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Biomedical subjects

K Tsuiki

Publications and source records attributed to K Tsuiki.

At least 19 recordsLinked to original sources
PubMed1992

Dipyridamole electrocardiography test for the detection of severe coronary artery stenoses.

To investigate the relationship between dipyridamole-induced ST depression and the severity of coronary artery stenosis, the dipyridamole injection test (D) at 0.568 mg/kg/4 min, and the symptom limited treadmill exercise test (T) were performed separately in 16 normal volunteers and 167 patients who underwent coronary arteriography [91 patients without myocardial infarction (non-MI group) and 76 patients with previous myocardial infarction (MI group)]. Standard 12-lead electrocardiogram and body surface mapping of 87 leads were recorded in both tests. None of the normal volunteers had significant ST depression (greater than or equal to 0.10 mV) in D or T. Regarding the non-MI group, D had as high an incidence of ST depression as T (83% vs 93%) in patients with maximal coronary stenosis greater than or equal to 90%, while in those with maximum coronary stenosis less than 90%, D had a lower incidence of ST depression than T (16% vs 48%, p less than 0.01). For the MI group, the incidence of ST depression was compared to the maximal coronary artery stenosis supplying the non-infarcted area. In patients with maximal coronary artery stenosis greater than or equal to 90%, D had as high an incidence of ST depression as T (71% vs 64%). While, D had a lower incidence of ST depression than T (19% vs 35%, p less than 0.05) in those with maximum coronary artery stenosis less than 90%. For the diagnosis of coronary artery stenosis of greater than or equal to 90%, D had as high sensitivity (non-MI group, 82% vs 93%; MI group, 71% vs 64%) and higher specificity (non-MI group, 84% vs 52%, p less than 0.01; MI group, 81% vs 65%, p less than 0.05) compared with T. This study demonstrated that dipyridamole ECG is a sensitive and specific test to detect severe coronary artery stenosis.

Adult↗
PubMed1991

Functional recovery of hibernating myocardium after coronary bypass surgery: does it coincide with improvement in perfusion?

To determine the relationship between functional recovery and improvement in perfusion after coronary artery bypass graft surgery (CABG), 49 patients were studied. Radionuclide angiography was performed before, 1 month after, and 6 to 12 months after CABG to evaluate regional wall motion. Exercise thallium-201 myocardial perfusion imaging was done before and 1 month after CABG to assess regional perfusion. Preoperative asynergy was observed in 108 segments, and 74 of them showed an improvement in wall motion 1 month after CABG (segment A). Sixty-six of these segments (89%) were associated with an improvement in perfusion. Eight segments that had not improved 1 month after CABG demonstrated a delayed recovery of wall motion 6 to 12 months after CABG (segment B). However, seven of eight segments (88%) already showed an improvement in perfusion 1 month after CABG. A total of 82 segments exhibited functional recovery after CABG and were considered hibernating segments. In the preoperative study segment B more frequently had areas of akinesis or dyskinesis than segment A (75% vs 34%, p less than 0.05). The mean percent thallium-201 uptake in segment B was lower than that in segment A (74% +/- 9% vs 83% +/- 8%, p less than 0.05). Functional recovery of hibernating myocardium usually coincided with an improvement in perfusion. However, delayed functional recovery after reperfusion was observed in some instances. Severe asynergy and severe thallium-201 defects were more frequently observed in these segments with delayed recovery. Hibernating myocardium might remain stunned during those recovery periods.

Coronary Artery Bypass↗
PubMed1991

Dilatation of the left ventricular cavity on dipyridamole thallium-201 imaging: a new marker of triple-vessel disease.

To investigate the significance and mechanism of dilatation of the left ventricular cavity on dipyridamole thallium-201 imaging, we performed both dipyridamole thallium-201 imaging and dipyridamole radionuclide angiography on 83 patients with known angiograms. The dipyridamole/delayed ratio of the left ventricular dimension from the thallium-201 image was defined as the left ventricular dilatation ratio (LVDR). An LVDR greater than the mean + two standard deviations in patients without coronary artery disease was defined as abnormal. Twenty-two of 83 patients showed an abnormal LVDR, and 18 of the 22 patients (82%) had triple-vessel disease. By defect and washout analysis, the sensitivity and specificity for correctly identifying the patients as having triple-vessel disease was 72% and 76%, respectively, whereas LVDR had a sensitivity of 72% and a specificity of 93%. When LVDR was used in combination with the defect and washout criteria, sensitivity increased to 84% without a loss of specificity. In those 22 patients with abnormal LVDRs, end-diastolic volume measured by radionuclide angiography did not change after dipyridamole infusion. Dilatation of the left ventricular cavity on dipyridamole thallium-201 imaging reflected relative subendocardial hypoperfusion induced by dipyridamole rather than actual chamber enlargement. The LVDR was moderately sensitive and highly specific for triple-vessel disease and provided complementary information to dipyridamole thallium-201 imaging.

Adult↗
PubMed1991

Signal-averaged body surface mapping for the assessment of low-amplitude potentials. Detailed maps during early ventricular activation in normal subjects.

Body surface isopotential maps around early ventricular activation were investigated in 30 normal subjects by the use of the authors' signal-averaged body surface mapping system. The number of beats averaged was 96-154 (mean, 127). Two distinct patterns were recognized in the appearance of a maximum at the onset of ventricular activation: the maximum in the first type (n = 16) was located on the right anterior chest; the maximum in the second type (n = 14) was on the central or left anterior chest. The site of the earliest ventricular activation was considered to be different in each of these types. During early ventricular activation, 25 subjects (83%) had two minima: one was on the left lateral chest and the other was on the left back. The two minima probably reflect two different receding activation fronts in the ventricles. The data in the present study are important to the understanding of the early ventricular activation process, as well as the diagnosis of heart diseases in which this process is disturbed.

Adolescent↗
PubMed1991

Coronary artery aneurysm without stenosis in association with Osler-Weber-Rendu disease--a case report.

A fifty-three-year-old woman presented with coronary artery aneurysm in association with Osler-Weber-Rendu disease (hereditary hemorrhagic telangiectasia) manifested also by large pulmonary arteriovenous fistulas. The arterial dye dilution curves were unusually distorted owing to the right-to-left shunts. The coronary artery aneurysm was located in multiple sites but was not accompanied by stenotic lesions. Coronary artery aneurysm without stenosis is a rare pathologic state and has not been previously reported in association with hereditary telangiectasia.

Arteriovenous Fistula↗
PubMed1991

Simultaneous assessment of left ventricular wall motion and myocardial perfusion at rest and during exercise by technetium-99m methoxy isobutyl isonitrile.

First-pass radionuclide ventriculography followed by myocardial SPECT with technetium-99m methoxy isobutyl isonitrile (Tc-99m MIBI) was performed on 12 patients with suspected coronary artery disease at rest and during exercise. Left ventricular wall motion and myocardial perfusion were assessed simultaneously and compared on a segment-by-segment basis. Segmental agreement between Tc-99m MIBI and Tl-201 with regard to the presence of perfusion defects was 95% (57/60) at rest and 93% (37/40) during exercise. With respect to the assessment of myocardial ischemia and/or infarction, abnormalities in regional wall motion agreed with the presence of myocardial perfusion defects in 18 out of 21 segments (86%). Simultaneous evaluation of regional wall motion and myocardial perfusion by Tc-99m MIBI may provide useful information for the assessment of myocardial ischemia.

Adult↗
PubMed1991

The response of left ventricular regional function to afterload stress in patients with old myocardial infarction and ventricular aneurysm.

The functional response of the left ventricle with scar to increased afterload, was examined in 15 patients with old myocardial infarction and left ventricular aneurysm (OMI). Interventional cine left ventriculography during elevating left ventricular pressure with methoxamine. Wall motion was assessed by the radial and the centerline method. Augmented afterload didn't change ejection fraction in patients with OMI, but normalized wall motion (Z) increased in the aneurysmal region and decreased in the remote region in both methods. In the remote region in patients with OMI, afterload stress shortened left ventricular pressure-radial length (P-L) loops along length axis, and reduced percent systolic radial shortening (SS). In the aneurysmal region, P-L loops showed systolic elongation of length at rest and the slope of end-diastolic point to end-systolic point became steeper with increased afterload, resulting in a decrease of aneurysmal expansion. In summary, with increasing afterload, wall motion decreased in non-infarcted regions and increased in aneurysmal regions, in left ventricles with aneurysm. This mechanism may be interpreted as afterload-induced shifts of P-L loops in each region.

Adult↗
PubMed1991

Significant stenosis of coronary arteries in patients with single and multiple vessel diseases without previous myocardial infarction.

To determine what degree of stenosis should be counted as a significant lesion in each of 3 major coronary arteries in classification of the number of vessels involved, coronary arteriographic percent diameter narrowing (by quantitative angiography) was compared with thallium-201 scinitgraphic redistribution on treadmill exercise in 47 patients with evidence of exercise myocardial ischemia and greater than or equal to 50% diameter narrowing (visual assessment) in at least 1 major coronary artery. Severity of exercise-induced myocardial ischemia for the entire left ventricle (assessed by averaged redistribution index) was separated most sufficiently with definition of 63-64% or greater between patient groups with no- and single-, single- and double-, and double- and triple-vessel diseases. Collaterals and intraventricular contractile interaction are possibly the factors making definition more severe in extensive coronary artery disease. Since the visual method gives an overestimation of stenosis, it was concluded that vessel diameter narrowing of 70% or more should be regarded as significant in patients with single and multiple vessel diseases if the visual method is used.

Adult↗
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↗