aging, which became longer in difficult tasks. Score of kana-searching test was correlated with MST and VST, but did not correlate with SRT and CRT. These findings suggest that reaction times may be useful for mass-screening of high-cortical functions in different ages as well as the kana-searching test.

Adult↗
PubMed1996

Systolic and diastolic mitral regurgitation in a patient with annulo-aortic ectasia demonstrated by color Doppler flow imaging.

A rare case of annulo-aortic ectasia is reported in a 65-year-old man who had aortic and mitral regurgitation during systole and diastole. He was hospitalized for further examination of the heart due to cardiomegaly and heart murmurs. Aortography revealed severe aortic regurgitation. On color Doppler flow imaging, we could detect red aortic regurgitant signals in the left ventricular cavity during diastole, and mosaic and blue mitral regurgitant signals in the left atrial cavity during systole and diastole associated with a relatively long R-R interval, respectively. The unique observation of diastolic mitral regurgitation is discussed.

Aged↗
PubMed1996

Peculiar patterns of aortic regurgitation and carotid pulse due to dysfunction of a Medtronic Hall prosthetic valve: a case report.

We describe a patient with dysfunction of a Medtronic Hall prosthetic valve showing peculiar patterns of aortic regurgitation and carotid pulse caused by valvular thrombosis. The aortic regurgitation was considered to be caused by a significant delay in prosthetic valve closure, manifested by a peculiar regurgitation pattern limited to early diastole, in association with widely split closing clicks and an abnormally low dicrotic notch in the carotid pulse. At surgery, fibrin thrombi were noted just below the prosthetic ring in the minor outflow region which restricted disc movement. The fibrin thrombi were removed and the valve was rotated 90 degrees. Following reoperation, all abnormalities disappeared.

Angiography↗
PubMed1995

Predisposing factors for severe mitral regurgitation in idiopathic mitral valve prolapse.

To elucidate predisposing factors for severe mitral regurgitation (MR) in idiopathic mitral valve prolapse (MVP), 124 MVP patients were classified into the following categories: 55 with isolated clicks (click group), 35 with a late-systolic murmur (late-SM group), and 34 with a holosystolic murmur (holo-SM group). Their clinical and echocardiographic findings were compared with those of 26 patients with spontaneous chordal rupture (rupture group). In 22 patients in the click group, 24 in the late-SM group, and 22 in the holo-SM group, follow-up studies were performed for a mean of 4.5 years (range 1 to 13.5). The mean age was youngest in the click group and oldest in the rupture group. The click and late-SM groups showed a female predominance, but the holo-SM and rupture groups showed a male predominance. There was no difference in the incidence of systemic hypertension among the 4 groups. Most patients in the click and late-SM groups had anterior leaflet prolapse. In the holo-SM and rupture groups, however, the incidence of posterior leaflet involvement was significantly increased. The incidence of thickened mitral valve increased in order of the click (8%), late-SM (21%), holo-SM (38%), and rupture (50%) groups. Six patients in the holo-SM group developed chordal rupture with severe MR during the follow-up period. In the click and late-SM groups, however, there were no complications and no development into a holo-SM. Thus, aging, male sex, posterior leaflet prolapse, thickened mitral valve, and holo-SM were found to be important predisposing factors for severe MR in idiopathic MVP.

Adult↗
PubMed1995

Non-selective cation current of guinea-pig endocardial endothelial cells.

1. Endocardial endothelial (EE) cells, isolated by the enzymatic treatment of guinea-pig heart, were used for whole-cell voltage clamp experiments. 2. The inward rectifier K+ current was observed in about half of the experiments. The contribution of Ca(2+)-dependent K+ current to the resting membrane conductance was also suggested. 3. After the K+ conductances were suppressed, removal of external Na+ revealed an inward cation current (1.2 pA pF-1, at -45 mV), whose slope conductance was a saturable function of external Na+ concentration. When Na+ was totally replaced by various monovalent cations, the order of the membrane conductances was K+ > Rb+ > Cs+ > Na+ > Li+. 4. This basal non-selective cation current was blocked by either Gd3+ or La3+, and showed slight outward rectification. 5. Addition of 20 mM Ca2+ or Ba2+, but not Mg2+ or Mn2+, to the Na(+)-free solution, induced an inward current, indicating that this current possesses a significant Ca2+ permeability. 6. In approximately 15% of the experiments, ATP and histamine induced another type of non-selective cation current, which showed different ion selectivity (Na+ > K+, Cs+) and rectification (inward). 7. The basal non-selective cation current is responsible for both the low resting potential and the leak Ca2+ influx of EE cells.

Adenosine Triphosphate↗