Testing for heart disease usually starts with simple, low-risk screenings and moves toward more detailed imaging or invasive procedures only when earlier results raise concerns. The specific tests your doctor orders depend on your symptoms, risk factors, and family history. Here’s what each major test involves, what it can and can’t detect, and what to expect.
Blood Tests: The Starting Point
Blood work is often the first step because it can reveal risk factors and, in some cases, active heart damage. The two most common panels are a lipid panel and cardiac biomarkers.
A lipid panel measures cholesterol and triglycerides in your blood. You’ll typically need to fast for 8 to 12 hours beforehand, drinking only plain water. During that fasting window, you should also avoid chewing gum, smoking, and exercise, since all of these can skew results. Let your provider know about any vitamins, supplements, or medications you take, as some may need to be paused.
If a heart attack or acute heart damage is suspected, providers test for troponin, a protein released when heart muscle cells are injured. Troponin is the primary biomarker used to detect a heart attack. Levels can rise for up to 12 hours after the event and remain elevated for up to two weeks, which gives doctors a wide detection window. A separate blood marker called NT-proBNP helps assess strain on the heart from heart failure. It doesn’t diagnose heart failure on its own, but elevated levels signal the heart is working harder than it should.
Electrocardiogram (ECG or EKG)
An ECG records your heart’s electrical activity through sensors placed on your chest, arms, and legs. A resting ECG takes just a few minutes while you lie still. It can detect signs of a previous heart attack, abnormal heart rhythms, and structural changes like thickening of the heart’s main pumping chamber.
An exercise ECG (often called a stress test) records the same electrical signals while you walk on a treadmill at increasing speed and incline. The idea is that some problems only show up when the heart is under demand. A large analysis of over 24,000 patients found that exercise ECG has a sensitivity of 68% and a specificity of 77% for detecting coronary artery disease. In plain terms, it catches about two-thirds of cases and correctly rules it out about three-quarters of the time. That’s useful but not perfect, which is why abnormal results usually lead to more advanced imaging.
Stress Testing With Imaging
When a basic treadmill test isn’t enough, or if you can’t exercise, doctors pair the stress test with imaging for a clearer picture. There are two main approaches.
Stress echocardiography uses ultrasound to watch how your heart muscle contracts during exertion or after a medication that mimics exercise. Exercise-based stress echo has a sensitivity of 83% and specificity of 84%, a meaningful step up from a plain ECG stress test. The medication-based versions perform similarly, with some drug combinations reaching specificity as high as 95%.
Nuclear perfusion imaging involves injecting a small amount of radioactive tracer into your bloodstream and then scanning your heart to see how well blood flows through the muscle. The standard version (SPECT) has a sensitivity of 82% and specificity of 76%. A newer version called PET offers better image quality, reaching 91% sensitivity and 89% specificity because it corrects for tissue interference that can blur SPECT images.
If you can exercise, most providers prefer exercise-based protocols because they also reveal your fitness level and how your blood pressure responds to effort. Medication-based stress tests are reserved for people with joint problems, severe deconditioning, or other limitations.
Echocardiogram at Rest
A standard echocardiogram, done without any stress component, uses ultrasound to measure heart chamber size, wall thickness, and how well the heart pumps. The key number it produces is your ejection fraction: the percentage of blood the left ventricle pushes out with each beat. A normal ejection fraction is above 55%. Heart failure can be diagnosed even when the ejection fraction looks relatively normal (above 40%) if the heart has trouble relaxing and filling properly, a condition called diastolic dysfunction.
This test is painless, takes 30 to 60 minutes, and involves no radiation. It’s commonly ordered when a doctor hears an abnormal heart sound, suspects valve disease, or wants to evaluate how well the heart is functioning after a cardiac event.
Coronary Calcium Scan
A coronary calcium scan uses a fast CT scanner to detect calcium deposits in the arteries that supply your heart. Calcium buildup is a direct sign of plaque, so this test quantifies how much atherosclerosis has already developed. Results are reported as an Agatston score.
- Score of 0: No calcium detected. This suggests a low chance of heart attack in the coming years.
- Score of 100 to 300: Moderate plaque deposits, associated with a relatively high risk of heart attack or other heart disease within 3 to 5 years.
- Score above 300: More extensive disease and a higher heart attack risk.
The scan takes about 10 minutes and doesn’t require fasting or contrast dye. It’s most useful for people at intermediate risk, where the result can tip a decision about whether to start preventive treatment. If your risk is already clearly high or clearly low, the scan is less likely to change your care plan.
Coronary Angiography
Coronary angiography is the most detailed way to see inside the heart’s arteries, but it’s also invasive. A thin catheter is threaded through a blood vessel in your wrist or groin up to your heart, and contrast dye is injected so the arteries show up on X-ray. This lets doctors see exactly where blockages are and how severe they are.
There is no single percentage of artery narrowing that automatically triggers this procedure. Instead, the decision is based on your symptoms, risk profile, and results from noninvasive tests. Blockages in the 30% to 70% range are considered intermediate and may require additional measurements during the catheterization itself to determine whether blood flow is meaningfully restricted. A sensor on the catheter tip can measure pressure differences across the narrowing, helping the cardiologist decide whether a stent or other intervention would help.
Because it carries small risks (bleeding, allergic reaction to contrast dye, and rarely, damage to blood vessels), angiography is typically reserved for situations where noninvasive testing points to significant disease, or when someone is having an acute event like a heart attack.
Genetic Testing for Inherited Risk
Some forms of heart disease run in families through specific gene mutations. The best-studied example is familial hypercholesterolemia, a genetic condition that causes dangerously high cholesterol from birth. Genetic testing looks at mutations in genes that control how your body clears cholesterol from the blood.
The severity of the mutation matters. Some mutations partially disable cholesterol receptors, while others knock them out entirely. People with complete loss-of-function mutations have the highest cholesterol levels and the earliest onset of coronary artery disease. Carrying a familial hypercholesterolemia mutation increases coronary artery disease risk more than threefold at the same cholesterol level compared to someone without the mutation. This is because the mutation means lifelong exposure to elevated cholesterol, not just a few years of high readings. Even people whose cholesterol is brought below 130 mg/dL with medication still carry higher risk if they have the mutation, which is why genetic testing adds useful information beyond a standard lipid panel.
Genetic testing is most valuable if you have a strong family history of early heart disease or very high cholesterol that doesn’t respond well to typical treatment. If a mutation is found, first-degree relatives can be screened with a simple blood test to catch the condition early.
Wearable Devices and At-Home Monitoring
Consumer wearables like the Apple Watch and Fitbit can now detect irregular heart rhythms, particularly atrial fibrillation. These devices use optical sensors on your wrist to track pulse patterns. To minimize false alarms from movement, the algorithms require at least 30 continuous minutes of irregular rhythm during periods of inactivity before triggering a notification.
In a large study of Fitbit users, the irregular heart rhythm detection had a positive predictive value of 98.2%, meaning when the device flagged an irregularity, it was almost always real atrial fibrillation. For users 65 and older, that number was still strong at 97%. The sensitivity was lower, around 68%, which means the device misses about a third of atrial fibrillation episodes. The Apple Heart Study, which enrolled over 400,000 participants, found that 34% of those who received an irregular rhythm notification had confirmed atrial fibrillation on follow-up monitoring.
These devices are useful for catching intermittent rhythm problems you might not feel, but they don’t replace clinical testing. They can’t detect blockages, valve problems, or heart failure. If your wearable flags something, it’s a prompt to get a proper ECG or longer-term monitor, not a diagnosis in itself.
How Testing Typically Progresses
Heart disease testing follows a logical sequence. It usually starts with a physical exam, blood work, and a resting ECG. If those raise concerns, or if your symptoms and risk factors warrant it, you move to stress testing or imaging. Invasive procedures like angiography come last, reserved for cases where the noninvasive evidence is strong enough to justify the small procedural risks. Not everyone needs every test. A 35-year-old with chest pain and normal blood work may need nothing beyond an ECG, while a 60-year-old with diabetes, high cholesterol, and exertional chest tightness may progress all the way to angiography within a few visits.