Search PubMed⌕ Search

Biomedical subjects

K Tsuiki

Publications and source records attributed to K Tsuiki.

At least 37 records · Page 2Linked to original sources
PubMed1991

The relationship between chest pain during thallium-201 scintigraphy with dipyridamole and myocardial ischemia.

Dipyridamole thallium-201 scintigraphy (DP-Tl) and coronary angiography were studied on 74 patients with suspected coronary artery disease. We compared the clinical features, hemodynamic responses, angiographic results and scintigraphic findings of patients who had chest pain during DP-Tl testing ('chest pain' group) with those of patients who did not have chest pain ('no pain' group). Thirty eight (51%) of the 74 patients developed chest pain. Heart rate and rate pressure product during DP infusion of 'chest pain' group were greater than those of the 'no pain' group (p less than 0.05). Ischemic ST depression was more frequently observed among 'chest pain' patients (p less than 0.01). There were no differences in angiographic severity of coronary artery disease between 'chest pain' and 'no pain' group. Also, we could find no differences in extent and severity scores of perfusion defects and washout abnormalities between the two groups. However, when patients with myocardial infarction were excluded, the 'chest pain' group had significantly greater extent and severity scores of washout abnormalities than the 'no pain' group (extent score: 38 +/- 8 vs 18 +/- 5, p less than 0.05, severity score: 55 +/- 15 vs 18 +/- 7, p less than 0.01). Our study indicated that in patients without myocardial infarction, patients with 'chest pain' had more severe ischemia than 'no pain' patients. But in patients with myocardial infarction, myocardial ischemia not accompanied by chest pain might be as severe as that with chest pain. The presence or absence of myocardial infarction might have great influence on results regarding the relation of chest pain to myocardial ischemia.

Adult↗
PubMed1991

Signal-averaged body surface mapping for the assessment of low-amplitude potentials. Relation between ventricular depolarization and repolarization in normal subjects.

To examine the relation between ventricular depolarization and repolarization, body surface isopotential maps at the end of the QRS complex were studied in 32 normal subjects using a signal-averaged body surface mapping system. The number of beats averaged was 96-154 (mean 126.2). In this study, there were 8 types of isopotential map patterns at the end of the QRS complex. Mean +/- SD of QRS duration, appearance time of repolarization, and disappearance time of depolarization were 82.0 +/- 8.7 msec, 71.8 +/- 10.5 msec, and 79.7 +/- 9.4 msec, respectively. Time duration of overlapping depolarization and repolarization was 8.6 +/- 6.4 msec. The early repolarization was widely distributed on the left anterior chest and the upper sternal region. These results demonstrated the difference between the appearance time of repolarization and the disappearance time of depolarization for each lead. We concluded that it is difficult to evaluate ECG waves in the terminal portion of the QRS complex with the dipolar theory only.

Adolescent↗
PubMed1991

Relation between the incidence of arrhythmias and ischemic ST-segment depression during dipyridamole electrocardiography test in patients with coronary artery disease.

To examine the incidence of arrhythmias in dipyridamole infusion and the relation between dipyridamole-induced arrhythmias and ST-segment depression, dipyridamole electrocardiography tests were performed on 100 patients with coronary artery disease. Dipyridamole was infused at a rate of 0.568 mg/kg for 4 min, and 87-lead body surface mapping was performed to determine ischemic ST-segment depression. Positive ischemic response was defined as greater than or equal to 0.10 mV horizontal or downsloping ST-segment depression below the baseline, lasting 80 msec after the J point. Arrhythmias were observed by continuous electrocardiographic monitoring using a CM-5 lead electrocardiography. With respect to ventricular premature contractions (VPC), a group of patients with previous myocardial infarction (MI group) had a significantly higher incidence than a group of patients without previous myocardial infarction (non-MI group) before (16.7% vs. 1.7%, p less than 0.01) and after (38.1% vs. 3.4%, p less than 0.005) the dipyridamole infusion. The incidence of supraventricular premature contractions (SVPC), however, was not significantly different between the MI and non-MI groups. A group of patients with positive ischemic response had a significantly higher incidence of SVPC after the dipyridamole infusion than a group of patients with negative ischemic response (p less than 0.005). However, there was no significant difference in the incidence of VPC between the negative and positive ischemic response groups. These results suggest that dipyridamole-induced VPC is not always associated with ischemic ST-segment depression, but dipyridamole-induced SVPC is associated with dipyridamole-induced ischemic ST-segment depression in patients with coronary artery disease.

Adult↗
PubMed1991

[Evaluation of silent myocardial ischemia by exercise radionuclide ventriculography: comparison between patients with and without old myocardial infarction].

We evaluated left ventricular systolic function during exercise in patients with silent or symptomatic myocardial ischemia by radionuclide ventriculography (RNV). The subjects consisted of 61 patients who had evidence of myocardial ischemia during exercise RNV defined as positive exercise electrocardiographic changes and angiographically documented coronary artery disease. The patients without angina during exercise (SMI) had less exercise-induced left ventricular systolic dysfunction than patients with angina (CP) (change in ejection fraction during exercise: delta EF; -1 +/- 13 vs -6 +/- 10%, p less than 0.05, systolic blood pressure/end-systolic volume in exercise divided by systolic blood pressure/end-systolic volume in rest: SP/ESV (ex/rest); 1.1 +/- 0.6 vs 0.8 +/- 0.3, p less than 0.05). The 61 patients were divided into two groups, that is, those with and without old myocardial infarction (OMI), and we compared the degree of left ventricular systolic dysfunction during exercise between SMI and CP by RNV in each group. In patients without OMI, SMI had less exercise-induced left ventricular dysfunction than CP (delta EF; 1 +/- 12 vs -10 +/- 8%, p less than 0.01, SP/ESV (ex/rest); 1.1 +/- 0.6 vs 0.7 +/- 0.2, p less than 0.01). However, there were no differences between SMI and CP with OMI. In conclusion, it was thought that SMI without OMI was less degree of myocardial ischemia, and that SMI with OMI was potentially caused by some factors except for the degree of myocardial ischemia.

Aged↗
PubMed1991

[Simultaneous assessment of wall motion and myocardial perfusion by technetium-99m methoxy isobutyl isonitrile].

The aim of this study was to assess whether or not myocardial uptake of Technetium-99m methoxy isobutyl isonitrile (Tc-MIBI) indicated myocardial viability. We performed simultaneous Tc-MIBI angiography and myocardial SPECT at rest on 12 patients with suspected coronary artery disease. Left ventricle was divided into 3 segments, and regional wall motion was graded as normal, hypokinesis and akinesis/dyskinesis. Myocardial uptake of Tc-MIBI was assessed as normal, reduced and absent in each segment. In segments with normal and reduced Tc-MIBI uptake, 7% (2 of 28) and 33% (2 of 6) showed wall motion abnormalities of akinesis/dyskinesis, respectively. However, all segments with absent Tc-MIBI uptake had asynergy of akinesis/dyskinesis (2 of 2, 100%). Myocardial Tc-MIBI uptake at rest indicated wall motion abnormalities and was considered to be useful for the evaluation of myocardial viability. First-pass radionuclide angiography followed by myocardial SPECT with Tc-MIBI demonstrated to be useful for the simultaneous assessment of the left ventricular wall motion and myocardial perfusion.

Coronary Circulation↗
PubMed1990

Segmental diastolic narrowing of epicardial coronary arteries in aortic regurgitation. Phase analysis by quantitative angiography of coronary artery diameter change during cardiac cycles.

A new finding of a segmental narrowing of the left anterior descending coronary artery in diastole (diastolic narrowing: DN) was reported. DN was found in 6 out of 45 patients (13.3%, 5 males, 1 female) with chronic aortic regurgitation (AR). It is likely that aortic regurgitation was more severe in terms of the history of heart failure, regurgitant fraction, left ventricular end-diastolic volume index and pressure, and aortic diastolic pressure in the patients with DN compared with those without DN. The phasic change of DN in cardiac cycles was analyzed by quantitative angiography, and indicated that DN commences at a point in mid-diastole when coronary vascular driving pressure (the instantaneous aortic and LV pressure difference) becomes abnormally reduced, reaches its maximum at end-diastole, and gradually recovers as aortic pressure increases during systole. In two patients, DN was no longer evident after valve replacement. We concluded that DN, a new coronary arteriographic finding, reflects the integrated severity of AR.

Angina Pectoris↗
PubMed1990

Clinical implications of exercise-induced chest pain: comparison of patients with and without pathologic Q waves in coronary artery disease.

We attempted to determine whether exercise-induced silent myocardial ischemia has different clinical implications in patients with and without pathologic Q waves. We studied 152 patients (121 men and 31 women) who had ischemic ST depression (greater than or equal to 0.05 mV) during exercise tests and greater than or equal to 70% narrowing in the three major coronary arteries. According to the presence or absence of chest pain during exercise, they were divided into symptomatic patients and asymptomatic patients: 104 patients without pathologic Q waves (Q(-) group) and 48 patients with pathologic Q waves (Q(+) group). In the Q(-) group, symptomatic patients (n = 56) had a significantly greater number of leads showing ST depression (p less than 0.0002), a greater maximum voltage of ST depression (p less than 0.005), a higher incidence of negative U waves (p less than 0.001), and a poorer blood pressure response (p less than 0.005) than asymptomatic patients (n = 48). However, in the Q(+) group, there were no significant differences between symptomatic (n = 24) and asymptomatic patients (n = 24) with regard to these parameters. We concluded that symptomatic patients without pathologic Q waves had more severe ischemia. On the other hand, in patients with pathologic Q waves, the severity of myocardial ischemia in asymptomatic patients might be equal to that in symptomatic patients. Chest pain during exercise testing is not a good predictor of myocardial ischemia in patients with pathologic Q waves. The presence or absence of pathologic Q waves is an important factor in the analysis of exercise-induced myocardial ischemia.

Chest Pain↗
PubMed1990

The clinical significance of exercise-induced ST segment changes in patients with previous inferior myocardial infarction.

To investigate the clinical significance of exercise-induced ST changes, we performed exercise body surface mapping (87 leads) in 52 patients (one-vessel disease [1 VD] n = 12, multivessel disease [MVD] n = 40) with previous inferior myocardial infarction (MI). ST isointegral maps were constructed and the locations of ST changes were compared with the findings of exercise thallium-201 (TI-201) myocardial scanning. Exercise-induced ST elevation was observed in 14 patients (27%) on the lower chest and on the back, corresponding to the infarcted area. Exercise-induced ST depression was observed more frequently in the MVD group (n = 30, 75%) than in the 1VD group (n = 2, 17%). Seventeen (77%) of 22 patients with ST depression had thallium-201 redistribution. There was a significant association between ST depression and TI-201 redistribution (chi2 = 13.1, p less than 0.001), but no association between ST depression and ST elevation. The body surface distribution of ST depression was shifted upward and rightward compared with its appearance in angina pectoris without MI. These findings suggest that exercise-induced ST depression reflects myocardial ischemia in patients with previous inferior MI.

Adult↗
PubMed1990

Abnormalities of early depolarization in patients with remote anterior myocardial infarction and ventricular septal hypoperfusion. Diagnosis of septal MI by BSM.

The authors conducted this study to find the difference in body surface isopotential maps in 46 patients with previous anterior infarction with and without septal involvement. Thallium-201 myocardial-perfusion imaging identified 25 patients with septal infarction (group P) and 21 without (group N). In contrast to group N, group P had a prominent minimum on the anterior chest during the early phases of the QRS. According to the results obtained, the following criteria for identifying patients with septal infarction (group P) were proposed (1). Criterion 1: The absolute value of the voltage of the minimum is equal to or greater than that of the maximum at 5 ms after the onset of the QRS; (2) Criterion 2: During the early portion of the QRS the voltage of the minimum reaches -0.10 mV at the same time or earlier than the maximum reaches 0.10 mV. Both criteria had higher sensitivities (100% and 100%), specificities (71.4% and 90.5%), and predictive accuracies (87.0% and 95.7%) than either Franklead vectorcardiograms or standard 12-lead electrocardiograms in the study population. Thus, body surface isopotential mapping is considered to be useful for the diagnosis of septal involvement in patients with previous anterior myocardial infarction.

Algorithms↗
PubMed1990

Use of body surface electrocardiographic mapping to localize the asynergic site in previous myocardial infarction.

Body surface electrocardiographic (ECG) maps of myocardial infarction were analyzed using the departure mapping technique, which represents the abnormal potential distribution out of normal ranges. Body surface ECG mapping using 87 leads was performed on 65 patients with previous myocardial infarction and on 40 normal volunteers. Potential departure maps at 10, 20, 30, 40, and 50 msec after the onset of QRS were constructed; each map indicated, if present, the area of abnormal decreased potential that is more than 2 standard deviations from the normal range (-2 SD area). In patients with myocardial infarction, the appearance time and the location of the -2 SD area were specific for the sites of left ventricular asynergy; the sensitivity and specificity were 86% and 100% for the asynergy of segment 2 (20 msec, on the upper left anterior chest), 87% and 97% for segment 3 (30 msec, on the middle anterior chest), 86% and 80% for segment 4 (20 or 30 msec, on the lower right anterior chest), and 88% and 90% for segment 5 (30, 40, or 50 msec, on the middle back), respectively. The sensitivity of these criteria was better than that of 12-lead ECG, while the specificity was comparable. In the analysis of body surface ECG mapping data, departure maps aid in depicting abnormalities and in making an accurate assessment. Body surface ECG mapping can be used to improve the diagnostic ability of ECG to detect myocardial infarction.

Adult↗
PubMed1990

Relation between localization of coronary artery disease and local abnormalities in ventricular activation during exercise tests.

To examine whether or not the location of local abnormalities on body surface isochrone maps reflects the site of myocardial ischemia, 48 coronary artery disease patients without myocardial infarction were studied. Eighty-seven unipolar electrocardiograms distributed over the anterior chest and the back were recorded simultaneously before and after the submaximal treadmill exercise. For each lead, the duration from the QRS onset to the time of the most rapid decrease in QRS voltage was measured (index of ventricular activation [IVA]). Based o the data provided by these 87 leads, IVA isochrone maps (IVA map) in preexercise and in postexercise, as well as IVA maps showing the difference between preexercise and postexercise, were constructed. The IVA was defined as abnormal when it exceeded (mean + 2 SD) the normal range. We called the area with the abnormal IVA, the "+2SD area." In patients having a stenosis in the left anterior descending artery, the +2SD area in each map was located mainly on the left anterior chest, whereas in patients having a stenosis in the right coronary artery, the +2SD area in each map was located mainly on the right lower thoracic surface. Moreover, the +2SD area of patients with both left anterior descending and right coronary artery disease appeared on both the left anterior chest and the right lower thoracic surface. In patients with left circumflex artery disease, however, the location of the +2SD area did not suggest a stenotic site because of its small population. On the other hand, it was difficult to determine the ischemic site from the body surface distribution of ST segment depression.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Body surface mapping of high-frequency components in the terminal portion during QRS complex for the prediction of ventricular tachycardia in patients with previous myocardial infarction.

To study the clinical significance of terminal QRS high-frequency components for the prediction of ventricular tachycardia, an 87-lead body surface signal-averaged mapping was performed in 21 healthy subjects (control) and in 41 patients with previous myocardial infarction (anterior, 20; inferior, 21). Mapping data were analyzed and averaged (129.7 +/- 26.5 beats) for 160 seconds, and the signal-averaged beat was filtered with a bidirectional bandwidth (80-250 Hz) digital filter. J-point was determined from the 87-lead RMS voltage of nonfiltered QRS. For each lead, we calculated the sum of the absolute value of filtered QRS from 20 msec ahead of the J-point to the J-point (A-20). The body surface distribution of A-20 was expressed as A-20 map. The maxima in A-20 maps were mainly located on the upper sternal region in healthy subjects, on the left anterior chest in patients with previous anterior myocardial infarction, and on the central anterior chest in patients with previous inferior myocardial infarction. In the patients in both the group with anterior myocardial infarction and the group with inferior myocardial infarction, the value of maximum was significantly greater than in the subjects in the control group (0.181 +/- 0.086 and 0.138 +/- 0.048, respectively, vs. 0.075 +/- 0.031 mV.msec; p less than 0.01). In patients with myocardial infarction (n = 41), the value of maximum was significantly greater with ventricular tachycardia (n = 11) than without ventricular tachycardia (n = 30) (0.240 +/- 0.076 vs. 0.130 +/- 0.043 mV.msec; p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

The role of late potentials in the assessment of myocardial degeneration in idiopathic dilated cardiomyopathy.

In order to determine whether or not late potentials indicate either a degree of myocardial fibrosis or necrosis, the relationship between late potentials and thallium-201 myocardial perfusion images was studied in 13 patients with idiopathic dilated cardiomyopathy. Late potentials were defined as low-amplitude waveforms having duration of over 20 msec after the end of the QRS complex using a high-resolution ECG (Marquette electronics, MAC 1). In the T1-201 myocardial perfusion image, the segmental perfusion state was assessed by use of a parameter called the uptake index (= normalized sector counts/maximal normalized sector counts) of each of 6 different segments. Segments which showed an uptake index of -2SD less than the normal value were judged to be abnormal. Late potentials were detected in 8 (61.5%) of the 13 patients. All of the patients showing late potentials also had ventricular tachycardia. Among the patients showing no late potential, ventricular tachycardia was observed in only one patient. Seven of the 8 patients showing late potentials and 3 of 5 patients not showing late potentials, however, had both a higher degree and a greater extent of abnormal perfusion images than the patients not showing late potentials. Therefore, late potentials may reflect a degree of myocardial fibrosis or necrosis in patients with dilated cardiomyopathy, those showing abnormal thallium images are apt to show late potentials, and these patients seem to be also at a high risk of suffering from ventricular tachycardia.

Adult↗
PubMed1990

Body surface electrocardiographic mapping to assess left ventricular diastolic overload in valvular heart disease.

In order to assess diastolic overload by electrocardiogram (ECG), we performed body surface ECG mapping (MAP), and then compared the results with echocardiographic, roentgenographic and cardiac catheterization findings. Eighty-seven unipolar electrocardiograms were simultaneously recorded for the following groups: 1) 40 normal subjects, 2) 46 patients with diastolic overload [32 patients with aortic regurgitation (AR) and 14 patients with mitral regurgitation (MR)]. QRS isopotential maps were constructed at 10, 20, 30, 40, 50 and 60 msec from the QRS onset. On the potential departure map, the area where the QRS voltage was greater than the normal limits (mean + 2SD of normal control) was designated as "+2SD area". In patients with diastolic overload, +2SD area was found on the left anterior chest and back at 40, 50 and 60 msec from QRS onset. Subjects were classified into the following 3 groups according to the location of their +2SD area: 1) group A (n = 23) in which the +2SD area was found on the left anterior chest and back, 2) group B (n = 17) in which the +2SD area was found only on the back, and 3) group N (n = 6) in which no +2SD area was found. Group A had a markedly greater left ventricular end-diastolic internal dimension than the other groups (A 63.6 +/- 6.8 mm, B 53.9 +/- 5.5 mm, N 50.7 +/- 6.0 mm, A vs. B, N p less than 0.01), and a greater cardiothoracic ratio than the other groups (A 58.5 +/- 5.6%, B 52.5 +/- 7.0%, N 52.3 +/- 4.7%, A vs. B, N p less than 0.01). There was no significant difference in wall thickness among the 3 groups. The regurgitation severity assessed by cardiac catheterization was greater in group A than in the other groups. Among AR patients, the +2SD area was located on the upper back and the upper anterior chest, whereas among MR patients, it tended to be located on the lower portions. The potential departure map is a useful noninvasive analytic method for determining the extent and grade of diastolic overload. Furthermore, the location of the +2SD area may be used to discriminate between AR and MR.

Adolescent↗
PubMed1990

[Effect of aminophylline on thallium-201 washout rate during myocardial perfusion imaging with dipyridamole].

Thallium-201 myocardial perfusion imaging with dipyridamole was performed on 78 patients (pts) with suspected coronary artery disease (CAD). Twenty eight pts had normal coronary arteries (control group), and 50 pts had 50% or greater stenosis in one or more major coronary arteries (CAD group). In control group, aminophylline (Am) was infused intravenously on 12 pts during dipyridamole testing. Mean washout rate (WR) of these 12 pts was greater than that of 16 pts without Am (42% vs 35%, p less than 0.01). Then normal limit of WR was defined separately from the pts of control group with and without Am. The sensitivity for detecting the pts with CAD by WR analysis which normal limit was calculated separately with and without Am was 92% (46/50). When normal limit of WR was determined from all pts in control group, the sensitivity decreased to 84% (42/50). Am significantly affected thallium-201 washout during dipyridamole testing. WR of CAD pts should be estimated by specific set of normal limit with and without Am.

Aminophylline↗
PubMed1989

Effect of diltiazem on coronary blood flow distribution in dog heart under ischemia.

Effect of intracoronary infusion of diltiazem (1 microgram/min) on regional myocardial blood flow (RMBF) was studied using 15-microns radioactive microspheres in 11 excised cross-circulated canine left ventricles. With total coronary blood flow (CBF) and heart rate (HR) held constant, regional ischemia was induced by ligating the left anterior descending coronary artery (LAD). Diltiazem at the dose used had no effects on ventricular Emax before and after LAD ligation. RMBF expressed by the counts divided by the counts averaged in all segments in each layer significantly (p less than 0.05) increased under diltiazem only in the low-flow region that had less than 50% RMBF before diltiazem; from 21% (+/- 12%) to 35% (+/- 18%) in the epicardial, from 22% (+/- 12%) to 32% (+/- 18%) in the midwall, and from 24% (+/- 10%) to 31% (+/- 12%) in the endocardial layers. We conclude that the beneficial effect of diltiazem on the ischemic heart involves a direct action on the coronary vascular system and does not necessarily depend on the concomitant changes in hemodynamics.

Animals↗