Quantitative gated blood pool tomographic assessment of regional ejection fraction: definition of normal limits.

OBJECTIVE: Our aim was to select a method of analysis for gated blood pool tomography that reduced variability in a group of normal subjects, allowed comparison with normal limit files and displayed results in the bull's-eye format. BACKGROUND: Abnormalities in left ventricular function may not be accurately detected by measures of global function because hyperkinesia in normal regions may compensate for abnormal regional function. Gated blood pool tomography acquires three-dimensional data and offers advantages over other noninvasive modalities for quantitative assessment of global and regional function. METHODS: Alternative methods for selecting the ventricular axis, calculating regional ejection fraction and choosing the number of ventricular divisions were studied in 15 normal volunteers to select the combination of parameters that produced the lowest variability in quantitative regional ejection fraction. Methods for quantitative comparison of regional ejection fraction with normal limit files and for display in the bull's-eye format were also examined. RESULTS: A fixed axis (the geometric center of the ventricle defined for end-diastole and used for end-systole) gave ejection fractions that were significantly higher in the lateral wall versus in the septum, 82 +/- 8 (mean +/- 1 SD) versus 39 +/- 17 (p less than 0.001) at the midcavity and 66 +/- 11 versus 21 +/- 20 (p less than 0.001) at the base. A floating axis system (axis defined individually for end-diastole and end-systole and realigned at the center) gave more uniform regional ejection fraction: 63 +/- 6 versus 64 +/- 8 (p = NS) at the midcavity and 44 +/- 16 versus 45 +/- 15 (p = NS) at the base. The coefficient of variability for regional ejection fraction was consistently lower using a floating axis. Calculating regional ejection fraction by dividing the regional stroke volume by the end-diastolic volume of the region gave a lower coefficient of variability and a more easily understood value than dividing the regional stroke volume by the total end-diastolic volume of the ventricle. Although the variability was lower using five versus nine ventricular divisions, nine regions offer greater spatial resolution. Comparison of regional ejection fraction with normal data identified regions greater than 2.5 SD below the mean as abnormal. We described the two-dimensional bull's-eye format as a method for displaying the regional three-dimensional data and illustrated abnormalities in patients with prior myocardial infarction. CONCLUSIONS: Gated blood pool tomography performed using a floating axis system, regional stroke volume calculation of ejection fraction and nine regions uses all the three-dimensional blood pool data to calculate regional ejection fraction, allow quantitative comparison with normal limit files, display the functional data in the two-dimensional bull's-eye format and demonstrate abnormalities in patients with myocardial infarction.

Safety profile of adenosine stress perfusion imaging: results from the Adenoscan Multicenter Trial Registry.

OBJECTIVES: The purpose of this study was to determine the safety of adenosine infusion at 140 micrograms/kg per min in conjunction with radionuclide imaging in 9,256 consecutive patients. BACKGROUND: Adenosine produces maximal myocardial hyperemia directly with a rapid onset of action. In addition, when used in conjunction with radionuclide perfusion imaging, it has proven efficacy for the diagnosis of coronary artery disease in patients unable to exercise. Because the ultrashort half-life (< 10s) allows dose titration and rapid reversal of side effects, it may be safer than other available pharmacologic agents. METHODS: Patients were prospectively entered at 21 clinical sites. Information on safety and adverse events during and immediately after adenosine infusion was maintained in the Adenoscan Multicenter Trial Registry. RESULTS: The infusion protocol was completed in 80% of patients, required dose reduction in 13% and was terminated early in 7%. Interpretable imaging studies were obtained in 98.7% of patients, and 0.8% of patients received aminophylline. Minor and well tolerated side effects were reported in 81.1% of patients. There were no deaths, one myocardial infarction, seven episodes of severe bronchospasm and one episode of pulmonary edema. Transient atrioventricular (AV) node block occurred in 706 patients (first-degree in 256, second-degree in 378 and third-degree in 72) and resolved spontaneously in most patients (n = 508) without alteration in the adenosine infusion. There were no sustained episodes of AV block. Patients > 70 years of age had an increased risk of developing AV block (age < 70, 7.05% vs. > or = 70, 9.44%, p = 0.001, relative risk 1.37). CONCLUSIONS: Adenosine infusion is safe. Vasodilator and negative dromotropic side effects are generally well tolerated. Serious side effects are relatively rare, and they reverse with termination of adenosine infusion. Interpretable radionuclide studies were obtained in 98.7% of patients and aminophylline reversal was seldom required.

Long-term survival in 618 patients from the Western Washington Streptokinase in Myocardial Infarction trials.

OBJECTIVES: The aim of this study was to determine whether streptokinase treatment improves long-term survival in patients with acute myocardial infarction. BACKGROUND: Thrombolytic treatment for acute myocardial infarction reduces early mortality and improves the 1-year survival rate, but the long-term (3 to 8 years) survival benefits of treatment and the relation between survival and baseline clinical characteristics, infarct size and ventricular function have not been established. METHODS: We assessed survival status at a minimum of 3 and a mean of 4.9 +/- 2.3 years in 618 patients randomized between 1981 and 1986 to receive conventional treatment (n = 293) or thrombolysis with streptokinase (n = 325) in the Western Washington Intracoronary (n = 250) and Intravenous (n = 368) Streptokinase in Myocardial Infarction trials. The relation between long-term survival and thrombolytic treatment, admission baseline clinical characteristics and late radionuclide tomographic thallium-201 infarct size and ejection fraction was assessed in a subset of patients. RESULTS: Survival at 6 weeks was 94% in patients who received streptokinase versus 88% in the control group (p = 0.01). However, survival at 3 years was 84% in the streptokinase group and 82% in the control group and for the total period of follow-up, there was no significant survival benefit (p = 0.16). Analysis by infarct location showed a higher survival rate at 3 years for patients treated with anterior infarction (76% vs. 67% for the control group), but no overall survival benefit (p = 0.14). Survival at 3 years for patients with an inferior infarction was 89% in the streptokinase group and 91% in the control group (p = 0.62). By stepwise Cox regression analysis, admission clinical variables associated with decreased long-term survival were anterior infarction, advanced age, history of prior infarction and the presence of pulmonary edema or hypotension. Although streptokinase therapy was associated with improved survival, it was not an independent determinant of survival (p = 0.069). Ejection fraction and thallium-201 infarct size measured approximately 8 weeks after enrollment had a strong association with long-term survival. Univariate analysis in a subgroup of 289 patients with complete data selected infarct size, ejection fraction, age and history of prior infarction as predictors of survival. In the multivariate model, only ejection fraction (p < 0.0001), age (p = 0.008) and prior myocardial infarction (p = 0.02) remained strong predictors. CONCLUSIONS: In these early trials of thrombolytic therapy for acute myocardial infarction, streptokinase improved early survival, but there was little long-term survival benefit. This failure to show an improvement in the 3- to 8-year survival rate may also reflect the need to study a larger group of patients or to initiate treatment earlier after symptom onset.

Appearance of abnormal Q waves early in the course of acute myocardial infarction: implications for efficacy of thrombolytic therapy.

OBJECTIVES: The purpose of this study was to determine the time course of the appearance of abnormal Q waves on the electrocardiogram (ECG) over the first 6 h of symptoms of myocardial infarction and to determine what implications, if any, such Q waves have for the efficacy of thrombolytic therapy. BACKGROUND: Severe myocardial ischemia can produce early QRS changes in the absence of infarction. Abnormal Q waves on the baseline ECG may not be an accurate marker of irreversibly injured myocardium. METHODS: Data from 695 patients who had no past history of myocardial infarction and whose admission ECG allowed prediction of myocardial infarct size in the absence of thrombolytic therapy (Aldrich score) were pooled from four prospective trials of thrombolytic therapy. The presence and number of abnormal Q waves on each patient's initial ECG were recorded. Four hundred thirty-six patients had left ventricular infarct size measured using quantitative thallium-201 tomography a mean (+/- SD) of 52 +/- 43 days after admission. RESULTS: Of patients admitted within 1 h of symptoms, 53% had abnormal Q waves on the initial ECG. Both predicted and final infarct size were larger in patients with abnormal Q waves on the initial ECG independent of the duration of symptoms before therapy (p < 0.001). Despite this finding, the presence of abnormal Q waves on the admission ECG did not eliminate the effect of thrombolytic therapy on reducing final infarct size (p < 0.0001). CONCLUSIONS: Abnormal Q waves are a common finding early in the course of acute myocardial infarction. However, there is no evidence that abnormal Q waves are associated with less benefit in terms of reduction of infarct size after thrombolytic therapy.

Fibrinolytic response during exercise and epinephrine infusion in the same subjects.

To determine whether exercise-induced increases in tissue plasminogen activator (t-PA) were related to plasma epinephrine concentration during exercise, 14 healthy men (aged 24 to 62 years) were studied during epinephrine infusions (10, 25 and 50 ng/kg per min) and graded supine bicycle exercise, beginning at 33 W and increasing in 33-W increments until exhaustion. Plasma epinephrine, active and total t-PA, active plasminogen activator inhibitor type 1 (PAI-1) and t-PA/PAI-1 complex concentrations were measured at each exercise and infusion level. During epinephrine infusion, active and total t-PA levels increased linearly with the plasma epinephrine concentration (respective slopes [+/- SEM] of 0.062 +/- 0.003 and 0.076 +/- 0.003 pmol/ng epinephrine). During exercise, t-PA levels did not increase until plasma epinephrine levels increased, after which both active and total t-PA levels again increased linearly with the plasma epinephrine concentration, but at twice the rate observed with epinephrine infusion (0.131 +/- 0.005 and 0.147 +/- 0.005 pmol/ng, respectively). The t-PA level in blood was directly proportional to the plasma epinephrine concentration during both exercise and epinephrine infusion, suggesting that epinephrine release during exercise stimulates t-PA secretion. In these healthy subjects, active plasminogen activator inhibitor type 1 and t-PA/PAI-1 complex levels were low (41 +/- 11 and 21 +/- 5 pmol/liter, respectively) and did not change significantly during exercise or epinephrine infusion. It is concluded that approximately 50% of the increase in t-PA during exercise is due to stimulated release of t-PA by epinephrine.(ABSTRACT TRUNCATED AT 250 WORDS)

Myocardial Infarction Triage and Intervention Project--phase I: patient characteristics and feasibility of prehospital initiation of thrombolytic therapy.

Prehospital initiation of thrombolytic therapy by paramedics, if both feasible and safe, could considerably reduce the time to treatment and possibly decrease the extent of myocardial necrosis in patients with acute coronary thrombosis. Preliminary to a trial of such a treatment strategy, paramedics evaluated the characteristics of 2,472 patients with chest pain of presumed cardiac origin; 677 (27%) had suitable clinical findings consistent with possible acute myocardial infarction and no apparent risk of complication for potential thrombolytic drug treatment. Electrocardiograms (ECGs) of 522 of the 677 patients were transmitted by cellular telephone to a base station physician; 107 (21%) of the tracings showed evidence of ST segment elevation. Of the total 2,472 patients, 453 developed evidence of acute myocardial infarction in the hospital; 163 (36%) of the 453 had met the strict prehospital screening history and examination criteria and 105 (23.9%) showed ST elevation on the ECG and, thus, would have been suitable candidates for prehospital thrombolytic treatment if it had been available. The average time from the onset of chest pain to prehospital diagnosis was 72 +/- 52 min (median 52); this was 73 +/- 44 min (median 62) earlier than the time when thrombolytic treatment was later started in the hospital. Paramedic selection of appropriate patients for potential prehospital initiation of thrombolytic treatment is feasible with use of a directed checklist and cellular-transmitted ECG and saves time. This strategy may reduce the extent and complications of infarction compared with results that can be achieved in a hospital setting.

Exercise training delineates the importance of B-cell dysfunction to the glucose intolerance of human aging.

Aging has been associated with glucose intolerance, insulin resistance, hyperinsulinemia, and diminished islet B-cell function. The relative contribution of these factors to the aging-associated changes in glucose tolerance has been difficult to discern, particularly so for B-cell function, since insulin sensitivity itself is a determinant of B-cell function and, therefore, comparisons of insulin levels and responses between old and young subjects are difficult. To reduce this effect, we compared B-cell function in 14 healthy older men (aged 61-82 yr; body mass index, 21-30 kg/m2), who were exercise trained for 6 months to improve insulin sensitivity, to that of 11 healthy young men (aged 24-31 yr; body mass index, 19-31 kg/m2), who were also trained. Insulin-glucose interactions were assessed by measuring indices of insulin sensitivity (SI) and glucose effectiveness at zero insulin (GEZI) using Bergman's minimal model. B-Cell function was assessed by determining the acute insulin responses (AIR) to glucose (AIRgluc) and arginine at 3 different glucose levels: fasting, approximately 14 mM, and greater than 28 mM (AIRmax). AIRmax provides a measure of B-cell secretory capacity, while the glucose level at which 50% of AIRmax occurs is termed PG50 and is used to estimate B-cell sensitivity to glucose. The insulin sensitivity and glucose effectiveness at zero insulin of the trained older subjects was similar to that of the trained young [SI: old, 5.1 +/- 0.6; young, 6.5 +/- 0.7 x 10(-5) min-1/pM (mean +/- SEM; P = NS); GEZI: old, 1.3 +/- 0.2; young, 1.7 +/- 0.2 x 10(-2) min (P = NS)]. Under these conditions, the fasting glucose levels (old, 5.4 +/- 0.2; young, 5.1 +/- 0.1 mM) and basal insulin levels (old, 49 +/- 6; young, 63 +/- 11 pM) were also similar in the two groups. AIRgluc values were lower in the exercised elderly (old, 253 +/- 50; young, 543 +/- 101 pM; P = 0.01). This decrease in stimulated insulin release was due solely to a reduction in the AIRmax (old, 1277 +/- 179; young, 2321 +/- 225 pM; P less than 0.005); the PG50 was not different (old, 8.9 +/- 0.4; young, 8.8 +/- 0.2 mM; P = NS). These differences in the older subjects were associated with a reduction in iv glucose tolerance (old, 1.49 +/- 0.15; young, 1.95 +/- 0.13%/min; P less than 0.05).(ABSTRACT TRUNCATED AT 400 WORDS)

Prognostic significance of late imaging results in technetium-99m-labeled red blood cell gastrointestinal bleeding studies with early negative images.

The prognostic significance of the results of late imaging in patients with early negative 99mTc-labeled red blood cell (RBC) gastrointestinal (GI) bleeding studies was examined in a retrospective review of studies performed on 48 patients. Twenty-two studies showed intraluminal accumulation of labeled RBCs only on late images acquired from 3-24 hr following RBC injection. Patients with late positive studies had larger transfusion requirements than those with negative late images (mean total units transfused: 7.3 versus 3.5 (p less than 0.05); mean units transfused following scan commencement: 4.5 versus 2.0 (p less than 0.005)). Patients with late positive studies more frequently required angiography (3/22 versus 0/26) and surgery (5/22 versus 2/26). Sites of bleeding were more commonly identified in the stomach or small bowel in patients with late positive studies, while colon bleeding sources were more commonly found in those with late negative studies. The location of intraluminal blood on late images did not reliably discriminate upper from lower tract hemorrhage. In patients with early negative GI bleeding studies, results of later imaging provide objective evidence of the presence or absence of continued intermittent hemorrhage, and suggest both the region of bowel responsible and the relative risk for requiring further invasive procedures.

Indium-111 leukocyte scintigraphic detection of myocardial abscess formation in patients with endocarditis.

Myocardial abscess formation in patients with bacterial endocarditis in most clinical settings, especially in patients with prosthetic valves, is a primary indicator for surgical valve replacement. We report the detection of myocardial abscesses using 111In leukocyte scintigraphy in three patients with prosthetic or native valve endocarditis and nondiagnostic echocardiograms. Leukocyte scintigraphy may allow identification of myocardial abscess formation earlier than other imaging modalities.

Enhanced bone metabolism induced by acupuncture.

A 29-yr-old man with several years of back pain was referred for a bone scan. High-resolution regional spot images of the skeleton were obtained following intravenous injection of 20 mCi 99mTc-methylene diphosphonate. Posterior and lateral images of the skull showed focal increased uptake in several regions of the skull. Upon questioning, the patient stated that he had received acupuncture treatment for his back pain several times in the same regions as the increased uptake. The needle placement was confirmed by the patient's acupuncturist. Acupuncture can cause enhanced bone metabolism demonstrated by increased activity on bone scans.

The influence of collimators on SPECT center of rotation measurements: artifact generation and acceptance testing.

Misalignment between the electronic and mechanical axes of rotation will result in artifact generation and image degradation during single photon emission computed tomography (SPECT) reconstruction. Acceptance and quality control testing procedures have not emphasized the variability in center of rotation (COR) measurements caused by collimators and the need to verify uniformity across the full collimator field of view (FOV). Variation from the mean COR across the FOV was tested in four different collimators using multiple point source acquisitions. The mean COR was different for each collimator and two of the four had a greater than 0.5 pixel difference from the mean COR on some area of the FOV. This variation makes these collimators unacceptable for SPECT acquisition. Thus, initial acceptance testing of SPECT collimators should verify a uniform COR across the full FOV and collimators with a variability from the mean COR greater than 0.5 pixels should be rejected.

Factors influencing serial measurements of cardiac volumes by count-based methods: effects of elevated catecholamines, position, and exercise on technetium-99m-blood radioactivity concentration.

Most radionuclide methods for measuring cardiac volume require a determination of the blood radioactivity concentration. Thus, changes in blood radioactivity over time or during interventions might lead to spurious volume estimates unless blood radioactivity is serially measured. The effects of elevated epinephrine, posture and exercise on 99mTc-labeled blood radioactivity concentration were studied in 15 young (mean age = 28 yr) and 14 older (mean age = 68 yr) healthy males. An epinephrine infusion of 50 ng/kg/min resulted in a 4.1% +/- 1.0% increase in 99mTc-blood radioactivity (p less than or equal to 0.001) compared to baseline. Sitting increased blood radioactivity concentration by 12.3% +/- 3.0% (p less than 0.0002) compared to the supine position and peak supine bicycle exercise caused an 11.0% +/- 1.7% increase (p less than or equal to 0.0001) compared to supine rest. There was a significantly greater increase during peak supine exercise in the young compared to the older subjects (15.0% +/- 2.3% versus 6.3% +/- 2.0%, p less than or equal to 0.01). The mechanism of the increase in blood radioactivity concentration is uncertain, but presumably reflects the addition of hemoconcentrated red blood cells from the spleen and/or the loss of plasma volume. Failure to correct for the increased blood radioactivity concentration during exercise or pharmacological interventions will result in a significant error in serial measurements of cardiac volumes by methods requiring RBC radioactivity measurements.

Imaging arterial thrombosis: comparison of technetium-99m-labeled monoclonal antifibrin antibodies and indium-111-platelets.

UNLABELLED: Imaging with the 99mTc-T2G1s monoclonal antifibrin antibody fragment (Fab') has demonstrated promise in the noninvasive detection of venous thrombi in humans. The purpose of this study was to determine whether chronic arterial thrombi can also be detected by antifibrin antibody imaging. METHODS: Eighteen subjects with chronic arterial thrombi were studied with planar and tomographic imaging at 0 to 24 hr postinjection of 99mTc-labeled T2G1s monoclonal antifibrin antibody fragment. Imaging with 111In-labeled platelets was also performed. Images were visually graded by two observers as 0, 1, 2 or 3 (no, faint, moderate or marked) uptake, and quantitative analysis of tomographic images was done in 13 subjects. RESULTS: On visual analysis of planar images, 44% (8 of 18) of antifibrin patient studies were 1.0 or more and 66% (10 of 18) were judged negative compared with 94% (15 of 16) of platelet patient studies judged 1.0 or more and 6% (1 of 16) judged as negative (p < 0.01). Visual analysis of tomographic images was similar, with 61% (11 of 18) of antifibrin studies graded 1.0 or more compared with 100% (17 of 17) of platelet studies (p < 0.01). The tomographic target-to-background ratio was higher with platelets than with antifibrin antibody (2.5 +/- 1.4 versus 1.8 +/- 1.0, p < 0.05). CONCLUSION: In the large-vessel chronic arterial thrombi studied, the results of 99mTc-labeled monoclonal T2G1s antifibrin Fab' imaging were positive in only one-half of the patients studied, significantly less than the findings with platelet imaging, which were positive in all subjects. The higher rate of positive images with labeled platelets than with labeled antifibrin antibodies may be largely due to thrombus age, with continued platelet deposition but little active fibrin deposition.

Four radionuclide methods for left ventricular volume determination: comparison of a manual and an automated technique.

This study compared the accuracy and reproducibility of three previously described and one new radionuclide method of measuring left ventricular volumes in 19 subjects using contrast ventriculographic volumes (n = 38, mean volume = 126.6 ml) as the gold standard. The four methods were compared using both manual and automated ROIs. For manual ROIs, the Links (189.7 ml, r = 0.85), Starling (183.2 ml, r = 0.77) and the new count ratio method (141.4 ml, r = 0.90) overestimated contrast volumes, while the Massardo method (122.5 ml, r = 0.91) provided accurate volumes. For the automated ROIs, we performed an interpolative background subtraction and used a 50% threshold of the highest count pixel to define the ventricular regions. The automated Massardo method severely underestimated the contrast volume (59.5 ml, r = 0.90), while the other automated methods yielded accurate volumes: Links (122.4 ml, r = 0.89), Starling (118.1 ml, r = 0.81) and the new count ratio method (125.0 ml, r = 0.90). The interobserver reproducibility of the automated methods was excellent (mean difference = 1%-4%) compared to the manual methods (2%-8%). Because no additional images, blood counting, attenuation, or decay correction were necessary, the manual Massardo method and the automated count ratio method are the simplest to perform. We conclude that automated determination of left ventricular volumes using the new count ratio method is rapid, accurate, reproducible and could readily be incorporated into routine clinical use.

Radionuclide cardiac volumes: effects of region of interest selection and correction for Compton scatter using a buildup factor.

The effects of region of interest (ROI) selection and correction for Compton-scattered photons using a buildup factor on radionuclide left ventricular volumes calculated by the Links method were compared in 19 humans with contrast ventriculography and in phantoms. Three different methods of ROI selection were compared: a manual ROI, a second derivative ROI and a 50% count-threshold ROI. In phantoms without Compton scatter correction, volumes were overestimated by 30% (manual ROI), 20% (derivative ROI) and 1% (count threshold ROI). In subjects, results without Compton scatter correction were similar with overestimates of 50% (manual ROI) and 20% (derivative ROI) and an underestimate by 3% (count threshold method). Correction for Compton-scattered photons with the use of a phantom-derived buildup factor resulted in improved accuracy for the manual ROI (+15%) and the derivative ROI (0%). A 50% count threshold ROI following interpolative background subtraction allows the accurate calculation of cardiac volumes without the need for scatter correction, while a second derivative ROI method requires a correction for Compton scatter with the use of a buildup factor.

Indium-111 white blood cell scan for infectious complications of polycystic renal disease.

This case report describes the localization of a unilateral renal abscess with [111In]oxine-labeled autologous leukocyte scanning in a febrile patient with polycystic renal disease, after other noninvasive imaging procedures failed to identify a source of infection. In polycystic renal disease, leukocyte scans have advantages over standard diagnostic modalities and are very helpful in planning appropriate therapy.

Evaluation of pulmonary systemic blood flow using ECG gated acquisition.

We propose a functional parametric analysis method using ECG-gated 99mTc-labeled red blood cell (RBC) imaging for detection and characterization of periodic variations in local blood activity in the lungs during cardiac cycle. We validated in animal experiments that such count variations correlate with cyclical pulmonary blood flow and may be used for evaluation of systemic-to-pulmonary shunts. Clinical studies were performed in 48 patients. After labeling the RBC pool with 99mTc, ECG-gated gamma camera images of both lung fields were acquired and processed to obtain Fourier transforms of time/activity functions in selected regions. The first harmonic parametric images of amplitude and phase were derived. There was an excellent correlation (r = 0.92) between activity variations and pulsatile flow measured by our method with that obtained by the thermodilution method in dog experiments (n = 10) after implantation of a systemic-to-pulmonary shunt. Patient studies showed the technique to be sensitive in detecting and quantifying abnormal systemic-to-pulmonary blood flow. Lung pulsatile flow can thus be noninvasively measured from functional parametric phase and amplitude images; the technique may be useful for detecting and quantifying abnormal systemic-to-pulmonary blood flow in man.

Diagnostic testing strategies for coronary artery disease: special issues related to gender.

Early reports of the prevalence, diagnosis, and outcomes of coronary artery disease (CAD) in women have led to the acceptance of several myths concerning noninvasive diagnostic studies in women. Many of the myths can be explained by age-related differences in prevalence, methodological errors that exclude women from enrollment, worse clinical baseline risk profiles, comorbid diseases at the time of interventions, and smaller coronary vessels. Awareness of these age-related prevalence factors in women and the potential for delaying the onset of CAD by estrogen treatment in postmenopausal women must be considered in assessing the accuracy of diagnostic studies. The critical role of noninvasive testing in women is to diagnose CAD accurately in a population with a lower prevalence of disease prior to the development of more severe clinical manifestations when therapeutic interventions have a high risk and a poor outcome. Exercise radionuclide ventriculography has lower specificity in women, which may be due to gender differences in the response to exercise. Radionuclide perfusion imaging for the detection of CAD is accurate, there is extensive published literature, and it is used widely. High-dose dipyridamole in combination with echocardiography is not widespread in the United States; most pharmacologic echocardiographic studies are performed using dobutamine, and there are no reports on gender differences using dobutamine echocardiography.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of myocardial infarction size on radionuclide and Doppler echocardiographic measurements of diastolic function.

To assess the relation between myocardial infarction size and diastolic function as measured by radionuclide ventriculography and Doppler echocardiography, 83 patients (aged 58 +/- 9 years) without significant valvular disease were studied 8 to 12 weeks after an acute myocardial infarction. Myocardial infarction size was measured by resting thallium-201 tomography. Peak early filling rate (in end-diastolic volumes/s) was measured by gated blood pool scintigraphy. Doppler measures of mitral inflow were peak early (E) and atrial (A) filling velocities, slopes of E and A, percent E and A filling, E/A ratio and diastolic filling period. In univariate analyses, there was a significant inverse correlation between infarction size and the peak early filling rate (r = -0.59, p less than 0.001), and this remained significant (r = -0.63, p less than 0.0001) in an analysis that included 2 other determinants of the filling rate, age and diastolic filling period. Infarction size was directly correlated to the peak E velocity (r = 0.37, p less than 0.01), deceleration of E (r = 0.41, p less than 0.01) and percent E filling (r = 0.31, p less than 0.01), and was inversely correlated to peak A (r = -0.27, p less than 0.05) and percent A filling (r = -0.26, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Rarity of preclinical alcoholic cardiomyopathy in chronic alcoholics less than 40 years of age.

Preclinical alcoholic cardiomyopathy, myocardial damage in the absence of overt congestive heart failure in chronic alcoholics, is well characterized at necropsy, but attempts to identify such a clinical entity before death have produced conflicting results. Studying subjects only at rest, the inclusion of older alcoholics and limitations of noninvasive techniques may explain some of the disagreement. To determine if preclinical alcoholic cardiomyopathy could be identified independent of the aforementioned limitations, 25 asymptomatic chronic alcoholics aged less than 40 years (mean 34), each of whom had consumed a minimum of 1 pint of whiskey or one 6-pack of beer greater than or equal to 5 days per week for greater than or equal to 5 years, underwent radionuclide ventriculography for measurements of systolic and diastolic function at rest, peak supine exercise and during recovery, and echocardiography for assessment of chamber size, wall thickness and left ventricular mass. Red blood cell levels of selenium and thiamine were measured to determine whether abnormalities were present in these 2 potential mediators of alcoholic cardiomyopathy. For comparison, an age-matched group of healthy control subjects was also studied. For alcoholics and control subjects at rest, mean ejection fraction (67 +/- 7% vs 71 +/- 6%) and diastolic peak filling rate (3.4 +/- 0.6 vs 3.3 +/- 0.6 end-diastolic volumes per second [EDV/s]) were similar.(ABSTRACT TRUNCATED AT 250 WORDS)