ECG: What It Is, How It's Used, and What Your Results Mean

When your doctor says you need an ECG, a test that records the electrical signals in your heart to check for irregular rhythms or damage. Also known as an electrocardiogram, it's one of the fastest, safest, and most common ways to see how your heart is really working. You don’t need to prepare. No needles. No fasting. Just lie down while small stickers are placed on your chest, arms, and legs. In less than 10 minutes, your heart’s rhythm is captured on paper or screen.

Doctors use ECGs to spot things like arrhythmia, abnormal heartbeats that can be too fast, too slow, or irregular, signs of a past heart attack, or even hidden heart muscle thickening. It’s not just for people with symptoms. If you’re over 40, have high blood pressure, or take heart meds, your doctor might order one just to check baseline function. And if you’ve felt dizzy, short of breath, or had chest tightness, an ECG can tell you if your heart is the cause—or if it’s something else.

What you see on the ECG trace isn’t just squiggles. The spikes and dips represent different parts of your heartbeat. A tall spike means your heart’s upper chambers fired. A flat line after that? That’s the pause before the lower chambers contract. A weird shape or missing spike? That could mean blocked arteries, a faulty valve, or an electrolyte imbalance. It doesn’t always mean something serious—but it does mean you need to talk to your doctor about it. Many people get abnormal results and never have another issue. Others find out they have a condition they didn’t know about, like atrial fibrillation, and start treatment before it gets worse.

ECGs are also used to monitor how well medications work. If you’re on drugs for heart rhythm problems, your doctor will check your ECG before and after to see if the dose is right. They’re also used in hospitals during stress tests, after surgery, or even during childbirth to watch the baby’s heart rate. And while an ECG won’t show blocked arteries directly, it can hint at them—especially if you’ve had chest pain or a history of heart disease.

Some conditions you’ll see covered in the posts below are directly tied to ECG findings. For example, if you’re on dipyridamole, a drug used to prevent blood clots and sometimes used in stress tests, your ECG is watched closely during the test. Or if you’ve been prescribed MAOIs, a type of antidepressant that can affect heart rhythm, your doctor may check your ECG before starting you on it. Even something as simple as a decongestant, like pseudoephedrine in cold meds, can cause your heart to race—and that change shows up on an ECG.

You’ll find posts here that explain how ECGs relate to real-world medication risks, how to interpret results without panic, and when a follow-up test like an echocardiogram or Holter monitor is needed. Whether you’ve just had one done, you’re worried about your heart, or you’re trying to understand why your doctor ordered it, the articles below give you clear, no-fluff answers. No jargon. Just what you need to know to make sense of your heart’s story.