Journal of cardiography最新文献

To evaluate the usefulness of single photon emission computed tomography (SPECT) with technetium-99m-pyrophosphate (99mTc-PYP) for estimating infarct size, we compared SPECT data with maximum creatine phosphokinase values. Background threshold was established in a series of phantom experiments. When a 40% cut-off was applied, the SPECT data most closely approximated actual phantom volumes. Therefore, the 40% cut-off level was used in the present study. In 10 patients with acute myocardial infarction, planar 99mTc-PYP myocardial scintigraphy and SPECT using a rotating gamma camera were performed two days after the initial myocardial infarction episode. The maximum creatine phosphokinase value (CPKmax) was also measured repeatedly following the episode. When the infarct size measured by SPECT using transaxial images and calculated by the pixel counts, it correlated very closely with CPKmax (r = 0.94). Most studies so far have reported that the CPKmax level reflects infarct size. We conclude that the infarct size as measured by 99mTc-PYP SPECT closely approximates the actual infarct size, and that this method is useful to determine the severity of infarcts clinically. Among the 10 patients in this series, three of five with infarcts greater than 60 ml died of pump failure. Therefore, we may be able to predict prognosis after accumulating more such cases and improving the methodology.

To elucidate the function of the pericardium, alterations in jugular phlebograms, intracardiac pressures and cardiac volumes induced by postural changes were examined in seven patients with complete absence of the left pericardium. Ten patients with ischemic heart disease were studied as controls. Jugular phlebograms in patients with complete absence of the left pericardium showed decreased depths of the x descent and the tall v waves followed by the deep y descents (M-shaped pattern) in the supine position. These jugular abnormalities were exaggerated in the left lateral decubitus position. By contrast, the jugular phlebograms tended to return to normal, but remained abnormal in the right lateral decubitus position. Right atrial pressure curves showed similar postural effects. However, the jugular phlebograms and right atrial pressure curves in patients with ischemic heart disease were not altered by postural changes. The characteristic alterations of the jugular phlebograms are useful indicators for diagnosing complete absence of the left pericardium. The lack of a prompt decrease in pericardial pressure during ventricular ejection due to the absence of the pericardium is one of the causes of a decreased depth of the x descent in pericardial defect. However, this cannot explain the postural alteration of the jugular phlebogram. Another possible mechanism is the decreased excursion of the tricuspid ring during systole. As indicated in our previous report, there is anterior movement of the cardiac apex during systole in cases of pericardial defect, which is exaggerated in the left lateral decubitus position and decreased in the right lateral decubitus position due to the lack of normal pericardial support. This anterior swinging motion may inhibit the descent of the tricuspid ring toward the apex, resulting in a decreased depth of the x descent of the jugular phlebogram and the right atrial pressure curve and their postural alterations. The right ventricular volume as calculated from cardiac computerized tomography and the right ventricular end-diastolic pressure were not altered significantly by postural changes in the control cases. These indices increased to a greater extent in the left lateral decubitus position than in other postures in cases with pericardial defects.(ABSTRACT TRUNCATED AT 400 WORDS)

Aortic flow velocity was measured by catheter-tip flow transducer in 25 patients who underwent left cardiac catheterization for non-invasive estimates by the impedance method. Disk electrodes were attached to the skin at the levels of the second thoracic vertebra in the posterior median line and the V8 lead position for electrocardiography. Alternating current, 350 micro-amperes, 50 KHz constant, was applied to the outer electrode, and impedance changes were detected via the inner electrode. The e wave, or height of the first derivative dz/dt wave of the electrical impedance was lower in cases of old myocardial infarction and higher in cases of aortic valve regurgitation, as compared with the values of the healthy control group. The time lag between the start of the upward deflection and the peak value of the dz/dt wave coincided with that of the aortic flow curve as measured at the aortic arch and descending aorta. These time lags were about 20 to 30 msec as compared with the ascending aortic flow curve, and were -20 to -30 msec as compared with the abdominal aortic flow curve. There was a close correlation between the maximum flow velocity measured at the aortic arch and the height of the e waves. The regression equation was: Y = 0.21X - 1.53, r = 0.88, p less than 0.01. These data suggest that the first derivative of electrical impedance change as obtained by the disk electrode method reflects aortic flow at the arch and descending aorta.

A 71-year-old woman with a history of previous myocardial infarction was transferred to our hospital for evaluation of chest pain and ventricular tachycardia. On admission, a loud mid-systolic ejection murmur accompanied by a thrill was found at the left sternal border in the third intercostal space, and it was significantly accentuated in the post-extrasystolic beat. Abnormal Q waves and ST elevations were noted in leads I, aVL and V5,6 on electrocardiograms. Echocardiograms, confirmed a septal-to-apical aneurysm, and a thin interventricular septum (IVS) with paradoxical motion. Right ventricular (RV) catheterization showed a pressure gradient of 21 mmHg between the outflow tract (RVOT) and the apex, and a mid-systolic ejection murmur was recorded in the RVOT on an intracardiac phonocardiogram. Coronary arteriograms revealed total occlusion of the left anterior descending artery in its proximal portion, and a 90% stenosis of the circumflex artery. A left ventriculogram demonstrated a septal-to-apical aneurysm with a markedly reduced ejection fraction of 0.16. A right ventriculogram showed obstruction to RVOT caused by systolic ballooning of the IVS. In this patient, the mid-systolic ejection murmur was probably caused by the obstruction of the outflow tract secondary to septal aneurysm following old myocardial infarction.

Magnetic resonance imaging (MRI) was performed in thirty-one patients with aortic dissection to evaluate its usefulness in diagnosing the site of communicating orifice between the true and false lumens and the presence of retrograde dissection. MRI revealed the site of the entry as a defect in the intimal flap in the images of 12 of 15 patients (80%). The site of the communicating orifice between the true and false lumens in the abdominal aorta could be determined in six of eight patients (75%). MRI diagnosis of retrograde dissection was successful in three patients. Cross-sectional analysis of the abdominal aorta based on the location of the true lumen revealed that the celiac and superior mesenteric arteries tended to arise from the true lumen when the latter was situated in the anterior part of the abdominal aorta. The right and left renal arteries arose from the true lumen when it was positioned anterolaterally. In conclusion, MRI was a useful diagnostic method for aortic dissection, especially for determining the site of entry in the thoracic aorta. The changes in signal intensity in the false lumen provided useful information for locating the communicating orifice between the true and false lumens and for diagnosis of retrograde dissection. Cross-sectional analysis of dissection in the abdominal aorta was useful for predicting the branching of the main arteries from the true or false lumen.

To elucidate the effects of coronary thrombolytic therapy in acute myocardial infarction, we observed serially the degree of left ventricular (LV) wall motion immediately after on day 1, and on days 7, 14, 21 and 28 after thrombolytic therapy, in 22 patients with acute anteroseptal myocardial infarction. Base-line coronary arteriography revealed significant lesions in the proximal portions of the left anterior descending artery of all the patients. The patients were categorized according to results of thrombolytic therapy as Group I-a: seven patients with spontaneous or successful recanalization within three hours of onset of chest pain; Group I-b: nine patients with successful recanalization between three and seven hours, with a mean of 4.8 hours from onset; and Group II: six patients in whom thrombolytic therapy was unsuccessful and infarct-related vessels remained totally occluded. The LV wall motion index (WMI) was defined as the sum of point scores for the degrees of regional wall motion at nine segments on serial two-dimensional echocardiograms, and used for quantitative assessments of LV function. Results were as follows: On day 1, immediately after thrombolytic therapy, the WMI of Group I-a was smaller than that of Group II. However, there was no significant difference between Groups I-a and I-b and between Groups I-b and II. These findings suggest that LV function cannot be recovered immediately after recanalization of occluded arteries unless recanalization occurs exceptionally early. Percent improvement of the WMI from days 1 to 28 in Group I-a, 65 +/- 14%, was significantly greater than that in Group I-b, 31 +/- 18%. However, Group II did not show significant improvement in the WMI. The WMI in Group I-a decreased significantly from days 1 to 7 (9.0 +/- 1.6 vs 7.1 +/- 1.8, p less than 0.05); whereas, the WMI in Group I-b showed no significant decrease until day 21. On day 1, the regional wall motion of the antero-apical wall was akinetic or dyskinetic in all patients studied. On day 28, it improved in six of seven patients in Group I-a, while it remained akinetic or dyskinetic in all patients in Groups I-b and II.(ABSTRACT TRUNCATED AT 400 WORDS)

The early distribution of thallium-201 (Tl-201) is related to blood flow within the limits of the physiological range. We examined the ratio of myocardial uptake of Tl-201 to the total dose administered at rest and during exercise, in order to assess myocardial blood flow. The usual dose of Tl-201 (2-3 mCi) was diluted to 20 ml of normal saline and 15 ml were injected intravenously as a bolus. Subsequently the remaining 5 ml were injected in the same manner. Myocardial Tl-201 uptakes after the first dose were comparable to those of the second dose at rest when myocardial uptake immediately before the second injection was subtracted and multiplied by 3 (r = 0.98). This technique was applied during exercise to evaluate coronary reserve. Symptom-limited exercise was performed using a sitting ergometer and the first dose of Tl-201 was administered. After the routine scintigraphy with multiple views was completed, a second dose was given at rest. Myocardial uptake was greater during exercise than at rest by 32.6 +/- 15.1% (mean +/- SD) in 18 normal subjects. This was significantly greater than that of 20 patients with coronary artery disease (5.8 +/- 15.3%; p less than 0.005). Tl-201 scintigraphy has inherent limitations as to its quantitation, while positron scintigraphy using 13N-NH3 has some advantages for calculations. Percent myocardial uptake of 13N during exercise was practically equal to that at rest in six normal subjects (97.1 +/- 25.0%), but it was slightly reduced in patients with coronary artery disease (90.1 +/- 18.2%).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute myocardial ischemia followed by protracted asynergy and subsequent resolution was defined as reversible ischemic myocardial damage. The purpose of this study was to confirm the existence of this entity and to illustrate the clinical features. The subjects consisted of 26 patients with typical acute myocardial ischemia who satisfied the above definition, and serial changes in left ventricular wall motion were observed by two-dimensional echocardiography. The left ventricle was divided into 11 segments and the movement was scored according to the dynamic behavior of each segment by five points ranging from normal (0) to dyskinesis (4), and evaluated semiquantitatively using the total score sum as the total asynergy score. Compared to the initial value, this score decreased to 57% after one week, 38% in two weeks, 22% in three weeks and 17% in four weeks. The asynergy persisted 23.7 +/- 13.5 days and ranged from two days to three months. The peak CPK ranged from 32 to 561 IU (mean 212 +/- 157 IU). Coronary arteriography revealed undisturbed flow of the responsible artery in both acute and chronic phases including four cases of successful PTCR. Comparison of the electrocardiographic changes and asynergy showed that diminished R wave amplitude, ST segment elevation and inverted T waves are frequently associated with persistence of asynergy, extensive asynergy can even occur in cases without a diminished R wave or abnormal Q wave and when asynergy resolves, ST segments tend to return to the baseline, but T wave inversion commonly persists. A transient Q wave was observed in 38% of the patients examined. The electrocardiogram became normal in an average of 111.3 +/- 75 days. In conclusion, there is a subgroup of reversible asynergy among cases of unstable angina pectoris or subendocardial infarction. The mechanism for this may be myocardial "stunning" following transient transmural ischemia. Recognition of this fact seems very important in the diagnosis and treatment of acute myocardial ischemia.

Synchrotron radiation available at the Photon Factory, National Laboratory for High Energy Physics, provides a new X-ray source which is highly suitable for K-edge subtraction. This is due to its high intensity, its parallelism and its monochromaticity, available in a monochromator system. Experiments were performed using wiggler synchrotron radiation. Since the beam size is relatively-small for in-vivo imaging, a phantom coupled with a detector was moved horizontally using a scanning table. K-edge subtraction was successfully applied both to the coronary artery phantom filled with barium sulphate, and to rat angiography using iodine contrast material. The potential use and value of energy subtraction was successfully demonstrated.

Membranous tricuspid atresia with right ventricular dysplasia and absent pulmonary valve is a very rare complex, and a unique type of tricuspid atresia. Three cases with this condition were presented with the echocardiographic evaluation. Two-dimensional echocardiography was performed in all patients, pulsed Doppler echocardiography in two, and contrast echocardiography in two patients. The echocardiographic findings characteristic of this complex were as follows: In the four chamber view, the interatrial and interventricular septa were aligned, and tricuspid valve atresia was of the membranous type. In the four-chamber view, the right ventricular wall was thin, irregular in shape, and it protruded aneurysmally into the left ventricular outflow tract. With systemic venous contrast echocardiography, the right ventricular cavity was opacified with contrast, four to five cardiac cycles after the appearance of contrast in the left ventricle. With pulsed Doppler echocardiography at the main pulmonary artery, antegrade flow was observed in ventricular systole, and retrograde flow in diastole. We conclude that these echocardiographic findings are useful in recognizing the morphology and hemodynamics of this complex.