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Biomedical subjects

J A Rothendler

Publications and source records attributed to J A Rothendler.

6 recordsLinked to original sources

Arm exercise-thallium imaging testing for the detection of coronary artery disease.

Patients with lower limb impairment are often unable to undergo a standard bicycle or treadmill test for the evaluation of coronary artery disease. To establish an alternative method of testing, 50 subjects (aged 56 +/- 10 years) performed arm ergometry testing in conjunction with myocardial thallium scintigraphy. All underwent coronary angiography; significant coronary artery disease (greater than or equal to 70% stenosis) in at least one vessel was present in 41 (82%) of the 50 patients. Thallium scintigraphy was found to have an 83% sensitivity and 78% specificity for detecting coronary disease, compared with a sensitivity and specificity of 54% (p less than 0.01) and 67% (p = NS), respectively, for exercise electrocardiography. In the subgroup of 23 patients who had no prior myocardial infarction or left bundle branch block and were not taking digitalis, thallium scintigraphy had a sensitivity of 80% versus 50% for exercise electrocardiography. Scintigraphy yielded a sensitivity of 84, 74 and 90% for one, two and three vessel disease, respectively. Noninvasive arm ergometry exercise-thallium imaging testing appears to be reliable and useful and should be considered in the evaluation of coronary artery disease in patients with lower limb impairment.

Adult

Diagnosis of pericardial effusions from routine gated blood-pool imaging.

Gated blood-pool scintigraphy (GBPS) is often obtained as the initial test to evaluate symptoms suggestive of left ventricular dysfunction. Since large pericardial effusions may also cause such symptoms, the ability to recognize them on routine GBPS is of clinical importance. Characteristic features of the "halo" sign surrounding the cardiac blood pool were developed, based on the GBPS of patients with known pericardial effusions. These criteria were then applied blindly to 154 consecutive patients who underwent both GBPS and echocardiography. All five patients with large effusions (approximately greater than 500 ml) were correctly identified by GBPS (sensitivity 100%); for patients with moderate effusions (approximately 150-500 ml), the sensitivity was only 33% (3/9). There were three false positives (specificity 98%). We conclude that large pericardial effusions can be identified with high sensitivity and specificity on routine GBPS. Although echocardiography remains the method of choice for the diagnosis of effusions, inspection for characteristics suggesting their presence on GBPS should be part of routine interpretations.

Echocardiography

Decrease in the ability to detect elevated lung thallium due to delay in commencing imaging after exercise.

Post-exercise elevation of the lung/myocardial thallium ratio and a high lung clearance rate between initial and delayed images have been reported to be markers for exercise-induced left ventricular (LV) dysfunction associated with coronary artery disease (CAD). We performed thallium exercise tests on 60 patients, 42 with CAD, in order to determine the effect of delaying initial imaging on detection of elevated lung thallium. In addition to images obtained at 2 minutes and at 2 hours after exercise, 18-minute images were also obtained to simulate such a delay. Because of rapid isotope clearance in those with initially elevated lung activity, there was decreased sensitivity of both the initial lung/myocardial ratio and lung thallium clearance for detecting CAD, using the 18-minute image as the initial post exercise study. We conclude that initial imaging should be done in the anterior view early after exercise to optimize detection of elevated lung thallium.

Adult

Persistent left superior vena cava and right superior vena cava drainage into the left atrium without arterial hypoxemia.

A 46 year old patient who presented with an acute myocardial infarction was discovered to have a systemic venous communication with the left heart during attempted insertion of a pulmonary flotation catheter. There was no evidence of cyanosis or systemic arterial desaturation. A right superior vena cava that emptied into the right superior pulmonary vein and a persistent left superior vena cava draining into the coronary sinus were confirmed pathologically after death related to a brain abscess. The embryology, physiology and noninvasive diagnostic approach to this unique venous anomaly are discussed.

Cardiac Catheterization

Effect of a delay in commencing imaging on the ability to detect transient thallium defects.

Sixty patients, 42 with coronary disease and 18 normals, were studied to assess the impact of a delay following exercise in commencing thallium imaging on the sensitivity for detecting ischemic transient defects. Three sets of images were obtained beginning 2 min, 18 min, and 2 hr after exercise. Each patient's images were separated into two pairs of studies for analysis: 2 min-2 hr and 18 min-2 hr. Of the 42 patients with coronary disease, a greater number had transient defects detected on the 2 min-2 hr compared with the 18 min-2 hr study (22 compared with 14, p less than 0.05). False positives were not increased by earlier imaging. We conclude that a modest (18 min) delay obtaining the first set of images causes a significant reduction in the ability to detect transient thallium defects, and that imaging should begin several minutes after exercise.

Adult

Technique for dual transducer echocardiography.

Circuitry for simultaneous recording from dual transducers on a single echocardiogram is presented. The technique may be used to compare the motion pattern and time intervals of separate intracardiac structures. The technique may be difficult, is limited by the size of the cardiac window, and may be most useful for research purposes.

Echocardiography