4 Cardiovascular Diagnostic Tests
Compare what electrocardiograms, stress tests, echocardiography, and cardiac catheterization assess, how patients prepare, and how findings and risks are interpreted.
What each test can show
Cardiovascular tests provide complementary information. An records electrical activity, evaluates the heart under increased workload, echocardiography images heart structure and function, and can directly assess coronary arteries and intracardiac pressures.
Results are interpreted alongside symptoms, medical history, and other tests. No single result should be interpreted in isolation.
Electrocardiograms
A standard 12-lead ECG records the heart’s electrical activity over a brief period. It can help identify rate and rhythm abnormalities, conduction changes, and patterns that may be associated with ischemia or heart-muscle injury.
Usually, no special preparation is needed. Wear clothing that allows access to the chest, avoid lotions or oils that may interfere with electrode contact, and tell the clinician about medications and symptoms. Electrodes are placed on the skin while the patient lies still. The test is painless and does not send electricity into the body. There is usually no post-test restriction, although mild skin irritation can occur when electrodes are removed.
A tracing may show a regular sinus rhythm, an irregular rhythm such as atrial fibrillation, or changes in rate, conduction, or ST-T segments. Abnormal findings can have several causes and generally require clinical interpretation. A normal brief ECG does not rule out an intermittent rhythm problem or every form of heart disease; longer monitoring or additional tests may be recommended.
A stress test evaluates how the heart responds when its workload increases. During an exercise stress test, the patient walks on a treadmill or pedals a stationary bicycle while the team monitors ECG, heart rate, blood pressure, symptoms, and exercise tolerance. If exercise is not appropriate or possible, medication may be used to create a stress response. Stress imaging may add echocardiography or nuclear imaging.
Follow the testing facility’s specific preparation instructions. Patients are commonly asked to wear comfortable clothes and walking shoes and may be told to avoid food, smoking, or caffeine for a specified period. Some medicines can affect results, but patients should not stop or change medications unless the care team directs them to. Report relevant conditions, medications, and symptoms before testing.
Report chest discomfort, unusual shortness of breath, dizziness, or other symptoms promptly. The team monitors the patient and can stop the test if needed. After exercise, the patient rests while heart rate and blood pressure are checked. Most patients can resume usual activity afterward unless instructed otherwise.
The team evaluates exercise capacity, symptoms, rhythm, blood-pressure response, and ECG or imaging changes. Exercise-related ST-segment changes or new wall-motion abnormalities may suggest reduced blood supply, but results are not a diagnosis by themselves. is monitored and generally safe; possible problems include chest pain, abnormal rhythm, dizziness, or, rarely, a serious cardiac event.
Echocardiography
An uses ultrasound to create images of the heart. A transthoracic (TTE) uses a probe on the chest and is the usual noninvasive study. A uses a probe passed into the esophagus to obtain images from closer to the heart. Stress echocardiography images the heart before and after exercise or medication-induced stress.
TTE usually requires no special preparation. For TEE, follow instructions about fasting and medications. Sedation is commonly used, so arrange a ride home and avoid driving until permitted by the care team. After TEE, wait to eat or drink until throat numbness has worn off and staff indicate that swallowing is safe; this helps prevent aspiration or choking. A sore throat or temporary hoarseness may occur. TTE generally has no recovery restrictions.
The report may describe chamber size, pumping function, including , heart-muscle motion, valves, and blood flow. Findings may include reduced pumping function, , , or an abnormal wall-motion pattern. Findings must be interpreted in context; a single measurement does not determine a diagnosis or treatment plan.
and angiography
In , a thin catheter is guided through a blood vessel—often at the wrist or groin—to the heart. uses contrast dye and X-ray imaging to show coronary arteries. Catheterization can also measure pressures or oxygen levels and may be combined with treatment, such as angioplasty and stenting.
Follow the facility’s instructions about fasting and medications. Tell the team about allergies or prior reactions to contrast, kidney disease, diabetes, pregnancy or possible pregnancy, and all prescription, over-the-counter, and supplement use. The team will specify which medicines to take or hold. Arrange transportation home, especially if sedation is used.
After the procedure, the patient is observed while heart rate, blood pressure, and the access site are checked. Follow instructions about keeping the access limb still, activity limits, wound care, fluids, and medications; these vary by access site and whether treatment was performed. A small bruise may occur. Report bleeding, increasing swelling, drainage, or worsening pain at the access site. Seek urgent help for uncontrolled bleeding, rapidly enlarging swelling, chest pain, shortness of breath, faintness, or a cold, numb, or discolored limb.
Angiography may show narrowed or blocked coronary arteries, and pressure measurements can help assess heart function. Possible complications include bleeding or bruising, contrast reaction, kidney injury, infection, abnormal rhythm, blood-vessel or heart injury, heart attack, or stroke. Serious complications are uncommon, but warning signs require prompt assessment.
Interpreting results and following instructions
Preparation and recovery instructions depend on the test and the patient, so follow the care team’s directions and report concerning symptoms promptly. A medication that may affect a stress-test result should not be skipped or changed independently; follow the testing team’s instructions. Similarly, a normal brief ECG cannot rule out every rhythm problem when symptoms such as palpitations continue, and longer rhythm monitoring or further evaluation may be needed.
Each test answers different questions: ECG records electrical activity, evaluates the heart under increased workload, echocardiography images heart structure and function, and catheterization can visualize coronary arteries and measure pressures. Findings need to be considered with symptoms, medical history, and other test results.