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Biomedical subjects

N Kanemoto

Publications and source records attributed to N Kanemoto.

At least 19 recordsLinked to original sources
PubMed1995

New markers of remote ischemia in patients with evolving inferior myocardial infarction.

Multivessel disease and decreased left ventricular ejection fraction (LVEF) are believed to be significant predictors of the outcome in patients with acute inferior myocardial infarction (AIMI). We attempted to determine new electrocardiographic (ECG) markers for detecting concomitant left anterior descending (LAD) disease and/or decreased left ventricular function in patients with AIMI. Eighty patients with AIMI were evaluated within 6 h of the onset of symptoms and grouped according to the presence (Group 1) or absence (Group 2) of concomitant LAD disease. All of the patients underwent coronary angiography and left ventriculography 4-6 weeks from the onset of their infarction. We studied the validity of two new ECG markers: S-T depression deeper in lead V5 than in V4 (S-T decreases V5 > V4) and negative U waves (NUs) > 0.5 mm (50 muV) in leads V4-6. The sensitivity and specificity of S-T decreases V5 > V4, NUs in V4-6, or both, in detecting concomitant LAD disease were 56% and 83%, 59% and 87%, and 35% and 98%, respectively. LAD lesions in patients who showed either of these new markers (74% of those with S-T decreases V5 > V4 and 80% of those with NUs in V4-6) were mostly in the proximal segments (AHA segments #6 or #7). Patients with either S-T decreases V5 > V4 or NUs in V4-6 tended to have asynergy in the anterolateral segment, while there was a strong correlation between the asynergy of the anterolateral and septal segments in patients who showed both ECG markers.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[Electrocardiographic characteristics of patients with left circumflex-related myocardial infarction in the acute phase without tented T waves or definite ST elevation].

Acute myocardial infarction (AMI) causing ST depression and T wave inversion has been diagnosed as subendocardial or non-Q myocardial infarction. However, some patients eventually develop strictly posterior infarction with a lesion of the left circumflex coronary artery (LCX). This study attempted to determine the electrocardiographic (ECG) characteristics of such myocardial infarction in 32 patients with definite AMI in whom ECG showed no hyperacute T waves or ST elevation and the LCX was an infarct-related coronary artery. ECG on admission (< 6 hours from the onset), at 24 hours, and on the 14th day were analyzed to evaluate QRS, ST, T, and U waves using calipers and magnifying lens. Sixty-six patients with normal circulation served as controls. The characteristic ECG findings on admission were ST depression in chest leads, and prominent positive U waves in leads V2 or V3 with relatively small T waves. Based on these results we proposed new ECG criteria: 1) ST depression > or = 0.1 mV in 2 consecutive chest leads, 2) prominent positive U wave > or = 0.1 mV in leads V2 or V3, 3) T/U ratio in leads V2 or V3 < or = 4. Considering two of the above criteria as positive, the sensitivity was 71.9%, the specificity 97.0%, and the diagnostic accuracy 88.8%. In 85.2% of the patients, ST depression returned to the baseline by 24 hours. As the amplitude of the U waves decrease gradually, the T/U ratio increased. The R/S ratio in leads V1 or V2 became > or = 1 by 24 hours in 46.4% and the amplitude of R wave in lead V1 increased gradually. T waves in the right precordial leads increased with time. These findings were consistent with isolated strictly posterior myocardial infarction. From these results we identified new ECG criteria: 1) R/S ratio in leads V1 or V2 > or = 1, 2) R wave > or = 0.7 mV in lead V1, 3) T wave > or = 0.5 mV in lead V1. Considering any of the above criteria as positive, the sensitivity was 72.0%, the specificity 87.9%, and the diagnostic accuracy 86.7% on the 14th day. These new ECG criteria of strictly posterior myocardial infarction with the LCX as an infarct-related coronary artery apply at less than 6 hours or at 24 hours from the onset of the symptoms.

Aged↗
PubMed1995

[Identical male twins showing progression from hypertrophic cardiomyopathy to dilated cardiomyopathy-like features].

Twenty-three-year-old identical male twins with hypertrophic cardiomyopathy which progressed into the dilated phase are reported. The younger brothers first presented at age 16 with an abnormal electrocardiogram. Hypertrophic nonobstructive cardiomyopathy with an asymmetric septal hypertrophy was diagnosed. He was treated with beta-blocker, but he stopped taking the drug as he had no symptoms at that time. He presented again at age 21 years with symptoms of apparent congestive heart failure. Echocardiography showed marked dilatation of the left ventricle with thin wall which was compatible with dilated cardiomyopathy. The elder brother presented with an initial echocardiogram showing systolic anterior movement of the mitral valve without asymmetric septal hypertrophy. He presented again with his brother aged 21 years when his echocardiogram showed slight dilatation of the left ventricle, although he did not complain of cardiac symptoms. These identical twins are the first reported cases of hypertrophic cardiomyopathy progressing to the deteriorated dilated phase.

Adult↗
PubMed1995

Structure and action of MIP (Mytilus inhibitory peptide)-related tetrapeptides synthesized with a multipeptide synthesizer.

Using a multipeptide synthesizer we synthesized 19 peptide libraries, each of which consisted of 19 MIP-related tetrapeptides, and isolated a number of peptides, which have an inhibitory effect on phasic contraction of the ABRM of Mytilus, from the libraries. To the present, the structures of about 30 species of the peptides were determined, and the peptides with the determined structures were synthesized. The structure and action of each synthetic peptide was compared with those of others to explain structure-activity relationship of MIPs.

Amino Acid Sequence↗
PubMed1994

Evaluation of a nine-lead Holter monitor for identifying and localizing ischemia and coronary artery disease detected by quantitative thallium-201 tomography.

We devised a nine-lead Holter monitor system with a lead-switching technique to record electrocardiograms from multiple sites in the anterior and the posterior or lateral chest. Leads CM1 to CM6, high lateral (HL), low lateral (LL), and low posterior chest (LB) were used. The sensitivity, specificity, and predictive accuracy of this system for identifying specific regions of myocardial ischemia and coronary artery disease were investigated in 130 patients with coronary artery disease. Anterolateral leads (CM4 to CM6, HL, and LL) showed high sensitivity for detecting anterior and lateral ischemia (69% to 100%) but low specificity (4% to 44%) compared with tomographic results. The specificity of these leads for identifying single-vessel disease was low (6% to 47%) although some leads showed high sensitivity (69% to 100%). In contrast, the LB lead exhibited high sensitivity and specificity for detecting inferior ischemia (70% and 95%, respectively) and right coronary artery (RCA) disease (74% and 93%, respectively). Consequently, ST depressions in the LB lead (anode) are specific for identifying inferior ischemia and RCA disease, whereas those in the anterior and lateral chest leads do not identify the ischemic region or the obstructed coronary artery.

Coronary Angiography↗
PubMed1994

An adult case of cardiac fibroma.

The patient, a 48-year-old woman with cardiac fibroma, is the second oldest patient with this disease in Japan. Her electrocardiogram showed findings compatible with old high lateral, posterior and possibly lateral myocardial infarction, regions which corresponded to the tumor site. In patients whose electrocardiogram suggests a previous myocardial infarction (pseudo myocardial infarction), the possibility of intramyocardial tumor should be taken into consideration.

Diagnosis, Differential↗
PubMed1993

[Successful excision of a left ventricular fibroma in an adult patient].

A 48-year-old woman with negative T waves in leads I, a VL and V4-6 in the ECG was examined. The cross-sectional echography and the MRI revealed that she had a tumor in the free wall of the left ventricle. Under the cardiopulmonary bypass, the intramural fibroma (6 by 6 by 4 cm) of the left ventricle was resected and the defect was repaired by sutures of the outer myocardial layers to keep the left ventricular volume. Forty eight days after the initial operation, a reoperation was performed by interrupted sutures of the whole myocardial layers. She is doing well without any troubles 14 months after the reoperation.

Electrocardiography↗
PubMed1993

[Early diagnosis and management of acute pulmonary embolism: clinical evaluation those of 225 cases].

To contribute for making early diagnosis and treatment of acute pulmonary embolism (APE), we investigated on clinical pictures of 225 patients with APE. Common underlying factors were heart disease, prolonged bed rest, post-surgical state, thrombophlebitis, malignant tumor and post-catheterization state in this order. Dyspnea, chest pain, tachycardia and shock were frequently seen as initial symptoms and signs. Blood screening showed leukocytosis, hypoxemia, hypocapnia and elevated serum LDH. Electrocardiographic findings highly demonstrated were ST.T abnormalities, such as T inversion with ST elevation in V1-3, ST depression in V4-6 and sinus tachycardia. Chest X-rays showed diminished pulmonary vascular marking and pulmonary artery dilation. Right ventricular dilatation were frequently seen on 2-dimensional echocardiograms. Pulmonary artery pressure were elevated up to 49/20 (30) mmHg. Twenty-five percent of the patients died, and the recurrence was seen in 4%. Thus, as soon as APE is suspected by above clinical findings, definitive diagnosis should be obtained by the lung perfusion scan and pulmonary arteriography, then oxygen and thrombolytic agents should be given immediately to prevent the fatal outcome.

Acute Disease↗
PubMed1992

A case of accessory mitral valve leaflet associated with solitary mitral cleft.

Accessory mitral valve leaflet is a rare congenital anomaly. More than half of the cases show other congenital cardiac defects and almost all of the cases show subaortic obstruction. We report a case of an accessory mitral valve tissue without outflow obstruction associated with mitral cleft of the posterior mitral leaflet. To our knowledge, this is the first reported case of the combination of these two congenital anomalies.

Adult↗
PubMed1992

Giant negative U waves in a patient with uncontrolled hypertension and severe hypokalemia.

A 66-year-old woman with a long history of hypertension had an electrocardiogram with giant negative U waves in left precordial leads despite hypokalemia. This seems to be the first report of giant negative U waves induced by uncontrolled hypertension with hypokalemia. The occurrence of negative U waves in the presence of profound hypokalemia is an important observation because it masks the electrocardiographic manifestation of hypokalemia.

Aged↗
PubMed1992

Intermittent anterior divisional block and far advanced right bundle branch block induced by vasospasm during exercise testing.

A patient is reported in whom exercise induced reversible ischemic left anterior fascicular block and far advanced right bundle branch block. Master's two step exercise test for pre-operative check-up revealed significant ST elevation in leads V1-5, negative U waves in leads V3-5 and fascicular blocks with retrosternal anginal chest pain. Long acting nitrate and nicorandil relieved the fascicular blocks.

Aged↗
PubMed1992

Early diagnosis of the site of infarction and the infarct-related coronary artery in patients with acute inferior myocardial infarction.

We evaluated the relationship between the site of infarction and the infarct-related coronary arteries from electrocardiograms (ECGs) recorded early after the onset of chest pain in patients with an initial acute inferior myocardial infarction (IMI). The subjects were 80 patients (mean age 57 +/- 12 years) with IMI admitted within 6 hours from the onset of chest pain. This was prior to the thrombolytic era. We analyzed the ECGs on admission, at 24 hours and at 4 weeks. All patients underwent left ventriculography and coronary angiography at 4-6 weeks from the onset of the IMI. Left ventricular ejection fraction (EF) and regional area changes were measured. The infarct-related coronary artery was determined by the site of the asynergy. Patients were allocated into 2 groups according to the infarct-related artery, i.e. right (RCA, n = 52) and left circumflex (LCX, n = 28). Parameters measured were ST elevation, amplitude and width of R wave and R/S ratio in leads V1 and V2, and amplitude of U waves in leads V1 to V3. We defined the U wave as a prominent positive U wave (PPU) if it was > 0.5 mm (50 microV) in height. A significantly greater number of patients with PPU showed asynergy in posterolateral segments compared to those without PPU. The EF was significantly lower in patients with PPU than in those without (46 +/- 12% vs 54 +/- 13%, p < 0.05). Patients with PPUs eventually showed ECG evidence of posterior infarction (increased R wave duration and R/S ratio > or = 1 in lead V1 or V2) by 4 weeks compared to those without PPUs. Also a significantly greater number of patients with PPUs developed posterior infarction shown by left ventriculograms than those without PPUs. As to the infarct-related coronary arteries, a significantly greater number of patients with LCX disease showed concomitant posterior infarction than those with RCA disease. Also, a significantly greater number of LCX patients showed PPUs and ST elevations in leads V5 and V6 than those with RCA disease. The sensitivity of PPUs and ST elevations in leads V5 and V6 suggesting LCX disease was 60% and the specificity was 98% with a predictive accuracy of 87%. Therefore, we conclude that PPUs in leads V1-3 and ST elevations in leads V5 and V6 are specific markers for the diagnosis of LCX-related infarction in the setting of evolving IMI.

Adult↗
PubMed1992

Electrical alternans of the T-U wave without change in the QRS complex.

A patient with myelocytic leukemia who showed electrical alternans of the T-U wave with no change in the QRS complex following chemotherapy is described. Electrocardiogram taken 4 days later showed ventricular quadrigeminy in which the T-U wave of the first sinus beat after the ventricular premature contraction was markedly less prominent compared to the successive two sinus beats which showed marked prolongation and inverted T-U waves. The causative factors for alternans of T-U waves may include hypochloremic alkalosis with hypopotassemia and myocardial damage by anticancer drugs such as daunomycin and aclarubicin chloride used for the underlying disease.

Aclarubicin↗
PubMed1992

A corrected transposition of the great arteries with situs inversus visceralis and cleft palate, but without other cardiac defects.

A 17-year-old female admitted for cleft palate surgery was referred for further evaluation of her cardiac condition. The patient had been diagnosed as dextrocardia at birth, without any cardiac murmurs. She has led a normal life. The apical impulse was felt at the fifth intercostal space at the right mid-clavicular line. The ECG and chest x-rays were strongly suggestive of corrected transposition of the great arteries (CTGA) with situs inversus visceralis. Findings of the two-dimensional and Dopplar echocardiograms showed CTGA with a mild morphologic tricuspid regurgitation without any other complicated cardiac anomalies. In the Japanese literature, 36 CTGA patients without associated cardiac defects have been reported. Of these, four patients revealed dextrocardia. To our knowledge, our patient is the first reported adult case without any cardiac defects, only minimal tricuspid regurgitation, situs inversus totalis and cleft palate.

Abnormalities, Multiple↗
PubMed1991

Significance of U wave polarities in previous anterior myocardial infarction.

The significance of the polarity of U waves in left precordial leads was evaluated in relation to myocardial perfusion (T1 201 myocardial scintigraphy) and left ventricular function (99m Tc radionuclide ventriculography) in 63 patients with clinical and electrocardiographic evidence of a previous anterior myocardial infarction. Patients were divided into three groups according to the polarity of the U waves: positive U waves, flat U waves, and negative U waves. Twelve matched patients served as normal controls. The following parameters were analyzed: (1) total number of abnormal Q waves; (2) total myocardial perfusion index and regional myocardial perfusion index; (3) global ejection fraction; (4) regional ejection fraction; and (5) number of diseased coronary arteries. The total myocardial perfusion index values were 43.9 +/- 1.0 in controls, 40.8 +/- 3.4 in the positive U wave group, 33.4 +/- 3.5 in the flat U wave group, and 30.3 +/- 4.4 in the patients with negative U waves. Global ejection fractions in these groups were, respectively, 63.9 +/- 8.6%, 65.0 +/- 11.8%, 53.6 +/- 8.1%, and 36.5 +/- 13.6%. The sensitivity of negative U waves suggesting a global ejection fraction of less than 45% was 91.6%, and the specificity was 82.1%. Therefore the size of myocardial infarction increased and left ventricular function decreased, in order, from patients with positive U waves, to those with flat U waves, to those with negative U waves, with statistically significant differences.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Intravenous recombinant tissue-type plasminogen activator (rt-PA) and urokinase (UK) in patients with evolving myocardial infarction--a multicenter double-blind, randomized trial in Japan.

Intravenous administrations of 2000 x 10(4)IU (33 mg) (rt-PA2) and 3000 x 10(4)IU (50 mg) (rt-PA3) of a new recombinant tissue plasminogen activator (rt-PA:TD-2061) derived from uterine endothelial cells and urokinase (UK) 96 x 10(4)IU were compared in a double blind, randomized trial of 198 patients with evolving myocardial infarction. All patients entered the trial within 6 h of the onset of symptoms and underwent baseline coronary angiography of the infarct-related coronary artery before thrombolytic therapy was instituted. Sixty minutes following thrombolytic therapy occluded infarct-related arteries were successfully reperfused in 41.5% of 66 patients in the UK, 76.4% of 72 patients in the rt-PA2, and 74.6% of 59 patients in the rt-PA3 group. Statistically significant differences were observed between the UK and rt-PA groups (p less than 0.01). Serum fibrinogen levels declined in all 3 groups at 60 min post-therapy by averages of 35.9 +/- 3.1% in the UK, 16.8 +/- 4.8% in the rt-PA2 and 17.5 +/- 4.5% in the rt-PA3 group. The difference between the UK and the rt-PA groups was statistically significant (p less than 0.01). Plasma plasminogen and alpha 2-plasmin inhibitor levels showed the same tendencies. Bleeding was the most commonly observed complication and was most commonly seen at the catheterization site. There was no difference in the incidence among the 3 groups. Hospital deaths occurred in 5.3%, 6.3%, and 4.7% of the cases in the UK, rt-PA2 and rt-PA3 groups, respectively. We conclude, therefore, that rt-PA achieves a significantly higher rate of recanalization with less extensive systemic fibrinogenolysis at the dose employed than does UK. The optimum intravenous dose of rt-PA for Japanese patients is considered to be 2000 x 10(4)IU (33 mg).

Blood Coagulation↗