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Objectives: Myocardial perfusion imaging (MPI) with positron emission tomography (PET) has advantages over single-photon emission computerized tomography, particularly for women. This investigation was undertaken to define the prognosis of a normal stress PET MPI study in women., Methods: The cohort comprised 457 women evaluated for suspected coronary artery disease (CAD) who had normal pharmacologic stress (82)Rb PET MPI. No patient had clinically evident CAD. Kaplan-Meier estimates were used to determine death and initial nonfatal cardiac event rates over 7 years. Log rank tests were used to assess the relationship between baseline cardiac risk and events during follow-up, and to contrast survival in the cohort with age- and gender-matched US census comparators., Results: During follow-up, there were 11 deaths (all nonischemic), 3 nonfatal myocardial infarctions, 3 percutaneous coronary interventions and 1 coronary artery bypass operation. Average risks of death and initial nonfatal cardiac events were 0.72 and 0.47% per year, respectively. Cardiac events were associated with a history of diabetes (p < 0.0003) and a family history of CAD (p < 0.05)., Conclusion: A normal cardiac PET study is associated with a very low rate of future cardiac events. Women with diabetes and a strong family history of CAD are more likely to sustain events and require close surveillance for the development of coronary disease., (Copyright © 2011 S. Karger AG, Basel.)

Study Objectives: To determine whether bone imaging with 99mTc methylene diphosphonate is a specific method of making the diagnosis of costochondritis in patients with chest pain who rule out for myocardial infarction., Design: Nonblinded prospective controlled study in 20 patients and 10 control subjects., Setting: Inpatient medical service of a tertiary teaching hospital., Patients: Two hundred consenting patients admitted to the hospital with chest pain and suspected myocardial infarction were examined. Those in whom acute myocardial infarction was ruled out were evaluated for the clinical signs of costochondritis, ie, tenderness over one or more costochondral junctions. Twenty patients who met the clinical criterion gave informed consent and were subjected to bone imaging. Ten control subjects with cancer who did not have clinical signs of costochondritis underwent bone imaging to rule out metastatic disease (normal in all cases)., Interventions: Bone imaging with I.V. 99mTc methylene diphosphonate., Measurements: Bone scans of the investigative patients and the control subjects were read by two independent nuclear medicine specialists., Results: Sixteen of the 20 patients with clinically diagnosed costochondritis showed increased technetium uptake at all costochondral junctions bilaterally; six of them also had increased uptake elsewhere on the chest wall (sternum, manubrium, or first rib). All 10 of the control patients likewise showed increased technetium uptake at all costochondral junctions bilaterally., Conclusions: Bone imaging with 99mTc methylene diphosphonate is not a specific method of making the diagnosis of costochondritis.

Unlabelled: This study evaluated the ability of dipyridamole PET myocardial perfusion imaging to detect coronary collaterals. A previous study showed an association between dipyridamole-induced coronary steal on PET imaging and the presence of coronary collaterals on angiography., Methods: Dipyridamole PET myocardial perfusion imaging using 82Rb was performed in 45 patients who had recent coronary angiography. The stress/rest count ratio (rubidium activity with stress divided by activity at rest)-was used to express the change in regional tracer uptake with dipyridamole and was calculated manually and automatically. The accuracy of the stress/rest count ratio for detecting coronary collaterals was determined., Results: A manual stress/rest count ratio < or = 0.80 identified coronary collaterals with 81% sensitivity, 92% specificity and 90% accuracy (p < 0.0001). An automated ratio < or = 0.80 had 90% sensitivity, 88% specificity and 90% accuracy (p < 0.0001). Vascular beds incorrectly identified by PET as having collaterals had an increased frequency of severe stenoses and abnormal wall motion., Conclusion: PET perfusion imaging using the stress/rest count ratio can serve as a unique imaging method to identify coronary collaterals noninvasively.

Unlabelled: The purpose of this study was to determine whether patients at high risk for clinical restenosis, following coronary angioplasty, could be identified by myocardial perfusion imaging performed with dipyridamole- 82Rb PET., Methods: Forty-five patients (34 men, 11 women; mean age 58.5 yr) who had successful single-vessel angioplasty and were asymptomatic had dipyridamole-82Rb PET at 1 and 3 mo after the procedure. Abnormal flow reserve in the distribution of the angioplasty artery on PET was considered to be a decrease of > or = 1 perfusion grade in response to dipyridamole (assessed qualitatively from tomographic images and polar coordinate maps). Follow-up was performed for 6 mo postangioplasty. Clinical restenosis was defined as recurrent angina similar to that occurring before angioplasty and/or > or = 50% stenosis at the angioplasty site documented angiographically. We analyzed abnormal flow reserve in the distribution of the angioplasty vessel to identify which patients were at high risk for clinical restenosis., Results: Fourteen patients developed clinical restenosis between 1 and 6 mo postangioplasty. Abnormal relative flow reserve in the distribution of the angioplasty vessel was present prior to the development of symptoms in 13 of 14 patients with clinical restenosis and in 8 of 31 patients without clinical restenosis (sensitivity 93%, specificity 74%, p < 0.0001). PET imaging successfully separated postangioplasty patients into groups with high (62%) and low (4%) risk of clinical restenosis., Conclusion: Abnormal relative flow reserve in the distribution of the angioplasty vessel on dipyridamole PET identifies asymptomatic postangioplasty patients at risk for clinical restenosis.

A resting perfusion defect detected during radioisotope myocardial perfusion imaging is generally thought to represent myocardial infarction. The administration of nitroglycerin during cardiac PET imaging results in improved resting defects, which suggests transiently abnormal resting perfusion with silent myocardial ischemia.

Background: To compare cost-effectiveness and utility of four clinical algorithms to diagnose obstructive coronary atherosclerotic heart disease (CAD), we compared exercise ECG (ExECG), stress single photon emission computed tomography (SPECT), positron emission tomography (PET), and coronary angiography., Methods and Results: Published data and a straightforward mathematical model based on Bayes' theorem were used to compare strategies. Effectiveness was defined as the number of patients with diagnosed CAD, and utility was defined as the clinical outcome, ie, the number of quality-adjusted life years (QALY) extended by therapy after the diagnosis of CAD. Our model used published values for costs, accuracy, and complication rates of tests. Analysis of the model indicates the following results. (1) The direct cost (fee) for each test differs considerably from total cost per delta QALY. (2) As pretest likelihood of CAD (pCAD) in the population increases, there is a linear increase in cost per patient tested but a hyperbolic decrease in cost per effect and cost per utility unit, ie, increased cost-effectiveness and decreased cost per utility unit. (3) At pCAD < 0.70, analysis of the model indicates that stress PET is the most cost-effective test, with the lowest cost per utility, followed by SPECT, ExECG, and angiography, in that order. (4) Above a threshold value of pCAD of 0.70 (for example, middle-aged men with typical angina), proceeding directly to angiography as the first test showed the lowest cost per effect or utility. This quantitative model has the advantage of estimating a threshold value of pCAD (0.70) at which the rank order of cost-effectiveness and cost per utility unit change. The model also allows substitution of different values for any variable as a way to account for the uncertainties of clinical data, ie, changing costs, test accuracy and risk, etc. This procedure, called sensitivity analysis, showed that the rank order of cost-effectiveness did not change despite changes in several variables., Conclusions: (1) Estimation of total costs of diagnostic tests for CAD requires consideration not only of the direct cost of the test per se (eg, test fees) but also of the indirect and induced costs of management algorithms based on the test (eg, cost/delta QALY). (2) It is essential to consider the clinical history (pCAD) when selecting the clinical algorithm to make a diagnosis with the lowest cost per effect or cost per utility unit. (3) Stress PET shows the lowest cost per effect or cost per utility unit in patients with pCAD < 0.70. (4) Angiography shows the lowest cost per effect or cost per utility unit in patients with pCAD > 0.70.

Transient dilatation of the left ventricular cavity on exercise thallium perfusion imaging is recognized as a marker of significant coronary disease, but the mechanisms that produce this finding are not fully understood. We studied 32 patients who underwent exercise thallium imaging and exercise echocardiography to determine the changes in left ventricular cavity size that underlie transient dilatation. Left ventricular area from the apical four-chamber view was used to approximate left ventricular cavity size. There were 24 patients who did not have transient dilatation (group 1) and 8 patients who did have transient dilatation (group 2) on thallium imaging. Systolic area decreased from rest to exercise in group 1 patients but not in group 2 patients. There was no significant change in diastolic area from rest to exercise in either group 1 or group 2 patients. Thus, exercise-induced systolic dysfunction, manifested as a failure to decrease left ventricular systolic cavity size in exercise, may be an important mechanism in producing scintigraphic transient dilatation.

The purpose of this review is to compare several modalities available for detection of coronary artery disease (CAD). We compare the clinical history, rest/exercise electrocardiogram (ECG), rest/stress left ventricular (LV) function by radionuclide or echocardiographic methods, myocardial perfusion imaging (MPI) by single photon emission computed tomography (SPECT) or positron emission tomography (PET), contrast coronary angiography, magnetic resonance imaging (MRI), spectroscopy (MRS) and angiography (MRA), and ultrafast cine computed tomography (UFCT) to assess LV function, myocardial perfusion, and coronary calcification. We compare the modalities by answering six questions: (1) Does the modality provide unique clinical information? (2) What is the observer error? (3) What are sensitivities and specificities to detect CAD? (4) What patient selection criteria should be applied for each modality? (5) What incremental benefit is obtained from one modality versus another modality? and (6) Where do the modalities fit in the overall scheme of diagnostic testing for CAD? PET MPI appears to be the best noninvasive test for CAD, followed by SPECT thallium-201 and then dobutamine echocardiography. MRA and UFCT may soon play a larger role because they visualize the arteries. Contrast coronary angiography remains the gold standard despite its limitations. Exercise ECG is the least accurate test. The choice of tests critically depends on patient selection--based on clinical history, age, gender, and risk factors to estimate the pretest, clinical probability of CAD.

Unlabelled: Technetium-99m-sestamibi images reflect tracer distribution at the time of injection. This "stay put" indicator allowed us to separate the effects of segmental left ventricular dysfunction per se versus myocardial blood flow on SPECT "perfusion" images in ten dogs., Methods: An electromagnetic flow probe and hydraulic occluder were placed on the LAD coronary artery. Sonomicrometry was used to measure segmental wall shortening. At peak myocardial blood flow induced by adenosine, 35-45 mCi 99mTc-sestamibi were injected without occlusion. At 1 hr postinjection, during normal contraction, 40-50 msec end-diastolic and end-systolic SPECT images (#1) were acquired to reflect normal myocardial blood flow distribution. Later, during total LAD occlusion, and without reinjection of isotope, another gated scan (#2) was acquired., Results: Coincident with abnormal contraction, large severe systolic defects [(28 +/- 5)% more severe compared to the baseline-scan #1; p < 0.01], and milder diastolic defects [(12 +/- 8)% more severe compared to the baseline-scan #1; p < 0.01] were observed during scan #2. Thus, abnormal contraction alone produced defects on SPECT images., Conclusion: Accordingly, defects in myocardial perfusion images must be interpreted as representing the integrated result of the combination of blood flow and segmental contraction heterogeneity.

Myocardial ischemia during routine daily activities was studied in patients with known coronary artery disease with an ambulatory radionuclide probe and recording device (VEST) and routine rest and exercise gated blood pool imaging. Seventeen patients were monitored for 60 minutes while sitting (baseline), standing in place, walking, eating (6 patients), and urinating (4 patients). Eleven of them (64%) failed to show an augmentation of at least 5% in the LVEF on an exercise gated blood pool imaging study (Group I) and 6 (36%) showed a normal response (Group II). Three patients (18%) in Group I experienced angina. Transient left ventricular dysfunction was detected by the VEST during walking, urinating or eating in 80% of the patients in Group I and 33% in Group II (p < 0.05). During walking, mean ejection fraction slightly decreased from 45 +/- 12% to 43 +/- 13% in Group I while the ejection fraction increased from 46 +/- 8% to 51 +/- 12% in Group II (p = 0.04 for the difference in responses). Standing in place and eating did not affect the mean ejection fraction. Urination in 4 patients in Group I caused a significant drop in ejection fraction in 3 patients for a mean change from 51 +/- 9% at rest to 42 +/- 15%. By contrast, none of the patients had angina or diagnostic ECG changes during the monitoring period.(ABSTRACT TRUNCATED AT 250 WORDS)

Radionuclide ventriculography is an accepted method for diagnosing left ventricular aneurysms, but false-negative studies have been associated with a mural thrombus filling the left ventricular cavity. We describe a patient with a left ventricular aneurysm due to myocardial infarction whose aneurysm scintigraphically "disappeared" from serial radionuclide ventriculograms. This was documented echocardiographically and pathologically to be due to the formation of a large mural thrombus. Review of the literature suggests that radionuclide ventriculography and echocardiography may be complementary techniques in the diagnosis of left ventricular aneurysm. Echocardiography may remain diagnostic when a mural thrombus has caused the loss of the characteristic scintigraphic findings on radionuclide ventriculography.

Patients with reduced left ventricular function or aneurysms have cavities that appear dark on SPECT thallium scintigrams. We hypothesized that a quantitative index, which relates thallium activity in the left ventricular cavity to that in the myocardium (C/M ratio), could provide information on left ventricular function. A group of 80 patients who had both exercise SPECT thallium imaging and cardiac catheterization were studied. The C/M ratio was obtained from the short-axis tomogram on both exercise and rest images. Counts in a 2 x 2 pixel region of interest in the left ventricular cavity were divided by the number of counts in the "hottest" area of the myocardium. Plotting the angiographically determined ejection fraction against the C/M exercise and rest ratios, we observed a linear correlation between ejection fraction and both C/M ratios, r = 0.65 for C/M exercise and r = 0.67 for C/M rest ratio (p < 0.00001). Using data from 12 normal cardiac catheterization patients, we established the lower limit of normal; 50% for ejection fraction and 0.40 for the C/M ratios. A C/M exercise ratio < or = 0.40 identified 26 of 31 patients with an ejection fraction < or = 50%. A C/M exercise ratio > 0.40 identified 39 of 49 patients with an ejection fraction > 50%. These calculations yielded a sensitivity of 83% and specificity of 78% for the C/M exercise ratio. A similar analysis for C/M rest ratio revealed sensitivity of 61% and specificity of 92%. The present study shows that an abnormal C/M ratio correctly distinguishes patients with abnormal from normal ejection fractions with an accuracy of 81%. The C/M ratio is easily obtained, requires minimal processing time and is highly reproducible. These attributes may enable this index to add supplementary information regarding left ventricular function in addition to perfusion from thallium imaging.

The increasing importance of the acquired immunodeficiency syndrome (AIDS) as a cause of large, clinically significant pericardial effusions has not been well documented. To determine the frequency and characteristics of large AIDS-associated pericardial effusions, we reviewed the records of 50 consecutive patients undergoing pericardiocentesis between 1985 and 1990; AIDS was the most common underlying illness and was present in 14 patients (28 percent). The pericardial fluid was diagnostic in three (21 percent) of the 14 cases (one bacterial, one positive for acid-fast bacilli, and one lymphoma). Of the 11 patients with nondiagnostic fluid, one underwent a pericardial biopsy which revealed granuloma consistent with mycobacterial disease, four had active pulmonary tuberculosis (TB), and two responded clinically to anti-TB therapy. Thus, in 8 (57 percent) of the 14 patients with AIDS, there was either definitive or suggestive evidence of mycobacterial disease. We conclude that AIDS is now a common underlying illness associated with large pericardial effusions and that mycobacterial disease may frequently be the etiology.

Twenty-four-hour ambulatory electrocardiographic monitoring was used to determine the incidence of arrhythmia while on-call and its relationship to stress and fatigue in 20 healthy medical interns. Mitral valve prolapse was present in 8 of 19 interns (42%). Heart rates ranged from a maximum of 103-167 beats/min (135 +/- 16) to a minimum of 38-61 beats/min (47 +/- 5). Interns had at least one episode of sinus tachycardia/h during 57% +/- 21% (range, 8-88%) of their hours on-call. Atrial premature beats (APB) were present in 19 of 20 (95%) and ventricular premature beats (VPB) in 12 of 20 (60%) subjects. APB/h ranged from 0 to 1.2 (0.4 +/- 0.3) and VPB/h from 0 to 23 (2 +/- 6). Three interns had multiform VPB and two had ventricular couplets. More APB/h occurred in interns under greater stress (0.5 +/- 0.4/h vs 0.3 +/- 0.1/h, p < 0.05) and combined stress and fatigue (0.6 +/- 0.4/h vs 0.2 +/- 0.2/h, p < 0.01). More VPB/h (5 +/- 9/h vs 0.5 +/- 0.6/h, p < 0.05) and higher (Lown) grade ventricular ectopy (2.3 +/- 1.6 vs 0.8 +/- 1.1; p < 0.05) occurred in interns under greater combined stress and fatigue. Mitral valve prolapse, sleep deprivation and caffeine intake were not associated with increased arrhythmia. The authors conclude that (1) rapid sinus tachycardia is frequent in interns while on-call and (2) interns experiencing greater stress and fatigue have more APB/h, VPB/h, and higher grade ventricular ectopy. These data support the notion that stress and fatigue may contribute to arrhythmia in healthy normal subjects.

Chagas disease is a leading cause of heart failure in Latin America. Sudden death occurs in approximately 40% of patients with heart failure due to Chagas disease. We report a single blind, cross-over trial of prolonged treatment with captopril and placebo in 18 Chagas disease patients with class IV NYHA heart failure. Ventricular dimensions, neurohormones, electrolytes and ventricular arrhythmias were analysed in 11 men and seven women receiving stable doses of digoxin and frusemide who were randomly divided into two intervention groups. Group I patients were given increasing doses of captopril up to 150 mg.day-1 maintained for 6 weeks, group II received the placebo. A 24 h Holter, 2-D echocardiogram, urinary catecholamines, plasma renin and electrolyte determinations were performed at the end of each phase. After a 2-week washout period, the two groups crossed over and another period of 6 weeks was observed. Ventricular arrhythmias were analysed by either Mann-Whitney or the Wilcoxon test. Remaining data were assessed by the Student t-test. A significant reduction in heart rate and urinary catecholamine levels, and enhanced plasma levels of renin, together with a reduction in ventricular couplets was found in the captopril-treated group. We conclude that captopril has a beneficial effect on neurohormones with a subsequently reduced heart rate and diminished incidence of ventricular arrhythmias in patients with Chagas disease. This effect might result in a reduction of mortality caused by the disease, suggesting the need for further investigations.

Asians historically have low total cholesterol levels and low incidence of coronary heart disease. In performing a coronary heart disease and total cholesterol screening in New York City's Chinatown, we obtained data supportive of previous studies, which focused on Japanese populations and described the influence of environment on total cholesterol. In the present study, Chinese living in Chinatown have higher levels of total cholesterol than would be expected from studies of Chinese living in Shanghai. For every age group examined, Asian-born Chinese living in Chinatown had higher total cholesterol levels than both urban and rural Chinese in Shanghai. In subjects less than or equal to 30 years of age, urban males in Shanghai had cholesterol levels of 160 +/- 34 mg/dL, compared with 206 +/- 38 mg/dL for Asian-born males in Chinatown. For females in the same age category, cholesterol levels were 162 +/- 35 mg/dL vs 224 +/- 45 mg/dL, respectively. Applying National Cholesterol Education Panel (NCEP) guidelines, the distribution of desirable, borderline-high, and high blood cholesterol levels for the Chinese in Chinatown (41%, 35%, and 23%, respectively) were similar to a group of Caucasians screened (42%, 32%, and 26%) and the group recently used to determine the prevalence of high blood cholesterol in American adults (43%, 30%, and 27%). Studies are needed to stratify the risk of coronary heart disease in other groups that traditionally have a low incidence of coronary heart disease, but which now have adopted Western lifestyles.

Increased lung thallium-201 activity occurs with exercise in patients with severe coronary artery disease as a result of increased pulmonary capillary wedge pressure. No study has shown resting lung kinetics in chronic congestive heart failure. To better understand the relationship between lung and myocardial thallium uptake and pulmonary capillary wedge pressure, this study was performed. Resting lung and myocardial thallium uptake, expressed as a ratio, were compared with simultaneous pulmonary capillary wedge pressure in 16 patients with congestive heart failure and cardiomyopathy, all New York Heart Association class IV. There were no variations in pulmonary capillary wedge pressure throughout the study protocol. There was a significant reduction in the lung/myocardium thallium ratio from 10 to 60 minutes (0.83 +/- 0.30 to 0.59 +/- 0.17; p less than 0.001). At 60 minutes after thallium injection there was a linear correlation between the lung/myocardium ratio and capillary wedge pressure with an r value of 0.62 (p less than 0.01). Thus thallium-201 washout is rapid despite persistence of pulmonary capillary wedge pressure elevation, indicating that clearance does not imply resolution of congestive heart failure. In addition, a significant but imprecise correlation was found between capillary pressure and the lung/myocardium ratio. Rapid changes in lung activity during the early postinjection period may limit the clinical use of the lung/myocardium ratio.

Left ventricular dysfunction during exercise is considered a relatively sensitive marker of ischemia in patients with coronary artery disease. The purpose of this study was to determine whether exercise-induced myocardial dysfunction was more severe in patients with angina than in patients with ischemia without angina. Seventy-seven patients with angiographically documented coronary artery disease and an abnormal left ventricular response to exercise were studied by means of gated blood pool imaging. The arteriographic and functional parameters of 24 patients with angina during exercise testing imaging. The arteriographic and functional parameters of 24 patients with angina during exercise testing were compared with those of 53 patients who were pain free at the time of the test. Both groups were similar with regard to rate of multivessel disease (50% vs 51%, p = NS) and prior myocardial infarction (46% vs 51%, p = NS), as well as age, sex, and history of angina. Mean global ejection fraction remained unchanged (but abnormal) in both groups of patients during exercise. Furthermore, evidence of new regional asynergy during exercise assessed by a five-point scoring system was found to be equally abnormal in the two groups. Results of this study suggest that the severity of exercise-induced global and regional left ventricular dysfunction is independent of the presence of absence of angina during exercise testing.

Chronic granulomatous disease is a rare disorder of the oxidative metabolism of the white blood cells that results in immunodeficiency. In a retrospective review of the records of forty-two patients who had chronic granulomatous disease, we identified thirteen patients who had a total of twenty skeletal infections. Two types of infection were noted: Type 1, which resulted from a direct spread of the infection from an adjacent focus, usually of fungus or mycobacteria, and Type 2, which resulted from hematogenous spread, usually of Nocardia or more common bacteria. The thoracic vertebrae, ribs, and metatarsals were the most commonly involved bones. All four patients in whom the vertebrae were involved had a Type-1 fungal infection. Paresis developed in three of these patients, and two of them died. Antibiotics alone effectively eradicated the infection in only one patient. Wide operative débridement combined with administration of antibiotics was the most successful treatment. Comprehensive preoperative imaging and several cultures are necessary to locate the infection in the bone and to identify the organism.

Eight patients in sinus rhythm, with varying degrees of isolated mitral stenosis (mitral valve area 0.6 to 1.3 cm2 and total pulmonary vascular resistance 5.0 to 17.5 U-m2), underwent supine rest and symptom-limited exercise radionuclide ventriculography to determine right ventricular (RV) and left ventricular ejection fraction (EF). Cardiac catheterization with hemodynamic measurements at rest and at peak exercise was performed within 24 hours of radionuclide ventriculography. Four of the 8 patients underwent corrective mitral surgery resulting in normal mean pulmonary artery pressures and total pulmonary vascular resistance at rest. These 4 patients had repeat radionuclide ventriculography at rest and during exercise 1 to 2 months after surgery. Preoperatively, all 8 patients had an abnormal exercise RVEF response (mean change +/- standard deviation [SD], -5.0 +/- 4.5%), coincident with an increase in mean pulmonary artery pressure during exercise (mean change, 15 +/- 5.0 mm Hg). The change in RVEF from rest to exercise, corrected for duration of exercise, correlated with peak exercise mean pulmonary artery pressure (r = -0.71, p = 0.05), as well as total pulmonary vascular resistance at rest (r = -0.82, p = 0.02). Postoperatively, all 4 patients who underwent surgical correction showed a normal RVEF response during exercise (mean change +/- SD, +6.8 +/- 4.0%). Thus, in patients with acquired mitral stenosis and no coronary artery disease (1) loading conditions and not contractility are prime determinants of RV exercise response, and (2) an exercise-induced decrease in RVEF may be a sensitive marker for increased total pulmonary vascular resistance and pulmonary hypertension.

Estimation of left-sided valvular insufficiency has been obtained using the ratio of left- to right-ventricular stroke counts, i.e., the regurgitant index. The present study was designed to evaluate the usefulness of the regurgitant index in identifying patients with isolated right-sided valvular insufficiency. We identified 12 patients with tricuspid or pulmonic regurgitation by at least two of the following criteria: pulsatile liver, positive Carvallo's sign, and pulsatile jugular-venous distension. In 9 of the 12 patients, the right-sided insufficiency was confirmed by catheterization or contrast echocardiography and flow-directed pulsed-echo Doppler. The regurgitant index in patients with right-sided insufficiency was 0.59 +/- 0.23. This was significantly different from patients with left-sided insufficiency (3.09 +/- 0.8; P less than 0.001) and from control subjects (1.49 +/- 0.32; P less than 0.001). In 11 of the 12 patients with right-sided regurgitant lesions, the regurgitant index was less than 1.0. The hepatic expansion fraction, a possible correlate of an expansile liver, has previously been found to be both sensitive and specific for the detection of patients with right-sided regurgitation. We calculated the hepatic expansion fraction in 6 patients with tricuspid regurgitation (including 3 with pulsatile livers) and 5 controls using the method of Handler et al.. In the present study, the hepatic expansion fraction in tricuspid-insufficiency patients was 4.3% as compared to 4.1% in normals (P = NS). In summary, this study suggests that the regurgitant index may be a sensitive tool for the diagnosis of right-sided regurgitant lesions, while the hepatic expansion fraction does not appear to be useful for identifying tricuspid insufficiency.

Timing abnormalities of myocardial contractility may occur as inter- or intraventricular asynchrony. Gated blood pool scintigraphy was performed on 21 patients with a normal ejection fraction and the following electrocardiograms: six normal, six with left bundle branch block, four with right bundle branch block and five with right ventricular pacemaker rhythm. A phase and amplitude of the first harmonic of the Fourier transform was obtained for each pixel, and left and right ventricles were trisected. A mean vector phase for each region was obtained by vector summation. Regional and global values were analyzed within each group and compared with normal values. The phase differences between the entire left and right ventricles (mean +/- standard deviation) were: 9 +/- 3 in the normal patients, 38 +/- 8 (p less than 0.01) in patients with left bundle branch block, -6 +/- 7 (p less than 0.05) in patients with right bundle branch block and 15 +/- 9 (difference not significant) in patients with pacemaker rhythm. The phase differences between left ventricular posterolateral and septal regions were -4 +/- 2 in the normal patients, 10 +/- 5 (p less than 0.01) in patients with left bundle branch block, -7 +/- 10 (p less than 0.05) in patients with right bundle branch block and 10 +/- 5 (p less than 0.01) in patients with pacemaker rhythm. Within the right ventricle, phase differences between the apical and septal segments were 14 +/- 9 in the normal patients, 14 +/- 10 (NS) in patients with left bundle branch block, -2 +/- 3 (p less than 0.01) in patients with right bundle branch block and -22 +/- 18 (p less than 0.01) in patients with pacemaker rhythm. Interventricular phase differences were greatest in patients with left bundle branch block and absent or reversed in right bundle branch block.(ABSTRACT TRUNCATED AT 250 WORDS)

Impaired diastolic function has been described in healthy elderly subjects. Pulmonary blood volume (PBV) changes with exercise have been associated with left ventricular dysfunction, but not directly related to diastolic abnormalities. Exercise-induced relative changes in PBV were measured using gated blood pool imaging with count density comparisons over the lung in 20 healthy volunteers: 13 elderly, age 76 +/- 5 years and seven young, age 27 +/- 4 years. Serial (first exercise stage, peak exercise, and post exercise) PBV ratios were measured and correlated to peak early filling rate, peak late filling rate, and percent atrial filling obtained from the resting left ventricular time-activity curve analysis. PBV ratios tended to be higher in elderly subjects, but reached significance only at the first stage of exercise (1.04 +/- 0.07 vs. 0.93 +/- 0.10, p less than 0.01). Significant correlations were found between PBV ratios at first exercise stage and peak early filling rate (r = -0.64), peak late filling rate (r = 0.47), and percent atrial filling (r = 0.48). A significant correlation was found between PBV changes at peak exercise and resting diastolic parameters. Exercise-induced PBV changes are associated with left ventricular diastolic dysfunction at rest. Diastolic abnormalities of the aged heart may explain the differential PBV response early into exercise between young and elderly healthy subjects.

Ventricular septal defect is a serious complication of acute myocardial infarction with a high mortality rate. Right ventricular dysfunction, which frequently accompanies septal defect, can be due to several etiologies. We describe two cases of septal defect following infarction, with sequential studies of right and left ventricular function. Right ventricular infarction was found in both patients. Postoperatively, the right ventricular ejection fraction improved significantly. The pathophysiology and expectation for recovery are discussed.

Ingested cobalt has previously been associated with the development of a congestive cardiomyopathy. Despite occasional reports of cardiomyopathy after industrial exposure to cobalt, this association remains controversial. In a study of 30 cemented tungsten carbide workers with a mean duration of exposure to cobalt of 9.9 +/- 5.3 years radionuclide ventriculography was performed to study right and left ventricular ejection fractions at rest and exercise. For the entire group, rest and exercise biventricular function was normal. There was, however, a weak but significant inverse correlation between duration of exposure and resting left ventricular function (r = -0.40, p less than 0.03). Workers with abnormal chest x ray findings (9/30) had relatively lower exercise right ventricular ejection fractions (45% +/- 6 v 52% +/- 7, p less than 0.02). An inverse relation was also found between rest and exercise right ventricular ejection fraction and severity of parenchymal abnormalities on x ray examination (r = -0.44, p less than 0.01 and r = -0.41, p less than 0.02). Diminished right ventricular reserve was probably due to fibrotic lung disease and early cor pulmonale. Although overt left ventricular dysfunction was not present, prolonged exposure to industrial cobalt may be a weak cardiomyopathic agent with unknown long term significance.

Myocardial perfusion imaging is generally performed as a static acquisition without regard for dynamic changes in the cardiac cycle. The effect of heart rate and ejection fraction on the appearance of left ventricular chamber size and wall thickness as perceived in 201Tl scintigrams has not, to our knowledge, been previously studied. A dynamic computer model of the left ventricle was constructed, capable of varying the heart rate and ejection fraction. Parallel slices through the model were convolved with experimentally derived 201Tl point spread functions at corresponding depths to incorporate the effects of scatter and attenuation. Both gated and static left anterior oblique images were created at three clinically encountered heart rates and ejection fractions, with constant end-diastolic volume and left ventricular mass. Results of the study indicate that perceived and quantified wall thickness increases and chamber size decreases appreciably with increasing ejection fraction and (slightly) with increasing heart rate. Thus, evaluation of wall thickness and chamber size in planar images should take into account variations in heart rate and contractility. This is especially pertinent to estimates of left ventricular hypertrophy and chamber size, attempted from nongated myocardial perfusion images.

Relative changes in pulmonary blood volume (PBV) were assessed serially at first stage, peak and post-supine exercise in 13 young normal volunteers and 33 coronary artery disease (CAD) patients. Gated blood pool imaging was used with time corrected count calculation of a region over the lung and comparison to the rest image. In normal subjects, the PBV ratio did not change with exercise but dropped significantly immediately post-exercise. In CAD patients, the PBV ratio increased in the first exercise stage, increased further at peak exercise, and fell significantly following exercise cessation. In the three stages studied, significantly higher PBV ratios were demonstrated in the CAD patients compared to normal subjects, but with significant overlap between the two groups. No significant relation was found between PBV changes and the number of diseased vessels, severity score (Gensini), left ventricular end-diastolic pressure, exercise-limiting symptoms, and left and right ventricular ejection fraction at rest and with exercise. Despite the different response of the PBV ratio to exercise between normals and CAD patients, a significant overlap limits the value of this ratio as a discriminator of the presence, severity or location of CAD.

The objective of this study was to compare the cost-effectiveness of four clinical policies (policies I to IV) in the diagnosis of the presence or absence of coronary artery disease. A model based on Bayes' theorem and published clinical data was constructed to make these comparisons. Effectiveness was defined as either the number of patients with coronary disease diagnosed or as the number of quality-adjusted life years extended by therapy after the diagnosis of coronary disease. The following conclusions arise strictly from analysis of the model and may not necessarily be applicable to all situations. As prevalence of coronary disease in the population increased, it caused a linear increase in cost per patient tested, but a hyperbolic decrease in cost per effect, that is, increased cost-effectiveness. Thus, cost-effectiveness of all policies (I to IV) was poor in populations with a prevalence of disease below 10%, for example, asymptomatic people with no risk factors. Analysis of the model also indicates that at prevalences less than 80%, exercise thallium scintigraphy alone as a first test (policy II) is a more cost-effective initial test than is exercise electrocardiography alone as a first test (policy I) or exercise electrocardiography first combined with thallium imaging as a second test (policy IV). Exercise electrocardiography before thallium imaging (policy IV) is more cost-effective than exercise electrocardiography alone (policy I) at prevalences less than 80%. 4) Noninvasive exercise testing before angiography (policies I, II and IV) is more cost-effective than using coronary angiography as the first and only test (policy III) at prevalences less than 80%. 5) Above a threshold value of prevalence of 80% (for example patients with typical angina), proceeding to angiography as the first test (policy III) was more cost-effective than initial noninvasive exercise tests (policies I, II and IV). One advantage of this quantitative model is that it estimates a threshold value of prevalence (80%) at which the rank order of policies changes. The model also allows substitution of different values for any variable as a way of accounting for the uncertainty inherent in the data. In conclusion, it is essential to consider the prevalence of disease when selecting the most cost-effective clinical approach to making a diagnosis.

A comparison of left ventricular function data derived from a low cost, portable electrocardiographic gated scintillation probe (nuclear stethoscope) with conventional scintiangiographic data was performed in 68 patients. Ejection fraction correlation (r = 0.86, p less than 0.005) was better in patients with uniform wall motion than in those with regional asynergy (r = 0.68 p less than 0.01). Probe variables reflecting systolic emptying rates, diastolic filling rates and timing intervals, and relative volumes analyzed in combination provided 100 percent sensitivity, specificity, and predictive value in detecting abnormal left ventricular performance. The results suggest that radionuclide angiography with an electrocardiographic gated scintillation probe is a sensitive, rapid and relatively inexpensive portable method of screening for cardiac dysfunction with a yield similar to that from the more costly gamma camera derived scintiangiogram.

Mitral valve prolapse has been associated with septal to aortic root angle abnormalities determined by echocardiography. Thallium 201 imaging in the anterior view permits visualization of the left ventricular long axis. In the present study, the vertical angle was defined as the angle formed by the long axis of the left ventricle and a horizontal line. The vertical angle was determined in 25 patients who had 201 TL stress testing and M-mode echocardiography. Group I (11 patients) had mitral valve prolapse and group II (14 patients) did not have mitral valve prolapse. The vertical angle and ultrasound were read blinded to each other. Height, weight, and body surface area were compared for the two groups, and receiver operator curve analysis performed. Vertical angle measured by TL 201 was significantly more vertical in patients with mitral valve prolapse. Receiver operator curve analysis showed that an angle of greater than 30 degrees successfully identified 9/11 patients with mitral valve prolapse, with a sensitivity of 82% and a specificity of 79%. There were no significant differences in height, weight, or body surface area between the two groups. Thus, patients with mitral valve prolapse have more vertically positioned hearts than patients without mitral valve prolapse, independent of body habitus. The different appearance of a vertically oriented heart may contribute to false-positive readings of TL 201 images.

Radionuclide angiography has been used for visualization of aortic arch pathology. Gated blood pool scintigraphy generally has been reserved for the evaluation of ventricular function. By observing the aorta in relation to other cardiac structures, additional information about relative size and shape is available, and can be integrated with ventriculographic observations. This may enhance understanding of the mechanism of disease in the individual patient. Five selected case histories illustrating this point are presented. The last example demonstrates the ability of the technique to uncover unsuspected thoracic aorta pathologic findings. The sensitivity and specificity of this technique to diagnose aortic disease requires further study.

In order to estimate the precision and accuracy of parameters derived from segmental multiharmonic Fourier analysis of gated blood-pool images, a Monte Carlo computer noise simulation was tested on five sample regional time-activity curves. The first three Fourier harmonics were retained and the precision and accuracy of parameters of ventricular function were calculated, varying the ejection fraction, segment size, and framing rate. Precision improved with higher ejection fraction, higher counts per frame, or higher framing rate. There was no change in precision as the framing rate changed at fixed total counts. Accuracy changed little with changing framing rate. Thus, for segmental analysis there is no advantage to using a higher framing rate. Regions five or more pixels in size are recommended for reliable results. This study provides useful information for the optimization of acquisition and processing conditions for regional gated blood-pool analysis.

Differences in vertical orientation of the left ventricle within the chest cavity cannot be corrected by gamma camera positioning. The effect of variations in vertical angulation on the appearance of the diagnostically important left anterior oblique (LAO) view has not been previously evaluated. In the current study, a computer simulation of a normal left ventricle was created and "imaged," varying only the degree of vertical rotation. The effect of six vertical positions on the LAO image was assessed visually and with horizontal and circumferential profile analysis. Results indicate a homogenous distribution of counts in the horizontal views. With increasing verticality, there are fewer counts in the valve plane, while the inferoapex initially increases in count density, and then progressively decreases. Quantification revealed count variations of up to 37% in the valve plane and 45% in the inferoapex due entirely to differences in vertical orientation of the left ventricular simulation. A survey of 167 patients who underwent routine stress thallium imaging showed a vertical angulation that varied from 7 degrees to 64 degrees (mean = 37 degrees) as determined from the anterior view. Clinical images were similar in appearance to computer generated images after correction for anterior view foreshortening. The present study suggests that the accuracy of current quantitative thallium methods to detect coronary artery disease might be enhanced by the use of a revised set of normal standards corrected for vertical orientation of the left ventricle.

Peripartum cardiomyopathy is a syndrome of undetermined etiology whose most common initial symptoms are those of congestive heart failure. The syndrome carries a five-year mortality estimated at 40%. Single noxious factors, such as viral infection, have been proposed as direct precipitants of this syndrome, but none have been conclusively linked to it. The cases of two patients with identifiable cardiac stress factors who developed peripartum cardiomyopathy are presented here: one with sepsis complicated by disseminated intravascular coagulopathy and severe anemia, and a second with an otherwise normal pregnancy who engaged in strenuous aerobic exercise throughout the last trimester. A review of previously published cases reveals the frequent association of multiple nonspecific cardiac stress factors that may predispose women to peripartum cardiomyopathy. Various cardiac stress factors may act synergistically with the stress of pregnancy to precipitate peripartum cardiomyopathy in susceptible women.

A prospective study was performed to determine the relation between quantitative signal-averaged parameters and ejection fraction (EF) and wall motion abnormalities determined by radionuclide ventriculography in patients with acute myocardial infarction (AMI). In 50 patients with AMI, signal-averaging of the surface QRS complex (200 beats; filter frequencies of 40 to 250 Hz and 80 to 250 Hz) was performed and radionuclide ventriculograms were recorded 8 +/- 5 days after AMI. Twenty-five of these patients (50%) had anterior wall AMI, 20 (40%) had inferior wall AMI and 5 (10%) had non-Q-wave AMI. The duration of the low-amplitude signals of less than 40 microV, the signal-averaged QRS complex and the root-mean-square voltage of the terminal 40 ms were determined. In addition to EF determinations, wall motion abnormalities were assessed for the presence or absence of dyskinetic, akinetic and hypokinetic segments. A wall motion score was constructed by separating the left and right ventricles into 21 segments in the anterior, left anterior oblique and lateral views. On the basis of the presence or absence of late potentials, the patients were separated into 2 groups: group I comprised 15 patients (30%) with late potentials and group II 35 patients (70%) without late potentials. The low-amplitude signals (49 +/- 12 vs 24 +/- 8 ms) and the signal-averaged QRS complex (122 +/- 20 vs 96 +/- 15 ms) were significantly longer and the root-mean-square voltage (13.8 +/- 4.9 vs 54.3 +/- 27.4 microV) significantly lower in group I than in group II.(ABSTRACT TRUNCATED AT 250 WORDS)

Left ventricular myocardial mass can be measured by 201Tl SPECT, but the effects of changes in heart rate and contractility have not been determined. We constructed a dynamic computer model simulating the contracting left ventricle. Thirty two summed static views at each of 3 heart rates and 3 ejection fractions were manufactured to simulate a 180 degrees acquisition. Each image set underwent tomographic reconstruction. Left ventricular mass was measured at a fixed percent threshold in each slice. The results show that left ventricular mass varied little with heart rate (4%) and only slightly more (8%) with ejection fraction. Thus, in the normal clinical setting, left ventricular mass measurements by SPECT are minimally affected by the dynamic state of the heart.

Radionuclide gated cardiac blood pool imaging was used to quantify the severity of valve regurgitation in 20 patients, by calculating the ratio of left ventricular to right ventricular stroke counts (end-diastolic minus end-systolic counts in right and left ventricular regions of interest). This ratio (the stroke index ratio) was substantially higher in patients with aortic and mitral regurgitation (3.91 +/- 1.45) than in a control group of 10 patients without regurgitation (1.32 +/- 0.15), p less than 0.001. The stroke index ratio correlated closely (r = 0.947) with measurements of regurgitant fraction derived from simultaneous determinations of total and forward stroke volumes during cardiac catheterization. After aortic and mitral valve replacement in 18 patients, the stroke index ratio decreased from 4.03 +/- 1.46 to 1.38 +/- 0.23 (p less than 0.001), a value not significantly different from that observed in patients without regurgitation. All three patients with residual postoperative regurgitation had a stroke index ratio greater than 2 standard deviations above the mean values for the control group (greater than 1.62), whereas the remaining 15 patients, who had no evidence of regurgitation, had values within the normal range. Therefore, radionuclide gated blood pool scanning provides a noninvasive method of quantifying valve regurgitation and assessing the results of medical or surgical interventions.

A delay of left ventricular isovolumic relaxation and decrease in myocardial compliance may result in a decline of measured early filling rates in elderly subjects. Previous studies of diastolic function, however, have not excluded coronary artery disease or addressed the contribution of atrial contraction to diastole. The present study evaluated radionuclide-derived diastolic variables in 13 healthy elderly volunteers aged 75 +/- 6 years without symptoms or risk factors for coronary disease who had normal findings on the stress electrocardiogram, stress gated blood pool imaging and two-dimensional echocardiogram. Results were compared with those of a group of 10 healthy young volunteers aged 26 +/- 5 years. High count, 32 frame, double-buffered gated blood pool acquisitions were obtained at rest in the left anterior oblique view with an RR interval variation less than 5%. Left ventricular time-activity curves were analyzed and flow-volume loops for each group were constructed. In the healthy elderly: peak early diastolic filling rate is decreased, time of peak early filling and time to first third of diastolic filling are delayed, and peak late left ventricular filling rate and percent of atrial filling volume are augmented, suggesting an adaptive response of the atria to diminished left ventricular compliance.

Sixty-five patients with ST elevation were retrospectively studied in order to evaluate the clinical significance and underlying mechanisms of ST-segment elevation during exercise. Of these, 50 patients had previous myocardial infarction (Group I) and 15 patients did not (Group II). Exercise thallium-201 imaging was performed on 30 patients, resting gated blood pool imaging was performed on 33 patients, and 23 underwent cardiac catheterization for clinical indications. When the two groups were compared, patients in Group I had more frequent multivessel disease (9/13 vs. 3/10, p less than 0.05), anterior infarctions (33/50 vs. 4/10, p less than 0.02), while Group II patients had more frequent single-vessel disease (7/10 vs. 4/13, p less than 0.05). For Group I patients, the most common reason for termination of exercise was fatigue and/or dyspnea (35/50 vs. 0/15, p less than 0.05), with an irreversible defect noted in both stress and delayed views on thallium imaging (20/24 vs. 1/6, p less than 0.05). In Group II, the most common reason for termination was angina (15/15 vs. 2/50, p less than 0.001), with reversible thallium defects noted more frequently (4/6 vs. 3/24, p less than 0.01). Thus, we conclude that in patients with Q waves, left ventricular dysfunction rather than ischemia is the mechanism for ST elevation. In these patients angina is rare, but fatigue, dyspnea, multivessel disease, and fixed thallium defects are common. In patients with non-Q-wave exertional ST elevation, ischemia is the rule, manifested by frequent chest pain and reversible thallium defects.

Serial gated blood pool scintigraphic monitoring of cardiac function with both a nonimaging scintillation probe and a conventional gamma camera-computer imaging system was performed in 101 patients receiving doxorubicin hydrochloride (Adriamycin) chemotherapy. Comparison of probe- and camera-derived ejection fractions (n = 287) correlated significantly (r = 0.70, p less than 0.005) as did the interstudy (n = 183) change in ejection fraction (r = 0.76, p greater than 0.005). Significant discordance in probe- and camera-derived ejection fraction change occurred in 3 (1.6%) of 183 interstudy intervals. Average intrastudy variability of absolute probe-derived ejection fraction was 2.9%. This variability was unrelated to the level of cardiac function. Thirteen patients (13%) developed clinical cardiotoxicity, including four at cumulative Adriamycin levels less than 450 mg/m2. Mean absolute camera ejection fraction decline for these patients was 21% from baseline evaluation, and mean absolute probe ejection fraction decline was 22%. The minimal absolute ejection fraction decline was 11% for patients with clinical congestive heart failure. Eight asymptomatic patients had therapy terminated before the development of clinical cardiotoxicity after a mean decline in absolute camera ejection fraction of 19 +/- 4% (SD) and in probe ejection fraction of 19 +/- 9% into abnormal ranges (a decline in magnitude equivalent to that in patients developing congestive failure). None of these five asymptomatic patients available for clinical follow-up at 6 months after termination of Adriamycin therapy subsequently developed signs of ventricular dysfunction. The majority of patients (83%) studied at 450 mg/m2 cumulative dose levels did not have a 15% or greater decline from baseline into the abnormal range.(ABSTRACT TRUNCATED AT 250 WORDS)

This review is directed at the clinically useful highlights of ultrasound and radionuclide testing in adults with coronary and valvular heart disease, intracardiac shunts, and hypertrophic and congestive cardiomyopathies. As a clinical toto, the radionuclide procedures are currently more useful than ultrasound examination in evaluating patients with known or suspected coronary artery disease. This includes both primary diagnosis and the more accurate estimation of left ventricular function in the presence of segmental asynergy. In patients with valvular disease, the radionuclide procedures are only indirectly useful, while the ultrasound examination is more often diagnostic. These two techniques are complimentary to one another in their ability to noninvasively evaluate and monitor both chamber size and ventricular function in virtually all patients. Recent research involving noninvasive ventricular imaging during physiologic and pharmacologic intervention holds promise for a more sophisticated noninvasive approach to patient management.