An EKG is needed whenever you have symptoms that suggest a heart problem, before certain surgeries, when starting medications that affect heart rhythm, or as part of screening for competitive athletes. It is not recommended as a routine test for healthy adults at low risk of heart disease. The U.S. Preventive Services Task Force specifically recommends against EKG screening in adults with no symptoms and low cardiovascular risk, giving it a grade D (not recommended). So while EKGs are one of the most common tests in medicine, the situations that genuinely call for one are more specific than many people assume.
Symptoms That Call for an EKG
The clearest reason to get an EKG is when you’re experiencing symptoms that could point to a heart problem. These include chest pain, shortness of breath, dizziness, fainting, unusual fatigue, a fluttering or skipping sensation in your heartbeat, a racing pulse, or bluish discoloration in your hands and feet. Any of these warrants an EKG because the test can quickly reveal whether the heart’s electrical activity is normal, whether there’s an irregular rhythm, or whether part of the heart muscle isn’t getting enough blood.
Chest pain is the most urgent trigger. If you’re in an emergency room with chest pain, an EKG is typically performed within minutes. It’s the fastest way to check for a heart attack in progress. That said, a standard 12-lead EKG catches only about 28 to 33 percent of acute heart attacks at the time of admission. Its specificity is excellent (around 97 percent, meaning a positive result is almost always real), but a normal EKG doesn’t completely rule out a heart attack. That’s why doctors often repeat the test, run blood work, or order additional testing if suspicion remains high.
Before Surgery
Not every surgery requires a preoperative EKG, but several situations make one necessary. Current guidelines recommend a preoperative EKG for anyone whose medical history or physical exam suggests heart disease. Beyond that, men between roughly 40 and 45 years old, women over 55, patients taking medications that can damage the heart, and those at risk for significant electrolyte imbalances are all candidates for preoperative testing.
The level of surgical risk also matters. If you’re scheduled for an intermediate-risk or vascular surgery, your doctor will assess your functional capacity (how much physical activity you can handle without symptoms) alongside your clinical risk factors to decide whether an EKG is warranted. For low-risk procedures like minor outpatient surgery, a preoperative EKG is rarely needed in otherwise healthy people.
Certain conditions make a preoperative EKG especially important: a heart attack within the past six weeks, unstable chest pain, heart failure, or a history of dangerous heart rhythms. These are considered major risk factors, and they typically trigger not just an EKG but a broader cardiac workup before any non-cardiac surgery can proceed.
Screening for Athletes
Young competitive athletes face a small but real risk of sudden cardiac death from undetected heart conditions like hypertrophic cardiomyopathy, a condition where the heart muscle thickens abnormally. Many sports medicine organizations and governing bodies recommend that pre-participation screening include a 12-lead EKG alongside a standard history and physical exam.
Interpreting athlete EKGs requires specialized criteria because regular intense training changes the heart’s electrical patterns. The International Criteria for EKG interpretation in athletes distinguishes between normal training-related changes (which are common and harmless) and genuinely abnormal findings. For example, certain patterns in the electrical signal that look concerning in the general population are considered normal in athletes under 16. Other findings, like specific patterns of wave inversion in certain leads or abnormal electrical depression, are red flags that call for further testing such as an echocardiogram or cardiac MRI.
Medication Monitoring
Several classes of medication can interfere with the heart’s electrical timing, specifically by prolonging something called the QT interval. When this interval stretches too long, the risk of a dangerous heart rhythm increases. Doctors typically order a baseline EKG before starting these medications and follow-up EKGs to monitor for changes.
The drug classes most commonly associated with this risk include:
- Antipsychotics such as haloperidol, ziprasidone, quetiapine, and olanzapine
- Heart rhythm medications such as amiodarone, sotalol, and flecainide
- Certain antibiotics, particularly macrolides and fluoroquinolones
- Some antidepressants, including older tricyclics and citalopram
- Other medications including ondansetron (a common anti-nausea drug) and certain migraine medications
If you’re prescribed any of these, your risk is higher if you’re older, female, or have low levels of potassium or magnesium. Your doctor may order periodic EKGs throughout treatment, not just at the start.
Monitoring Chronic Heart Conditions
People with known heart conditions often need periodic EKGs to track changes over time. Atrial fibrillation, the most common heart rhythm disorder, is one key example. Screening for atrial fibrillation has been studied mostly in people over 65, using everything from single EKG recordings to continuous monitors and consumer wearable devices. Detecting it matters because untreated atrial fibrillation significantly raises the risk of stroke.
That said, guidelines remain cautious about broad screening programs. While finding atrial fibrillation early sounds appealing, it hasn’t been conclusively shown that screening everyone over a certain age improves stroke rates or survival enough to justify the cost. For now, EKG screening for atrial fibrillation is most clearly warranted when you have symptoms (palpitations, unexplained fatigue, lightheadedness) or when your doctor identifies risk factors like high blood pressure, diabetes, or a history of heart failure.
When an EKG Isn’t Enough
An EKG is a snapshot of your heart’s electrical activity over a few seconds. It’s fast, painless, and inexpensive, but it has real limitations. It tells your doctor about rhythm problems, electrical conduction issues, and signs of current or past heart attacks. What it can’t do is show how well your heart pumps, whether your valves are working properly, or what the heart muscle looks like structurally.
That’s where other tests come in. An echocardiogram uses ultrasound to create a moving image of the heart, making it better for diagnosing structural problems, evaluating the extent of heart disease, or assessing how effectively the heart is pumping blood. A stress test measures how the heart performs under physical exertion, which can reveal problems that don’t show up at rest. In practice, an abnormal EKG often serves as the gateway to these more detailed tests. If your EKG shows something unusual, your doctor will likely follow up with an echocardiogram or stress test to clarify what’s going on.
When You Probably Don’t Need One
If you’re a healthy adult with no symptoms, no heart disease risk factors, and no upcoming surgery or new medication that affects heart rhythm, a routine EKG provides little benefit. The U.S. Preventive Services Task Force found insufficient evidence that screening EKGs in low-risk people prevent heart attacks or improve outcomes, and the risk of false positives (abnormal-looking results that lead to unnecessary follow-up testing, anxiety, or even invasive procedures) outweighs the potential benefit.
This doesn’t mean you should ignore heart health. Regular blood pressure checks, cholesterol testing, and lifestyle factors like exercise and diet remain the most effective screening tools for cardiovascular risk in people without symptoms. An EKG becomes valuable when there’s a specific clinical reason to look at your heart’s electrical activity, not as a general wellness check.