You might have heard of an ECG test or Electrocardiogram. It is a common and useful test that helps your doctor understand how your heart is working. Think of it as taking an electrical picture of your heart activity. This guide will walk you through the complete ECG procedure and what you need to know about it. So, let’s get started.
What is an ECG?
Your heart is like a sophisticated pump that uses electrical signals to beat. An ECG machine records these electrical signals as they travel through your heart. It’s a quick, non-invasive and usually painless test. The results are shown as wavy lines on paper or a screen. These waves have specific names and shapes like P waves, QRS complexes, and T waves. Let’s look at what they mean.
What do the waves mean on your ECG?
When you look at an ECG tracing, you will see different bumps and dips that represent specific electrical events in your heart. These are nothing but the waves. It includes:
- P-wave: This little bump shows when the upper chamber of your heart contracts.
- QRS complex: This is usually the tallest and sharpest part of the tracing. It represents the contraction of your lower chamber (the ventricles), which is the main pumping section of your heart.
- T-wave: This bump shows when your ventricle relaxes and resets electrically before the next beat.
When to get an ECG?
Your doctor might suggest you get an ECG if you are experiencing symptoms that could be related to your heart. These might include:
- Pressure and chest pain
- Breathlessness
- Heart palpitations (feeling like your heart is racing, pounding, or skipping beats)
- Unexplained seizures
- Cyanosis (bluish skin)
- Syncope (fainting spells)
- Chronic fatigue or dizziness
- If you have a family history of heart disease
ECGs are also used to diagnose conditions like heart attacks and abnormal heart rhythms and to check the effect of certain medications or medical conditions on your heart.
What preparations are needed for an ECG test?
Getting ready for an ECG is really simple. To help get the clearest recording:
- Remove jewellery and metallic items
- Shave the chest hairs
- Avoid caffeine or cold water before the test
- Wear comfortable clothes
- Avoid applying oil, lotion, or powder on your body
Following these steps helps make sure your test is quick and provides accurate results.
What happens during an ECG test?
The test itself is straightforward. You’ll usually lie down comfortably. A technician will place small, sticky pads called electrodes on specific spots on your chest, arms, and legs. These pads are connected by wires to the ECG machine. The machine then records the electrical signals from your heart for a few moments.
The whole process, from placing the electrodes to getting the recording, typically takes only about 10 minutes. It’s painless, as the electrodes just stick to the skin.
How to estimate your heart rate from an ECG?
Your heart rate is one of the first things checked on an ECG. It’s measured in beats per minute (bpm). Here are a few ways you can estimate it yourself from the ECG paper:
- 300 Method: Look for two consecutive QRS complexes. Count the number of large square boxes between them and divide 300 by that number.
Example: If there is only 1 box, then your heart rate is about 300/1 = 300 bpm.
Example: If there are 4 large boxes, your heart rate is about 300/4 = 75 bpm.
Example: if there are 9 boxes, your heart rate slows down to 33.
- The 1500 method: This is more precise. Count the number of small boxes between two consecutive QRS complexes. Divide 1500 by that number.
- 6-second method: Count the number of QRS complexes for 30 consecutive large boxes. Multiply the output by 10, and that represents the beats per minute.
Example: If there are 15 QRS complexes within 30 large boxes, then your heart rate is 15*10 = 150 bpm.
What else does the doctor look at when reading your ECG?
While you can estimate the rate, your doctors look at many other things to get a full picture.
- Rate: By this, your doctor checks how fast or slow your heart is beating.
- Rhythm: Is the heartbeat regular and steady, or is it irregular? A normal steady rhythm comes from the heart’s natural pacemaker (called the sinus node) and is called sinus rhythm. Irregular rhythms are called arrhythmias.
- Intervals: Doctors measure the time between the different waves (like the time between the start of P waves and the start of QRS complexes). These timings tell them how quickly the electrical signals are moving through different parts of your heart. If these intervals are too long or too short, it can indicate a problem with the electrical conduction system.
- Wave shapes and size: The doctors examine the appearance of each wave (P, QRS, T). Are they the right shape? Are they too big or too small? Changes in the shape of the QRS complex or T wave, or changes in the segment between the QRS and T waves, can be very important signs of issues like a heart attack or lack of blood flow to the heart muscle.
How to check if your ECG report is normal?
You should always have a doctor interpret your ECG report. While you can calculate your heart rate, determining if the entire tracing is normal requires medical expertise.
A doctor will look at all the factors mentioned above – rate, rhythm, intervals and wave shapes – and compare them to what’s considered normal. They also consider your specific symptoms, medical history, and other health factors.
A report might be considered normal if all these measurements and observations fall within the expected ranges and there are no signs of abnormalities. However, even a seemingly small variation might be significant depending on your health.
What is the cost of an ECG?
The cost of an ECG test can vary. You can typically get one done at government hospitals, private clinics, hospitals or diagnostic labs. The price depends on the location, the type of facility, and potentially the specific type of ECG ordered.
Generally, in India, the cost might range from Rs 200 to 500. If you have health insurance or are covered under schemes like Ayushman Bharat Health Card, the cost might be lower or covered.
Remember, the ECG is a valuable tool, but it’s just one piece of information your doctor uses to assess your heart health. Always discuss your ECG results with your healthcare provider.
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