The role of exercise radionuclide angiocardiography in predicting future cardiac events in patients with acute myocardial infarction.

UNLABELLED: Left ventricular ejection fraction (LVEF) during exercise radionuclide angiocardiography is a useful prognostic index for patients with acute myocardial infarction (AMI). However, most previous studies were performed before reperfusion therapies (i.e., thrombolysis and coronary angioplasty) were widely used. Therefore, because reperfusion therapy has become a standard therapeutic option, we reexamined the prognostic value of rest LVEF and exercise LVEF determined by radionuclide angiocardiography in patients with AMI at the time of hospital discharge. METHODS: The retrospective analysis included 419 consecutive patients with AMI who underwent ergometric stress radionuclide angiocardiography before hospital discharge, 44 +/- 14 d after the onset of AMI. RESULTS: During a mean follow-up of 4.6 y, cardiac events occurred in 101 (24.1%) patients. Cardiac events included recurrent MI (33 patients, 7.9%), unstable angina (49 patients, 11.7%), congestive heart failure (16 patients, 3.8%), and ventricular tachycardia (3 patients, 0.7%). The LVEF at peak exercise was significantly lower in the group with cardiac events (P = 0.0140). However, no significant difference was observed in the rest LVEF between patients with and without cardiac events. On the basis of multivariate analysis using a Cox proportional hazards model, only peak LVEF (P = 0.0246) was found to be an independent predictor of cardiac events. In the patient subsets with a peak LVEF >50% or <50%, the event-free rate was 81.0% versus 62.4% (P = 0.0007), respectively. Regardless of the presence or absence of reperfusion therapy, the lower peak LVEF was associated with a decrease in the event-free survival rate. CONCLUSION: In the current reperfusion era, the lower peak LVEF as measured by radionuclide angiocardiography at the time of discharge is a useful predictor of subsequent cardiac events in patients with AMI.

Probing the Site for r-Process Nucleosynthesis with Abundances of Barium and Magnesium in Extremely Metal-poor Stars.

We suggest that if the astrophysical site for r-process nucleosynthesis in the early Galaxy is confined to a narrow mass range of Type II supernova (SN II) progenitors, with a lower mass limit of Mms=20 M middle dot in circle, a unique feature in the observed distribution of [Ba/Mg] versus [Mg/H] for extremely metal-poor stars can be adequately reproduced. We associate this feature, a bifurcation of the observed elemental ratios into two branches in the Mg abundance interval -3.7

Early detection of anthracycline-induced cardiotoxicity by radionuclide angiocardiography.

For the early detection of myocardial damage associated with anthracycline therapy, electrocardiography, echocardiography, and radionuclide angiocardiography were used to assess cardiac function in 37 patients receiving anthracyclines (ie, adriamycin and daunorubicin at a total dose of 100-2,030 mg/m2). None of the patients developed clinical congestive heart failure. There were no significant changes of electrocardiographic and echocardiographic parameters after anthracycline administration. The left ventricular ejection fraction did not change significantly on radionuclide angiocardiography. However, the 1/3 peak filling rate (PFR) corrected by the end-diastolic count (EDC) (1/3 PFR/EDC) and the 1/3 filling fraction (1/3 FF), the indices of early diastolic function, showed a significant decrease. These findings suggest that the 1/3 PFR/EDC and 1/3 FF determined by radionuclide imaging are useful for detecting silent myocardial damage induced by anthracyclines.

Continuous ambulatory radionuclide monitoring of left ventricular function: effect of body position during ergometer exercise.

UNLABELLED: We assessed the reliability of a continuous ambulatory radionuclide monitoring system (the VEST system, Capintec, Inc., Ramsey, NJ) for measurement of left ventricular performance during exercise in the upright and supine positions. METHODS: Sixteen healthy male volunteers (aged 32-46 yr; mean age 37 +/- 4 yr) were studied. All volunteers underwent ergometer exercise testing in both the upright and supine positions, and left ventricular performance was determined with the VEST system. RESULTS: The resting heart rate, systolic blood pressure, pressure rate product, relative end-diastolic volume, relative end-systolic volume and left ventricular ejection fraction (LVEF) all showed no differences between the upright and supine positions. At peak exercise, the heart rate, systolic blood pressure and pressure rate product showed no differences between the upright and supine positions. In the upright position at peak exercise the relative end-diastolic volume was increased (83% +/- 9% to 91% +/- 11%, p < 0.001); the relative end-systolic volume remained unchanged (34% +/- 3% to 33% +/- 15%), and LVEF was significantly increased from 58% +/- 6% to 66% +/- 11% (p < 0.01). In the supine position at peak exercise, the relative end-diastolic volume remained unchanged (85% +/- 5 to 83% +/- 7%), the relative end-systolic volume was increased (35% +/- 5% to 43% +/- 13%, p < 0.01), and LVEF was decreased from 58% +/- 5% to 48% +/- 17% (p < 0.01). These results indicated inferior data collection by the VEST system in the supine position. CONCLUSION: Since the detector of the VEST system may be too small, the data collection is impaired during exercise in the supine position by shifting the heart with deep respiration. The VEST system is very useful for determining left ventricular performance when applied in the sitting or upright position. However, in the supine position during exercise, the use of the VEST system should be avoided because it might indicate an artifactual deterioration of left ventricular performance.