Multicenter clinical trial to evaluate the efficacy of correction for photon attenuation and scatter in SPECT myocardial perfusion imaging.

BACKGROUND: Soft tissue attenuation is a prominent cause of single-photon emission computed tomography (SPECT) imaging artifacts, which may result in reduced diagnostic accuracy of myocardial perfusion imaging. A method incorporating simultaneously acquired transmission data permits nonuniform attenuation correction and when incorporating scatter correction and resolution compensation may substantially reduce interpretive errors. METHODS AND RESULTS: A prospective multicenter trial was performed recruiting patients with angiographically documented coronary disease (n=96) and group of subjects with a low likelihood of disease (n=88). The uncorrected and attenuation/scatter corrected images were read independently, without knowledge of the patient's clinical data. The detection of >/=50% stenosis was similar using uncorrected perfusion data or with attenuation/scatter correction and resolution compensation (visual or visual plus quantitative analysis), 76% versus 75% versus 78%, respectively (P=NS). The normalcy rate, however, was significantly improved with this new methodology, using either the corrected images (86% vs 96%; P=0.011) or with the corrected data and quantitative analysis (86% vs 97%; P=0.007). The receiver operator characteristic curves were also found to be marginally but not significantly higher with attenuation/scatter correction than with tradition SPECT imaging. However, the ability to detect multivessel disease was reduced with attenuation/scatter correction. Regional differences were also noted, with reduced sensitivity but improved specificity for right coronary lesions using attenuation/scatter correction methodology. CONCLUSIONS: This multicenter trial demonstrates the initial clinical results of a new SPECT perfusion imaging modality incorporating attenuation and scatter correction in conjunction with 99mTc sestamibi perfusion imaging. Significant improvements in the normalcy rate were noted without a decline in overall sensitivity but with a reduction in detection of extensive coronary disease.

Cardiac involvement in scleroderma.

In summary, cardiac involvement in systemic sclerosis can be manifested as myocardial disease, pericardial disease, conduction system disease, or arrhythmias. Clinical cardiac involvement is a poor prognostic factor. Asymptomatic cardiac abnormalities are frequent, and all cardiac abnormalities are seen more often in diffuse scleroderma. Unlike other organs, the role of vascular involvement is unclear. At present, treatment of cardiac scleroderma is essentially symptomatic and empiric. The role of vasodilation and immunosuppression needs further exploration.

Mitral annular descent velocity by tissue Doppler echocardiography as an index of global left ventricular function.

Mitral annular descent has been described as an index of left ventricular (LV) systolic function, which is independent of endocardial definition. Echocardiographic tissue Doppler imaging is a new technique that calculates and displays color-coded cardiac tissue velocities on-line. To evaluate mitral annular descent velocity as a rapid index of global LV function, we performed tissue Doppler imaging studies in 55 patients, aged 56 +/-15 years, within 3 hours of radionuclide ventriculographic ejection fraction. Tissue Doppler M-mode studies were obtained from each of 6 mitral annular sites, as follows: inferoseptal and lateral from apical 4-chamber views, anterior and inferior from apical 2-chamber views, and anteroseptal and posterior from apical long-axis views. Only 1 patient with severe mitral annular calcification was excluded. The group mean 6-site average peak mitral annular descent velocity was 5.5 +/- 1.9 cm/s (range 2.4 to 10.5), and the group mean ejection fraction was 49 +/- 18% (range 17 to 80%). The 6-site average peak annular descent velocity correlated linearly with LV ejection fraction (r = 0.86, SEE = 1.02 cm/s): LV ejection fraction = 8.2 (average peak mitral annular descent velocity) + 3%. The 6-site peak mitral annular descent velocity average >5.4 cm/s was 88% sensitive and 97% specific for ejection fraction >50%. The peak mitral annular descent velocity from the apical 4-chamber view (average from inferoseptal and lateral sites) correlated most closely with the LV ejection fraction (r = 0.85) as an individual view. Peak mitral annular descent velocity by tissue Doppler imaging has the potential to estimate rapidly the global LV function.

Thallium perfusion defects predict subsequent cardiac dysfunction in patients with systemic sclerosis.

OBJECTIVE: To determine the significance of thallium perfusion defects in patients with systemic sclerosis (SSc). METHODS: This is a followup study of a series of 48 SSc patients who underwent thallium perfusion scans in the early 1980s. Their cardiac history and survival information over the last 10 years were obtained as part of the Pittsburgh Databank's yearly evaluation. We determined the frequency of subsequent development of arrhythmias requiring treatment or of congestive heart failure through patient and physician information. RESULTS: Patients with larger thallium perfusion defects had a significantly increased risk of developing subsequent cardiac events or death. The size of the initial thallium defect was the best predictor of later adverse events compared with other disease-related features, in a logistic regression analysis. CONCLUSION: We conclude that patients with SSc who have significant thallium perfusion defects are at a significantly increased risk of developing subsequent cardiac disease or death.

Assessment of biventricular cardiac function in patients with a Novacor left ventricular assist device.

Novacor left ventricular assist devices were implanted in 10 patients. We used blood-pool radionuclide angiography and echocardiography to evaluate the response of the left and right ventricle to the left ventricular assist. Radionuclide angiography was done before and after implantation of the Novacor left ventricular assist devices in all cases. All patients had diffuse left ventricular enlargement; the mean left ventricular ejection fraction before Novacor left ventricular assist device implantation was 17% +/- 7%. After implantation of the Novacor left ventricular assist devices the left ventricular ejection fraction improved to 47% +/- 19%, with the pump on a 1:1 assist ratio (p < 0.005). The right ventricular ejection fraction before the Novacor left ventricular assist device implantation was 21%, which improved to 32% with the Novacor left ventricular assist devices (p < 0.01). Doppler echocardiography was carried out in nine patients with the left ventricular assist devices. In five patients the aortic valve remained closed throughout systole. In four patients partial aortic valve opening was noted. At an assist ratio of 1:3, complete opening of the aortic valve was noted in all cases (n = 9); the left ventricular ejection fraction decreased to 31%. We conclude that the Novacor left ventricular assist device substantially improves both right ventricular ejection fraction and left ventricular ejection fraction, although the aortic valve typically remains closed.

Comparison of left ventricular function by echocardiographic automated border detection and by radionuclide ejection fraction.

Echocardiographic automated border detection can provide on-line estimates of left ventricular cavity area by differentiating blood from tissue backscatter characteristics. The objective of this study was to assess the ability of short-axis measurements of left ventricular cavity area by automated border detection to determine left ventricular function by comparing these measurements to radionuclide measures of ejection fraction in the same patients. Eighty-eight consecutive patients, aged 53 +/- 14 years, underwent automated border detection studies within 2 hours of radionuclide ventriculography. Short-axis imaging with automated border detection was attempted at basal, midpapillary muscle, and apical levels. Maximal left ventricular length was also measured from apical 4- and 2-chamber views by standard imaging. Fractional area change--(end-diastolic area-end-systolic area)/end-diastolic area--was determined at each short-axis level. Volumes and ejection fractions were calculated using: volume = 5/6 (midventricular area).length. Simpson's rule for 3 short-axis measurements was calculated using: volume = (length/12) (5.basal area + 2.mid-area + 4.apical area). Technically adequate automated border detection data could be obtained on 69 patients (78%) at basal and mid-levels, and at all 3 short-axis levels in 66 patients (75%). Correlations with radionuclide ejection fraction were as follows: midventricular fractional area change--R = 0.84, SEE = 12%, y = 0.86 x - 7; area-length ejection fraction--R = 0.89, SEE = 9%, y = 0.96 x - 4; and Simpson's rule--R = 0.91, SEE = 8%, y = 0.89 x + 1.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac and skeletal muscle disease in systemic sclerosis (scleroderma): a high risk association.

To examine the possible relationship between cardiac and skeletal muscle disease in systemic sclerosis, we reviewed computerized records of 1095 consecutive patients with systemic sclerosis. One hundred eighty three (17%) had skeletal myopathy. Thirty-nine (21%) of the 183 fulfilled criteria for myocardial disease, compared with 90 (10%) of the 912 without myopathy (p < 0.0001.) Nineteen (10%) of the 183 had clinical CHF compared with 38 (4%) of the remainder (p < 0.002.) Fifteen (8%) of the patients with myopathy died of cardiac causes compared with 27 (3%) of the 912 without myopathy (p < 0.002.) Twenty-five patients with coexistent myopathy and myocardial disease, in the absence of other identifiable contributing causes, were identified. This group was characterized by a high incidence of cardiac conduction abnormalities (60%) and by the severity of the myocardial dysfunction and arrhythmias, both atrial and ventricular that they experienced. Eighteen of these 25 patients died; 12 (67%) died suddenly. Eight of the 18 (44%) had intractable CHF, which directly contributed to their deaths. Myocardial fibrosis was the predominant histologic abnormality at autopsy. However, autopsy of a patient who died in the context of acute "myocarditis" showed severe myocytolysis with contraction band necrosis but without inflammation or fibrosis; this is consistent with possible ischemically mediated injury. We conclude that skeletal and cardiac muscle disease in systemic sclerosis are associated. Patients with myopathy are at increased risk for CHF, sustained symptomatic arrhythmias, and cardiac death, particularly sudden death.

Continuous on-line monitoring of left ventricular function with a new nonimaging detector:validation and clinical use in the evaluation of patients post angioplasty.

A new miniaturized nonimaging radionuclide detector (Cardioscint, Oxford, England) was evaluated for the continuous on-line assessment of left ventricular function. This cesium iodide probe can be placed on the patient's chest and can be interfaced to an IBM compatible personal computer conveniently placed at the patient's bedside. This system can provide a beat-to-beat or gated determination of left ventricular ejection fraction and ST segment analysis. In 28 patients this miniaturized probe was correlated against a high resolution gamma camera study. Over a wide range of ejection fraction (31% to 76%) in patients with and without regional wall motion abnormalities, the correlation between the Cardioscint detector and the gamma camera was excellent (r = 0.94, SEE +/- 2.1). This detector system has high temporal (10 msec) resolution, and comparison of peak filling rate (PFR) and time to peak filling (TPFR) also showed close agreement with the gamma camera (PFR, r = 0.94, SEE +/- 0.17; TPFR, r = 0.92, SEE +/- 6.8). In 18 patients on bed rest the long-term stability of this system for measuring ejection fraction and ST segments was verified. During the monitoring period (108 +/- 28 minutes) only minor changes in ejection fraction occurred (coefficient of variation 0.035 +/- 0.016) and ST segment analysis showed no significant change from baseline. To determine whether continuous on-line measurement of ejection fraction would be useful after coronary angioplasty, 12 patients who had undergone a successful procedure were evaluated for 280 +/- 35 minutes with the Cardioscint system.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of acute alterations in left ventricular loading conditions on peak filling rate in the denervated (transplanted) ventricle.

Peak filling rate is an indicator of left ventricular (LV) diastolic function. It is influenced by heart rate, loading conditions, sympathetic nervous system activity, ejection fraction and other factors. To determine the effect of altered loading conditions on peak filling rate, independent of heart rate and sympathetic nervous system activity, 12 patients were studied 3 weeks after orthotopic heart transplantation. Plasma catecholamine level, heart rate and ejection fraction were not changed by any maneuver. Nitroglycerin caused a decrease in pulmonary artery wedge pressure (9 +/- 2 to 6 +/- 1 mm Hg, p less than 0.001) and in absolute peak filling rate (46.0 +/- 3.0 to 42.8 +/- 2.5 kcts/s, p less than 0.01), but no change in normalized peak filling rate. Volume infusion increased pulmonary artery wedge pressure (9 +/- 2 to 12 +/- 2 mm Hg, p less than 0.001) and absolute peak filling rate (46.0 +/- 3.0 to 51.5 +/- 5.3 kcts/s, p less than 0.01), but peak filling rate normalized to stroke volume was unchanged. During nitroglycerin and volume infusions, there was a high correlation between changes in pulmonary artery wedge pressure and absolute peak filling rate (r = 0.82, p less than 0.001). With normalization of peak filling rate, these variables correlated less well. With methoxamine, 4 patients demonstrating systolic dysfunction had a decrease in absolute and normalized peak filling rate despite a large increase in pulmonary artery wedge pressure. The other 8 patients without systolic dysfunction had an increase in pulmonary artery wedge pressure with increased absolute but unchanged normalized peak filling rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in left ventricular systolic function that accompany rejection of the transplanted heart: a serial radionuclide assessment of fifty-three consecutive cases.

To examine the functional changes that accompany the development of rejection of the orthotopically transplanted heart, radionuclide ventriculograms, right heart catheterizations, and endomyocardial biopsies were performed at weekly intervals during the posttransplantation hospitalization of 53 consecutive transplant recipients. Left ventricular ejection fraction decreased in those (n = 10) who had sequential biopsies that changed from no rejection to moderate rejection (63% +/- 7% to 57% +/- 7% respectively, p = 0.007). There was an associated decrease in the peak ejection rate (4.4 +/- 1.0 to 3.9 +/- 0.8 end-diastolic volumes per second, p = 0.008) and an increase in the time to peak ejection rate (137 +/- 27 msec to 153 +/- 20 msec, p = 0.004) that accompanied the development of rejection. There was a similar decrease in left ventricular ejection fraction in those (n = 9) who had sequential biopsies that changed from no rejection to mild rejection (63% +/- 6% to 59% +/- 8%, p = 0.009). Only two of 19 patients whose biopsies changed from no rejection to either mild or moderate rejection did not have an associated decrease in ejection fraction. In patients who had a biopsy that showed definite rejection, which was then followed by histologic resolution after treatment (n = 11), left ventricular ejection fraction increased from 56% +/- 8% to 61% +/- 8%, p = 0.03. There were no significant changes in any of the parameters of diastolic function or in any of the hemodynamic parameters measured, which were associated with either the development or resolution of rejection.(ABSTRACT TRUNCATED AT 250 WORDS)

Noninvasive evaluation of supraventricular tachycardias.

In this article we discuss the role of noninvasive methods in evaluation of supraventricular tachycardias. The limitation of Holter monitoring and exercise testing is discussed. A significant portion of the article is devoted to the role of esophageal recording, body surface potential mapping, and phase image analysis, areas that are often underutilized but that have potential in the diagnosis of supraventricular tachycardias.

A controlled clinicopathologic study of myocardial fibrosis in systemic sclerosis (scleroderma).

Clinicopathologic correlations of myocardial fibrosis were examined in 54 autopsied patients with scleroderma and 54 age and sex matched autopsy controls. Thirty eight (70%) of the patients with scleroderma had myocardial fibrosis compared to 20 (37%) of the controls (p less than 0.005). There was no significant difference in the prevalence of contraction band necrosis in the patients with scleroderma (22%) compared to controls (17%). Patients with scleroderma with left ventricular dysfunction in the absence of other causative factors clinically had a greater prevalence of both advanced myocardial fibrosis (60%) and contraction band necrosis (40%) than did the other patients with scleroderma or the controls. We conclude that patients with scleroderma with the greatest likelihood of advanced myocardial fibrosis can be identified clinically, and their findings are consistent with the presence of microvascular coronary vasospasm, a "myocardial Raynaud's phenomenon."

Acute myocardial dysfunction and recovery: a common occurrence after coronary bypass surgery.

To evaluate whether acute myocardial dysfunction was common in the early postoperative period, serial hemodynamic measurements and radionuclide evaluation of ventricular function were performed before and after operation in 24 patients undergoing elective coronary bypass surgery. All patients had uncomplicated surgery, and no patient sustained an intraoperative infarction. In 96% of patients, significant depression in right and left ventricular ejection fraction was seen postoperatively, reaching a nadir at 262 +/- 116 min after coronary bypass. Left ventricular ejection fraction was 58 +/- 12% preoperatively and 37 +/- 10% at trough. Right ventricular function displayed a similar pattern. These findings were also associated with depressed cardiac and left ventricular stroke work index despite maintenance of adequate ventricular filling pressures and mean arterial pressure. The depression in ventricular function was partially reversible within 8 to 10 h after surgery. Left ventricular ejection fraction had increased to 55 +/- 13% at 426 +/- 77 min after coronary bypass and showed complete recovery within 48 h. Left ventricular end-systolic and end-diastolic volume index increased significantly postoperatively, but recovery in left ventricular ejection fraction was mostly due to decreases in end-systolic volume index (50 +/- 22 ml at trough and 32 +/- 16 ml at recovery). Depressed myocardial function was independent of bypass time, number of grafts placed, preoperative medications or core temperatures postoperatively. Postoperative therapy with pressors or inotropic agents delayed but did not prevent the occurrence of postoperative ventricular dysfunction. Despite improvements in operative techniques and methods of myocardial protection, postoperative left ventricular dysfunction continues to be common in patients undergoing cardiopulmonary bypass surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

The scalar electrocardiogram of the orthotopic heart transplant recipient.

The 12-lead scalar electrocardiograms of heart transplant recipients were examined prior to hospital discharge (N = 191), and at 1 (N = 162), 2 (N = 97), and 3 years (N = 46) after transplantation. At the pre-discharge point, 46% had right bundle branch block (RBBB) QRS morphology (QRS duration greater than or equal to 120 msec: 20 patients, less than 120 msec: 67 patients). This finding tended to be manifest on the first day following transplantation; its prevalence remained constant over 3 years of follow up. Rejection, ischemic time, preoperative pulmonary vascular resistance, and donor age were not associated with the presence of RBBB morphology. A subgroup of 46 consecutive patients (21 with RBBB morphology) underwent right-sided heart catheterization and radionuclide angiography prior to discharge. RBBB morphology was not associated with any hemodynamic abnormality at catheterization. Based on the radionuclide study, RBBB morphology was associated with a greater left anterior oblique angle required for the best visual separation of the ventricles during acquisition of the study (angle of interventricular septal plane to sagittal plane: 69 +/- 11 versus 59 +/- 9 degrees; p = 0.019), and with the presence of right ventricular dysfunction (13 of 21 versus 6 of 25 patients; p = 0.009). The high prevalence of RBBB morphology in heart transplant recipients appears to be related to posterior rotation of the long axis of the heart in the transverse plane, probably resulting from the surgical technique, and to right ventricular dysfunction.

Spontaneous whole blood platelet aggregation in insulin-dependent diabetes mellitus: an evaluation in an epidemiologic study.

Spontaneous whole blood platelet aggregation (SWBPA) was examined in a case-control study, comparing a consecutive series of IDDM subjects (n = 30) to age, and sex matched controls. Subjects were free of platelet altering medications. Platelet aggregation was measured by the percent fall in single platelet count after 15 minutes of both shaking (SK) and magnetic stirring (ST). IDDM subjects showed a significantly greater percent fall in SK (means = 12.1) and ST (means = 34.0) compared to controls (SK means = 8.4, p less than 0.01; ST means = 24.3, p less than 0.05). Long-term repeat testing on 15 subjects (diabetics and non-diabetics) up to 4 months apart showed a correlation of 0.7 for SK, p less than 0.01 but only 0.4 for ST. In a further series of IDDM subjects (n = 176) those with macrovascular disease (n = 27) showed significantly greater percent fall in SK (p less than 0.05), and ST (p less than 0.05). We conclude that SWBPA is a simple useful epidemiological technique (shaking being more repeatable than stirring) which relates to both diabetes and macrovascular disease.

Comparison of a supplemented Rose Questionnaire to exercise thallium testing in men and women.

The Rose Questionnaire has had high specificity and variable sensitivity when compared to physician identification of the symptom complex of angina pectoris. We assessed the accuracy of a supplemented Rose Questionnaire in a series of 198 patients by comparing the Questionnaire to exercise thallium test evidence of coronary artery disease. The Rose diagnosis of angina had 26% sensitivity, 79% specificity, 42% positive predictive value, and 65% negative predictive value. The Rose diagnosis of myocardial infarction had 26% sensitivity and 90% specificity. The Rose diagnosis of angina or infarction yielded a sensitivity of 44%, specificity of 72%, positive predictive value of 67%, and negative predictive value of 50%. Supplemental questions designed to identify atypical ischemic pain led to increased sensitivity of up to 68% that was offset by decreased specificity. While the Questionnaire's sensitivity for coronary disease was greater for women than men (57 vs 40%), the overall accuracy was the same because specificity was lower (63 vs 80%).

Electrocardiographically discrete right and left ventricular QRS complexes: a case report.

A patient with congestive cardiomyopathy manifested a right ventricular QRS followed after 80 msec. by a left ventricular QRS in response to a single atrial depolarization. The ventricular sequence was reversible when the left ventricle was paced directly. Virtually the entire ipsilateral ventricular ejection period occurred during diastolic filling of the contralateral ventricle. Triggered left ventricular pacing, using the right ventricular electrogram as trigger, shortened the QRSRV-QRSLV interval and resulted in a reduction of left ventricular filling pressure and a significant rise in cardiac output. These findings indicated an independent contribution of this unique form of interventricular conduction disturbance to deterioration in hemodynamic performance.