Can you tell me how precise is a nuclear stress ecg at detecting narrowing of the coronary arteries?

Nuclear stress test: I assume you are referring to a nuclear myocardial perfusion stress test where images are acquired and not an EKG treadmill stress without imaging. Patients with normal stress myocardial perfusion SPECT studies have a <1% rate of having a future cardiac event (death or acute myocardial infarction) .

Yes: When done correctly, this study is good. A positive nuclear stress study indicates significant occlusion of the coronary arteries, and an increased risk for acute heart attack. Such patients will benefit from aggressive treatment such as medications, life style changes, stent placement or surgery. A negative study indicates no significant risk for a heart attack. Discuss findings with your Doctor.

Dr Werner agreed

Usually accurate: Nuclear stress test using exercise (tread mill or drug induced tachycardia) as well as resting phases for comparison. Test detects ischemic or infarcted heart muscle which can be correlated with coronary artery supplying that portion of cardiac muscle.Test is considered usually quite accurate.

Dr Khondker agreed

Not very precise.: Generally a coronary artery needs to be 70% blocked (narrowed) to be detected by a nuclear stress test. Most people with coronary symptoms will be detected. But a large percent of sudden heart attacks occur from plaque rupture. A person with a 20% narrowing can become 100% blocked suddenly due to plaque rupture. Also stress tests can be falsely negative (normal) despite significant blockage.