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Biomedical subjects

R Uren

Publications and source records attributed to R Uren.

26 records · Page 2Linked to original sources
PubMed1980

Noninvasive prediction of multivessel disease after myocardial infarction.

In 65 patients with a previous transmural myocardial infarction (anterior in 33, inferior in 32), exercise thallium scanning was compared with 12-lead exercise electrocardiography to see if multivessel disease could be detected. At coronary arteriography 40 patients were shown to have multivessel disease ( greater than or equal to 70% diameter stenosis in two or three vessels) and 25 patients had one-vessel disease. On the exercise scan thallium defects corresponding to the electrocardiographic site of infarction were present in all patients. Patients wih one-vessel and multivessel disease were separated by exercise-induced angina, perfusion defects on the exercise thallium scan in more than one specific vasculare area, and a positive exercise ECG associated with angina, but not by a positive exercise ECG alone. Of the 40 patients with multivessel disease, 85% had defects in more than one vascular area on the thallium scan and 70% had a positive exercise ECG (p = NS). Of the 37 patients with thallium defects in more than one specific vascular area, 92% had multivessel disease, compared with 72% of the 39 patients who had a positive exercise ECG (p < 0.05). periinfactional ischemia was present in 38 of the 65 patients (58%) ( 14 of 25 with one-vessel disease and 24 of 40 with multivessel disease), and did not correlate with the severity of the corresponding coronary artery disease. When thallium defects that resolved were noted in a second vascular area, they were associated with a resolving rather than a constant defect in the vascular area where the infarction had occurred ( p < 0.005). In patients after a transmural myocardial infarction, multivessel disease can be better differentiated from one-vessel disease by thallium scanning than by exercise electrocardiography.

Adult↗
PubMed1979

Serial exercise thallium myocardial perfusion scanning and exercise electrocardiography in the diagnosis of coronary artery disease.

Serial exercise thallium-201 myocardial perfusion scanning (exercise and 4-hour redistribution) was compared to rest and exercise electrocardiography (ECG) for the detection of coronary artery disease in 125 patients with known or suspected coronary artery disease. All patients underwent coronary arteriography and 108 were found to have significant coronary artery lesions. The serial exercise thallium scan was significantly more sensitive than rest and exercise ECG in detecting coronary artery disease (94% v. 83% P less than 0.01). The sensitivity of a reversible thallium perfusion scan abnormality and a positive exercise ECG for detecting exercise induced myocardial ischaemia in coronary artery disease was similar (69% v. 63%). The exercise thallium scan complemented the exercise ECG, and the sensitivity of the combined test was significantly greater than the exercise ECG alone (84% v. 63% P less than 0.001). The specificity for coronary artery disease of the exercise ECG was 65% and that of the exercise thallium-201 myocardial perfusion scan was 82% (P = NS). Thallium-201 myocardial perfusion scanning complements the rest and exercise ECG in the non-invasive detection of coronary artery disease.

Adult↗
PubMed1979

Regional ejection fraction: a quantative radionuclide index of regional left ventricular performance.

Radionuclide measurements of regional left ventricular ejection fraction were evaluated as a quantitative index of regional left ventricular function. Left ventricular regional ejection fractions were derived from background-corrected, time-activity curves in 43 patients assessed by both gated equilibrium radionuclide angiocardiography and left ventricular contrast angiography. From a single, modified left anterior oblique projection, the regional change in background corrected counts was determined in each of three anatomic regions. The normal range for regional radionuclide ejection fraction was determined in 10 patients with normal contrast ventriculograms and without obstructive coronary artery disease at coronary arteriography. Regional ejection fraction was compared with percent segmental axis shortening and extent of akinetic segments in corresponding regions of the contrast ventriculogram. Radionuclide and roentgenographic methods were in agreement as to the presence or absence of abnormal wall motion in 83 of 99 left ventricular regions (84%) in 33 patients evaluated prospectively. Comparison of regional ejection fraction demonstrated significant differences between regions with roentgenographically determined normokinesis (75 +/- 3%, mean +/- SEM), hypokinesis (44 +/- 3%, p less than 0.0005) and akinesis (24 +/- 5%, p less than 0.005). We conclude that the left ventricular regional ejection provides a reliable quantitative assessment of regional left ventricular performance.

Adult↗
PubMed1979

Multivessel coronary artery spasm.

A 60-year-old patient with variant angina was shown to have myocardial ischemia in two different regions supplied by separate major coronary arteries. Neither artery had significant coronary atherosclerotic obstruction. Ventricular fibrillation was noted during ST-segment elevation in anteroseptal leads. The attacks of pain and arrhythmias disappeared during nifedipine therapy.

Angina Pectoris↗
PubMed1978

Myocardial perfusion scanning with thallium--201 for the non-invasive diagnosis of coronary artery disease.

Thallium--201 myocardial perfusion scanning has been evaluated in Australia in patients with coronary artery disease. Myocardial scans reliably detect both acute myocardial infarction and the transient myocardial ischaemia of angina pectoris. The non-invasive nature, ease of study, and the ability to scan patients with conventional cameras makes thallium--201 an attractive additional diagnostic agent for patients with suspected coronary artery disease. Although thallium--201 reliably indicates perfusion defects in the myocardium, its diagnostic use at the moment should be reserved to clarify such diagnostic problems in patients with coronary artery disease which cannot be satisfactorily explained by conventional investigation.

Angina Pectoris↗