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Biomedical subjects

S C Port

Publications and source records attributed to S C Port.

25 records · Page 2Linked to original sources
PubMed1985

Assessment of single vessel coronary artery disease: results of exercise electrocardiography, thallium-201 myocardial perfusion imaging and radionuclide angiography.

The sensitivity of the commonly used stress tests for the diagnosis of coronary artery disease was analyzed in 46 patients with significant occlusion (greater than or equal to 70% luminal diameter obstruction) of only one major coronary artery and no prior myocardial infarction. In all patients, thallium-201 perfusion imaging (both planar and seven-pinhole tomographic) and 12 lead electrocardiography were performed during the same graded treadmill exercise test and radionuclide angiography was performed during upright bicycle exercise. Exercise rate-pressure (double) product was 22,307 +/- 6,750 on the treadmill compared with 22,995 +/- 5,622 on the bicycle (p = NS). Exercise electrocardiograms were unequivocally abnormal in 24 patients (52%). Qualitative planar thallium images were abnormal in 42 patients (91%). Quantitative analysis of the tomographic thallium images were abnormal in 41 patients (89%). An exercise ejection fraction of less than 0.56 or a new wall motion abnormality was seen in 30 patients (65%). Results were similar for the right (n = 11) and left anterior descending (n = 28) coronary arteries while all tests but the planar thallium imaging showed a lower sensitivity for isolated circumflex artery disease (n = 7). The specificity of the tests was 72, 83, 89 and 72% for electrocardiography, planar thallium imaging, tomographic thallium imaging and radionuclide angiography, respectively. The results suggest that exercise thallium-201 perfusion imaging is the most sensitive noninvasive stress test for the diagnosis of single vessel coronary artery disease.

Adult↗
PubMed1984

Effects of intraaortic balloon counterpulsation on myocardial blood flow in patients with severe coronary artery disease.

The purpose of this study was to test the hypothesis that myocardial blood flow distal to a critical stenosis would increase during intraaortic balloon counterpulsation. Accordingly, 13 patients with severe coronary artery disease were studied at the time of elective preoperative insertion of an intraaortic balloon catheter. Hemodynamic measurements and measurements of myocardial blood flow were made before and during counterpulsation. Myocardial blood flow was measured with a xenon-133 washout technique. Compared with control measurements, the heart rate decreased from 87.8 +/- 18.8 to 82.8 +/- 13.4 beats/min (p = 0.02) and systolic arterial pressure decreased from 112.1 +/- 17.9 to 97.8 +/- 14.8 mm Hg (p = 0.004) during counterpulsation. Diastolic arterial pressure increased from 72.2 +/- 10.1 to 120.2 +/- 21.4 mm Hg (p = 0.00002) during counterpulsation. Myocardial blood flow for the entire group decreased from 48.8 +/- 14.1 to 42.6 +/- 11.0 ml/100 g per min (p = 0.008). Regional flows in the left anterior descending and circumflex distributions also decreased. Left anterior descending artery blood flow decreased insignificantly from 51.5 +/- 14.4 to 47.4 +/- 11.7 ml/100 g per min (p = not significant), while circumflex flow decreased from 50.7 +/- 12.2 to 41.1 +/- 8.9 ml/100 g per min (p = 0.008). When normalized for the rate-pressure product, myocardial blood flow was 53 +/- 16 X 10(-4) at rest and 55 +/- 12 X 10(-4) (p = not significant) during counterpulsation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

First-pass radionuclide angiography during bicycle and treadmill exercise.

BACKGROUND: Treadmill testing is usually preferred over cycle ergometry because of the greater sensitivity in diagnosing coronary artery disease. Treadmill testing has only recently been used with radionuclide angiography (RNA) because patient motion makes RNA imaging difficult. In this study we evaluate the comparability of treadmill and cycle exercise RNA with a dual isotope motion correction technique. METHODS AND RESULTS: Volunteer patients (n = 27) performed first-pass RNA during maximal exercise using both cycle ergometer and treadmill. Exercise capacity was greater during treadmill exercise (8.1 +/- 2.4 vs 7.5 +/- 2.2 METs). Twenty-three of 27 treadmill and all cycle ergometer exercise studies were technically adequate. Maximal heart rate was greater during treadmill exercise (150 +/- 24 vs 143 +/- 25 beats * min-l), however, systolic blood pressure was greater during cycle ergometry (174 +/- 23 vs 188 +/- 25 mmHg), resulting in no difference in heart rate times systolic blood pressure (25.7 +/- 7.2 vs 26.9 +/- 6.0). There were no differences between treadmill and cycle ergometer for peak exercise left ventricular ejection fraction (56% +/- 13% vs 57% +/- 14%) (r = 0.89). Calculated left ventricular end-diastolic volume was not different at rest (183 +/- 42 ml vs 176 +/- 44 ml) but differed significantly at peak exercise (282 +/- 75 ml vs 231 +/- 60 ml). The clinical impression, based on wall motion and left ventricular ejection fraction was very similar between treadmill and cycle ergometer. CONCLUSION: Treadmill exercise RNA is feasible, with about 85% of studies likely to be technically adequate. The overall clinical results are very similar to cycle exercise RNA, although the ordinarily expected advantages of treadmill exercise were largely absent.

Adult↗