Kenneth Gerber

Assessment of right ventricular function at rest and during exercise in patients with coronary heart disease: A new approach using equilibrium radionuclide angiography

Abstract To evaluate a new method of calculating right ventricular ejection fraction by equilibrium radionuclide angiography and to assess its response during supine bicycle exercise, 20 normal persons and 50 patients with angiographically documented coronary artery disease were studied. Each subject underwent a resting equilibrium and first pass right ventricular study as well as symptom-limited graded bicycle exercise while supine. The correlation between the two methods in all 70 cases was good (r = 0.81). Inter- and intraobserver variability was small (3.9 ejection fraction units or less) and serial reproducibility (two studies performed 2 weeks apart) was also good (4 ejection fraction units or less). There was no difference in the right ventricular ejection fraction at rest when normal subjects and patients with coronary disease were compared (0.49 ± 0.10 versus 0.46 ± 0.08). Ejection fraction increased with exercise in normal subjects (0.49 ± 0.10 to 0.64 ± 0.12, p

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

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

Nuclear bone imaging in metastatic cancer of the prostate.

A reproducible technique of bone scanning in prostatic cancer is described that helps ensure the production of successive studies of highly comparable technical quality. Through an analysis of survival data based on changes in distribution, anatomic extent, and intensity of bone scan abnormalities in patients with advanced prostatic cancer, it is demonstrated that alterations in the appearance of the bone scan correlate closely with disease activity and have great prognostic significance.

Effect of Nitrates on Left Ventricular Size and Function During Exercise: Comparison of Sublingual Nitroglycerin and Nitroglycerin Paste

Abstract To compare the effects of sublingual nitroglycerin and nitroglycerin paste on left ventricular size and performance during supine bicycle exercise, equilibrium radionuclide angiography was performed in 36 persons classified into two groups of normal subjects and two groups of patients with angiographically proved coronary heart disease. Each group underwent a control exercise study, and then one group of normal subjects and one group of patients were restudied after the administration of 0.6 mg of nitroglycerin or 2 inches (5 cm) of nitroglycerin paste (but not both). Data were collected at rest and at peak exercise. In normal subjects exercise resulted in increased ejection fraction, decreased end-systolic volume and little change in end-diastolic volume. After either drug, volumes at rest markedly decreased, and during exercise, ejection fraction increased to levels comparable with pre-drug levels. After nitroglycerin paste the reduction in volume seen at rest persisted during exercise, but after sublingual nitroglycerin end-diastolic volume increased during exercise (88 ± 43 to 113 ± 30 ml [mean ± standard deviation]; p In patients with coronary disease , ejection fraction did not change during exercise, but both end-diastolic and end-systolic volumes increased. After either drug ejection fraction at rest was unchanged, although ventricular volumes were markedly lower ( p Thus, sublingual nitroglycerin and nitroglycerin paste improved left ventricular function during exercise. The effect of paste on end-diastolic volume appeared sustained, whereas that of sublingual nitroglycerin was transient, confirming the hypothesis that reduction in end-diastolic volume and, by implication, left ventricular wall tension, is a major mechanism of nitrate action.

The Value of Nuclear Bone Imaging in Advanced Prostatic Cancer

The nuclear bone scan is a highly sensitive means of detecting skeletal metastasis in patients with prostatic cancer. Serial bone imaging provides an accurate method to follow the response of osseous metastases to treatment and to detect relapsing disease in the skeleton. In selected instances the nuclear bone scan can provide information about vertebral metastases that can be important for planning palliative treatment of pain.

Comparative effects of ionic anc nonionic contrast materials on coronary and peripheral blood flow.

Contrast materials may alter coronary blood flow (CBF) by a direct vasodilating action or indirectly by changing determinants of myocardial oxygen requirements (MVO2). The current study compared the vasodilatory actions of ionic (Renografin 76, R76) and nonionic contrast materials (iohexol and metrizamide) after direct injection into the coronary and femoral circulation of anesthetized dogs. R76 did not cause a significantly greater increase in CBF compared with nonionic materials in spite of causing significantly greater increases in osmolality of blood in the coronary sinus. Concomitant with the peak increase in CBF, the ionic materials caused sharp decrease in peak left ventricular (LV) systolic pressure and dp/dt, while the nonionic materials increased these major determinants of MVO2. In contradistinction to the effects on CBF, ionic contrast material caused substantially and significantly greater increase in femoral blood flow, compared with the nonionic materials. In conclusion, these studies infer that the increase in CBF with contrast materials involves both indirect vascular and metabolic actions, while the increase in FBF is due to a direct vascular action.

Effects of low osmolality contrast materials on coronary hemodynamics, myocardial function, and coronary sinus osmolality in normal and ischemic states.

The effects of intracoronary administration of contrast materials on regional and global left ventricular (LV) function and coronary sinus osmolality were assessed in six anesthetized dogs with segmental myocardial ischemia produced by critical stenosis of the circumflex coronary artery. Effects caused by Renografin (sodium meglumine diatrizoate), two new low osmolality contrast agents (Hexabrix and Hexabrix with added calcium ions), and metrizamide were evaluated. In a nonischemic state, Renografin produced an early (0-10 seconds) decrease in LV contractility followed by a late (10-20 seconds) rebound augmentation in contractility. In the presence of regional ischemia, there are prolongation of the depression of the myocardial contractile state. The monoacid dimer, Hexabrix, demonstrated a similar biphasic response, although the initial depression of myocardial contractility was significantly less than that observed with Renografin. Hexabrix with added calcium ions and metrizamide produced only augmentation in global and regional parameters of LV contractile function. This lack of depressant effects was also observed in the ischemic state. Renografin caused a significantly greater increase in coronary sinus osmolality (Tp) as compared with Hexabrix, Hexabrix-Ca++, and metrizamide. The increases in osmolality in response to the latter three contrast agents were statistically indistinguishable.

Detection and assessment of severity of regional ischemic left ventricular dysfunction by digital fluoroscopy

Abstract Digital intravenous ventriculography (DIV) was used to detect and assess the severity of regional and global left ventricular (LV) function in the presence of graded levels of coronary stenosis. DIV was performed on six anesthetized dogs with a coronary blood flow probe and micrometer controlled occluder on the circumflex coronary artery (CXA) and pairs of sonic dimension crystals in the posterointerior (ischemic area) and anterior (control area) walls of the LV in the control state, with subtotal occlusion of the CXA (STEN), and with CXA occlusion (OCL). Global analysis at each stage included area-length calculation of end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF). Regional analysis included calculation of area displaced by anterior wall (AA), and posteroinferior wall (IA), average amplitude of excursion of the anterior wall (AE), and posteroinferior wall (IE). STEN caused significant increase in AA (14.4 ± 2.2%) and decreases in EF (−19.7 ± 2.5%), IA (−36.6 ± 4.2%), and IE (−30.8 ± 5.3%) ( p p

Evaluation of left ventricular function in chronic pulmonary disease by exercise gated equilibrium radionuclide angiography

To assess left ventricular (LV) response to supine bicycle exercise, we studied 10 normal (group 1). 10 patients with coronary artery disease (CAD) (group 2), 12 patients with severe obstructive lung disease (COPD) (group 3), and eight patients with both CAD and COPD (group 4) by gated equilibrium radionuclide angiography. Most individuals in all groups also had pulmonary catheter-obtained measurements of LV filling pressures during exercise. Normal individuals increased their ejection fraction (EF) during exercise by increasing stroke volume (SV) and reducing end-systolic volume (ESV) without changing end-diastolic volume (EDV); pulmonary artery (PAP) and wedge (PAW) pressures were unaltered. CAD patients (group 2) showed no change in EF with increased EDV, ESV, SV, and PAW. COPD patients (group 3) exhibited decreases in EDV, ESV, and SV, accounting for abnormal EF responses in 6 of 12; PAW was unchanged and the marked elevation of PAP correlated with reduced EDV. Group 4 patients (CAD plus COPD) had abnormal EF responses with increased EDV and ESV without change in SV. Thus an abnormal LV function response to exercise in COPD patients may be multifactorial, thereby indicating the possible need for therapeutic modalities in addition to those employed in alleviating pulmonary parenchymal disease.

Radionuclide analysis of ejection time, peak ejection rate, and time to peak ejection rate: response to supine bicycle exercise in normal subjects and in patients with coronary heart disease

Using equilibrium radionuclide angiography, we evaluated the ejection time (ET), peak ejection rate (PER), and time to peak ejection rate (TTp) at test and during supine bicycle exercise in 39 subjects, divided into three groups: group 1 = 13 normal subjects; group 2 = 10 patients with a previous infarction (MI); and group 3 = 16 patients with coronary disease without a previous MI. Normal subjects had greater ejection fractions and PERs than the other two groups at rest or peak exercise (p less than 0.05). PER was no more useful than ejection fraction in identifying cardiac dysfunction at either rest or exercise. The time of its occurrence varied with the group studied, and was slightly but significantly later in systole in groups 2 and 3 when compared to normals (p less than 0.05), though substantial overlap between groups occurred. During exercise, absolute ET shortened in all groups, but actually increased as a function of the R-R interval. The time to peak ejection rate (normalized for the R-R interval) was greater in the noninfarct group (group 3) patients (p less than 0.05) when compared to the group 1 or group 2 individuals at peak exercise. In conclusion, equilibrium radionuclide angiography is a useful technique for the quantification and characterization of events during systole, and is capable of providing information on the timing of events during ejection. Tardokinesis, or the delay of ventricular ejection, is not seen in the response of global indices of left ventricular function to exercise stress. While global early systolic indexes may not detect regional dyssynchrony, their timing during stress may occasionally aid in discerning the presence of cardiac dysfunction.