Simultaneous measurement of left ventricular function and myocardial perfusion during a single exercise test: dual isotope imaging with gold-195 m and thallium-201

The state of left ventricular function and myocardial perfusionare important determinants of prognosis in patients with coronaryartery disease and information on both can be valuable for planningindividual patient management. We have studied the feasibilityof simultaneous measurement of left ventricular ejection fractionwith ultra short-lived gold-195 m (half life 30.5 seconds) andmyocardial perfusion with thallium-201, at rest and after exercisewith a single-crystal gamma camera. The results with first-passradionuclide angiocardiography (RNA) using gold-195 m at restwere reproducible and agreed closely with the results obtainedusing technetium-99 m equilibrium radionuclide angiocardiography(r = 0.93). Ejection fraction by firstpass gold-195 m RNA duringsemi-supine ergometric exercise decreased by >5% in 13 outof 18patients with coronary artery disease and stable angina.Simultaneous myocardial imaging with thallium-201 was abnormalin all patients. The change in regional wall motion abnormalityscore during exercise correlated with the change in myocardialperfusion (r = 0.71, P<0.01) and with the change in globalleft ventricular ejection fraction (r = 0.77, P<0.001). Thewidely differing energy levels and half-lives of gold-195 mand thallium-201 made it possible to separate clearly the imagesdue to each radionuclide. This study has demonstrated the feasibilityof simultaneous or sequential assessment of left ventricularfunction and myocardial perfusion during a single exercise test,a technique which can offer advantages in clinical evaluationof patients with coronary artery disease.     

Radionuclide assessment of regional differences in left ventricular wall motion and myocardial perfusion in idiopathic dilated cardiomyopathy

Regional variations in left ventricular contractility and myocardialperfusion are frequent in idiopathic dilated cardiomyopathyand might result from an increase in left ventricular wall stressresponsible for regional wall motion abnormalities. The aimof the study was to perform radionuclide studies in patientswith idiopathic dilated cardiomyopathy to assess regional leftventricular wall motion and myocardial perfusion abnormalitiesin this myocardial disease. We studied 29 men referred withidiopathic dilated cardiomyopathy and normal coronary angiograms.Rest radionuclide left ventriculography and exercise thallium-201tomography were performed in all patients. The thallium-201tomograms were divided into 20 segments for each patient. Meanleft ventricular ejection fraction was 27±11%; 17 patientshad diffuse hypokinesia (mean left ventricular ejection fraction:24±9%) and 12 patients had predominant regional hypokinesia(mean left ventricular ejection fraction: 32±12%). Ofall 580 tomographic segments, 186 had a reduction of thallium-201uptake at exercise. Among them, reversibility was found in 53%.On the whole, 68% (158/232) of anterior, inferior and apicalsegments had a perfusion abnormality, compared with 8% (28/348)of septal and lateral segments (P<0.0001). Left ventricular wall motion and myocardial perfusion abnormalitiesare heterogeneous and not evenly distributed in dilated cardiomyopathy.The alterations are predominant on the myocardial regions delineatingthe antero-posterior axis of the left ventricle. These findingssuggest the possible role of increased left ventricular wallstress on this axis.     

Coronary angioplasty and left ventricular function in single vessel coronary artery disease.

Left ventricular function was investigated in 86 patients with single vessel coronary artery disease before and three to six months after successful angioplasty. Before angioplasty thallium-201 perfusion scintigraphy and technetium-99m gated equilibrium ventriculography in most patients showed that stress testing (exercise and ice water stimulation and isometric handgrip respectively) induced myocardial perfusion defects that were associated with a mean (SD) drop in left ventricular ejection fraction from 64 (6)% to 56 (7)%. After angioplasty there was residual coronary stenosis of less than or equal to 20% of the diameter of the vessel in 78 patients (group 1) and of between 20 and 50% in eight patients (group 2). After the procedure the perfusion defects seen during stress resolved in 86% of group 1 and in 87% of group 2. Despite the apparent improvement in myocardial perfusion left ventricular dysfunction persisted in group 2--that is during stress the left ventricular ejection fraction fell from 65% (6) to 56% (5). In group 1, on the other hand, the improvement in myocardial perfusion was associated with significant improvement in left ventricular function with a normal increase in ejection fraction from 63 (5) at rest to 67 (6) during stress. Radionuclide studies, one to six weeks after angioplasty in 30 group 1 patients showed continuing left ventricular decompensation during stress in nine (30%) of them despite correction of perfusion defects. But reinvestigation three to six months after the procedure showed recovery of left ventricular function with an increase in ejection fraction from 66 (5) at rest to 69 (7) during stress. These data indicate that coronary angioplasty procedures that give a residual stenosis of </= 20% improve myocardial perfusion and the response of the left ventricle to stress. The functional improvement may be delayed for up to three months, however, possibly because arterial healing at the angioplasty site is delayed. On the other hand, when the residual stenosis is between 21 and 50% of the diameter of the vessel subclinical left ventricular dysfunction during stress may persist indefinitely.     

Coronary angioplasty and left ventricular function in single vessel coronary artery disease

Left ventricular function was investigated in 86 patients with single vessel coronary artery disease before and three to six months after successful angioplasty. Before angioplasty thallium-201 perfusion scintigraphy and technetium-99m gated equilibrium ventriculography in most patients showed that stress testing (exercise and ice water stimulation and isometric handgrip respectively) induced myocardial perfusion defects that were associated with a mean (SD) drop in left ventricular ejection fraction from 64 (6)% to 56 (7)%. After angioplasty there was residual coronary stenosis of less than or equal to 20% of the diameter of the vessel in 78 patients (group 1) and of between 20 and 50% in eight patients (group 2). After the procedure the perfusion defects seen during stress resolved in 86% of group 1 and in 87% of group 2. Despite the apparent improvement in myocardial perfusion left ventricular dysfunction persisted in group 2--that is during stress the left ventricular ejection fraction fell from 65% (6) to 56% (5). In group 1, on the other hand, the improvement in myocardial perfusion was associated with significant improvement in left ventricular function with a normal increase in ejection fraction from 63 (5) at rest to 67 (6) during stress. Radionuclide studies, one to six weeks after angioplasty in 30 group 1 patients showed continuing left ventricular decompensation during stress in nine (30%) of them despite correction of perfusion defects. But reinvestigation three to six months after the procedure showed recovery of left ventricular function with an increase in ejection fraction from 66 (5) at rest to 69 (7) during stress. These data indicate that coronary angioplasty procedures that give a residual stenosis of 相似文献   

Myocardial bridging of the left anterior descending artery: Evaluation using exercise thallium-201 myocardial scintigraphy

Seven patients with myocardial bridging of the left anterior descending coronary artery were evaluated by means of thallium-201 exercise scintigraphy. The degree of systolic narrowing was 60–70% in five patients and 75–80% in two patients. All patients had presented with chest pain. The resting electrocardiogram was normal in six patients; there were ST segment and T-wave abnormalities in one patient. No patient complained of chest pain during exercise. The exercise electrocardiogram was negative in six patients and inconclusive in one patient. Exercise myocardial scans were negative in all seven patients. We conclude that no evidence of ischemia was demonstrated in patients with myocardial bridging of the left anterior descending coronary artery as determined by exercise electrocardiography and stress thallium-201 scintigraphy.     

Comparison of exercise radionuclide angiocardiography and thallium-201 myocardial perfusion imaging in coronary artery disease

First pass radionuclide angiocardiography and thallium-201 myocardial perfusion imaging were performed at rest and during exercise in 48 patients with chest pain: 39 with angiographically documented coronary artery disease and 9 with normal coronary arteries. Maximal graded upright bicycle exercise was used for both studies to assure identical exercise conditions. All nine patients without coronary artery disease had normal exercise thallium images, normal exercise regional wall motion and at least a 5 percent absolute increase in left ventricular ejection fraction during exercise (normal exercise left ventricular reserve). Ischemic S-T segment depression was demonstrated in 17 (44 percent) of the 39 patients with coronary artery disease. Findings on the two exercise tests were concordant in all cases. New or augmented thallium perfusion defects were detected in 24 (62 percent) of the 39 patients, whereas abnormal exercise left ventricular reserve was present in 33 (85 percent) (p <0.05). There was a close concordance between exercise-induced perfusion defects and regional wall motion abnormalities. The magnitude of change in ejection fraction from rest to exercise was significantly greater in patients with an abnormal exercise thallium study than in those with a normal study (−8 ± 2 percent versus −1 ± 1 percent, p <0.05). Both radionuclide studies were abnormal In 21 (54 percent) of the 39 patients, whereas both were normal only in 3 patients, all of whom had single vessel disease. Abnormal exercise left ventricular reserve was present in 12 patients with normal exercise thallium studies.     

Myocardial perfusion and left ventricular performance during exercise-induced ST-segment depression in apparently healthy subjects

Ischemic-like ST-segment depression seen during exercise in apparently healthy subjects has previously been noted, but the cause of this change is unknown. The aim of this study was to investigate the pathophysiology of this electrocardiographic change. Ten healthy subjects who developed an electrocardiographic "ischemic" pattern of ST change during treadmill exercise testing were studied. All subjects underwent both thallium-201 myocardial perfusion imaging and radionuclide angiocardiography at rest and during exercise at a time when abnormal ST changes appeared, and demonstrated a normal homogeneous pattern of thallium-201 distribution on both rest and exercise images. Overall, left ventricular ejection fraction rose from 0.60 +/- 0.06 (mean +/- SD) at rest to 0.65 +/- 0.07 with exercise. None of the subjects had regional wall motion abnormalities at rest or during exercise. These results are different from the findings observed in patients with coronary heart disease and angina pectoris in whom regional abnormalities in both perfusion and left ventricular performance have been noted during exercise. Therefore it would seem that myocardial ischemia is not likely to be a tenable explanation for the electrocardiographic "ischemic" changes in these apparently healthy subjects.     

Exercise thallium-201 myocardial imaging in left main coronary artery disease: Sensitive but not specific

To determine the usefulness of thallium-201 scintigraphy for identifying left main coronary artery disease, the results of scintigraphy at rest and during exercise were compared in 24 patients with 50 percent or greater narrowing of the left main coronary artery and 80 patients with 50 percent or greater narrowing of one or more of the major coronary arteries but without left main coronary involvement. By segmental analysis of the scintigrams, perfusion defects were assigned to the left anterior descending, left circumflex or right coronary artery, singly or in combination, and the pattern of simultaneous left anterior descending and circumflex arterial defects was used to identify left main coronary artery disease. Of the 24 patients with left main coronary artery disease, 22 (92 percent) had abnormal exercise scintigrams. Despite this high sensitivity, the pattern of perfusion defects was not specific; the “left main pattern” was found in 3 patients (13 percent) with left main coronary artery disease but also in 3 (33 percent) of 9 patients with combined left anterior descending and left circumflex arterial disease, 4 (19 percent) of 21 patients with three vessel disease and 3 (6 percent) of 50 patients with one or two vessel disease but excluding the group with left anterior descending plus left circumflex arterial disease.The pattern of perfusion defects in the patients with left main coronary artery disease was determined by the location and severity of narrowings in the coronary arteries downstream from the left main arterial lesion. Concomitant lesions in other arteries were found in all patients with left main coronary disease (one vessel in 1 patient, two vessels in 7 patients and three vessels in 16). For this reason, it is unlikely that even with improvements in radiopharmaceutical agents and imaging techniques, myocardial perfusion scintigraphy will be sufficiently specific for definitive identification of left main coronary artery disease.     

Radionuclide assessment of right and left ventricular exercise reserve after total correction of tetralogy of Fallot

First pass radionuclide angiocardiography under conditions of rest and exercise was utilized to evaluate a group of 16 postoperative patients who had undergone total surgical correction of tetralogy of Fallot. Functional data were related to thallium-201 myocardial imaging at rest, a noninvasive means of detecting right ventricular hypertrophy. All 16 patients were asymptomatic and 15 demonstrated normal right ventricular ejection fraction (equal to or greater than 45 percent) at rest. However, 13 patients manifested abnormal right ventricular ejection fraction responses to exercise (normal response is an absolute increment in an ejection fraction of 5 or greater percent). For the entire group, right ventricular ejection fraction at rest was 55 ± 2 percent, whereas at exercise it was 52 ± 2 percent (p = not significant). In contrast, left ventricular ejection fraction responses were normal in all patients. Thallium-201 imaging revealed substantial right ventricular uptake consistent with residual right ventricular hypertrophy, which was quantifiable in all patients. Thus, abnormalities in right ventricular performance during exercise may be detected readily by this radionuclide approach in these postoperative patients despite their asymptomatic clinical status and generally normal right ventricular performance at rest.     

Myocardial perfusion after aortic implantation for anomalous origin of the left coronary artery from the pulmonary artery

Postoperative myocardial perfusion and function were evaluated using thallium-201 myocardial imaging and technetium-99m cardiac pool imaging in five patients with an anomalous left coronary artery arising from the pulmonary artery. The patients underwent reimplantation of the left coronary artery at an age ranging from 10 months to 13 years. Postoperative electrocardiographic and radionuclide studies were performed both at rest and during stress 1 to 4 years after the operation. Electrocardiograms which were abnormal preoperatively returned to normal after surgery except that the T wave in lead aVL remained negative. Postoperatively, left ventricular ejection fraction measured by technetium-99m cardiac pool imaging was normal in all patients. Postoperative thallium-201 myocardial imaging, however, showed a perfusion defect with incomplete redistribution at the high-lateral or antero-lateral segment in all patients after a stress test. These data suggest that although myocardial ischaemic change decreases and global cardiac function improves after establishment of a dual coronary artery system, severe myocardial damage remains at the high-lateral or antero-lateral segment.     

Improved myocardial ischemia and left ventricular function during exercise after successful percutaneous transluminal coronary angioplasty

Percutaneous transluminal coronary angioplasty (PTCA) was performed in 42 patients with effort angina, 28 (67%) of them underwent successful angioplasty. Treadmill exercise testing, thallium-201 myocardial scintigraphy and radionuclide ventriculography were performed before and after PTCA for evaluation of the improvement of myocardial ischemia and left ventricular function at rest and during exercise. The average exercise duration by treadmill testing in 14 successful cases increased from 14 +/- 4 (mean +/- S.D.) to 16 +/- 2 minutes (p less than 0.05). Sixteen of 28 the patients were studied by thallium-201 myocardial scintigraphy. Before PTCA, regions of decreased thallium-201 uptake after exercise were observed in 12 of the 16 patients. After angioplasty, no distinct defects were recognizable in 9 of the 12 patients, and in the remaining three, a significant decrease in defects was recognized. Fifteen of the 28 patients were studied by radionuclide ventriculography. The mean ejection fraction was 61 +/- 5% at rest and 56 +/- 11% during exercise (N.S.) before PTCA. After angioplasty, the ejection fraction was unchanged at rest (61 +/- 5 to 62 +/- 4%), but increased significantly during exercise (62 +/- 4 to 74 +/- 4%, p less than 0.001). In conclusion, left ventricular function was improved by successful PTCA due to improvement of myocardial ischemia. The long term results require further study.     

Exercise and rest technetium-99m-tetrofosmin lung uptake: correlation with left ventricular ejection fraction in patients with coronary artery disease

Increased lung uptake of thallium-201 (Tl-201) and technetium-99m (Tc-99m) MIBI in myocardial perfusion imaging is a reliable marker of left ventricular dysfunction. The goal of our study was to establish whether the lung-to-heart (L/H) uptake ratio with a newer cardiac imaging agent, Tc-99m tetrofosmin, can also provide valuable information about left ventricular function. We studied 60 patients with recent coronary artery diseases (CAD) undergoing first-pass radionuclide ventriculography to calculate left ventricular ejection fraction (LVEF) and myocardial perfusion imaging to calculate the L/H ratio. Group A consisting of 30 CAD patients with higher LVEF (> or =40%) had a significantly lower L/H ratio than group B consisting of 30 CAD patients with abnormal LVEF (<40%) during exercise and rest. In groups A and B, the exercise and rest L/H ratios did not differ significantly. However, a statistically significant inverse correlation was found between the L/H ratio and LVEF during exercise and rest among the 60 patients. L/H ratios, measured by 99mTc-tetrofosmin imaging, provide clinically useful information with which to predict left ventricular dysfunction in CAD patients.     

Idiopathic hypertrophic subaortic stenosis: evaluation of anginal symptoms with thallium-201 myocardial imaging.

The evaluation of angina pectoris in patients with idiopathic hypertrophic subaortic stenosis is difficult in those in the age group prone to coronary artery disease. Ten patients with angina pectoris, normal coronary angiograms and idiopathic hypertrophic subaortic stenosis were studied with thallium-201 myocardial imaging performed in conjunction with submaximal treadmill exercise testing. The resting electrocardiogram demonstrated left ventricular hypertrophy with S-T segment abnormalities in seven patients, thereby vitiating the further increase in S-T segment abnormalities that developed in these patients during exercise or in the postexercise period. Of the three patients with a normal resting electrocardiogram, one had significant exercise-induced S-T segment depression. Thallium-201 myocardial imaging revealed no significant perfusion defects in 9 of the 10 patients (90 percent). In one patient with severe left ventricular hypertrophy significant perfusion defects developed after exercise that were not present at rest. Stress thallium-201 myocardial perfusion imaging is a useful noninvasive technique that assists in ruling out the presence of significant coronary artery disease in patients with idiopathic hypertrophic subaortic stenosis.     

Peak systolic blood pressure/end-systolic volume ratio: Assessment at rest and during exercise in normal subjects and patients with coronary heart disease

To assess the utility of a recently proposed index of left ventricular performance, the ratio of peak left ventricular systolic pressure to end-systolic volume, equilibrium radionuclide angiography was used to determine end-systolic volume and the systolic blood pressure obtained by cuff sphygmomanometer to determine peak systolic pressure. Data were analyzed at rest and during supine bicycle exercise in 15 normal subjects (Group 1), 50 patients with coronary artery disease (Group II) and 9 patients with obstructive lung disease and no evidence of coronary artery disease on clinical examination including exercise thallium imaging (Group III). In 15 subjects the correlation between the resting angiographic and radionuclide pressure/volume ratio was excellent (r = 0.929, p <0.005).Forty-seven (94 percent) of the 50 patients in Group II had a depressed pressure/volume ratio at rest or an abnormal change in this ratio during exercise, whereas only 43 (86 percent) of this group had an abnormal ejection fraction at rest or during exercise. Additionally, 3 of 15 subjects in Group I had an abnormal ejection fraction response, defined as less than 0.05 ejection fraction unit increase with exercise (specificity 80 percent), whereas all subjects in Group I had a normal increase in pressure/volume ratio (specificity 100 percent). At rest, neither index identified more patients with coronary artery disease than the other. Of the nine patients in Group III, six had an abnormal ejection fraction response to exercise, whereas only one had an abnormal pressure/volume ratio response.It is concluded that the end-systolic pressure/volume ratio is a useful index of left ventricular performance. In some patients during supine exercise stress it may be more sensitive than the ejection fraction response alone in identifying the presence of coronary artery disease.     

New developments in pharmacologic stress imaging.

The clinical usefulness of cardiac imaging modalities that rely upon the detection of perfusion defects and wall motion disturbances requires conditions that provoke a heterogeneity of coronary flow and a myocardial oxygen imbalance, respectively. Traditionally, this has been achieved by exercise stress testing. Many patients cannot perform dynamic exercise sufficiently for various reasons. Pharmacologic stress has been proven to be an attractive alternative for physical exercise. Currently, several stressing agents are used in conjunction with thallium-201 scintigraphy, 2-D echocardiography and, recently, MRI. The most employed agents include vasodilators, such as dipyridamole and adenosine, and catecholamines, such as dobutamine (Table VI). The predominant rationale of thallium-201 perfusion scintigraphy is based on the creation of a flow maldistribution between territories supplied by normal arteries and those supplied by stenotic arteries that does not necessarily require ischemia. Dipyridamole and adenosine, as rather selective coronary vasodilators, are well suited to provoke such a condition and may be classified as the ideal markers of myocardial perfusion. 2-D echocardiography and MRI have the potential to provide noninvasively derived information of cardiac dynamics and regional myocardial function. To assess the functional significance of coronary artery disease, detection of wall motion abnormalities and alterations in ejection fraction require the presence of myocardial ischemia. Dobutamine, as a widely applied inotropic agent in the management of severely depressed left ventricular contractile function, seems to be an appropriate pharmacologic stressor when heart failure is absent. By increasing contractility, heart rate, and systolic arterial pressure, it is capable of inducing an imbalance between myocardial oxygen demand and supply, leading to ischemia in patients with coronary artery disease.(ABSTRACT TRUNCATED AT 250 WORDS)     

Myocardial thallium-201 scintigraphy for assessment of viability in patients with severe left ventricular dysfunction.

Many patients with ischemic heart disease and depressed left ventricular (LV) function have asynergic zones with sustained microcirculatory perfusion and myocardial metabolic activity that exhibit improved systolic function after coronary revascularization. The 2 predominant noninvasive techniques used to determine myocardial viability in patients with severely depressed LV function are thallium-201 (201Tl) scintigraphy and positron emission tomography (PET). Myocardial extraction of 201Tl is unaltered under experimental conditions of myocardial stunning or short-term hibernation (characterized by decreased flow and ischemic dysfunction). Akinetic or dyskinetic LV wall segments can exhibit normal or near normal 201Tl uptake as long as some residual flow is present. 201Tl scintigraphy can identify viable asynergic segments when performed on patients with severe coronary artery disease who are in the resting state. Many of these patients have initial resting defects that demonstrate delayed redistribution, or mild persistent defects that show improved perfusion and function after revascularization. There is a direct correlation between the extent of 201Tl uptake in zones of severe regional myocardial asynergy and the magnitude of improvement in resting LV ejection fraction after coronary bypass surgery. Rest 201Tl scintigraphy may help in the selection of patients with coronary artery disease and severely depressed LV function who would benefit the most from revascularization.     

Value and limitations of stress thallium-201 scintigraphy in evaluating the viability of infarcted myocardial segments

The aim of this study was to evaluate the value and limitations of stress thallium-201 scintigraphy in evaluating the viability of infarcted myocardial segments following percutaneous transluminal coronary angioplasty (PTCA) and aortocoronary bypass surgery. The relative thallium activity (RTA: the ratio of the count rate in the infarcted segment to that in the intact segment) obtained from delayed images of stress myocardial scintigraphy was used as an index of myocardial viability and was compared with the following parameters. 1) Thallium-201 myocardial perfusion images were made during transient coronary arterial occlusion (PTCA) in eight patients with old myocardial infarction. The RTA of delayed images after successful PTCA was compared with those of stress thallium-201 scintigraphy. There were no significant differences of the RTA between delayed images following PTCA and those of stress myocardial scintigraphy. We therefore, presumed that incomplete redistribution of the delayed images of stress thallium-201 scintigraphy did not truly reflect the degree of coronary stenosis. 2. Regional ejection fraction of the left ventricle after postextrasystolic potentiation (PESP) using equilibrium radionuclide ventriculography was studied in 18 patients with old myocardial infarction, and was compared with the RTA of delayed images of stress myocardial scintigraphy. A significant correlation was observed between the changes in regional ejection fraction by PESP and the RTA three hours after exercise. 3. The RTAs of early and delayed thallium-201 scintigrams were measured at rest in 30 patients with old myocardial infarction, and were compared with the RTA of delayed thallium 201 scintigrams after exercise.(ABSTRACT TRUNCATED AT 250 WORDS)     

Systolic and diastolic left ventricular dysfunction in middle-aged asymptomatic non-insulin-dependent diabetics.

Radionuclide ventriculographic studies were performed at rest and during exercise in 15 middle-aged asymptomatic patients with non-insulin-dependent diabetes mellitus (NIDDM) whose mean age was 58.7 +/- 10.5 years (mean +/- SD), and in 10 age- and sex-matched normal control subjects. The patients had neither clinical evidence of cardiovascular diseases nor obvious perfusion defects during maximal exercise testing with thallium-201 myocardial scintigraphy. The average left ventricular ejection fraction (LVEF) at rest was 69.1 +/- 5.3% in the diabetic patients and 65.6 +/- 4.2% in the control subjects, and during exercise, the average LVEFs were 68.3 +/- 6.9% and 72.1 +/- 5.0%, respectively. The changes in LVEF during exercise were -0.7 +/- 7.6% in the diabetic group and +6.5 +/- 2.6% in the control group (p < 0.01). However, the filling fraction during the first third of diastole at rest was significantly less in the diabetic group than in the control group (p < 0.05), the time to peak filling rate (TPF) was longer, and the TPF/R-R, normalized by the R-R interval and expressed as a percentage, was greater in the NIDDM patients than in the control subjects. There was close correlation between the abnormal response of LVEF to exercise and the reduced early diastolic filling in the diabetic patients. We concluded that 1) not only the response of LVEF to exercise but also the early left ventricular diastolic filling at rest are impaired in middle-aged asymptomatic NIDDM patients, and 2) some common factors could cause dysfunction of both the systolic and diastolic left ventricles in NIDDM patients, possibly latent global myocardial ischemia or metabolic myocardial disturbances.     

Usefulness for evaluation of the left ventricular disorders by apexcardiographic A-wave ratio in patients with hypertrophic cardiomyopathy

Usefulness for evaluation of left ventricular disorders by apexcardiographic A-wave ratio was studied in 48 patients with hypertrophic cardiomyopathy. These subjects were divided into 3 groups: A-wave ratio less than or equal to 15% (group 1), 16% less than or equal to A-wave ratio less than or equal to 29% (group 2), and A-wave ratio greater than or equal to 30% (group 3). A-wave ratio was found to have a positive correlation with Time constant T (r = + 0.71), left ventricular end-diastolic pressure (r = +0.46), and left ventricular atrial kick (r = +0.55). During exercise, ejection fraction decreased significantly (p less than 0.05) in group 3 as compared to group 1. During treadmill exercise test, rise of systolic blood pressure was significantly (p less than 0.05) poor, and there was a large number of ST depression (p less than 0.05) in group 3. It was recognized by exercise thallium-201 myocardial scintigraphy, that the frequency of perfusion defect was 30% in group 3. In conclusion, high A-wave ratio may strongly suggest impaired left ventricular diastolic function, and, there was correlated to abnormal hemodynamic state during exercise. Apexcardiographic A-wave ratio proved to be useful in patients with hypertrophic cardiomyopathy. It is useful for evaluation of left ventricular disorders.