Usefulness of intravenous propranolol in predicting left anterior descending blood flow during anterior myocardial infarction

The effect of propranolol on precordial ST-segment elevation was studied in 24 patients with acute anterior myocardial infarction. The electrocardiographic response to the drug was correlated with the early angiographic appearance of the left anterior descending coronary artery (LAD). After a 30-minute observation period, intravenous propranolol (average dose 3.5 +/- 2.2 mg) was given a mean of 2.8 +/- 1.9 hours after the onset of persistent chest pain. Coronary angiography was performed 3.6 +/- 2.0 hours after the onset of symptoms. Patients were classified into 2 groups according to the angiographic findings. Group A consisted of 7 patients with a stenotic but patent LAD and 1 patient with excellent collateral blood flow to that area. Group B consisted of 16 patients with a completely occluded LAD and poor or absent collateral blood flow. Patients in group A showed a mean reduction in precordial ST-segment elevation of 77 +/- 18% and patients in group B showed a mean reduction of 13 +/- 14% (p less than 0.005). Left ventricular ejection fraction at discharge was 0.6 +/- 0.07 in group A and 0.37 +/- 0.08 in group B (p less than 0.001). Thus, the electrocardiographic response to intravenous propranolol given early in the course of acute anterior myocardial infarction predicts the presence of blood flow to the infarcting zone. The combination of residual blood flow and reduction of ST-segment elevation secondary to propranolol is associated with preservation of ventricular function.     

Mechanisms and time course for the disappearance of thallium-201 defects at rest in dogs: Relation of time to peak activity to myocardial blood flow

The kinetics of thallium (Tl)-201 in ischemic myocardium was studied with a balloon constrictor to create a fixed reduction in distal left anterior descending coronary arterial pressure in 19 dogs. After 30 to 60 minutes of partial occlusion, Tl-201 was administered intravenously. Tracer activity was monitored continuously for 4 hours in both the normal and reduced flow zones using implanted miniature cadmium telluride radiation detectors. Microsphere-determined regional myocardial blood flow, heart rate, mean arterial pressure, mean left atrial pressure, mean distal left anterior descending coronary arterial pressure and sonomicrometer-determined myocardial wall thickness did not change significantly during each study. Thallium-201 time-activity curves for the normal zones (flow 1.00 ml/min per g or more) demonstrated an initial rapid increase to 80 to 90 percent of peak, an early peak (mean 20 minutes) and then a monoexponential decrease in activity (decay constant λ = 0.0013 min^?1). Thallium-201 time-activity curves for mildly and moderately ischemic zones (flow = 0.40 to 0.99 ml/min per g) demonstrated a progressive delay in the time to peak activity with progressive reductions in flow (r = 0.84). Thallium-201 time-activity curves for severely ischemic zones (flow less than 0.40 ml/min per g) demonstrated a rapid initial increase, and then no further increase in activity, probably because of cell death with a resultant decreased ability to accumulate Tl-201.When the Tl-201 activity ratio (reduced/normal flow zone) was calculated as a function of time for each dog, there was a progressive increase in this ratio over time for all dogs, although the rate of increase was slower for dogs with increasing degrees of flow reduction. This increasing ratio over time would correspond to disappearance of an initial Tl-201 resting scintiscan defect over time. The mechanism for the increasing ratio in dogs with mild or moderate flow reduction was both clearance of Tl-201 from normal zones and accumulation of Tl-201 by ischemic zones. However, the mechanism for the increasing ratio in dogs with severe flow reductions was a faster rate of Tl-201 loss from the normal compared with the reduced flow zone.     

An ambulatory ventricular function monitor: validation and preliminary clinical results

A device for the continuous measurement of left ventricular (LV) function was tested in a series of 34 subjects. The instrument consisted of 2 arrays of radiation sensitive cadmium telluride detectors held in place over the region of the left ventricle and lung by a vest-like garment (hence the name VEST). The VEST electronic instrumentation included analog-to-digital converters, a battery pack, microprocessor and gating device, which were worn in a back pack. Data generated by the VEST, including the digitized average electrocardiogram, RR interval, counts/13 ms in each radiation detector, and time since commencement of data recording, were recorded on a cassette tape recorder every 2 minutes for subsequent analysis. At the conclusion of conventional multigated blood pool imaging, the VEST was positioned and worn by the subjects while supine, standing in place and walking. The correlation of ejection fraction calculated independently from the VEST and scintillation camera data was greater than 0.95. The inter-record reproducibility of the ejection fraction measured by the VEST in sedentary subjects was less than 3%.     

Circulating immune complexes in Hodgkin's disease

Levels of circulating immune complexes (CIC) in the serum of patients with Hodgkin's disease were measured by the Raji cell radioimmunoassay. Elevated levels of immune complexes (mean value of 49 μg/ml ± 21 SE) were detected in 20 of 40 (50 per cent) untreated patients. After treatment, the level of CIC was normal (< 15 μg/ml) in 39 of 41 patients. Recurrent disease developed in two of the 39 patients with normal post-treatment levels of CIC and in one of the two patients with elevated post-treatment levels during the follow-up period of six months to six years. Elevated levels of CIC were detected in patients with Hodgkin's disease in stages I, II and III but not in stage IV. No significant correlations were found in the frequency of elevated levels of CIC or the values observed, and the presence or absence of symptoms (fever, sweats, weight loss) or the histologic subtype of the tumor. Our data indicate that the measurement of CIC by the sensitive and specific Raji cell assay may prove useful in the management of patients with Hodgkin's disease. In particular, serial measurement of the level of CIC could be employed to monitor the response to treatment and to detect recurrent diseases.     

A convenient approximation of life expectancy (the “DEALE”): II. Use in medical decision-making

We show how to use a bedside approximation of life expectancy in quantitative decision-making. This method, the declining exponential approximation of life expectancy (DEALE), enables the physician to collate various survival data with information on morbidity to determine a quality-adjusted expected survival for a potential management plan. The keystone in the DEALE approach is the approximation of survival by a simple exponential function. This approximation makes it possible to translate data from various literature sources (life expectancy tables, five-year survival rates, survival curves, median survival) into a single, unified mortality scale. In this paper, we use the DEALE method to obtain approximations of quality-adjusted life expectancy and illustrate the application of the method in a quantitative analysis of a clinical decision.     

Impaired catabolism of very low-density lipoprotein-triglyceride in a family with primary hypertriglyceridemia

In this report, kinetic studies of plasma very low-density lipoprotein-triglyceride (VLDL-TG) were examined in five brothers (three affected and two unaffected) from a family with primary hypertriglyceridemia. Synthesis and catabolism of VLDL-TG were studied by in vivo labelling of plasma TG with 3H-glycerol, and multicompartmental analysis of the plasma die-away curves. Results of the kinetic studies revealed the following information: (1) one brother, who had the highest plasma TG level and was obese, had both overproduction and a reduced fractional catabolic rate (FCR) of VLDL-TG; (2) second brother, who had moderate hypertriglyceridemia, had a low FCR and high-normal synthesis of VLDL-TG; (3) a third, who had only mildly elevated TG, had a low FCR and normal synthesis of VLDL-TG; and (4) the two normolipidemic brothers had neither overproduction nor decreased FCR of VLDL-TG. The composition of the soluble apoproteins of VLDL was normal. The apoprotein E phenotypes were E4/3 in four brothers, and E3/2 in the fifth. We have reached the following conclusions regarding this family: (1) the common kinetic abnormality of VLDL-TG metabolism in the hypertriglyceridemic brothers was a low clearance of VLDL-TG; (2) impaired catabolism of VLDL could not be explained by the apoprotein C or E patterns; and (3) the most severe hypertriglyceridemia occurred when the decreased FCR was present in conjunction with VLDL-TG overproduction due to obesity. Thus, a moderate defect in catabolism of plasma TG appears to be responsible for one familial form of primary hypertriglyceridemia.     

A Road Map to Foster Wellness and Engagement in Our Workplace—A Report of the 2018 Summer Intersociety Meeting

The 2018 radiology Intersociety Committee reviewed the current state of stress and burnout in our workplaces and identified approaches for fostering engagement, wellness, and job satisfaction. In addition to emphasizing the importance of personal wellness (the fourth aim of health care), the major focus of the meeting was to identify strategies and themes to mitigate the frequency, manifestations, and impact of stress. Strategies include reducing the stigma of burnout, minimizing isolation through community building and fostering connectivity, utilizing data and benchmarking to guide effectiveness of improvement efforts, resourcing and training “wellness” committees, acknowledging value contributions of team members, and improving efficiency in the workplace. Four themes were identified to prioritize organizational efforts: (1) collecting, analyzing, and benchmarking data; (2) developing effective leadership; (3) building high-functioning teams; and (4) amplifying our voice to increase our influence.     

Cardiac hypertrophy: Useful adaptation or pathologic process?

An extensive body of evidence supports the concept that cardiac hypertrophy and normal cardiac growth develop in response to increased hemodynamic loading and abnormal systolic and diastolic stresses at the myocardial fiber level. The pattern of hypertrophy reflects the nature of the inciting stress. Experimental studies indicate that if the stress is moderate, gradually applied, and the animal young and healthy, physiologic hypertrophy of muscle with normal contractility develops. In this circumstance, cardiac hypertrophy may be regarded as a useful adaptation to increased hemodynamic loading. When the inciting stress is severe, abruptly applied, or the animal old or debilitated, pathologic hypertrophy develops: in this circumstance, the cardiac muscle produced is abnormal and exhibits depressed contractility. Of particular clinical relevance is the intermediate situation which seems to develop in many patients with chronic left ventricular pressure-overload and perhaps also in left ventricular volume-overload. In this situation, chronic left ventricular pressure or volume overload is initially matched by adequate hypertrophy in the appropriate pattern. Eventually, in some patients, hypertrophy fails to keep pace with the hemodynamic overload so that a systolic stress imbalance occurs at the myocardial fiber level and left ventricular pump failure ensues. If this situation persists uncorrected, it is possible that the increasingly high wall stresses will convert physiologic to pathologic hypertrophy. The task of the clinician is to identify this intermediate stage and to correct the abnormal hemodynamic loading before the transition to pathologic hypertrophy becomes complete.     

Primary empty sella syndrome, ACTH hypersecretion, and normal adrenocortical function. Report of two cases

Although the primary empty sella syndrome (PESS) is associated with normal endocrine function or subtle pituitary insufficiency, pituitary hormone hypersecretion associated with PESS has also been recognized. ACTH hypersecretion and primary empty sella syndrome have previously been reported in patients with either Cushing's disease or Addison's disease. This report describes two unique patients with ACTH hypersecretion, primary empty sella syndrome, and normal cortisol dynamics. The investigators speculate that this association may have resulted from infarction of hyperplastic adenohypophyseal corticotrophes due to production of an ACTH peptide with reduced biologic activity. These two cases emphasize that primary empty sella syndrome may be associated with ACTH hypersecretion and normal adrenocortical function.     

Myocardial scintigraphy with technetrium-99m pyrophosphate during the early phase of acute infarction.

To determine the sensitivity of myocardial scintigraphy with technetium-99m pyrophosphate during the early phase of acute myocardial infarction, 31 patients admitted to the coronary care unit with prolonged ischemic pain underwent imaging within 4 to 8 hours and again at 24 hours after the onset of symptoms. In 11 of 15 patients with documented acute myocardial infarction, increased focal myocardial uptake was demonstrated on early myocardial scintigraphy. Focal uptake was observed in only 2 of 16 patients with unstable angina pectoris. Three or four patients with normal early scintigrams had massive transmural myocardial infarction. Normal early scintigrams in these three patients may have reflected poor perfusion because the images were abnormal at 24 hours. In four patients the extent of technetium-99m pyrophosphate uptake increased more than 20 percent at 24 hours without other evidence of infarct extension. In the other seven patients, there was no significant change in the area of the abnormal radioactive uptake between early and delayed scintiscans. This study suggests that technetium-99m pyrophosphate scintigraphy can defect acute myocardial infarction as early as 4 hours after the onset of symptoms although the sensitivity rate (73 percent) is less than that at 24 hours.