Functional significance of myocardial perfusion defects induced by dipyridamole using thallium-201 single-photon emission computed tomography and two-dimensional echocardiography
- Baylor College of Medicine, Houston, TX (USA)
The mechanisms responsible for inhomogeneous myocardial blood flow after oral administration of a large dose (300 mg) of dipyridamole were assessed in 27 patients with serial thallium-201 single-photon emission computed tomography (SPECT) and simultaneous 2-dimensional echocardiograms. Myocardial tomographic images were obtained 50 minutes and 3 to 4 hours after administration of dipyridamole. Two-dimensional echocardiograms were recorded at baseline and then every 15 minutes for 60 minutes. Dipyridamole caused only a mild reduction in blood pressure (from 129 +/- 18 to 126 +/- 16 mm Hg) and a mild increase in heart rate (from 69 +/- 15 to 73 +/- 4 beats/min). Sixteen patients had perfusion defects after dipyridamole by SPECT, which underwent partial or total filling-in. Fourteen of these patients (87.5%) had either a new abnormality or further deterioration of a preexisting wall motion abnormality by 2-dimensional echocardiography, and thus were considered to have developed transient ischemia during dipyridamole administration. Ten of 11 patients (91%) with normal perfusion or fixed defects by SPECT had no further deterioration in wall motion after oral dipyridamole, and were thus considered to have no evidence of myocardial ischemia. In conclusion, most patients with transient thallium-201 defects after dipyridamole develop transient worsening of resting wall motion by 2-dimensional echocardiography, suggestive of true myocardial ischemia. Because myocardial oxygen demand, as indicated by the heart rate-blood pressure product, did not change significantly, the mechanism of myocardial ischemia in these patients is likely to be diminished regional blood flow related to a subendocardial steal induced by dipyridamole.
- OSTI ID:
- 6170555
- Journal Information:
- American Journal of Cardiology; (USA), Journal Name: American Journal of Cardiology; (USA) Vol. 66:10; ISSN 0002-9149; ISSN AJCDA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Effect of maintenance oral theophylline on dipyridamole-thallium-201 myocardial imaging using SPECT and dipyridamole-induced hemodynamic changes
Reversible cold-induced abnormalities in myocardial perfusion and function in systemic sclerosis
Related Subjects
62 RADIOLOGY AND NUCLEAR MEDICINE
BETA DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
BLOOD FLOW
BLOOD PRESSURE
BODY
CARDIOVASCULAR AGENTS
CARDIOVASCULAR DISEASES
CARDIOVASCULAR SYSTEM
COMPUTERIZED TOMOGRAPHY
DAYS LIVING RADIOISOTOPES
DIAGNOSIS
DIAGNOSTIC TECHNIQUES
DISEASES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
EMISSION COMPUTED TOMOGRAPHY
HEART
HEAVY NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MUSCLES
MYOCARDIUM
NUCLEI
ODD-EVEN NUCLEI
ORGANS
PATIENTS
RADIOISOTOPES
SECONDS LIVING RADIOISOTOPES
SINGLE PHOTON EMISSION COMPUTED TOMOGRAPHY
THALLIUM 201
THALLIUM ISOTOPES
TOMOGRAPHY
ULTRASONOGRAPHY
VASODILATORS