Robert A. Slutsky

Left ventricular volumes by gated equilibrium radionuclide angiography: a new method.

To compare radionuclide end-diastolic (EDV) and end-systolic (ESV) volumes with angiographic volume, we studied 52 patients with equilibrium radionuclide angiography using 99mTc-human serum albumin within 48 hours of contrast angiography. Each RR interval was divided into 20–28 equally timed frames and a time-activity curve generated. End-diastolic counts were taken at the early peak of the curve and end-systolic counts at its nadir. Counts were divided by the total number of processed heart beats and normalized for: 1) dose per body surface area; 2) plasma volume; and 3) counts/ml of plasma. A cardiac phantom was developed and serial volumes were studied using a normalization factor. Radionuclide values were expressed as dimensionless units and compared with either biplane angiographic volumes (in the patient studies) or known phantom volumes. Good correlations were obtained with methods 1 and 2 in 35 patients (r > 0.84), but the best correlation was obtained in 17 patients when normalization for counts/ml of plasma was used (r = 0.98; y = 0.255 x −0.121). The standard error of the estimate (SEE) was ± 11.5 ml for EDV and ± 7.3 ml for ESV. The phantom study also showed an excellent correlation (r = 0.99), with a SEE of ± 6.5 ml. We conclude that a radionuclide method independent of geometric assumptions can be used to estimate left ventricular volume in man.

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

Relationship of QRS amplitude changes during exercise to left ventricular function and volumes and the diagnosis of coronary artery disease.

Preliminary studies have suggested that QRS-amplitude changes due to exercise-induced alterations in ventricular volume and function can improve the diagnostic value of the exercise test. To evaluate this, electrocardiographic data and equilibrium radionuclide angiographic images were recorded simultaneously in 18 normal subjects and 60 coronary artery disease patients at rest and during supine bicycle exercise. In 24 of the 60 coronary artery disease patients, left ventricular volumes were also calculated. The measured QRS amplitudes were the R waves in V5, X, Y and Z, the Q wave in Z and the sum of amplitudes of R waves in X and Y and the Q wave in Z (2iR). The mean left ventricular ejection fraction increased significantly from rest to peak exercise in the normal subjects; however, the mean left ventricular ejection fraction and mean volumes did not change significantly in the coronary patients. There was no significant difference in the mean QRS-amplitude changes during exercise between the coronary artery disease patients and the normal subjects in any of the measured leads. The sensitivity and specificity of exercise-induced QRS-amplitude changes for coronary disease were lower than ST-segment changes. For ST-segment changes, the sensitivity was 57% and specificity was 100%; the best sensitivity and specificity for QRS amplitude occurred in RZ, 48% and 67%, respectively. When ejection fraction was related to 2R at rest and peak exercise for both normal subjects and coronary patients the correlations were fair (0.50, 0.51 respectively); however, the correlation between the magnitude of 2R and ejection fraction change from rest to peak exercise was poor and did not improve with any other measured QRS amplitudes or by separating normal subjects from coronary patients with and without previous myocardial infarction. There were also poor correlations between end-diastolic and endsystolic volumes to QRS amplitudes at rest, peak exercise and their magnitude of change from rest to peak exercise. Thus, R-wave amplitude changes during exercise testing have little diagnostic value and are not related to exercise-induced changes in left ventricular function or volumes.

The initial chest x-ray in acute myocardial infarction. Prediction of early and late mortality and survival.

To evaluate the importance of the initial chest x-ray in predicting mortality and survival after acute myocardial infarction, the degree of pulmonary congestion, cardiothoracic ratio and left-heart dimension on the initial chest x-ray obtained from 273 patients within 24 hours of admission after acute myocardial infarction were related to early (30 days) and late (6 months, 1 year) mortality. The chest films were divided into four degrees of pulmonary venous congestion: grade 0 — no pulmonary congestion (n = 141); grade 1 redistribution of pulmonary blood flow (n = 38); grade II interstitial pulmonary edema (n = 61); grade III localized alveolar edema (n = 20); grade IV — diffuse alveolar edema (n = 13). In the absence of pulmonary congestion, 94% of the patients survived the first month and 88% of them survived 1 year; when the heart size was also normal, more than 96% of patients survived 1 month and more than 91% survived 1 year. The 30-day mortality was significantly (p < 0.005) higher with grades II, III and IV pulmonary venous congestion than with grade 0, and late mortalities increased significantly (p < 0.005) with any degree of pulmonary venous congestion compared with grade 0. Mortalities with grades II and III congestion were similar, and less than 50% of the patients were alive after 1 year. With grade IV, only 18% of patients survived after 30 days and none after 1 year. Without pulmonary venous congestion, 24% of patients with increased initial left-heart dimension (> 50 mm/m2) and increased cardiothoracic ratio (> 0.50) died during the subsequent year, compared with only 6% of patients with normal initial heart dimension and 9% with normal initial cardiothoracic ratio. Early and late mortality in patients without pulmonary venous congestion was significantly lower (p < 0.01) than in patients with any degree of pulmonary venous congestion, regardless of left-heart dimension or cardiothoracic ratio. Thus, the degree of congestion and left-heart size on the initial chest x-ray after acute myocardial infarction are highly useful for defining groups with increased risk of dying or surviving within the first month or the first year after the acute event.

Improvement of exercise-induced left ventricular dysfunction with oral propranolol in patients with coronary heart disease☆

The effect of propranolol on global cardiac function during exercise was analyzed with equilibrium fadionuclide angiography in 10 patients with ischemic heart disease. All patients had angina pectoris and S-T segment depression of more than 0.1 mv during treadmill exercise when not taking propranolol. Each patient was stressed with supine bicycle exercise to the same work load on a maintenance dose of propranolol (120 to 400 mg/day) and on a second occasion without the drug, the two tests being separated by an average of 16 days. The mean heart rate was reduced both at rest and during exercise after propranolol, but propranolol caused no significant reduction of the left ventricular ejection fraction at rest. In the study without administration of propranolol the average ejection fraction during exercise decreased from 0.56 ± 0.09 (standard deviation) to 0.50 ± 0.14. With propranolol, the ejection fraction was improved from the control value in every patient, the average value during peak exercise reaching 0.60 ± 0.15. Thus, the average ejection fraction increased by 22 percent (±12 percent) relative to the value during the same exercise without propranolol (P < 0.001). In 16 other patients with ischemic heart disease who did not take propranolol, reproducibility of the ejection fraction both at rest and at peak exercise on two occasions within 15 days was good (r = 0.95 and 0.97, respectively). It is concluded that oral propranolol therapy in patients with coronary artery disease can ameliorate left ventricular dysfunction induced by exercise and thereby may reduce myocardial ischemia.

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.

Left ventricular ejection fraction and first third ejection fraction early after acute myocardial infarction: Value for predicting mortality and morbidity

Abstract In 102 patients with acute myocardial infarction total ejection fraction was measured 1 to 4 days after hospital admission with simultaneous measurement of first third ejection fraction, using first pass radionuclide angiography, in 44. Ejection fraction was reduced ( 0.52. Nine of 21 patients (43 percent) with a first third ejection fraction value of Thus, relatively early after admission for acute myocardial infarction total ejection fraction can fail to show left ventricular dysfunction in one third of patients, whereas the first third ejection fraction appears to be highly sensitive for detecting depressed left ventricular function. A total ejection fraction of

Reproducibility of ejection fraction and ventricular volume by gated radionuclide angiography after myocardial infarction.

To validate the repeated use of radionuclide equilibrium angiography for determining left ventricular (LV) ejection fraction (EF) and end-diastolic and end-systolic volumes (EDV and ESV), 25 patients were studied on an hourly basis an average of 9.1 days after acute myocardial infarction. Data were processed with a semi-automatic computer program which develops an averaged-volume curve from an assigned LV region-of-interest. LV EDV and ESV were derived from a previously described method which correlates well with contrast angiography (r = 0.977, y = 0.0255x - 0.121). Comparison between initial and subsequent equilibrium EF and between initial and subsequent volumes showed excellent correlation. Excluding three anginal episodes, the EF variation between studies averaged 0.03 +/- 0.02.

The response of left ventricular function and size to atrial pacing, volume loading and afterload stress in patients with coronary artery disease.

To assess the response of left ventricular function and size to volume loading, atrial pacing and afterload stress, we studied 35 patients using equilibrium radionuclide angiography. All subjects had coronary heart disease, as evidenced by contrast angiography or previous myocardial infarction.Fifteen patients received 500 ml of normal saline given as two rapid 250-ml infusions. Ejection fraction increased after the second infusion (0.49 to 0.55, p < 0.05), as did end-diastolic volume (p < 0.05), but there was little change in end-systolic volume or the ratio of systolic blood pressure to end-systolic volume. Eight patients were subjected to phenylephrine afterload stress, with a mean elevation of systolic blood pressure of 44.6 ± 12 mm Hg (p < 0.01 vs rest). Ejection fraction declined (0.52 ± 0.1 to 0.41 ± 0.13, p < 0.01), end-diastolic and end-systolic volumes increased (p at least < 0.01), and the ratio of systolic pressure to end-systolic volume decreased (2.31 ± 1.64 to 1.46 ± 0.67 mm Hg/ml, p < 0.05). Twelve patients underwent atrial pacing (from 80–130 beats/min), resulting in a decrease in ejection fraction, a decrease in end-diastolic and end-systolic volumes (p < 0.05) and an increase in the pressure-volume ratio (2.00 ± 0.30 to 2.45 ± 1.02 mm Hg/ml, p < 0.05).We conclude that alterations in loading conditions affect indexes of left ventricular performance. The ejection fraction is reduced by elevations in blood pressure and increased by volume infusion, but appeared reduced by atrial pacing, probably due to the offsetting changes in heart rate and preload. The pressure-volume ratio did not change with volume loading, decreased with afterload stress and increased with atrial pacing. Thus, equilibrium radionuclide angiography can be used to assess noninvasively the effects of physiologic and pharmacologic interventions on left ventricular performance in patients with coronary heart disease.

Perfluoroctylbromide as a blood pool contrast agent for liver, spleen, and vascular imaging in computed tomography.

Perfluoroctylbromide (PFOB) in emulsion form was tested as a blood pool imaging agent for computed tomography (CT) in five animals (three dogs and two pigs). Computed tomography of the kidneys, liver, spleen, and mediastinum was performed in the control state and at various time intervals after the end of PFOB infusion. The attenuation coefficient of the vascular space increased by 117 Hounsfield units (HU) (range 105–128 HU), the liver by 54 HU (range 43–70 HU), and the spleen by 77 HU (range 69–86 HU) 30 to 50 min after the end of PFOB infusion, 5 ml/kg. The vascular space enhanced by 25 HU for every g of PFOB/100 ml of blood and remained at almost a constant level for hours after the end of infusion. In conclusion, PFOB emulsion, in addition to hepatosplenic enhancement, produces prolonged and substantial opacification of the vascular space, allowing CT imaging of the heart and vascular structures minutes to hours after the end of infusion.