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Biomedical subjects

Y Koiwaya

Publications and source records attributed to Y Koiwaya.

90 records · Page 5Linked to original sources
PubMed1982

Immediate appearance of coronary collaterals during ergonovine-induced arterial spasm.

Angiographically demonstrable collateral flow occurred immediately when coronary arterial spasm was induced by ergonovine in two patients with angina who had organic stenosis of less than 40 percent. These findings suggest that coronary collaterals may develop in response to intermittent brief myocardial ischemia in man, and that collaterals may be preserved even if they are closed at rest and can immediately function when a coronary artery is acutely occluded.

Angina Pectoris↗
PubMed1982

Hemodynamic effects of intravenous diltiazem in patients with recent myocardial infarction.

The hemodynamic effects of intravenous diltiazem, 0.2 mg/kg, were examined in eight patients with recent myocardial infarction. Diltiazem lowered mean aortic pressure (87.0 +/- 3.3 to 79.9 +/- 3.1 mmHg, P less than 0.01) and systemic vascular resistance (1353.0 +/- 136.2 to 964.9 +/- 101.7 dynes.sec.cm-5, P less than 0.01), and increased cardiac index (3.77 +/- 0.27 to 4.72 +/- 0.41 liters/min/sq m, P less than 0.01) and stroke index (57.5 +/- 4.5 to 69.4 +/- 7.6 ml/beat/sq m, P less than 0.05). No significant changes in the left ventricular end-diastolic, right atrial, and pulmonary arterial pressure, or heart rate were noted after diltiazem. These results suggest that the negative inotropic effects of diltiazem are negligible even in patients with recent myocardial infarction. The electrocardiogram should be observed carefully, however, since the PR interval was further prolonged in one patient who had first-degree atrioventricular block before diltiazem.

Adult↗
PubMed1981

Increased exercise tolerance after oral diltiazem, a calcium antagonist, in angina pectoris.

Effects of diltiazem, a recently introduced calcium antagonist, on exercise performance were studied in nine coronary disease patients with effort angina. The duration of exercise before the onset of angina and the time to the onset of ischemic ST depression 2 hours after 90 mg of oral diltiazem were compared with those 2 hours after oral placebo and a few minutes after 0.3 mg of sublingual nitroglycerin. Diltiazem prolonged the duration of exercise in all nine patients (average 2.5 minutes, p less than 0.001) and delayed the onset of ischemic ST depression (average 2.4 minutes, p less than 0.001). The increment of the duration of exercise and the time to the onset of ischemic ST depression following 90 mg of oral diltiazem were almost equivalent to that following sublingual nitroglycerin. These results in fixed coronary atherosclerosis indicate the clinical antianginal efficacy of diltiazem which persists for at least 2 hours after oral administration.

Adult↗
PubMed1981

Coronary arterial spasm in single coronary artery.

A 48-year-old man developed severe chest pain and became unconscious. Coronary cineangiography revealed single coronary artery of the type L2b by Sharbaugh and White. Ergonovine, 0.2 mg i.v., produced coronary arterial spasm in the right coronary artery. This case suggests that coronary arterial spasm might be a cause of sudden death in patients with single coronary artery. However, an association of single coronary artery and coronary arterial spasm might be coincidental.

Coronary Angiography↗
PubMed1981

Plasma concentration of diltiazem after oral administration in normal volunteers.

The plasma concentration and hemodynamics of diltiazem after oral administration of 90 mg were studied in nine normal volunteers. Diltiazem was rapidly absorbed within three hours, and mean peak plasma concentration was 93.3 +/- 12.6 ng/ml (mean +/- SE). The plasma level gradually declined soon after, and almost no diltiazem was determined in 24-hours. Heart rate and blood pressure decreased slightly but significantly (P less than 0.001 and P less than 0.005, respectively). No prolongation of PR interval was demonstrated.

Administration, Oral↗
PubMed1980

The change in the left atrial dimension during diastole. Echocardiographic assessment of mitral stenosis.

The change in the left atrial dimension during diastole was examined in patients with mitral stenosis using echocardiography. The left atrial emptying fraction (LAEF), defined as the ratio of enddiastolic dimension to endsystolic dimension of the left atrium, was 0.65 +/- 0.03 (mean +/- SE) for normal subjects, 0.86 +/- 0.01 for low grade mitral stenosis, and 0.92 +/- 0.01 for high grade stenosis. The LAEF correlated well with mitral valve area index (r = -0.70), but the correlation between E-F slope of the anterior mitral leaflet and mitral valve area index was less significant (r = 0.48). In patients who received mitral valve replacement the LAEF and the left atrial dimension significantly improved. The left atrial emptying fraction is an easily obtainable and reliable index to estimate the severity of mitral stenosis, even in patients who have undergone mitral valvular surgery.

Adult↗
PubMed1980

Simultaneous closure of the tricuspid and mitral valve in Ebstein's anomaly.

Echocardiographic studies of a 23-year-old man with Ebstein's anomaly and type B Wolff-Parkinson-White syndrome showed almost simultaneous closure of the tricuspid and mitral valve. After administration of edrophonium chloride, the tricuspid valve closed 20 msec earlier than the mitral valve. However, the closure of the mitral valve preceded that of the tricuspid valve after administration of ajmaline and atropine sulfate by 90 msec and 60 msec, respectively, concomitant with obliteration of preexcitation. From these observations, the simultaneous closure of the tricuspid and mitral valve of this case appears to depend on the preexcitation of the right ventricle.

Adult↗
PubMed1979

Early closure of the tricuspid valve in a case of Ebstein's anomaly with type B Wolff-Parkinson-White Syndrome.

Echocardiographic studies of a 19-year-old female with Ebstein's anomaly and type B Wolff-Parkinson-White syndrome showed an earlier closure of the anterior tricuspid leaflet (ATL) than of the anterior mitral leaflet (AML), contrary to the previous reports. The interval between the closure of the ATL and the AML was 20 msec and 30 msec, respectively, before and after administration of edrophonium chloride. However, closure of the AML preceded that of the ATL after administration of atropine sulfate and during supraventricular tachycardia by 10 msec and 60 msec, respectively, concomitant with the shortening of the duration of the QRS complex. We conclude that early closure of the ATL may depend on preexcitation of the right ventricle.

Adult↗
PubMed1979

Beneficial effect of diltiazem, a new antianginal drug, on angina pectoris at rest.

The effect of oral administration of diltiazem, a new 1,5-benzothiazepine derivative, on the frequency of anginal attack at rest was studied in 8 patients. Our own experience showed that diltiazem gave excellent results in patients with ST elevation (variant type) but its effect was insufficient in the patients whose ST segment was depressed during the attack.

Aged↗
PubMedDate not supplied

Coronary angiographic findings in infarct-related arteries following 1 month of medical treatment.

PURPOSE: We undertook the present study to determine first whether coronary angiographic (CAG) features, suggestive of ruptured atherosclerotic plaque, develop in infarct-related arteries of patients receiving conventional medical therapy without thrombolytic agents, and if they develop, what the incidence is, and second whether the sites where the CAG features develop are specific to infarct-related lesions. METHODS: We reviewed the CAG findings of 127 consecutive patients one month after myocardial infarction (MI), including 72 consecutive patients who received medical therapy (Group I) and 55 patients who underwent intracoronary urokinase infusion (Group II). RESULTS: Angiographic evidence of ruptured plaque was present in 24/44 (54.5%) patent infarct-related arteries in Group I and in 27/43 (62.8%) in Group II. Similar findings were only noted in 2/52 (3.8%) patent non-infarct-related arteries with significant stenosis in Group I, and in 0/45 (0.0%) in Group II. CONCLUSION: On angiography, ruptured plaque was commonly found in patent infarct-related arteries in both groups, and was highly specific for the site of infarction. Thrombolytic therapy seemed to have no apparent effect on lesion morphology 1 month after MI.

Anticoagulants↗
PubMedDate not supplied

Effect of graded coronary stenosis on regional myocardial blood flow and left ventricular function.

Dogs with 70% stenosis of the left circumflex coronary artery showed a reduction of myocardial blood flow with a minimal impairment of left ventricular wall motion. Eighty to ninety percent stenosis produced a marked reduction of flow and wall motion, and ST elevation close to 100% occlusion, but delayed antegrade run-off was found. The effectiveness of collaterals to protect against left ventricular dysfunction was supported.

Animals↗
PubMedDate not supplied

Nitrate tolerance: hemodynamic effects of intravenous isosorbide dinitrate after sustained oral isosorbide dinitrate administration.

To determine whether hemodynamic effects of isosorbide dinitrate (ISDN) diminish and disappear during sustained administration, nine patients with recent myocardial infarction received 10 mg of ISDN intravenously before and 1, 4, 12, 24, and 48 weeks after sustained oral administration of 20 mg of the slow-release form of ISDN four times daily. Blood pressure always decreased after intravenous ISDN; the decrease tended to be diminished when preceded by oral ISDN, but no further attenuation in blood pressure was noted. The decrease in blood pressure was associated with consistent and nonsignificant increases in heart rate after intravenous ISDN. Plasma ISDN levels were not affected by prior oral ISDN. Plasma isosorbide 2-mononitrate and isosorbide 5-mononitrate levels were consistently higher when preceded by oral ISDN. The results suggest that the hemodynamic and metabolic properties of ISDN are preserved even after sustained therapy.

Administration, Oral↗