Is EKG a Good Annual Screening Test for Heart Disease?

An electrocardiogram (EKG) measures your heart's electrical activity and may detect a heart attack.  

I was not worried about my heart on the day of my annual physical. At 63, I was a non-smoker with a BMI of 20 who regularly exercised and took no daily medicines. I had an EKG, which showed no abnormalities. The day after, I had a heart attack in an unlikely scenario.

Of note: Healthcare providers perform EKGs to diagnose heart attacks or arrhythmias in people with chest pain, heart palpitations, and heavy sweating. Generally, EKGs do not predict future heart attacks, but certain findings on an EKG may indicate an increased risk of heart attack.

Read on to learn how an EKG and other tests may detect heart attacks, including silent ones. 

Personal Story

I awoke that morning with an odd, persistent ache in my left arm and vague jaw pain. I noticed a tightness in my chest—not exactly painful, but uncomfortable and strange. 

My daughter told me to get dressed and took me to the emergency room. My chest discomfort worsened on the short drive to the hospital. I began to feel queasy and developed a dry, throat-clearing cough.

Within minutes of arriving at the emergency room, I was wheeled into the hospital's cath lab, where a cardiac team prepared to perform an emergency angioplasty. During an angioplasty, a cardiologist uses a balloon to stretch open blocked arteries and allow blood to flow to the heart.

Later, I learned that some plaque had ruptured in my left anterior descending artery (LAD), causing a blockage. A stent opened the blood vessel and restored blood flow.

My recovery protocol was pretty standard: A few days in the hospital, regular visits to a cardiologist, and a regimen of medicines to prevent another heart attack.

Of course, the looming question: Why did a "low cardiac risk" person like me have such a major cardiac event? Healthcare providers said my heart attack was unusual, and they could not pinpoint the cause with 100% certainty.

Heart Attack Signs

Signs and symptoms of a heart attack may include:

• Anxiety
• Chest pain
• Cough
• Feeling dizzy or lightheaded
• Heart palpitations
• Heavy sweating
• Nausea
• Passing out
• Shortness of breath
• Vomiting

Heart attacks may present differently in certain people, such as older adults, those with diabetes, and women. For example, heart attacks may cause little to no chest pain, unexplained fatigue, and weakness.

Call 911 immediately if you or someone near you develops signs and symptoms of a heart attack. An ambulance often gets you to the hospital quickly, and emergency medical technicians can treat you as soon as they arrive.

Silent Heart Attack

Sometimes, heart attacks do not cause symptoms, also known as silent heart attacks. Typically, healthcare providers do not diagnose silent heart attacks until the person develops an arrhythmia (irregular heartbeat), another heart attack, or heart failure.

People who are likelier to have a silent heart attack than others include people with diabetes, which may affect how they feel pain, or people assigned female at birth.

What Is an EKG?

An EKG is a test that measures your heart’s electrical activity. Every time your heart beats, an electrical signal goes through it. The electrical signal tells your heart’s chambers to squeeze in rhythm, helping pump blood throughout your body. An EKG displays those electrical signals as wavy lines on a monitor.

A healthcare provider examines those lines and looks for abnormalities, such as:

• The electrical signals are weak
• Your heart beats too slowly or quickly
• Your heart chambers are enlarged
• Your heart rhythm is irregular

Healthcare providers often use EKGs to detect heart conditions like arrhythmias and heart attacks.

Can an EKG Detect a Heart Attack?

An EKG is one of the most common tests healthcare providers use to detect a heart attack. People with heart attack symptoms often receive an EKG immediately upon arriving at an emergency room.

Healthcare providers can use EKGs to detect previous heart attacks and assess the risk of future ones.

Previous Heart Attack

An EKG may show permanent changes in your heart’s electrical activity following a heart attack. In other words, an EKG can show if you previously had a heart attack but did not know it. Sometimes, healthcare providers notice signs of a silent heart attack days to months after it occurs.

Predict a Future Heart Attack

A study published in 2019 found that an EKG is likelier to detect abnormalities in people with a high risk of heart disease than others. The researchers noted that EKGs may help detect and treat heart disease earlier than average, which may help prevent heart attacks.

Other Tests That Can Help Detect a Heart Attack

A healthcare provider may order other tests to confirm a heart attack diagnosis or determine damage in your heart.

Other tests that may detect a heart attack include:

• Blood tests: Cardio biomarkers like creatine kinase-MB (CKMB), myoglobin, and troponin are proteins that a healthcare provider can measure in your blood. Those proteins indicate damage to your heart muscle.
• Coronary angiography, or angiogram: A healthcare provider will administer a dye through your blood vessels. An angiogram shows how well the dye flows, which may detect blockages. An angiogram may not detect smooth blockages in the blood vessels. Women are more likely to have smooth blockages than men.
• Heart imaging tests: A healthcare provider may use a CT scan or an echocardiogram (ultrasound) to produce images of the heart and ensure it works correctly.
• Nuclear heart scan: This test shows damage in your heart due to a lack of blood flow. Nuclear heart scans use radioactive material that may cause harm to pregnant or breastfeeding people. 
• Stress test: This test shows how well your heart works when exercising. Sometimes, healthcare providers use medicines that get your heart working hard if you cannot exercise. A stress test can measure the damage caused by a heart attack or if you have coronary artery disease (CAD). CAD is a common cause of heart attacks if fatty substances build up in the vessels that supply blood to your heart.

A Quick Review

An EKG may detect a heart attack by measuring your heart's electrical activity. The test helps identify silent heart attacks days to months after they happen and may assess heart attack risk in some people.

Call 911 right away if you or someone near you has heart attack signs and symptoms, like chest pain, heart palpitations, and heavy sweating. A healthcare provider will likely administer an EKG immediately upon arrival at an emergency room.