Understanding Your ECG Results
You’ve had an ECG. Now you have a piece of paper with wavy lines, numbers, and medical terms. What does it all mean?
While only your doctor can interpret your ECG in the context of your overall health, understanding the basics can help you be a more informed patient.
What Is an ECG?
An electrocardiogram (ECG or EKG) records the electrical activity of your heart. Every heartbeat is triggered by an electrical impulse that travels through the heart muscle, causing it to contract and pump blood.
The ECG machine captures this electrical activity and prints it as a graph with waves and patterns.
The Basic Waves of an ECG
| Wave | What It Represents |
|---|---|
| P Wave | Electrical impulse starting in the upper chambers (atria) |
| QRS Complex | Electrical impulse spreading through the lower chambers (ventricles) |
| T Wave | Recovery phase of the ventricles |
What Your Doctor Looks For
1. Heart Rate
| Finding | Meaning |
|---|---|
| Normal (60-100 beats per minute) | Heart is beating at normal rate |
| Tachycardia (>100 bpm) | Heart beating too fast |
| Bradycardia (<60 bpm) | Heart beating too slow (can be normal in athletes) |
2. Heart Rhythm
| Finding | Meaning |
|---|---|
| Normal sinus rhythm | Regular rhythm, normal pattern |
| Atrial fibrillation | Irregular, chaotic rhythm from upper chambers |
| Premature beats | Extra beats that occur early |
| Heart block | Delay or blockage of electrical impulses |
3. Wave Shapes and Intervals
| Finding | What It May Indicate |
|---|---|
| Tall/widened QRS | Enlarged heart chambers |
| ST elevation | Possible heart attack (acute) |
| ST depression | Possible lack of blood flow to heart |
| T wave inversion | Possible heart muscle damage or lack of blood flow |
| Prolonged QT interval | Risk of dangerous arrhythmias |
| Left ventricular hypertrophy | Thickened heart muscle from high blood pressure |
Common ECG Findings and What They Mean
| Finding | Meaning | Next Step |
|---|---|---|
| Normal ECG | No electrical abnormalities detected | Routine follow-up |
| Sinus tachycardia | Fast but normal rhythm | Evaluate cause (fever, anxiety, thyroid, etc.) |
| Sinus bradycardia | Slow but normal rhythm | May be normal in athletes; evaluate if symptomatic |
| Premature atrial contractions (PACs) | Early beats from upper chambers | Usually benign; monitor |
| Premature ventricular contractions (PVCs) | Early beats from lower chambers | Usually benign if occasional; evaluate if frequent |
| Atrial fibrillation | Irregular, often fast rhythm | Needs treatment (blood thinners, rate control) |
| Left ventricular hypertrophy | Thickened heart muscle | Manage blood pressure |
| Old myocardial infarction | Evidence of past heart attack | Cardiac evaluation, risk factor management |
| ST-T wave changes | Possible lack of blood flow | Further cardiac evaluation |
What an ECG Does NOT Show
An ECG is valuable but has limitations. It does NOT show:
Blockages in arteries – For that, you may need stress test or angiogram
Heart valve problems – Those require echocardiogram
Heart failure – May need echocardiogram for diagnosis
Future heart attack risk – ECG alone can’t predict
Cholesterol levels – Those need blood tests
When Is an ECG Ordered?
| Situation | Reason |
|---|---|
| Routine screening (age 40+) | Establish baseline; detect silent issues |
| Chest pain | Check for heart attack or lack of blood flow |
| Palpitations | Detect arrhythmias |
| Shortness of breath | Check heart involvement |
| Pre-employment (certain jobs) | Safety for physically demanding or safety-sensitive positions |
| Before surgery | Ensure heart can handle procedure |
| Monitoring known heart conditions | Track changes over time |
| High blood pressure | Check for heart effects |
| Diabetes | Annual screening for heart involvement |
Types of ECG
| Type | What It Does | When Used |
|---|---|---|
| Resting ECG | Standard test lying down | Routine screening, baseline |
| Stress ECG (Exercise Stress Test) | ECG during treadmill exercise | When symptoms occur with activity; check for blockages |
| Holter Monitor | Portable ECG worn 24-48 hours | Catch intermittent arrhythmias |
| Event Monitor | Worn longer; patient activates when symptoms occur | Rare symptoms |
Preparing for an ECG
No special preparation needed
Avoid applying lotion or oil to chest before test
Wear a two-piece outfit (easy access to chest)
Avoid coffee or smoking for 2 hours before (caffeine affects heart rate)
Tell your doctor about medications
The Procedure: What to Expect
You’ll lie down on an examination table
The technician cleans small areas on your chest, arms, and legs
Small stickers (electrodes) are attached to these areas
Wires connect the electrodes to the ECG machine
You’ll lie still for about 1-2 minutes while the machine records
The entire procedure takes 5-10 minutes
You can resume normal activities immediately
Is it painful? No. The electrodes just stick to your skin. Removal may cause slight discomfort but no pain.
Good News: PhilHealth Coverage
Under the Konsulta (YAKAP) program, ECG is covered for members who are:
40 years old and above
Younger with cardiovascular risk factors (hypertension, diabetes, family history)
The Takeaway
An ECG is a simple, quick, and painless test that provides vital information about your heart. While understanding the basics is helpful, always discuss your results with your doctor, who can interpret them in the context of your overall health.
Health Screen Laboratory and Diagnostic Center, we offer ECG services with digital equipment and fast results interpreted by experienced physicians.