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Biomedical subjects

R Shimada

Publications and source records attributed to R Shimada.

At least 37 records · Page 2Linked to original sources
PubMed1985

Exaggerated posterior aortic wall excursion. A new echocardiographic feature of atrial septal defect with left to right shunt?

In 32 adult patients with a secundum type atrial septal defect (ASD) and normal pulmonary vascular resistance, the posterior aortic wall excursion (AoE) was measured using M-mode echocardiography, before, 16.2 +/- 4.5 days after, and 2.4 +/- 1.1 years after operative repair of the ASD. This parameter was also measured in 50 control subjects. The AoE index (AoE corrected for body surface area) in patients with ASD was significantly greater than in disease-free subjects (0.81 vs 0.59 cm, p less than 0.01). When the AoE index was plotted against the pulmonary to systemic blood flow ratio (Qp/Qs) obtained by the Fick method, a single linear relationship was evident (r = 0.65, p less than 0.01). The index normalized within 1 month after the operation; left ventricular dimension index became normal only 1 year after the operation. The right ventricular dimension index remained enhanced even 1 year after the operation. We suggest that exaggerated AoE might be another echocardiographic feature of ASD with normal pulmonary vascular resistance.

Adolescent↗
PubMed1984

Noninvasive assessment of right ventricular systolic pressure in atrial septal defect: analysis of the end-systolic configuration of the ventricular septum by two-dimensional echocardiography.

This study was performed to determine if 2-dimensional echocardiography (2-D echo) can be used to predict right ventricular (RV) systolic pressure. Ninety-one patients with atrial septal defect were studied prospectively. Analysis of the end-systolic configuration of the ventricular septum (VS) in the short-axis 2-D echocardiogram allowed classification of patients into 4 groups: type A (67 patients)--the VS was more circular at end-systole than at end-diastole; type B (9 patients)--the VS curvature at end-systole was same as or further flattened compared with that at end-diastole; type C (9 patients)--the VS was straight at end-systole; type D (6 patients)--the VS curvature at end-systole was reversed so that it was convex toward the left ventricle. Between these types, the RV pressure was different. The RV systolic pressure ranged from 18 to 55 mm Hg (mean 34 +/- 1) in type A, 46 to 55 mm Hg (50 +/- 1) in type B, 60 to 76 mm Hg (66 +/- 2) in type C, and 72 to 118 mm Hg (93 +/- 7) in type D. The RV systolic pressure was statistically different between types except for types C and D. These data indicate that the end-systolic configuration of the VS in the short-axis 2-D echocardiogram may be useful for the semiquantitative assessment of the RV systolic pressure in patients with atrial septal defect.

Adolescent↗
PubMed1984

Diagnosis of tricuspid stenosis by M-mode and two-dimensional echocardiography.

A decreased diastolic slope (EF slope) of the tricuspid valve on the M-mode echocardiogram may not indicate the presence of tricuspid stenosis (TS). To explore diagnostic echocardiographic signs of TS, we examined an M-mode and 2-dimensional (2-D) echocardiogram in 9 patients with documented TS of rheumatic origin and in 14 patients with rheumatic heart disease who showed a decreased EF slope (less than 40 mm/s) but did not have TS. By M-mode echocardiography, the EF slope was not different between patients with TS (24.4 +/- 2.2 mm/s) and those without TS (27.4 +/- 2.0 mm/s). The early diastolic excursion (DE amplitude) of the tricuspid valve was significantly lower (p less than 0.001) in patients with TS (7.6 +/- 1.0 mm) than in patients without TS (13.9 +/- 0.6 mm). Two-dimensional echocardiograms of the tricuspid valve revealed diastolic doming in all patients with TS. Diastolic doming of the tricuspid valve was detected most often (all of 7 patients) in the apical 4-chamber view. In contrast, no patients without TS who had a decreased EF slope on the M-mode echocardiogram showed diastolic doming. These data suggest that a reduced DE amplitude of less than or equal to 10 mm associated with a decreased EF slope on the M-mode echocardiogram and diastolic doming of the tricuspid valve on the 2-D echocardiogram are useful echocardiographic signs in the diagnosis of TS.

Adult↗
PubMed1984

Arrhythmia during insulin-induced hypoglycemia in a diabetic patient.

The temporal relationship between the level of blood glucose and the frequency of ventricular premature contractions (VPCs) during 24 hours was examined in a 45-year-old man with diabetes mellitus who was treated with a regular insulin injection. The number of VPCs increased sharply when the blood glucose level fell to about 50 mg/dL while the patient was awake. There was a minimal increase in VPCs during sleep, despite a decrease to 21 mg/dL in the blood glucose level. The insulin tolerance test produced frequent VPCs during hypoglycemia, which was suppressed by glucose administration. Changes in the level of plasma epinephrine correlated well with changes in the frequency of VPCs. These data suggest that increased levels of plasma epinephrine may have played a role in the genesis of VPCs that occurred during insulin-induced hypoglycemia.

Arrhythmias, Cardiac↗
PubMed1983

Cardiac effects of aprindine in patients with or without cardiac dysfunction: echocardiographic and clinical evaluation.

Cardiac effects of aprindine, a relatively new antiarrhythmic agent, were investigated by means of echocardiography in nine patients with ventricular arrhythmias. Three patients had normal cardiac function, and six patients had dilated cardiomyopathy. Aprindine was administered orally in a dosage of 50 to 75 mg/d. The plasma concentrations were 0.86 +/- 0.12 micrograms/ml. No worsening of cardiac signs and symptoms was noted within four weeks. An antiarrhythmic effect was noted in six of the nine patients. Significant changes in end-diastolic dimension or ejection fraction were not observed. Changes in contractile state were also assessed using the peak systolic blood pressure-end-systolic dimension relationship in three patients; none of them showed a decrease in cardiac contractility. This study suggests that aprindine, in a dose sufficient to suppress arrhythmias, does not make cardiac function deteriorate, as evaluated echocardiographically, even in patients with cardiac dysfunction.

Adolescent↗