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Biomedical subjects

T Masuyama

Publications and source records attributed to T Masuyama.

At least 109 records · Page 6Linked to original sources
PubMed1992

Sequential appearance of fibronectin, collagen and elastin during fatty streak initiation and maturation in hypercholesterolemic fat-fed rabbits.

To elucidate whether tissue fibronectin increases in the early stages of atherogenesis induced by hypercholesterolemia without mechanical trauma, we investigated sequential changes in the distribution of tissue fibronectin during fatty streak initiation and maturation in the aortas of hypercholesterolemic fat-fed rabbits. The presence of fibronectin was examined on immunoperoxidase stained tissue specimens with the aid of a microscope-photometric technique. Twenty male albino rabbits were used. Cholesterol supplemented chow (1%) was given for 4 weeks (n = 6), 8 (n = 5) or 14 weeks (n = 5). A membrane-like layer positive for fibronectin was observed along the endothelium in the normal aorta. After 4 weeks of the cholesterol-feeding, fatty streaks were initiated in the intima, where fibronectin was more densely accumulated than the normal intima. After 8 weeks of the cholesterol-feeding, fatty streaks were expanding, associated with the dense staining for fibronectin. After 14 weeks, fibronectin was still concentrated in the endothelial layer and also in the superficial areas of the thickened intima, but decreased in the deep areas of the thickened intima where collagen and elastin appeared as bundles. The photometric data of fibronectin supported these visual observations. Thus, fibronectin appeared early and disappeared later in the intima during the process of fatty streak initiation and maturation. These findings suggest that in hypercholesterolemia without mechanical endothelial injury, fibronectin may play an important role in an early process of atherogenesis.

Animals↗
PubMed1992

Contributors of characteristic mitral flow velocity pattern in congestive heart failure--from clinical observations back to experimental validations.

Mitral flow velocity pattern in patients with left ventricular (LV) diastolic dysfunction usually includes decreased peak early diastolic filling velocity (E), slowed deceleration of the early diastolic filling wave and increased peak filling velocity at atrial contraction (A). However, the abnormal mitral flow velocity pattern can be normalized in the presence of concomitant congestive heart failure. In such cases E can be equal to or even higher than normal, its deceleration is normal or faster than normal value, and A can be normal or lower than normal value. Clinical observations in patients with severe heart failure showed that the mitral flow velocity pattern changes with vasodilating therapy, reflecting the changes in the left atrial (LA) to LV pressure difference rather than those in the absolute LA pressure or LV pressure alone. This was validated in the canine study in which levels of LV dysfunction were made by the injection of microspheres into the left coronary artery to study the interrelation among the mitral flow velocity pattern and LA and LV pressures. In this experiment, the changes in the mitral flow velocity pattern could not be explained by the changes in LA or LV pressure alone but was better explained by the changes in the LA to LV pressure difference. Not only LA-LV crossover pressure but also LA compliance seem to be important as determinants of LA pressure level in diastole. In addition to LV relaxation rate, incompleteness of relaxation, elastic recoil and LV passive elastic properties, extracardiac constraint is also considered to be an important determinant of the level of the LV diastolic pressure and hence of the mitral flow velocity pattern at least in the presence of congestive heart failure. Thus, mitral flow velocity pattern is determined by the interaction of LA and LV pressures, both of which are affected by chamber properties as well as loading conditions.

Animals↗
PubMed1992

Doppler assessment of left ventricular diastolic filling pattern during the convalescent stage of acute myocardial infarction. Effects of infarct size and coronary thrombolysis.

Pulsed Doppler echocardiography was used to study left ventricular diastolic filling pattern (LVDFP) over the convalescent stage of acute myocardial infarction (AMI) in 25 patients. Twelve normal subjects served as a control group. The patients were divided on the basis of enzymatically estimated infarct size into 2 groups: 7 as the large AMI group, and the other 18 as the small AMI group. Peak early diastolic filling velocity (E) and the ratio of E to peak filling velocity at atrial contraction (E/A ratio) were determined from the Doppler transmitral flow velocity recordings at 1 and 4 weeks after the onset of AMI. At 1 week E and E/A ratio were significantly lower in the small AMI group compared to the control and the large AMI groups, however, there was no significant difference in E and E/A ratio between the control and the large AMI groups. E/A increased with cumulative CK release among the patients (r = 0.54, p < 0.01). In the following 3 weeks E and E/A ratio decreased only in the large AMI group, and E and E/A ratio at 4 weeks weakly correlated with pulmonary capillary wedge pressure (r = 0.63, p < 0.01 and r = 0.65, p < 0.01) and ejection fraction (r = 0.50, p < 0.05 and r = 0.62, p < 0.01) among the patients. There was no significant difference in E or E/A ratio between patients with and without coronary thrombolysis. Thus, LVDFP in the early convalescent stage of AMI was characterized by low E and E/A ratio in patients with small AMI, however, a "pseudonormalized" pattern was observed in patients with large AMI. The effect of the infarct size on LVDFP diminished in the late convalescent stage of AMI. LVDFP in patients with AMI appears to be influenced by the infarct size and by the time of study. The effect of coronary thrombolysis on LVDFP was not evident throughout the convalescent stage of AMI in this study.

Convalescence↗
PubMed1992

[Evaluation of left ventricular relaxation by mitral regurgitant curve].

To examine whether left ventricular (LV) isovolumic relaxation can be assessed noninvasively using a continuous-wave Doppler technique, we compared Doppler-determined parameters derived from mitral regurgitation (MR) velocity curve with micromanometer-derived indices of LV relaxation, peak negative dP/dt and tau, in 9 patients with MR (5 with dilated cardiomyopathy, 2 with old myocardial infarction and 2 with rheumatic MR). The rate of LV pressure decay (delta P/delta t) at aortic valve closure was calculated from the recordings of MR jet velocities based on the simplified Bernoulli equation. The time constant of LV pressure decay (tD) was determined as the time from the aortic valve closure to the point where the velocity declined by (1/e)1/2. Doppler-determined delta P/delta t correlated well with hemodynamic peak negative dP/dt (r = 0.97, p < 0.001), and tD with hemodynamic tau (r = 0.89, p < 0.005). Thus, we concluded that left ventricular isovolumic relaxation can be noninvasively assessed with a continuous-wave Doppler technique in the presence of mitral regurgitation.

Blood Flow Velocity↗
PubMed1991

Pulmonary venous flow velocity pattern as assessed with transthoracic pulsed Doppler echocardiography in subjects without cardiac disease.

Pulmonary venous flow velocity pattern (PVFVP) was analyzed in 53 subjects (aged 25 to 77 years, mean 47) without cardiovascular disease who underwent transthoracic pulsed Doppler echocardiography. The forward flow velocity pattern was biphasic in 37 of the 53 subjects, with each of the 2 peaks in systole and diastole; flow was triphasic with 2 peaks in systole and the other peak in diastole in the remaining 16 subjects. Peak systolic and diastolic flow velocity ranged from 28 to 84 cm/s and from 27 to 71 cm/s, respectively. Mean systolic flow velocity was significantly greater than mean diastolic flow velocity (53 +/- 12 vs 47 +/- 11 cm/s, p less than 0.01). Systolic flow velocity and the ratio of systolic to diastolic flow velocity increased and diastolic flow velocity decreased with aging (r = 0.52, p less than 0.001, r = 0.70, p less than 0.001 and r = -0.49, p less than 0.001, respectively). Reverse flow occurred during the atrial contraction phase and its velocity (mean 20 cm/s) increased with aging (r = 0.56, p less than 0.001). The parameters of PVFVP were compared with the ratio of peak early diastolic filling velocity to peak filling velocity at atrial contraction (E/A ratio) measured in the transmitral flow velocity pattern. As E/A ratio increased, systolic flow velocity and systolic/diastolic flow ratio and peak reverse flow velocity decreased (r = -0.40, p less than 0.01, r = -0.67, p less than 0.001 and r = -0.68, p less than 0.001, respectively) and diastolic flow velocity increased (r = 0.58, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Effects of coronary angioplasty on left ventricular diastolic filling in patients with old myocardial infarction: a study with pulsed Doppler echocardiography.

To examine the effects of percutaneous transluminal coronary angioplasty (PTCA) on left ventricular diastolic filling in patients with an old myocardial infarction, transmitral flow velocity pattern was measured using pulsed Doppler echocardiography before and after PTCA for the peak early diastolic filling velocity (E) and the ratio of the early diastolic filling to peak atrial filling velocities (E/A ratio) in 73 patients with coronary artery disease. These patients were classified into three groups: 34 patients without previous myocardial infarction (no MI group), 16 patients with an old myocardial infarction in whom a non-infarct-related vessel was reperfused by PTCA (MI-1 group), and 23 patients with an old myocardial infarction in whom the infarct-related vessel was reperfused by PCTA (MI-2 group). The degree of improvement in left ventricular diastolic filling was calculated using the values before PTCA as controls. The % increases in E and E/A ratio were 20 +/- 15 and 25 +/- 19%, respectively, in the no MI group and 27 +/- 20 and 18 +/- 16%, respectively, in the MI-1 group and there was no significant difference between these groups. The % increases in E and E/A ratio in the MI-2 group were 7 +/- 19 and 6 +/- 17%, respectively, and were significantly (P less than 0.05) less than those in the no MI and MI-1 groups. An increase in E, E/A ratio or both by 20% or more was observed in 21 of the 34 (62%) patients of the no MI group, in 10 of the 16 (63%) patients of the MI-1 group and in six of the 23 (26%) patients of the MI-2 group. Thus, reperfusion of a non-infarct-related vessel in patients with an old myocardial infarction improves left ventricular diastolic filling to the same degree and with the same frequency as in patients without myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Spontaneous near disappearance of bilateral coronary artery-pulmonary artery fistulas.

Although coronary artery fistula is a relatively rare anomaly, it sometimes develops with advancing age, requiring surgical removal. We report a unique case of a patient whose bilateral coronary artery-pulmonary artery fistulas nearly disappeared in the course of four years. This case is interesting in view of recognizing one of the natural courses of this entity.

Angiography↗
PubMed1990

Coronary collaterals assessed with myocardial contrast echocardiography in healed myocardial infarction.

The epicardial coronary collateral vessels are visualized with coronary angiography, but this method does not provide significant information about the myocardial perfusion supplied with the collaterals. In this study, myocardial contrast echocardiography (MCE) was performed to assess the coronary collaterals in 29 patients with old myocardial infarction. MCE was performed by intracoronary injection of 2 ml agitated amidotrizoate sodium meglumine. The peak background-subtracted gray level (PGL) in the infarct area was determined from the digitized echocardiographic images obtained before and after injection into the noninfarct and donor artery. PGL was compared with the 3-point coronary angiographic grades of collaterals. PGL in the infarct area was significantly lower in patients with poor collaterals than in patients with moderate to good collaterals (5 +/- 4 vs 18 +/- 8 U mean +/- standard deviation, p less than 0.01). PGL in the infarct area was less than 10 U in the 3 patients with severe asynergy despite the moderate to good collateral supply, suggesting that activity of the collaterals was not good enough to preserve the wall motion effectively. It is concluded that (1) the degree of MCE enhancement in the infarct area generally corresponded to the collateral grades assessed with coronary angiography, and (2) MCE may provide a measure of the collateral perfusion.

Adult↗
PubMed1990

Effects of nitroprusside on transmitral flow velocity patterns in extreme heart failure: a combined hemodynamic and Doppler echocardiographic study of varying loading conditions.

To explore the mechanisms of change of left ventricular diastolic filling associated with preload and afterload reduction, the influence of nitroprusside on the transmitral flow velocity pattern, pulmonary capillary wedge pressure and left ventricular pressure interaction was studied in 11 patients with end-stage heart failure. Pulsed Doppler echocardiographic recordings of mitral inflow were obtained with simultaneous high fidelity left ventricular and phase-corrected pulmonary capillary wedge pressure recordings before and during levels of nitroprusside infusion. With nitroprusside, left ventricular systolic and end-diastolic pressures decreased by 14% and 41% (p less than 0.05, p less than 0.05), respectively, and cardiac output increased by 67% (p less than 0.05). The pulmonary capillary wedge-left ventricular crossover pressure decreased by 41% (p less than 0.05), but the time constant of isovolumetric left ventricular pressure decrease T was insignificantly changed. Isovolumetric relaxation time and acceleration and deceleration times of the early diastolic filling wave were significantly prolonged with nitroprusside infusion (p less than 0.05, p less than 0.05 and p less than 0.05, respectively). Peak early diastolic filling velocity was maintained (65 +/- 11 to 62 +/- 13 cm/s, p = NS) in spite of the decreased absolute crossover pressure. Changes in peak early diastolic filling velocity correlated weakly with changes in the crossover pressure (r = 0.48, p less than 0.05) and correlated better with the crossover to left ventricular minimal pressure difference (r = 0.78, p less than 0.05). Peak early diastolic filling velocity appears to be most affected by the early diastolic pulmonary capillary wedge to left ventricular pressure difference rather than the absolute pulmonary capillary wedge pressure. The lack of peak flow velocity change during nitroprusside infusion could be explained by either the associated decrease in left ventricular minimal pressure or downward shift of left ventricular diastolic pressure by the same amount as the decrease in pulmonary capillary wedge pressure. This may reflect a reduction of external constraint to ventricular distensibility produced by a reduction in filling volume in patients with a markedly dilated ventricle. Thus, a prolonged early diastolic filling period and preserved peak early diastolic filling velocity in spite of decreased left ventricular filling pressure and constant relaxation rate are associated with the beneficial effects of nitroprusside on left ventricular function in patients with severe congestive heart failure.

Blood Flow Velocity↗
PubMed1990

Doppler echocardiographic quantitation of cross-sectional area under various hemodynamic conditions: an experimental validation in a canine model of supravalvular aortic stenosis.

The hemodynamic effects on cross-sectional area calculated with the continuity equation were assessed in canine experiments. In 13 open chest dogs, 46 supravalvular aortic stenoses were created by aortic root banding. The cross-sectional area of the stenosis was calculated by Doppler echocardiography with application of the continuity equation before and after the following hemodynamic interventions: protocol 1, atrial pacing at 90, 120, 150 and 180 beats/min after sinus node crush; protocol 2, preload reduction by mild and severe clamping of the inferior vena cava; and protocol 3, afterload augmentation by mild and severe clamping of the descending aorta. In each observation, a dimension of the stenosis was directly measured by two-dimensional echocardiography, and the cross-sectional area was determined as a reference standard. As a result of the hemodynamic interventions, significant changes were observed in stroke volume and pressure gradient (protocol 1), in cardiac output, stroke volume and pressure gradient (protocol 2) and in heart rate, cardiac output and pressure gradient (protocol 3). Despite these changes in hemodynamic variables, the Doppler-derived cross-sectional area showed no significant change for a given stenosis. In addition, areas calculated with the continuity equation (x) agreed well with those determined by two-dimensional echocardiography (y) (r = 0.96, p less than 0.001, y = 0.97x + 0.02, SEE = +/- 0.06 cm2). Thus, it is concluded that Doppler echocardiography with application of the continuity equation accurately predicts the stenotic cross-sectional area over a wide range of hemodynamic conditions in supravalvular aortic stenosis.

Animals↗
PubMed1990

Carcinogenicity of sublimed urethane in mice through the respiratory tract.

The carcinogenicity of sublimed urethane (ethyl carbamate) in air was examined with mice. JCL:ICR mice were nursed in a plastic cage inside a vinyl chamber which was ventilated 4 times per hour. The mice were exposed to urethane gas for various periods by passing air which contained a high concentration of sublimed urethane (1.29 micrograms/ml) into the vinyl chamber, or by placing a vessel containing crystalline urethane inside the vinyl chamber so that it was filled with spontaneously-sublimed urethane gas at a low concentration (0.25 microgram/ml). When female mice were killed 5 months after exposure, lung tumor frequency increased almost linearly with the number of days of exposure in the low concentration experiment, but increased in a non-linear manner in the high concentration experiment. In terms of nearly the same total dose, i.e., (concentration of urethane gas in air) X (days of inhalation), one day of exposure to urethane gas at the low concentration induced lung tumors at a significantly higher frequency than 1/4 day of exposure to urethane gas at the high concentration. When male mice were killed at 12 months after exposure to examine the progressive change of induced tumors, malignant, invasive and metastatic tumors were found to have been induced more frequently in the lung after exposure to urethane gas at the low concentration (0.25 microgram/ml for 10 days) than at the high concentration (1.29 microgram/ml for 4 days), although the total dose in the former group was about half of that in the latter. Continuous exposure to urethane gas for a longer period at the low concentration seems to be more efficient for the induction, promotion and/or progression of lung tumors than the exposure for a shorter period at the high concentration.

Administration, Inhalation↗
PubMed1990

Serial measurement of integrated ultrasonic backscatter in human cardiac allografts for the recognition of acute rejection.

Cyclic variation of integrated ultrasonic backscatter (IB) was noninvasively measured in the septum and left ventricular posterior wall using a quantitative IB imaging system to assess the alterations in the acoustic properties of myocardium associated with acute cardiac allograft rejection. The study population consisted of 23 cardiac allograft recipients and 18 normal subjects. In each cardiac allograft recipient, one to eight (mean, four) IB studies were performed, each within 24 hours of right ventricular endomyocardial biopsy performed for rejection surveillance. The magnitude of the cyclic variation of IB in the posterior wall was 5.9 +/- 0.9 dB in normal subjects and 6.2 +/- 1.3 dB in the cardiac allograft recipients without previous or current histological evidence of acute rejection (n = 17, p = NS vs. normal subjects). The magnitude of cyclic variation of IB in the septum was 4.8 +/- 1.1 dB in normal subjects and 3.8 +/- 2.0 dB in the cardiac allograft recipients (n = 15, p = NS vs. normal subjects). A significant decrease in the septal IB measure was observed in cardiac allograft recipients with left ventricular hypertrophy (wall thickness of at least 13 mm) (2.6 +/- 1.7 dB, n = 8, p less than 0.05 vs. normal subjects). IB studies were done before and during moderate acute rejection in 11 recipients (14 episodes). During moderate acute cardiac rejection, the magnitude of the cyclic variation in IB decreased from 6.7 +/- 1.3 to 5.1 +/- 1.4 dB in the posterior wall (n = 14, p less than 0.05) and from 4.2 +/- 2.1 dB to 2.9 +/- 1.8 dB in the septum (n = 12, p less than 0.05). These data suggest 1) the magnitude of the cyclic variation in IB of the septum is different in cardiac allografts with cardiac hypertrophy and normal subjects, possibly reflecting regionally depressed myocardial contractile performance and 2) acute cardiac rejection in humans is accompanied by an alteration in the acoustic properties of the myocardium. This change is detectable by serial measurement of the magnitude of the cyclic variation in IB, both in the septum and in the posterior wall.

Echocardiography↗
PubMed1990

Quantitative color flow imaging to measure the two-dimensional distribution of blood flow velocity and the flow rate.

A quantitative Doppler color flow imaging was employed to measure the two-dimensional distribution of blood flow velocity and flow rate in a large vessel. Regional blood flow velocity was determined by converting the color intensity at the respective pixel into corresponding flow velocity and correcting the flow velocity for spatial ultrasound beam incident angle. Instantaneous flow rate was determined precisely from the image of velocity distribution on the cross-section of the flow tract in a steady flow model circuit. In clinical application, the differences in phasic changes in two-dimensional velocity distribution in the ascending aorta, between normal subjects and the patient with aortic regurgitation, were clearly depicted. The quantitative color flow imaging may have great potential to determine noninvasively and real-timely the two-dimensional distribution of flow velocity as well as flow rate in a large vessel.

Aortic Valve Insufficiency↗
PubMed1989

Limited atrial compensation to reduced early diastolic filling in hypertensive patients with advanced left ventricular hypertrophy: a Doppler echocardiographic study.

To assess atrial contribution to left ventricular (LV) filling in hypertension, we studied, using pulsed Doppler echocardiography, 22 hypertensive patients without apparent LV hypertrophy (LVH), 12 hypertensive patients with LVH, and 24 age-matched normal subjects. From mitral flow velocity waveform, we determined peak velocity of early diastolic filling flow (peak E), peak velocity of late diastolic filling flow (peak A), and the peak A/peak E ratio (peak A/peak E). Peak E decreased in hypertensives without apparent LVH and showed a further decrease in hypertensives with LVH compared with normal subjects (57 +/- 8 [mean +/- SD]; P less than 0.001, 46 +/- 7; P less than 0.0001, vs 65 +/- 10 cm/s). On the other hand, peak A/peak E increased in hypertensives without apparent LVH, and greatly increased in hypertensives with LVH (1.06 +/- 0.14; P less than 0.001, 1.40 +/- 0.29; P less than 0.0001, vs 0.79 +/- 0.21). However, increased peak A was not significantly different between the hypertensive groups (60 +/- 8 vs 64 +/- 8; NS, both; P less than 0.001 vs 50 +/- 10 cm/s for normal subjects). In hypertensives, we found no significant correlation between peak A and the wall thickness index (WTI, determined as mean LV wall thickness normalized by LV diastolic dimension), whereas peak E was significantly correlated with WTI (r = -0.65; P less than 0.001). Our findings indicate that atrial contraction can not fully compensate the decrease in early diastolic filling caused by advanced LVH. We conclude that atrial compensation for reduced early diastolic filling is limited in hypertensive patients with advanced left ventricular hypertrophy.

Adult↗
PubMed1989

Semiquantitative evaluation of aortic regurgitation by Doppler echocardiography: effects of associated mitral stenosis.

The accuracy of pulsed and continuous wave (CW) Doppler methods for evaluating aortic regurgitation (AR) was compared in patients with and without mitral stenosis (MS), with aortic root angiography as a gold standard. AR was diagnosed with pulsed Doppler echocardiography, by the detection of broad frequency spectral patterns in the isovolumic relaxation time. If these indications were present, AR was graded by examining the extent of diastolic turbulence in the left ventricular cavity (flow mapping method). With CW Doppler echocardiography, AR was diagnosed by the detection of a peak velocity of greater than 2 m/s; if this velocity was attained, AR was graded by measuring the time from the peak velocity to half the peak velocity (half-time method). The angiographic grade corresponded to that determined by the pulsed and CW Doppler methods in 37 and 37 of 46 patients without MS, respectively. Angiographic grade corresponded to the grade determined by the pulsed and CW Doppler methods in 13 and 17 of the 23 patients with MS, respectively. Eight of 10 discrepancies between pulsed Doppler and angiographic grades were due to overestimation of AR by the flow mapping method, apparently because the transmitral jet produces diastolic turbulence in the left ventricular cavity independent of AR. On the other hand, three of six discrepancies between CW Doppler and angiographic grades were due to the incapability of detecting signals of AR by CW Doppler echocardiography. Thus both the pulsed and the CW Doppler methods are useful to evaluate AR in patients without MS. In patients with MS, however, AR is most accurately diagnosed by the detection of AR signals in the isovolumic relaxation time by pulsed Doppler echocardiography, and the degree of AR is more accurately assessed by the CW Doppler half-time method.

Adult↗
PubMed1989

Ultrasonic tissue characterization with a real time integrated backscatter imaging system in normal and aging human hearts.

Experimental studies have shown that variation in the magnitude of integrated ultrasonic backscatter during the cardiac cycle represents acoustic properties of myocardium that are affected by pathologic processes; however, there are few clinical studies using integrated backscatter. Forty subjects without cardiovascular disease (aged 22 to 71 years, mean 41) were studied with use of a new M-mode format integrated backscatter imaging system to characterize the range of cyclic variation of integrated backscatter in normal subjects. Cyclic variation in integrated backscatter was noted in both the septum and the posterior wall in all subjects. The magnitude of the cyclic variation of integrated backscatter and the interval from the onset of the QRS wave of the electrocardiogram to the minimal integrated backscatter value were measured using an area of interest of variable size for integrated backscatter sampling and a software resident in the ultrasound scanner. The magnitude of cyclic variation was larger for the posterior wall than for the septum (6.3 +/- 0.8 versus 4.9 +/- 1.3 dB, p less than 0.01). The interval to the minimal integrated backscatter value was 328 +/- 58 ms for the septum and 348 +/- 42 ms for the posterior wall (p = NS). There was a weak correlation between the magnitude of cyclic variation of integrated backscatter and subject age for the posterior wall (r = -0.47, p less than 0.01), but this was not significant for the septum (r = -0.21) (partially because of inability to exclude specular septal echoes) and septal endocardium.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Right coronary artery occlusion: its role in the mechanism of precordial ST segment depression.

To investigate the mechanism of precordial ST segment depression during right coronary artery occlusion, precordial ST segment shifts and myocardial lactate metabolism were evaluated during coronary angioplasty in 10 patients with (group A) and 7 patients without (group B) precordial ST segment depression during balloon occlusion of the right coronary artery, and in 17 patients with precordial ST segment depression during balloon occlusion of the left anterior descending artery (group C). A 12 lead electrocardiogram was continuously recorded in each patient. Blood lactate in the aorta and great cardiac vein was measured during the procedure, and the lactate extraction ratio in the anterior wall was determined both before and during balloon occlusion. Eight of the 10 patients in group A and 1 of the 7 patients in group B had a dominant large right coronary artery. There were no significant differences in summed ST segment elevation in leads II, III and a VF between group A (0.56 +/- 0.26 mV) and group B (0.46 +/- 0.19 mV) during balloon occlusion of the right coronary artery, and no significant differences in summed ST segment depression in leads V1 to V6 during balloon occlusion between group A (0.44 +/- 0.26 mV) and group C (0.38 +/- 0.14 mV). Lactate extraction ratio before balloon occlusion was similar among the three groups. Patients in group A had a higher lactate extraction ratio during (38 +/- 11%) compared with before (30 +/- 11%) (p less than 0.05) balloon occlusion despite precordial ST segment depression.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗