Myocardial perfusion abnormalities in patients with hypertrophic cardiomyopathy: assessment with thallium-201 emission computed tomography
Myocardial ischemia may play a critical role in the symptomatic presentation and natural history of hypertrophic cardiomyopathy (HCM). To assess the relative prevalence and functional significance of myocardial perfusion abnormalities in patients comprising the broad clinical spectrum of HCM, we studied 72 patients (ages 12 to 69 years, mean 40) using thallium-201 emission computed tomography. Imaging was performed immediately after maximal exercise and again after a 3 hr delay. Regional perfusion defects were identified in 41 of the 72 patients (57%). Fixed or only partially reversible defects were evident in 17 patients, 14 of whom (82%) had left ventricular ejection fractions of less than 50% at rest. Twenty-four patients demonstrated perfusion defects during exercise that completely reversed at rest; all had normal or hyperdynamic left ventricular systolic function (ejection fraction greater than or equal to 50%). Perfusion abnormalities were present in all regions of the left ventricle. However, the fixed defects were observed predominantly in segments of the left ventricular wall that were of normal or only mildly increased (15 to 20 mm) thickness; in contrast, a substantial proportion (41%) of the completely reversible defects occurred in areas of moderate-to-marked wall thickness (greater than or equal to 20 mm, p less than .001). Neither a history of chest pain nor its provocation with treadmill exercise was predictive of an abnormal thallium study, since regional perfusion defects were present in 10 of 18 (56%) completely asymptomatic patients, compared with 31 of 54 (58%) symptomatic patients. These data indicate that myocardial perfusion abnormalities occur commonly among patients with HCM. Fixed or only partially reversible defects suggestive of myocardial scar and/or severe ischemia occur primarily in patients with impaired systolic performance.
- Research Organization:
- National Heart, Lung, and Blood Institute, Bethesda, MD
- OSTI ID:
- 5652637
- Journal Information:
- Circulation; (United States), Vol. 76:6
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CARDIOVASCULAR DISEASES
DIAGNOSIS
MYOCARDIUM
EMISSION COMPUTED TOMOGRAPHY
EXERCISE
PATIENTS
PERFUSED ORGANS
THALLIUM 201
BETA DECAY RADIOISOTOPES
BODY
CARDIOVASCULAR SYSTEM
COMPUTERIZED TOMOGRAPHY
DAYS LIVING RADIOISOTOPES
DIAGNOSTIC TECHNIQUES
DISEASES
ELECTRON CAPTURE RADIOISOTOPES
HEART
HEAVY NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MUSCLES
NUCLEI
ODD-EVEN NUCLEI
ORGANS
RADIOISOTOPES
SECONDS LIVING RADIOISOTOPES
THALLIUM ISOTOPES
TOMOGRAPHY
550601* - Medicine- Unsealed Radionuclides in Diagnostics