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R Ajisaka

Publications and source records attributed to R Ajisaka.

68 records · Page 4Linked to original sources
PubMed1986

Digital subtraction angiography: image-sequence analysis for regional myocardial perfusion dynamics.

Digital subtraction angiography with selective coronary injections of contrast media has enabled us to obtain clear images, not only of the artery, but of the capillary and venous phases of the myocardial perfusion. In the present study, densitometry was used to estimate regional myocardial perfusion dynamics in 10 control cases and 11 anterior myocardial infarction cases. The time density curve showed that contrast material increased rapidly in the arterial phase and appeared to be washed out monoexponentially in the venous phase. The time from the onset of contrast medium injection to the maximal density of the contrast medium (Tp), and the time constant obtained from the washout curve (Tc) were analyzed. In the control group, Tp in the apical region was slightly prolonged as compared with Tp in the anterobasal region, but the difference was not significant (5.2 +/- 0.5 vs 4.2 +/- 0.4 sec: mean +/- SEM). Tc did not definitely change in any portion of the myocardium (anterobasal 5.1 +/- 0.5, anterior 4.8 +/- 0.5, apex 4.6 +/- 0.5 sec, respectively). In anterior myocardial infarction, Tp in the marginal region was significantly prolonged compared to Tp in the control region (6.0 +/- 0.3 vs 4.7 +/- 0.3 sec, p less than 0.01). Tp was prolonged for more than 10 sec in the infarcted region. Tc in the marginal region was markedly prolonged compared to Tc in the control region (7.4 +/- 0.9 vs 4.4 +/- 0.5 sec, p less than 0.025). Tc could not be determined in the infarcted regions because data acquisition time of our apparatus was inadequate.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Angiography↗
PubMed1986

[Sigmoid septum causing left ventricular outflow tract obstruction: a case report].

A 67-year-old man with a sigmoid septum causing the left ventricular outflow obstruction by inotropic stimulation was reported. This patient was admitted to the Hospital of the University of Tsukuba because of chest pain. Phonocardiography revealed a systolic ejection murmur which was intensified by amyl nitrite inhalation. A carotid pulse tracing showed a mid-systolic dip and a secondary slow wave during amyl nitrite inhalation. M-mode echocardiography demonstrated neither systolic anterior motion of the mitral valve (SAM) nor mid-systolic closure of the aortic valve at rest. Two-dimensional echocardiography revealed a basal interventricular septum markedly protruding into the left ventricle (sigmoid septum). The remainder of the septum and the left ventricular free wall were not hypertrophied, and no enlargement of the left ventricular cavity was observed. During exercise tests, blood pressure dropped significantly. Cardiac catheterization showed a pressure gradient within the left ventricle with isoproterenol infusion and post-extrasystolic potentiation. These findings suggest that left ventricular outflow tract obstruction could occur in a patient with sigmoid septum by inotropic stimulation, producing a fall of blood pressure during exercise.

Aged↗
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↗
PubMed1985

[Quantitative analysis of myocardial perfusion by digital subtraction angiography].

Digital subtraction angiography (DSA) has been adopted to detect ischemic myocardial areas and to quantitatively evaluate the degrees of myocardial perfusion abnormalities. Subtraction for selective coronary arteriography was performed sequentially between mask and enhanced images in the same cardiac phases by means of ECG signals. We obtained three distinct perfusion phases which we termed the arterial, capillary, and venous phases. Densitometry of the circumferential cardiac wall was performed on these sequential images. The results were compared with 201Tl myocardial scintigrams and cine angiograms. In the arterial phase, the abnormalities of the coronary artery, such as stenosis, obstruction and collaterals were represented. In the capillary phase, contrast materials served as markers of myocardial perfusion and delineated infarctions as areas of low contrast enhancement compared to the normally perfused myocardium. In the venous phase, the infarcted areas were represented as areas with greater relative contrast enhancement than that of the normal myocardium. Circumferential analysis of perfusion could provide more detailed information about myocardial ischemic areas and the degrees of ischemia. Although we used invasive selective coronary arteriography, DSA techniques have numerous merits such as excellent temporal resolution, spatial resolution, and good contrast resolution, over conventional methods. Quantitative DSA methodology which we developed provided not only anatomical information about the main coronary arteries but new information about abnormalities of peripheral myocardial perfusion.

Angiography↗
PubMed1985

[Regional myocardial perfusion abnormality detected by digital subtraction angiography in a case of patent ductus arteriosus with coronary arterial fistulae].

A 19-year-old woman with patent ductus arteriosus and increasingly severe chest pain received various examinations including exercise stress radionuclide test, which revealed hypokinesis and decreased myocardial perfusion in the apex and left ventricular dilatation. Conventional selective coronary arteriography and newly-developed ECG synchronized digital subtraction angiography (DSA) were performed to identify the genesis of her myocardial ischemia. Selective coronary arteriography revealed congenital coronary arterial fistulae in the right and left coronary arteries. The largest fistula was observed around the obtuse marginal artery terminating in the left ventricle. Although stenosis of the left circumflex and left anterior descending arteries (LAD) were not observed, the LAD appeared to be hypoplastic. Hypoplasia of the LAD and the steal phenomenon by arterial fistula could have been responsible for the myocardial ischemia in the apex, but this method did not clearly reveal the area and the degree of myocardial ischemia in the apex. Sequentially subtracted images during the arterial and capillary phases were obtained by utilizing ECG-synchronized DSA for selective coronary arteriography. For these images, densitometric analysis was adapted to the myocardial region, i.e. circumferential densitometry using 21 segments around the left ventricular wall. Decreased myocardial perfusion was clearly demonstrated in the apex in capillary phase images. Moreover, circumferential analysis provided detailed information about the area and the degree of impaired peripheral circulation in the myocardium. This analysis by DSA may prove useful for evaluating myocardial perfusion abnormalities.

Adult↗
PubMed1985

[Apical hypertrophy and catecholamine].

Catecholamine is suspected to be related to the pathogenesis of hypertrophic cardiomyopathy (HCM). To investigate the contribution of catecholamine to apical hypertrophy (APH) which is a special type of HCM, 16 normal controls, 49 +/- 4 years old; 14 patients with APH, 55 +/- 6 years old; 18 patients with other types of HCM, 53 +/- 8 years old; and 12 patients with left ventricular hypertrophy due to valvular heart diseases (VHD), 49 +/- 10 years old, were studied during treadmill exercise tests, supine ergometer tests and intravenous infusions of isoproterenol (ISP) (0.02 micrograms/kg/min for 5 min). Echocardiograms and/or electrocardiograms were obtained during the procedures. During ergometer exercise, there was no significant difference in increase of heart rates among all groups. Ergometer exercise increased the level of plasma catecholamine in the group VHD, and there was a similar but less marked tendency in the APH. During the ISP infusion, "mechanical" reaction was relatively low in the APH compared to those in the other groups. The giant negative T waves in the HCM, mostly in the APH, lessened during exercise and during the ISP infusion. Among those in whom negative T wave changes of more than 0.5 mV occurred during exercise, the wall motion of the left ventricle was more active during exercise. Giant negative T waves changed diurnally and were less deeper during daytime than at night.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiomyopathy, Hypertrophic↗
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↗
PubMed1984

[Pathophysiology of asymmetric septal hypertrophy with special reference to the response to isoproterenol administration].

To investigate the pathophysiological significance of asymmetric septal hypertrophy (ASH), echocardiograms were recorded in 25 patients with hypertension (HT) (12 with ASH, 13 with symmetric hypertrophy (SH), 19 patients with hypertrophic non-obstructive cardiomyopathy (HNCM) (eight with ASH, 11 with SH), and 12 patients with hypertrophic obstructive cardiomyopathy (10 with ASH and two with SH). In eight patients with ASH, 12 patients with SH and eight normal controls, echocardiograms were also recorded during intravenous infusion of 0.02 mu/kg/min of isoproterenol. There were no significant differences in end-diastolic dimension (EDD), end-systolic dimension (ESD), percent fractional shortening (%FS), interventricular septal excursion (IVSE) and posterior wall excursion (PWE) between patients with ASH and patients with SH. Among patients with ASH, interventricular septal thickness (IVST) and its ratio to posterior wall thickness (IVST/PWT) were significantly larger in HOCM than in others. Before isoproterenol infusion, there was no significant difference in the normalized peak rate of change of left ventricular dimension during systole (pVs) between ASH and SH, and between ASH and NC. However, 5 min after isoproterenol infusion, pVs was significantly greater in ASH (7.0 +/- 2.4/sec) than in SH (4.9 +/- 1.3/sec) and in NC (4.5 +/- 1.1/sec) (p less than 0.05 and p less than 0.05, respectively). This study suggests that ASH is related to hyperfunction of the catecholamine-beta receptor system.

Adult↗
PubMed1983

Role of exercise echocardiography as a predictor of coronary artery disease. Detection of exercise-induced asynergy by M-mode echocardiography.

Left ventricular asynergy has been shown to occur commonly in patients with coronary artery disease (CAD) and to be induced or exaggerated by exercise. The purpose of this study is to report on a method to detect asynergy and estimate its severity by M-mode echocardiographic analysis of left ventricular wall motion at rest and during supine ergometric exercise. Sixteen patients with CAD underwent graded supine ergometric exercise until anginal pain occurred or apparent ischemic changes were noted on ECG. This study was done using the following criteria: 1) Asynergy at rest was defined as occurring when the amplitudes of the interventricular septum and/or the posterior left ventricular wall were below normal values at rest. 2) Asynergy during exercise was defined as occurring when one or both of the two amplitudes were more than 2 mm below the values at rest (severe) or were unchanged in spite of sufficient exercise load (mild). The results were as follows: 1) In the normal subjects, the septal and posterior wall amplitudes increased during exercise (ranging from 7 mm to 9 mm for the septum, and from 13 mm to 16 for the posterior wall). In patients with CAD, asynergy at rest was demonstrated in only 3 cases (19%), whereas septal and/or posterior wall asynergy during exercise was noted in 75% of cases. 2) The location of exercise-induced asynergy detected by echocardiography showed a good correlation with that of coronary artery lesions (greater than or equal to 75% stenosis) recognized by angiography. 3) Significant differences were observed between changes in left ventricular dimensions in patients with CAD and those of normals during exercise. In the normal subjects, left ventricular end-systolic dimension (ESD) decreased without significant change in end-diastolic dimension (EDD) during exercise. On the other hand, both ESD and EDD increased during exercise in patients with CAD. Although echocardiographic analysis of left ventricular wall motion during exercise has some limitations, this study suggests that asynergy induced or exaggerated by ergometric exercise can be successfully detected by M-mode echocardiography.

Adult↗
PubMed1983

[Isoproterenol infusion stress two-dimensional echocardiography in detecting coronary artery disease].

Dynamic exercise two-dimensional (2-D) echocardiography has been utilized as a valuable method in the diagnosis of coronary artery disease (CAD). However, there are some limitations in this technique including inability to apply for patients whose physical capacity is limited. Moreover, appropriate echocardiographic recordings are frequently difficult because of bodily movements and/or hyperventilation during exercise. In order to overcome these limitations, we examined whether isoproterenol (ISP) infusion stress 2-D echocardiography could detect transient LV asynergy or not. The subjects consisted of 19 cases with angina pectoris (AP), 16 with old myocardial infarction (OMI), nine with atypical chest pain syndrome and six with miscellaneous heart disease. ISP stress test was performed prospectively as follows: ISP was infused at a rate of 0.02 microgram/kg/min until anginal pain occurred or significant ST depression (elevation) developed. Real time 2-D echocardiograms were obtained in the short-axis or apical RAO views of the LV before and every one minute during ISP infusion test. Coronary artery stenosis was considered to be present if the narrowing was 50% or more in the luminal diameter. The results were as follows: Adequate echocardiographic recordings were obtained in 86.1% of LV segments at rest, and in 82.2% during ISP infusion. Echocardiographic recordings during ISP infusion were feasible in almost all cases. LV wall motion abnormalities were detected in 12 (86%) of the 14 subjects with OMI and two (29%) of the seven subjects with AP at rest, while induced or exaggerated in nine (64%) of the 14 subjects with OMI and all of the 7 subjects with AP during ISP infusion. On the other hand, LV wall motion remained entirely normal during ISP infusion in 11 (92%) of the 12 subjects without CAD. In 4 (40%) of these 10 subjects without CAD, electrocardiographic judgements were positive in the ISP stress test. None had hazardous arrhythmias or severe anginal pain. ISP infusion stress 2-D echocardiography possessed feasibility of detecting LV wall motion abnormalities because this method could exclude difficulty of recordings due to bodily movements and/or hyperventilation seen in exercise echocardiography. Compared with ISP stress electrocardiography, 2-D echocardiography seemed to be superior with respect to the specificity in detecting CAD. In conclusion, ISP stress echocardiography is a safe and useful method in the diagnosis of CAD.

Adult↗