ECG vs Echo vs Angiogram: Which Test Really Detects Heart Problems?

Chest pain often raises alarm, but many people take reassurance from a “normal ECG report.” However, as cardiologists warn, an electrocardiogram alone cannot rule out heart disease. Recently, Dr. Chaitanya Challa, MBBS, MD, PDCC, FCCS, a Hyderabad-based cardiologist, explained on Instagram why patients and families should not depend only on an ECG to confirm heart health.

According to Dr. Chaitanya, the human heart works through three major systems — the electrical system, the muscular system, and the blood-flow system. An ECG reflects only the electrical activity. “ECG is like checking the current of your heart,” he said. While it is useful for identifying rhythm disturbances or severe ongoing heart attacks, it does not provide information about the pumping strength or blood supply of the heart.

The muscular function of the heart is assessed through an echocardiogram (2D Echo), which shows the pumping capacity. Meanwhile, the actual blood flow through the coronary arteries can only be accurately identified by an angiogram. “ECG for the current of your heart, Echo for the muscle of your heart, and Angiogram for the blood flow of the heart,” Dr. Chaitanya emphasized.

The doctor explained that in cases where blood flow is severely compromised, ECG and 2D Echo may show changes. However, if the blockage is partially compensated, both tests may appear normal, even though the arteries are significantly narrowed. This is why some patients, despite having normal ECGs during routine check-ups, later suffer sudden heart attacks.

He gave an example often seen in practice: a patient undergoes an ECG that shows no abnormality, yet months later develops a cardiac event. The reason is simple — the test was not designed to reveal hidden blockages unless they were already affecting the heart’s rhythm or muscle function.

Dr. Chaitanya highlighted two major options for imaging blood flow. A CT angiogram, done using a CT machine with contrast dye, is a quick and non-invasive way to check blood flow in individuals who are otherwise healthy but want reassurance. “This can be done once every five years, takes just a few minutes, and tells you about the blood supply of your heart,” he explained.

However, for people experiencing symptoms such as chest pain or breathlessness, a full-fledged coronary angiogram performed in a hospital cath lab is the recommended option. Unlike CT scans, this test directly visualizes blockages and allows doctors to treat them immediately if required. That said, experts caution that angiography is an invasive procedure and not routinely recommended for everyone. It is best reserved for patients with symptoms or those at high risk of coronary artery disease.

The key message is clear: a normal ECG should never be the final word when it comes to heart health. For those with a family history of heart disease, unexplained chest discomfort, or risk factors like diabetes and hypertension, further evaluation with echocardiography and angiography is critical.

Heart disease diagnosis remains a global health priority, as cardiovascular disease is the leading cause of death worldwide and in India, accounting for nearly one-third of all deaths (World Health Organization 2023). This makes awareness of ECG limitations, understanding when to do an angiogram, and knowing the role of an echocardiogram more important than ever.

Relying on ECG alone can give a false sense of security. As Dr. Chaitanya summed it up, understanding the three systems of the heart and using the right test at the right time can save lives.

References:

1. World Health Organization. Cardiovascular Diseases (CVDs). Updated 11 September 2023. https://www.who.int/news-room/fact-sheets/detail/cardiovascular-diseases-(cvds).

(Rh/Eth/ARC/MSM)