Yasushi Terashima

Thallium-201 myocardial SPECT findings at rest in sarcoidosis

In 41 patients with sarcoidosis (diagnosed according to criteria recommended by the Committee on Diffuse Pulmonary Disease, Ministry of Health and Welfare, Japan 1988), thallium-201 (201Tl) myocardial SPECT was performed to investigate: (1) the ability of201Tl SPECT to detect cardiac involvement of sarcoidosis with images recorded at rest and 2 hours later, and (2) the relationships between201Tl myocardial SPECT findings and the activity of sarcoidosis or endomyocardial biopsy findings. As to the abnormal findings in201Tl myocardial SPECT, (1) a low density area was seen in 13 of 41 cases (31.7%) and non-uniform uptake was found in 17 cases (41.5%), (2) the mean washout ratio (n=39) was 16.5±7.4%, which is significantly (p < 0.05) lower than that found in normal subjects, 23.9±7.5 % (n=10). Of the 19 patients judged visually to be normal, 5 patients had a reduced mean washout ratio less than 12%. Thus, the incidence of abnormal findings including all types of abnormality, on201Tl myocardial SPECT in sarcoidosis was 63.4% (26/41 cases). In studying the relationship between201Tl myocardial SPECT findings and the activity of sarcoidosis (as measured by the serum ACE (angiotensin converting enzyme) or lysozyme level, or the presence of more than 30% symphocyte fraction in BALF (broncho-alveolar lavage fluid)), 20 (80%) of 25 cases with201Tl abnormality were judged to be active sarcoidosis, while only 6 (37.5%) of 16 cases with normal findings on201Tl SPECT were judged to be active. This suggests that there is a significant (p < 0.01) relationship between the presence or absence of an abnormal finding on201Tl myocardial SPECT and the activity of sarcoidosis. Among 13 patients examined by endomyocardial biopsy, 10 patients had abnormal findings on201Tl myocardial SPECT and 7 of these 10 patients had no histological evidence of cardiac sarcoidosis. In all of these 7 patients, however, sarcoidosis was judged to be active. This suggest that endomyocardial biopsy is of limited value in the diagnosis of cardiac sarcoidosis.

Usefulness of resting thallium-201 delayed imaging for detecting myocardial viability in patients with previous myocardial infarction

To test the feasibility of resting thallium-201 (201Tl) initial and delayed scintigraphy for detecting the area of viable myocardium, we performed single photon emission computed tomography (SPECT) in 57 patients with previous myocardial infarction (MI). All had received coronary arteriography (CAG) and left ventriculography (LVG). Initial and delayed myocardial imagings were carried out 10 min and 2 hours, respectively, after the injection of201Tl at rest. Redistribution was judged by visual interpretation and/or the circumferential profile curve, and found in the infarcted or its adjacent area in 40 of the 57 cases (70.2%). A negative washout (net increase of201Tl uptake in delayed image) was detected in 17 of these 40 cases. In 10 of the 57 patients, both exercise and rest-injected201Tl myocardial images were obtained at exercise and rest, and compared visually. The areas of abnormal perfusion were smaller in the resting delayed images than those seen after exercise in 9 of the 10 cases, and were equal in one case. Thus, resting201Tl delayed myocardial scintigraphy appears to reduce the underestimation of the size of the viable myocardium by the usual201Tl images obtained after exercise or by single initial images obtained at rest in patients with previous MI.

The Effect of Nitroglycerin on the Capacitance of the Human Pulmonary “Venous” System

We performed a computer simulation of four bouts of successive left-sided heart failure aggravated at intervals of one week. Each bout resulted in a decrease in the level of the left ventricular output curve to 70% of the preceding output curve level, while the right ventricular output curve was maintained unchanged. At each bout of acute left-sided heart failure, there occurred a transient oliguria and a gradual increase in the left atrial pressure. When the ordinate was the pulmonary “venous” volume and the abscissa was left atrial pressure, the pulmonary “venous” volume and left atrial pressure increased linearly (obliquely to the right), with progress of left-sided heart failure every week. By definition, the unstressed volume of the pulmonary “venous” system was unchanged.

Mental Arithmetic Produces Pulmonary and Systemic Venoconstriction

We have shown previously that human pulmonary “venous” system volume—pressure relationships (V, ordinate; P, abscissa) can be expressed as a function of the pulmonary “venous” volume, representing V, and the mean pulmonary capillary wedge pressure, representing P. We also described a method for comparing V–P lines before and after the administration of nitroglycerin. In the present report we describe the effect of the performance of mental arithmetic on human pulmonary “venous” system capacitance. By definition, the pulmonary “venous” system consists of pulmonary veins and the left atrium. When subjects were performing mental arithmetic, a nodding response was used because any verbal response resulted in an increase in the pulmonary capillary wedge pressure. Mental arithmetic caused a right-ward shift in the V–P line and a decrease in slope, when compared with controls, indicating pulmonary venoconstriction. In 37 patients, most of whom had ischemic heart disease, the effective unstressed volume increased (P < 0.01) and the compliance (ΔV/ΔP) decreased (P < 0.01) during the performance of mental arithmetic. The mean pulmonary capillary wedge pressure in the supine position increased (P < 0.01). This decreased compliance indicates pulmonary venoconstriction, while the effective unstressed volume increase suggests an increase in the pulmonary blood volume. Epinephrine and norepinephrine levels in plasma increased during mental arithmetic, suggesting that sympathetic neurohormonal influences were, at least in part, responsible for the observed pulmonary and systemic venoconstriction. We conclude that the human pulmonary “venous” system is under neurohormonal control.

Human Pulmonary Venous Return Curve: Effect of Dopamine

Pulmonary “venous” compliance (Cp“v”) and pulmonary arterial compliance (Cpa) were determined using radionuclide angiocardiography and a floating catheter in patients with various cardiac diseases. A pulmonary venous return curve was constructed from these measurements, and the effect of dopamine on the pulmonary venous return curve was evaluated. At the same time the pulmonary “venous” volume—pressure relationship and its response to dopamine was documented.