Medically reviewed by Dr. Khalil Iqbal, M.B.B.S., F.C.P.S. (Cardiology), Consultant Cardiologist, Al-Nasar Lab & Diagnostic Centre. Updated August 2026.
Quick answer: An ECG records the heart’s electrical activity and takes minutes. An Echo uses ultrasound to show heart structure and pumping strength. An ETT records an ECG while you walk on a treadmill to reveal problems that only appear under strain. CT coronary angiography shows the coronary arteries themselves.
Book a cardiac test: call 0300 0341944 or request an appointment here.
What is the difference between ECG, Echo, ETT and angiography?
These four heart related tests are often confused because they all examine the heart, but each answers a different question. An ECG looks at electrical rhythm. An Echo looks at structure and function. An ETT looks at how the heart behaves under stress. Angiography looks directly at the arteries supplying the heart.
| Test | What it shows | Time needed | Preparation |
|---|---|---|---|
| ECG (Electrocardiogram) | Heart rhythm, rate, evidence of a past or current heart attack | 5 to 10 minutes | None |
| Echo (Echocardiography) | Chamber size, valve function, pumping strength (ejection fraction) | 20 to 40 minutes | None |
| ETT (Exercise Tolerance Test) | Whether the heart is starved of blood during exertion | 30 to 45 minutes | Light meal, comfortable shoes, some medicines paused on advice |
| CT Coronary Angiography | Narrowing or blockage inside the coronary arteries | 20 to 30 minutes | Fasting, contrast injection, heart rate control |
What does an ECG test show?
An ECG places small electrodes on your chest, arms and legs to record the electrical signal that makes your heart beat. It is quick, painless and involves no radiation. It can reveal an irregular rhythm, an unusually fast or slow heart rate, signs of a heart attack happening now or in the past, and strain on the heart muscle.
Its limitation is that it captures only the moments you are attached to the machine. A normal ECG at rest does not rule out a problem that appears when you exert yourself, which is exactly why the ETT exists.
What does an Echo test show?
Echocardiography is an ultrasound scan of the heart. A probe on the chest sends sound waves that produce a moving image of the heart in real time. It shows the size of each chamber, how well the valves open and close, how strongly the muscle contracts, and whether there is fluid around the heart.
The key number most patients hear about is the ejection fraction, the percentage of blood pumped out of the main chamber with each beat. It is the standard measure of pumping strength and is central to diagnosing and monitoring heart failure. Read more about echocardiography at Al-Nasar Lab.
What is an ETT and who needs one?
An ETT, also called a stress test or treadmill test, records your ECG and blood pressure while you walk on a treadmill that gradually gets faster and steeper. The purpose is to make the heart work hard enough to reveal a reduced blood supply that stays hidden at rest.
It is commonly ordered for chest pain or breathlessness that occurs on exertion, to assess exercise capacity after a cardiac event, and as part of pre operative or fitness assessment. You should wear comfortable shoes and clothing, eat only lightly beforehand, and ask your doctor whether to pause any regular heart medicines. See our ETT test page for details.
What is CT coronary angiography?
CT coronary angiography uses a CT scanner with a contrast dye injection to produce detailed images of the coronary arteries themselves. Unlike conventional angiography, no catheter is threaded into the arteries, so it is non invasive and requires no hospital admission.
It is particularly useful when symptoms are unclear or when an ETT result is borderline, because it shows the arteries directly rather than inferring blockage from indirect signs. Because the heart is constantly moving, image quality depends heavily on scanner speed, which is why higher slice count scanners matter for this study. Read more about CT coronary angiography in Lahore.
Which heart test do you actually need?
- Palpitations or an irregular pulse: ECG first
- Breathlessness, swollen ankles, suspected heart failure: Echo
- Chest pain or breathlessness that comes on with exertion: ETT
- Known risk factors with unclear or borderline results: CT coronary angiography
- Pre operative or general cardiac assessment: often ECG plus Echo together
These are general patterns, not a substitute for a cardiologist’s judgement. Your doctor selects the test based on your symptoms, risk factors and examination.
Are these tests safe?
ECG and Echo involve no radiation and carry essentially no risk. An ETT is performed with medical supervision and monitoring throughout, and is stopped immediately if you develop symptoms. CT coronary angiography involves a radiation dose and an iodine based contrast injection, so tell the team about kidney problems, asthma, diabetes medication or any previous contrast reaction.
Cardiac testing at Al-Nasar Lab
Al-Nasar Lab & Diagnostic Centre provides ECG, echocardiography, ETT and CT coronary angiography at its main Johar Town campus, our full service site where cardiac imaging, CT, MRI and nuclear medicine are available together. That means if one test leads to another, it can usually be completed without travelling elsewhere.
Find your nearest branch or call 0300 0341944 to book.
Frequently Asked Questions
How much do heart tests cost in Pakistan?
Pricing differs by test and by centre, with ECG the lowest cost and CT coronary angiography the highest. For current Al-Nasar Lab pricing, call 0300 0341944 or see the individual test pages linked above.
Do I need to fast before an ECG or Echo?
No. Neither test requires fasting. Fasting is generally required only for CT coronary angiography, and a light meal is advised before an ETT.
Can an ECG detect a blocked artery?
Not directly. An ECG can show signs that the heart muscle is or has been starved of blood, but it cannot see the arteries. Angiography is the test that shows blockages themselves.
What is a normal ejection fraction?
A normal ejection fraction is generally around 55 to 70 percent. Lower values may indicate reduced pumping function, but the number must be interpreted alongside your symptoms and history.
Is an ETT dangerous if I have heart disease?
The test is performed under continuous medical supervision precisely because it puts the heart under controlled stress. Your doctor decides whether it is appropriate, and it is stopped at once if concerning symptoms or ECG changes appear.
This article is for general information and is not a substitute for medical advice. Please discuss your symptoms and results with a qualified doctor.
