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Biomedical subjects

R Ajisaka

Publications and source records attributed to R Ajisaka.

At least 37 records · Page 2Linked to original sources
PubMed1996

[What terminal cancer patients seek from nurses in treatment at home].

We have provided care at home for 29 patients who were terminally ill, and from the fact that 3 of them needed excretion care, we learned something important for successful nursing care. The first necessity is the technical skill and knowledge of nursing care for the terminal cancer patients. We need to be able to provide guidance for the patient or family. The second is prompt consultation anytime when the patient or family needs it. The key to success is to create a medical network system for terminal cancer patients. The third is to provide support for the patient and family so that they pass the time without pain and meaningfully.

Caregivers↗
PubMed1995

Effects of L- and DL-carnitine on patients with impaired exercise tolerance.

We designed this study to determine whether orally administered L- and DL-carnitine can improve exercise tolerance in a group of patients with exercise intolerance. Nineteen patients with cardiac disease were randomly divided into 2 groups, an L-carnitine treatment group (n = 9) and a DL-carnitine treatment group (n = 10). Eight additional age-matched patients served as an untreated control group. Subjects in both carnitine treatment groups underwent cardiopulmonary exercise testing on a cycle ergometer in order to determine peak exercise time, peak oxygen uptake (VO2), lactate threshold (LT) and ventilatory threshold (VT) before and after the oral administration of 900 mg/day of L- or DL-carnitine for 2 weeks. Basal values of peak exercise time, peak VO2, LT and VT did not differ significantly among the 3 groups. Peak exercise time and peak VO2 tended to be increased in the L-carnitine treatment group, and tended to be decreased in the DL-carnitine treatment group. Both LT and VT (ml/kg/min) were significantly improved (LT: from 9.7 +/- 0.6 to 10.8 +/- 1.0, p < 0.05; VT: from 9.8 +/- 0.8 to 11.8 +/- 1.9, p < 0.02) by the administration of L-carnitine, while LT was significantly decreased (from 11.0 +/- 2.0 to 9.6 +/- 1.2, p < 0.05) and VT tended to be decreased by the administration of DL-carnitine (from 11.6 +/- 2.0 to 10.8 +/- 2.4). In the untreated control group, no significant changes were observed in the values of exercise tolerance between the 2 series of exercise testings. In neither group did carnitine modify hemodynamic parameters at rest or during exercise. In conclusion, this study demonstrated that L-carnitine increases and DL-carnitine decreases exercise tolerance in patients with impaired exercise tolerance.

Administration, Oral↗
PubMed1995

Exercise-induced rise in arterial potassium is enhanced in patients with impaired exercise tolerance.

We assessed the changes in arterial potassium concentration during exercise and recovery in relation to exercise tolerance in patients with impaired exercise tolerance. Sixteen patients with cardiac disease were subjected to a cardiopulmonary exercise test on a cycle ergometer. Arterial potassium and lactate concentrations were measured every minute during and after exercise, and ventilatory threshold (VT) and lactate threshold (LT) were identified. Before exercise, arterial potassium concentration was 3.8 +/- 0.3 mEq/l. It increased to 4.1 +/- 0.3 mEq/l at LT (p < 0.002 versus at rest), to 4.2 +/- 0.3 mEq/l at VT, and to 4.8 +/- 0.5 mEq/l at peak exercise (p < 0.001 versus at LT, p < 0.001 versus at VT). At an exercise intensity equivalent to 30, 40, 50 or 60% of predicted maximum oxygen uptake, the increase in arterial potassium showed a negative and significant correlation with %LT (r = -0.62 approximately -0.72, p < 0.01 approximately 0.05) and %VT (r = -0.62 approximately -0.75, p < 0.001 approximately 0.05), where %LT and %VT represent the ratios of LT and VT to the predicted maximum oxygen uptake, respectively. There was a good correlation between the rate of fall in potassium concentration during recovery and its increase during exercise. It was concluded that in patients with impaired exercise tolerance, the greater the degree of exercise intolerance, the greater the increase in arterial potassium concentration during exercise, and the steeper the fall in potassium concentration during recovery. Because the rise in potassium concentration during exercise and its fall during recovery were greater when the exercise level exceeded the anaerobic threshold, exercise levels below the anaerobic threshold are recommended for patients with cardiac diseases.

Aged↗
PubMed1995

Usefulness of hyperventilation thallium-201 single photon emission computed tomography for the diagnosis of vasospastic angina.

To establish a safe and sensitive diagnostic procedure for detecting coronary vasospasm, we utilized 201-thallium myocardial SPECT combined with hyperventilation (HV-SPECT) in 29 patients with vasospastic angina (VAP) and 11 controls. Twenty-five of 29 patients with VAP and 5 of 11 controls developed transient perfusion defects on HV-SPECT, resulting in a sensitivity and specificity calculated at 86% and 55%, respectively. Overall accuracy in identifying corresponding vessels with coronary vasospasm, respectively. Coronary vasospasm tended to be identified more accurately in the left anterior descending branch and the right coronary artery than in the circumflex branch (75%, 71% and 50%, respectively). The hyperventilation test induced ischemic ECG changes in 11 of 29 patients with VAP, yielding a sensitivity of 38%. Analyzing the washout rate of HV-SPECT in patients with VAP, both the extent and severity scores of patients with ischemic ECG changes were larger than those of patients without. No serious complications occurred during HV-SPECT. In conclusion, HV-SPECT was a safe and sensitive procedure as a primary diagnostic approach for VAP. From the results of washout analysis, HV-SPECT could detect more mild myocardial ischemia than could the ECG, and seemed quite useful especially for detecting coronary vasospasm accompanied by minimal ischemic ECG changes.

Adult↗
PubMed1995

Resting asynchronous left ventricular contraction abnormality analyzed by a phase method in spastic angina pectoris.

UNLABELLED: Quantitative phase analysis of equilibrium ventriculography was performed to study the character of left ventricular (LV) wall motion abnormalities in patients with spastic angina pectoris, who may have clinically and electrocardiographically silent ischemia combined with myocardial stunning, during rest and hyperventilation stress testing. METHODS: Phase analysis of the left ventricle at rest was performed by equilibrium radionuclide ventriculography in 13 control subjects and 36 patients with spastic angina pectoris. First-pass methodology along with hyperventilation stress testing was performed to assess spasm occurrences. Phase analysis of equilibrium multigated blood-pool scintigrams was performed to evaluate LV asynchrony at rest. RESULTS: The mean s.d. of LV phase distribution in the patients with variant and vasospastic angina was greater than that in the healthy control subjects (11.28 +/- 1.79 and 10.02 +/- 1.57 degrees versus 6.16 +/- 1.07 degrees). In addition, the mean s.d. of LV phase distribution in the variant angina group was greater than that in the vasospastic angina group. Furthermore, a linear correlation was found between the s.d. of LV phase distribution at rest and the percent decrease in ejection fraction during hyperventilation stress. CONCLUSION: Asynchronous LV contraction without significant hypokinesis was detected at rest in spastic angina pectoris. The severity of this asynchronous contraction corresponded well with decreases in ejection fraction during hyperventilation stress testing. Thus, analysis of the s.d. of LV phase distribution at rest is expected to provide useful information regarding LV asynchrony in spastic angina pectoris.

Adult↗
PubMed1993

[Myocardial ischemia detected by isoproterenol stress cardiac blood-pool scintigraphy: significance of asynchrony as an index of myocardial ischemia].

It is well known that left ventricular regional contraction abnormality (hypokinesis: hypo) occurs during myocardial ischemia. However, it is uncertain whether left ventricular asynchronous contraction (asynchrony) is an index of myocardial ischemia. To validate asynchrony as an index of myocardial ischemia, isoproterenol infusion stress (ISP) cardiac blood-pool scintigraphy (RI angiography) was performed in patients with ischemic heart disease. The subjects were classified into 2 groups: 1) 15 patients with coronary artery disease (CAD) and 2) 8 patients with "normal" coronary arteries (NC). None had any electrical ventricular conduction disturbance. ISP was administered with increasing doses of 0.02, 0.04, 0.08 microgram/kg/min at 3-min intervals, and it was terminated in the event of angina, significant ST changes or target heart rate. Symptom-limited ergometer exercise testing (EX) was also administered in 14 patients. Regional decrease in amplitude and phase delay identified by phase analysis was diagnosed as hypo and asynchrony, respectively. ISP myocardial scintigraphy was also performed in 15 patients. Results were as follows: ISP and EX induced asynchrony in 14 (93%) and 13 patients (93%), respectively, while, did hypo in 4 (27%) and 9 (64%), respectively. Ten (67%) of 15 patients had asynchrony without hypo in ISP; whereas, only 4 (28%) of 14 patients did in EX. ISP-induced asynchrony occurred in one of 8 patients with NC. The locations of ISP-induced asynchrony and those of EX-induced asynchrony were concordant in 11 (79%) of 14 patients. Asynchrony on the ISP RI angiogram was observed at the same sites of redistribution on the ISP myocardial scintigram. We concluded that asynchrony itself is a sensitive and specific index of myocardial ischemia.

Adult↗
PubMed1992

Quantitative phase analysis of myocardial wall thickening by technetium-99m 2-methoxy-isobutyl-isonitrile SPECT.

Regional wall thickening was assessed by ECG-gated SPECT using technetium-99m 2-methoxy-isobutyl-isonitrile (99mTc-MIBI). For myocardial segments with an optimal short axis, regional count changes from end-diastole to end-systole were used to calculate the regional wall thickening. Functional images displaying amplitude, % wall thickening (% WT), and phase were generated by a fundamental Fourier analysis. In the control subjects, % WT analysis showed heterogeneous contraction among the left ventricular wall segments. The amplitude values showed a similar pattern to the %WT values. Phase images demonstrated that the timing of ventricular contraction was almost homogenous between the various wall segments. In the CAD patients, regional decreases in amplitude and %WT corresponding to zones of reduced perfusion were shown in the ischemic segments. Phase images also indicated asynchronous contraction in these segments. Phase analysis of regional wall thickening in 99mTc-MIBI scintigraphy seems to be useful for understanding regional myocardial function in combination with perfusion scanning.

Aged↗
PubMed1992

Perfusion and mechanical analysis with technetium-99m 2-methoxy-isobutyl-isonitrile in a case of dilated cardiomyopathy.

With technetium-99m 2-methoxy-isobutyl-isonitrile (99mTc-MIBI), regional wall thickening in a patient with dilated cardiomyopathy was analyzed by the first component Fourier method. The regional wall thickening was compared with thallium-201 and 99mTc-MIBI SPECT imaging. Thallium-201 SPECT images showed mildly reduced perfusion in the posterior wall and redistribution in the septum, whereas 99mTc-MIBI images showed heterogeneous accumulation around the left ventricular circumference. By means of phase analysis, diffusely decreased wall thickening and discontinuity of percent wall thickening in neighboring segments were observed throughout the left ventricle. Regional wall motion and wall thickening correlated roughly. However, discrepancies between the mechanical function and myocardial perfusion, and discrepancies in regional myocardial perfusion between thallium-201 and 99mTc-MIBI were observed.

Aged↗
PubMed1992

Left atrial function in ischemic heart disease assessed by intravenous digital subtraction angiography.

To investigate changes in left atrial morphology and dimensions during the cardiac cycle, the atrium was visualized by intravenous digital subtraction angiography (DSA). The study subjects consisted of 22 male patients whose average age was 54.5 +/- 8.6 years. They had ischemic heart disease without mitral valve disease and were in sinus rhythm. They were 11 patients with old myocardial infarction (OMI group) and 11 who had chest pain without evidence of infarction (AP group). DSA was performed in the continuous mode. Contrast material (35 ml) was injected at a rate of 18 ml/sec via a catheter in the superior vena cava and subtraction images were obtained at a speed of 30 frames/sec in the right anterior oblique projection. The left atrial and left ventricular margins were traced manually, their areas were calculated, and fractional changes in area were analyzed. The left ventricular ejection fraction (LVEF) was calculated by densitometry. Cardiac catheterization was performed in 16 patients and the left ventricular end-diastolic pressure (LVEDP) and mean pulmonary arterial wedge pressure (PAWP) were measured. The entire left atrium was clearly imaged using DSA. Phase analysis of the time-area curves in the right anterior oblique projection revealed that the left atrial area was maximal during left ventricular end-systole (%LA1 = 100%), it decreased during early left ventricular diastole (%LA2), and then increased slightly again during mid-diastole (%LA3). After left atrial contraction, the minimum area was obtained (%LA4). The left atrium showed a two-stage decrease in the area due to passive emptying and active contraction during left ventricular diastole. Passive emptying (%LA1-%LA2) was significantly less in the OMI group than in the AP group (6.3 +/- 3.6 vs 13.3 +/- 4.8%, p < 0.01, respectively). In all 22 subjects, passive emptying correlated with LVEF (r = 0.70, p < 0.001) and LVEDP (r = -0.58, p < 0.05). There was no difference in active contraction (%LA3-%LA4) between the 2 groups (26.0 +/- 5.7% in the OMI group, 28.2 +/- 8.4% in the AP group), and it did not correlate with LVEF or LVEDP. The ratio of passive emptying to active contraction [(%LA1-%LA2)/(%LA3-%LA4)] correlated with LVEF (r = 0.63, p < 0.01). These findings suggested that impaired left ventricular diastolic function and a relative increase in atrial contraction were present in patients with a lower LVEF. The %LA4 correlated with LVEDP and PAWP (r = 0.65, r = 0.63, p < 0.01, respectively). In conclusion, DSA proved to be a useful method for investigating left atrial morphology and function.

Aged↗
PubMed1991

A study of ventricular contraction sequence in complete right bundle branch block by phase analysis.

Twenty-four patients with complete right bundle branch block (CRBBB) combined with and without left axis deviation (LAD) on ECG, were compared with 17 normal subjects to evaluate the right ventricular contraction sequence and pattern in detail. Blood pool scintigrams were obtained in the left anterior oblique projection, and these images were analyzed by first component Fourier harmonics. In the normal subjects, the phase value distribution representing the pattern of ventricular contraction was almost homogeneous in both the right and left ventricles (RV & LV). In the CRBBB patients without LAD, the phase images showed apparent phase delay in the right ventricle. In the CRBBB patients with LAD, the phase images showed many different contraction patterns varying from normal to RV phase delay, owing to the effects of the hemi-block. Quantitative analysis of the absolute values, showed that the mean (RV-LV) value was 6.6 +/- 8.4 msec in the normal subjects. In the CRBBB patients without LAD, the duration of the QRS complex correlated with the mean (RV-LV) value, whereas no difference was observed between the duration of the QRS complex and the standard deviation of the right ventricle. Using phase analysis the degree of the RBBB can be determined from the phase images, and can be quantitatively analyzed as in electrical studies.

Adult↗
PubMed1991

Plasma concentrations of endothelin-1 and endothelin-3 are altered differently in various pathophysiological conditions in humans.

Several studies have indicated that endothelin-1 (ET-1) and endothelin-3 (ET-3) are produced by different cells. Although ET-1 is produced by vascular endothelial cells, these cells do not produce ET-3. In the present study, we measured plasma concentrations of both ET-1 and ET-3 by sandwich-enzyme immunoassays which we developed recently in patients on chronic hemodialysis, age-matched normal subjects, patients with acute myocardial infarction, patients undergoing surgery, and healthy subjects before and after strenuous endurance exercise. Plasma levels of ET-1 and ET-3 were demonstrated to be altered differently in the above conditions in humans. Although the exact origin of circulating endothelins has yet to be elucidated, the different alterations of plasma levels suggest that both ET-1 and ET-3 may play different roles in physiological and/or pathophysiological responses to various conditions in humans.

Adult↗
PubMed1991

[Effects of aging on right and left ventricular function in patients with right bundle branch block].

The effect of aging on cardiac function in patients with right bundle branch block (RBBB) was commonly unknown, so left ventricular function and right ventricular function were investigated, using first-pass radionuclide angiography. Twenty-six patients with RBBB and 28 normal subjects were studied at rest and during bicycle exercise. Patients with RBBB but normal cardiovascular systems aged 33 to 75 years were divided into those within 60 years (n = 17) and those over 65 years (n = 9). Using the same method, normal subjects aged 38 to 83 years were divided into those within 60 years (n = 18) and those over 65 years (n = 10). Mean age between normal subjects and patients with RBBB didn't differ significantly. The response of left ventricular ejection fraction in normal groups rose during exercise, but its exercise tolerance function declined with aging. Left ventricular diastolic filling in normal groups declined at rest and during exercise with aging. Left ventricular function in RBBB groups showed the same results as those of normal groups. The response of right ventricular ejection fraction and its exercise tolerance function in normal groups was not influenced by aging. However, in contrast, right ventricular function in RBBB groups decreased with aging. We suggest that the mechanism of decrease of right ventricular function in aging patients with RBBB may be caused by the change of right ventricular contraction which is affected by the aging process.

Adult↗
PubMed1990

Mechanisms of stress-induced ST elevation and negative T-wave normalization studied by serial cardiokymogram in patients with a previous myocardial infarction.

Seventeen patients with a previous myocardial infarction were studied during pacing to characterize the clinical correlates of ST elevation, to analyze the relation between ST elevation and negative T-wave normalization and to investigate the mechanism of these electrocardiographic changes. Myocardial ischemia was evaluated by measurement of blood lactate, and wall motion was analyzed using cardiokymographs concurrently and serially. Results show that ST elevation and negative T-wave normalization were most marked in leads containing abnormal Q waves, that ST elevation greater than or equal to 1 mm during pacing was associated with a significant increase in left ventricular end-diastolic pressure and deterioration of left ventricular wall motion and that the magnitude of ST elevation and negative T-wave normalization was significantly correlated, but the latter appeared earlier and more markedly. In addition, there was no significant correlation between the extent of either ST elevation or negative T-wave normalization and myocardial lactate production. Thus, ST elevation and negative T-wave normalization are caused by abnormal left ventricular wall motion rather than myocardial ischemia. Negative T-wave normalization is a more sensitive marker of abnormal wall motion than ST elevation in patients with a previous myocardial infarction.

Cardiac Pacing, Artificial↗