The Missing Test in Your Annual Check-Up

Think about what happens at a routine annual health check-up. The lab draws your blood. Over the next few days, you get back a neat report: cholesterol levels, kidney function, liver enzymes, thyroid hormones, blood sugar. If something is off, your doctor catches it early — often years before you would have noticed any symptoms.

This system works remarkably well. Millions of people manage diabetes, thyroid disorders, and kidney disease because a routine blood test flagged the problem long before it became dangerous.

Now here's the uncomfortable question: where is the heart on that list?

Cardiovascular disease is the number one cause of death worldwide responsible for roughly 18.6 million deaths every year. That's nearly one in three of all deaths on the planet. More than all cancers combined. And yet in the standard annual check-up, there is no direct test for the heart.

18.6 million

lives lost every year to cardiovascular disease worldwide — and 80% of premature heart attacks are considered preventable with early detection.

Source: WHO Cardiovascular Disease Factsheet, 2023; Roth et al., The Lancet, 2020

"But what about the ECG?"

You might be thinking: don't doctors sometimes include an electrocardiogram (ECG) in a check-up? They do, sometimes. But here's what most people don't realize — the standard resting ECG is not a very good screening tool for the most common form of heart disease.

The ECG works by sticking electrodes on your skin and measuring tiny electrical voltages produced by your heartbeat. The problem is that those electrical signals have to travel through layers of skin, fat, muscle, bone, and lung tissue before reaching the electrodes. Every tissue layer distorts the signal differently. It's a bit like trying to listen to someone whispering in the next room — through a thick, uneven wall. You might catch the general rhythm, but the fine details get lost.

The consequence is sobering. Studies have shown that a resting ECG has a sensitivity of only about 50% for detecting myocardial ischaemia — the reduced blood flow that signals coronary artery disease. In practical terms, that means the ECG can look perfectly normal in someone whose heart is already in trouble.

A landmark study in the New England Journal of Medicine found that initial ECGs appeared normal in up to 30% of patients who were later confirmed to have had a heart attack.

Pope et al., New England Journal of Medicine, 2000

With machine-learning powered analysis, MCG continues to expand its role in modern cardiovascular care.

This isn't a failure of the doctors using the ECG — it's a fundamental limitation of the physics. Electrical signals get distorted by the body's tissues because different tissues conduct electricity very differently (muscle, fat, bone, and lung all have vastly different electrical conductivities). The ECG sees a blurred, attenuated shadow of what's actually happening inside the heart.

The silent killer

Coronary artery disease — the gradual buildup of cholesterol plaque inside the arteries that supply blood to the heart muscle — develops silently over decades. There is usually no pain, no breathlessness, no warning whatsoever. In many cases, the very first symptom is a heart attack. Or worse, sudden cardiac death.

This is not a rare edge case. The majority of people who suffer a heart attack had no prior diagnosis of heart disease. They felt fine. Their last check-up was normal. The plaque was building up quietly, year after year, completely undetected.

The current gold-standard diagnostic for coronary artery disease is coronary angiography — a procedure where a catheter is inserted into an artery (usually in the wrist or groin), threaded up to the heart, and contrast dye is injected to visualise the coronary arteries under X-ray. It's effective, but it's also invasive, expensive, involves ionizing radiation and nephrotoxic contrast agents, and is only performed after disease is already suspected. It is a confirmation tool, not a screening tool.