Myocardial imaging with extractable cations and inert tracers: The effects of flow and metabolism

Selwyn, Andrew P.; Fox, Kim; Shillingford, John

doi:10.1002/clc.4960010202

Cited by 11 publications

(3 citation statements)

References 28 publications

(53 reference statements)

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“…Time-activity graphs with tables of the counts per minute in each area of interest were recorded with the serial images of regional myocardial perfusion from each study. [5][6][7] The nature, intention and potential dangers of the procedure were explained to each patient before each study. Subjects gave signed consent as required by the Hospital Ethics Committee, and Isotope Panel clearance was obtained before the studies.…”

Section: Krypton-81m Scintigraphymentioning

confidence: 99%

Patterns of disturbed myocardial perfusion in patients with coronary artery disease. Regional myocardial perfusion in angina pectoris.

Selwyn¹,

Forse²,

Fox³

et al. 1981

Circulation

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SUMMARY Fifty patients who presented with angina pectoris were studied to examine the disturbances of regional myocardial perfusion during stress. Each patient underwent 16-point precordial mapping of the ECG during an exercise test, and coronary and left ventricular angiography. Regional myocardial perfusion was assessed using an atrial pacing test and a short-lived radionuclide, krypton-81m. Eleven patients had negative exercise tests and uniform increases in myocardial activity of krypton-81m of 98 ± 18.0% during pacing. Ten patients performed 30,000-43,000 J in positive exercise tests. These patients showed abnormal coronary anatomy and increases in myocardial activity of krypton-81m to remote and jeopardized myocardium at the onset of pacing. However, further pacing produced a decrease in activity in the affected segment of 68.0 ± 9.0% accompanied by ST-segment depression and angina. Twelve patients achieved 26,000-32,000 J in positive exercise tests and had significant coronary artery disease. Atrial pacing produced increased activity of krypton-81m to remote myocardium. The jeopardized segment at first showed no change and then a decrease in regional activity of krypton-81m (89.0 ± 17%) accompanied by ST-segment depression and chest pain. Seventeen patients achieved only 7000-22,000 J in positive exercise tests. These patients showed abnormal coronary anatomy and developed decreases in regional activity of krypton-81m to the affected segment of myocardium starting at the onset of atrial pacing and decreasing by 88 ± 7.0% below control. We conclude that different patterns of disturbed myocardial distribution of krypton-81m are present during stress-induced ischemia in patients with coronary artery disease. There was a close temporal relationship between these disturbances and ST-segment depression. In this study we assessed disturbances of regional myocardial perfusion in patients with angina pectoris and coronary artery disease. Changes in the regional myocardial distribution of the short-lived krypton-81 m has been measured during atrial pacing and then related to the patient's symptoms, ECG during exercise and the findings at coronary arteriography.

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Section: Krypton-81m Scintigraphymentioning

confidence: 99%

Patterns of disturbed myocardial perfusion in patients with coronary artery disease. Regional myocardial perfusion in angina pectoris.

Selwyn¹,

Forse²,

Fox³

et al. 1981

Circulation

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“…Previous work has shown that when the catheter seated in the aortic sinus is sta ble a constant infusion of 81 mKr can be used to continuously image changes in regional myocardial perfusion (Selwyn et al .. 1978a). Further, provided the alterations in heart rate are within those seen in this study the concentration of indicator delivered to the coronary circulation is not altered (Selwyn et al .• 1978a,c).…”

Section: Discussionmentioning

confidence: 63%

The Effects of Propranolol on Myocardial Perfusion and Metabolism during Acute Regional Ischaemia

et al. 1978

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“…Time-activity graphs were calculated by a Deltron-Nova 1220 digital computer and corrected for the decay of rubidium-81 (half-life 4.56 hours). [8][9][10][11][12] A Wilcoxon test for paired differences was used to test changes in end-diastolic pressure, blood pressure and heart rate. An analysis of variance was used to examine the significance of changes in the regional myocardial activity of krypton-81m.…”

Section: Methodsmentioning

confidence: 99%

The effect of acute regional myocardial ischemia on the angiographic anatomy of coronary arteries.

Selwyn¹,

Fox²,

Clay³

1979

Circulation

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SUMMARY Twenty-eight anesthetized dogs were studied to investigate the effects of regional myocardial ischemia on the angiographic appearance of large coronary arteries. Left ventricular (LV) and left coronary angiograms were recorded before and after the diameter of the left anterior descending coronary artery (LAD) was reduced by 60-70%. The left ventricular end-diastolic pressure (LVEDP) and the epicardial ECG showed no regional dyskinesia or ischemia. After the LAD was narrowed, we produced regional ischemia with atrial pacing in eight dogs and with 0.4 mg of ergonovine maleate i.v. in five dogs. Repeat angiograms during each episode of ischemia showed that the LAD associated with the dyskinetic segment transiently failed to opacify. This was reversed by intravenous nitroglycerin. In another five dogs, we produced regional ischemia by injecting microspheres into the LAD. Repeat angiograms showed narrowed vessels and impaired opacification of the associated segment of the LAD. This was partially reversed by intravenous nitroglycerin. A dynamic assessment of changes in regional myocardial perfusion was recorded in 10 more dogs using krypton-81m. Stenosis (60-70%) of the LAD produced no changes in regional perfusion. Atrial pacing produced an immediate redistribution with increases in perfusion (112 ± 14% [mean + SD]) to remote myocardium and decreases (78 ± 9.0%) in the affected segment. These experiments showed that when several interventions are used to produce acute regional myocardial ischemia, the angiographic appearance of the coronary arteries changes. This change consisted of a transient failure to opacify the length of the artery associated with the ischemic segment. This suggests that the reversible disappearance of a large coronary artery during an episode of myocardial ischemia may not necessarily be due to coronary spasm. THE NEED to rationalize the treatment of angina pectoris has encouraged research into the pathophysiology of this condition.' Atherosclerotic narrowing of coronary arteries is thought to limit appropriate changes in regional blood flow needed to meet myocardial metabolism, but this theory does not explain spontaneous angina. Fleckenstein has shown some of the biochemical pathways and responses that influence the tone of coronary artery strips in vitro.

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Myocardial imaging with extractable cations and inert tracers: The effects of flow and metabolism

Cited by 11 publications

References 28 publications

Patterns of disturbed myocardial perfusion in patients with coronary artery disease. Regional myocardial perfusion in angina pectoris.

Patterns of disturbed myocardial perfusion in patients with coronary artery disease. Regional myocardial perfusion in angina pectoris.

The Effects of Propranolol on Myocardial Perfusion and Metabolism during Acute Regional Ischaemia

The effect of acute regional myocardial ischemia on the angiographic anatomy of coronary arteries.

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