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Biomedical subjects

S Koseki

Publications and source records attributed to S Koseki.

At least 55 records · Page 3Linked to original sources
PubMed1987

Impaired left ventricular rapid filling during exercise in patients with hypertrophic cardiomyopathy.

The influence of exercise on left ventricular diastolic filling was evaluated in 14 patients with hypertrophic cardiomyopathy (HCM) and 14 normal controls (NC) by dynamic exercise echocardiography. Using X-Y digitizer and computer, normalized peak rate of change of the left ventricular dimension during systole (pVs) and the rapid filling phase (pVd) were determined from the left ventricular echocardiograms at rest and during exercise when heart rate reached 100 beats/min. At rest and during exercise, pVs was significantly higher in HCM (3.2 +/- 0.4/s at rest, 4.3 +/- 1.4/s during exercise) than in NC (2.4 +/- 0.5/s at rest, 3.0 +/- 0.4s during exercise) (p less than 0.001, p less than 0.001, respectively), but pVd in HCM (4.2 +/- 1.0/s at rest, 5.8 +/- 1.0/s during exercise) was not significantly different from that in NC (4.1 +/- 1.0/s at rest, 6.0 +/- 0.7/s during exercise). The ratio of pVd to pVs (pVd/pVs) in HCM did not show significant increment during exercise (1.35 +/- 0.38 to 1.43 +/- 0.35), though that ratio in NC was significantly increased by exercise (1.67 +/- 0.22/s to 1.97 +/- 0.19/s, p less than 0.001). There was no correlation between pVd and the degree of left ventricular hypertrophy. These results suggest that diastolic reserve to exercise is depressed in HCM and that other factors besides left ventricular hypertrophy may account for diastolic abnormality.

Adult↗
PubMed1986

Daily variations of ECG and left ventricular parameters at exercise in patients with anginal attacks but normal coronary arteriograms.

In 21 patients with typical exercise-induced anginal pain but normal coronary arteriograms (group N) and in 14 patients with angiographically proved coronary stenosis (group C), symptom-limited ergometer exercise ECG and radionuclide angiocardiography were performed twice on two different days. Exercise-induced ST changes showed larger variations between the two exercise tests in group N than in group C ([delta ST1-delta ST2]: 0.07 +/- 0.06 mV in group N, 0.03 +/- 0.03 mV in group C, p less than 0.05). Rate pressure product and left ventricular ejection fraction at exercise also showed larger variations between the two tests in group N than in group C (p less than 0.001, p less than 0.05, respectively). However, substantial overlaps existed in some cases in the two groups. In conclusion, some of the patients with exercise-induced anginal pain but normal coronary arteriograms may have a variable threshold of exertional chest pain probably caused by variation in coronary vascular tone, and the other patients may have a fixed threshold of chest pain caused by other mechanisms.

Adult↗
PubMed1985

Significance of ST-segment and T wave changes in the resting electrocardiograms of patients with exertional angina, studied by exercise radionuclide angiocardiograms.

In order to investigate the clinical significance of ST-T changes in resting ECG in angina pectoris, symptom-limited ergometer exercise radionuclide angiocardiography with ECG was performed in 60 patients with exertional angina. In those with normal ECG at rest (Group N), left ventricular ejection fraction (EF) did not change during exercise (71 +/- 5% to 71 +/- 6%). In those with only ST change at rest (Group ST) and those with only T change at rest (Group T), EF decreased significantly during exercise (68 +/- 5% to 63 +/- 7%, p less than 0.01; 68 +/- 6% to 61 +/- 7%, p less than 0.001). In those with ST and T changes at rest (Group ST + T), EF was low at rest (58 +/- 11%) and decreased further at exercise (52 +/- 8%, p less than 0.001). In those whose negative or flat T wave became more negative during exercise, EF was low both at rest and at exercise. In conclusion, ST and T changes at rest in patients with exertional angina might suggest a depressed reserve of myocardial function for exercise.

Adult↗
PubMed1984

Functional significance of coronary collateral vessels during exercise evaluated by radionuclide angiocardiography: the importance of supplying arteries.

To investigate the function of coronary collateral vessels, especially from view point of supplying arteries, radionuclide angiocardiography was performed before and during a symptom-limited ergometer exercise in 54 patients with effort angina. In single vessel disease, during exercise, left ventricular ejection fraction (EF) (%) increased in the cases with coronary collateral vessels (supplied from patent arteries) (72 +/- 7----77 +/- 8, p less than 0.025), but decreased in those without (66 +/- 10----61 +/- 10, P less than 0.001). In multivessel disease, EF decreased during exercise even in those with collaterals (supplied from stenosed arteries) (67 +/- 10----59 +/- 8, p less than 0.001). It is concluded that angiographic appearance of the coronary arteries supplying collateral vessels is a major predictive factor of the function of coronary collateral vessels and of left ventricle during exercise.

Adult↗
PubMed1983

Dissociation between regional myocardial dysfunction and ECG changes during myocardial ischemia induced by exercise in patients with angina pectoris.

In order to investigate the relation between regional myocardial function and electrical changes during myocardial ischemia in humans, left ventricular echocardiogram and ECG were recorded during supine ergometer exercise in 16 patients with coronary artery disease until angina or ischemic ECG appeared. During exercise in 13 patients a decrease of left ventricular posterior wall excursion or of interventricular septum excursion occurred earlier than the appearance of ST-T change on ECG. In two patients the excursion decreased at the same time as the ST-T change. Significant regional myocardial dysfunction occurred at 30 +/- 15 seconds and ECG changes occurred at 90 +/- 60 seconds (p less than 0.001). Percent systolic wall thickening occurred in similar fashion. Results support the hypothesis that regional contractile abnormalities may provide a more sensitive indicator of myocardial ischemia than ST-T changes in humans.

Aged↗
PubMed1983

Myocardial mechanics of athletic hearts in comparison with diseased hearts.

Parameters of myocardial mechanics were measured by means of echocardiography in 31 competitive runners and 17 judo (Japanese wrestling) champions and were then compared with those in 25 normal control subjects, 15 patients with volume-overloaded (aortic regurgitation, AR) and 13 with pressure-overloaded (hypertension, HT) hearts, 14 patients with dilated cardiomyopathy (DCM), and 11 patients with hypertrophic cardiomyopathy (HCM). In runners, the ratio of left ventricular radius to wall thickness (R/Th) was maintained in the normal range, but fractional shortening (FS) and decreased slightly (p less than 0.01). Patients with decompensated DCM and AR had an increased R/Th (p less than 0.001) and a decreased FS (p less than 0.001). In judo champions, FS was maintained in the normal range, but R/Th had decreased (p less than 0.001). In patients with HT, R/Th had decreased slightly (p less than 0.05), but FS and peak systolic wall stress were maintained in the normal range. In patients with HCM, FS was maintained in the normal range, but R/Th had decreased (p less than 0.001). It is concluded that, at rest, hearts of runners are cardiomechanically similar to those of patients with compensated AR or DCM and probably have greater cardiac reserve, whereas hearts of judo champions are similar to those of HCM patients with inappropriate hypertrophy.

Adolescent↗
PubMed1983

Effect of exercise on left ventricular diastolic filling in athletes and nonathletes.

To evaluate the effect of exercise on left ventricular diastolic filling, the following were measured at rest and during exercise in 14 control subjects and 15 athletes, using digitized M-mode echocardiography: the peak early diastolic lengthening rate of the left ventricular dimension and the filling volume and the filling fraction during the first 0.10 s of diastole. During ergometer exercise performed at a level that increased the heart rate to 100 beats/min, there were significant increases in the peak normalized lengthening rate of the left ventricular dimension (control subjects, 4.2 +/- 1.3 vs. 6.1 +/- 1.1 s-1, mean +/- SD, P less than 0.001; athletes, 5.3 +/- 0.9 vs. 7.4 +/- 1.1 s-1, P less than 0.001), filling volume (control subjects, 15 +/- 12 vs. 33 +/- 10 ml, P less than 0.001; athletes, 21 +/- 12 vs. 63 +/- 18 ml, P less than 0.001), and filling fraction (control subjects, 21 +/- 14 vs. 42 +/- 17%, P less than 0.005; athletes, 21 +/- 13 vs. 54 +/- 12%, P less than 0.01). The peak lengthening rate of the left ventricular dimension, the filling volume, and the filling fraction were significantly greater in athletes than in control subjects during exercise (P less than 0.005, P less than 0.001, and P less than 0.05, respectively). Augmented early diastolic filling may be a mechanism to provide adequate filling for the ventricle at high heart rates produced by exercise, especially in athletes.

Adolescent↗
PubMed1983

Evaluation of left ventricular reserve in left ventricular diseases: non-invasive analysis of its determinants by dynamic exercise echocardiography.

To analyze the determinants of left ventricular (LV) reserve non-invasively, LV echocardiograms were taken during ergometer exercise in 52 LV disease patients (19 with hypertension [HT], 22 with aortic regurgitation [AR] and 11 with dilated cardiomyopathy [DCM] with various severities. In mild cases [HT], at exercise, fractional shortening (FS) increased, and at higher-grade exercise, an increase of LV enddiastolic diameter (Dd) was added to more increase of FS, to increase stroke volume (SV). In moderately severe cases [HT, AR or DCM], FS did not change or decreased at exercise. In severe cases [AR or DCM], FS was low at rest, and at exercise decreased further with an increase of LV systolic stress and no significant increase of Dd, resulting in a decrease of SV. The responses of LV parameters in volume-overload (AR) or dilated myocardial (DCM) hearts were poorer than in pressure-overload (HT) hearts, in moderately severe cases. In conclusion, exercise echocardiography can show non-invasively that the interrelationship among the determinants of LV reserve is different by the severities and the types of LV diseases, and this method is useful, especially in discriminating mild cases objectively.

Adult↗
PubMed1983

The influence of exercise on left ventricular outflow tract obstruction, left ventricular performance and electrocardiogram in hypertrophic cardiomyopathy.

To investigate exertional changes in hypertrophic cardiomyopathy (HCM), 42 patients with HCM were studied by echocardiography and ECG at a supine ergometer exercise. In 12 cases with left ventricular (LV) outflow tract obstruction at rest (Group I), systolic anterior movement (SAM) of mitral valve was intensified during exercise; and among 30 cases without obstruction at rest (Group II), in 6 cases (Group IIA) SAM appeared during exercise. SAM might be further intensified 1 minute after exercise. Inverted T-wave was seen at rest especially in Group IIB (no SAM both at rest and during exercise), and tended to become less deep during exercise with an increase of LV wall motion. In conclusion, in HCM, LV outflow tract obstruction may be produced or intensified during exercise. Inverted T-wave in HCM may become less deep during exercise, with accelerated LV function.

Adolescent↗
PubMed1982

Indications, applications and future prospects of diagnostic examinations in clinical cardiology.

Nowadays there are various kinds of diagnostic examinations in the field of clinical cardiology. In this field, information concerning structure, dimension (hypertrophy and dilatation) and cardiac function is essentially important. For the diagnosis of valvular and congenital heart diseases and of cardiomyopathy, ultrasonic examinations are more useful; for ischemic heart disease, nuclear medicine is superior. Angiocardiography provides as much information but it is invasive. A combination of an exercise-test with the examinations mentioned above is useful for the detection of left ventricular and coronary reserves. The determinants of left ventricular reserve, being related to the prognosis of the patients, can be analyzed by exercise echocardiography. Exercise echocardiography can reveal instantaneous changes in myocardial ischemia during exercise. Regional and global left ventricular performances revealed by exercise radionuclide angiocardiography can lead us to a new interpretation of an exercise ECG.

Coronary Disease↗
PubMed1982

Influence of ergometer exercise on aortic pressure-diameter relationship in healthy men.

In order to investigate the change of the aortic pressure-diameter relationship during exercise, M-mode echograms and/or two-dimensional echograms of the aortic root and of the abdominal aorta were taken before and during supine ergometer exercise in 15 healthy men. The difference of the angle of the ultrasonic beam to the aorta between before and during exercise was too small to influence the measured values. The exercise, which elevated heart rate to 100 beats/min, caused a shift of the pressure-diameter relationship curve of the aortic root to a lower diameter (on an average, end-systolic diameter: from 3.1 to 2.9 cm, p less than 0.001; end-diastolic: from 2.9 to 2.7 cm, p less than 0.001). This was also seen in the abdominal aorta. Stroke volume showed no change during exercise. Total peripheral vascular resistance decreased. Central aortic volume decreased. In conclusion, exercise induces active constriction of aorta with dilatation of arterioles. This might be beneficial to push the blood into the peripheral tissues.

Adult↗
PubMed1982

[Evaluation of left ventricular asynergy by parasternal and subcostal M-mode echocardiography].

In 47 patients with old myocardial infarction (MI), parasternal and subcostal M-mode echocardiograms (M-mode) guided by the two-dimensional echocardiogram (2D) were recorded to evaluate left ventricular asynergy quantitatively, and were compared with 2D findings. By placing the transducer at the left sternal border, the short-axis views of the left ventricle (LV) by 2D at the level of the chorda tendineae and papillary muscle were recorded. The LV wall was divided into 4 segments; including (1) anterior wall (AW) and anterior septum (AS), (2) lateral wall (LW), (3) posterior wall (PW), and (0) inferior wall (IW) and posterior septum (PS), and asynergy was analyzed on moving images. The AS and PW were recorded by parasternal M-mode, and the PS and LW were recorded by subcostal approach. Asynergy by M-mode was defined when septal amplitude was less than 3 mm, LW or PW amplitude was less than 9 mm, % systolic thickening (% ST) of the septum was less than 17%, and % ST of the LW or PW was less than 25%. Of 25 patients with anterior MI, asynergy of the AW and AS wass s present in 19, LW asynergy in 10, PW asynergy in 2, and IW and PS asynergy in 1 by 2D, meanwhile, M-mode detected asynergy of AS in 21, and LW asynergy in 15. Of 15 patients with inferior MI, asynergy of the PW and PS was present in 4 and 7, respectively by 2D, but by M-mode asynergy was present in 11 and 14, respectively. In 31 patients underwent left ventricular cineangiography, detection rate of asynergy by angiography was compared with that by echocardiography. In 124 segments by cineangiography, wall motion characteristics were correctly identified in 83% by 2D and 91% by M-mode. Of 25 patients with anterior MI, amplitude of the AS was 3 approximately -5 mm in 19, and %ST of the AS wa 0 approximately 6% in 2, but amplitude of the PS was within normal range in 24. Of 15 patients with inferior MI, amplitude of the AS was within normal range in all, and amplitude of PS was 3 approximately -8 mm in 13 and %ST of PS was 10% in 1. This study shows that combined use of parasternal and subcostal M-mode detects asynergy more sensitively than 2D alone even in its quantitative sense, and therefore, not only 2D but M-mode in essential for evaluation of LV asynergy. Asynergy of PS was present in inferior MI, and this segment was not injured in anterior MI, while AS asynergy was present in anterior MI. When analysing asynergy of the interventricular septum, it should be subdivided into two parts including AS and PS. Subcostal M-mode detected PS asynergy that was not visualized by routine cineangiography. In inferior MI, subcostal M-mode is recommended for detection of PS asynergy.

Adult↗
PubMed1981

Evaluation of left ventricular performance and of its reserve by radionuclide angiocardiography: comparison with other methods.

This study was performed, i) to compare radionuclide angiocardiography with the other methods, and ii) to evaluate its usefulness in investigating left ventricular performance and its reserve. Radionuclide angiocardiography, chest X-ray film, chest X-ray cinegraphy, echocardiography, two-dimensional echocardiography, pulsed Doppler flowmetry, cardiokymography, myocardial imaging, contrast ventriculography and coronary arteriography were performed (:also at exercise) in 105 subjects including various kinds of cardiac patients. Radionuclide angiocardiography could be performed both at rest and at exercise, contrary to invasive methods. In detailed analysis of left ventricular mechanics in non-ischemic heart disease, echocardiography at rest and at exercise may be appropriate, because of its high image resolution. In evaluation of ischemic heart diseases, radionuclide angiocardiography at rest and at exercise might be appropriate, because of bidirectional informations and its high success rate. Two-dimensional echocardiography with M-mode echocardiography might compensate for it, particularly for continuous informations during exercise. Detection of regional wall motion dysfunction at exercise is more specific than exercise ECG and is more sensitive than exercise myocardial imaging. From many kinds of examinations, appropriate one should be selected according to the purpose of investigators. Much more technical progress in these methods can be expected.

Adolescent↗
PubMed1979

Dynamic exercise echocardiography.

To evaluate left ventricular (LV) reserve, we developed a method of dynamic exercise echocardiography (DEE). Forty-six healthy persons and 47 cardiac patients performed bicycle ergometer exercise in the supine position. A special table was used on which the subjects could be firmly attached at shoulder level to prevent bodily movements which might disturb the recordings. In 83% of the subjects in whom a clear echocardiogram was obtained at rest, a clear echocardiogram was also obtained during dynamic exercise. During exercise, cardiac output estimated from the echocardiogram and that from the dye-dilution method showed an excellent correlation. The changes of the mean velocity of LV circumferential shortening during exercise permitted discrimination between older and younger healthy men, and also between healthy subjects and those with either mild or severe LV dysfunction. We conclude that DEE is useful for evaluating LV reserve.

Adult↗