🩻 Purpose of ECG

An ECG helps:

• Detect irregular heartbeats (arrhythmias)
• Diagnose heart attacks
• Find blockages or damage in the heart

📈 Waves of the ECG and What They Mean

Let’s break down each part of the ECG in simple terms:

1. ✅ P Wave

• Shows: Atrial depolarization (beginning of atrial contraction).
• Means the SA Node is working.
• If missing or irregular, it could be arrhythmia (irregular heartbeat).

💡 Example: If the P wave is absent, the “starter” of the heart isn’t working well.

2. ✅ PR Segment

• Shows: Atria have finished contracting and the signal is moving to the AV node.
• Lasts 0.12–0.20 seconds.
• If it takes longer, it might be a first-degree heart block (signal delay).

3. ✅ QRS Complex

• Shows: Ventricular depolarization (ventricles are contracting).
• Also includes atrial repolarization (atria resetting after contraction).
• If abnormal, it may mean:
  • Bundle branch block
  • Ventricular problems
  • Fast abnormal rhythms (tachycardia)

💡 Real-life example: Like two strong pumps (ventricles) pushing blood forcefully out to the lungs and body.

4. ✅ ST Segment

• Shows: Ventricles have finished contracting.
• If depressed: possible ischemia (lack of oxygen to heart).
• If elevated: possible heart attack (myocardial infarction).
• Normally lasts about 0.08 seconds.

💡 Think of this as the “cool down” time for the heart muscles.

5. ✅ T Wave

• Shows: Ventricular repolarization (ventricles are getting ready for the next beat).
• Abnormal T waves can indicate:
  • Electrolyte imbalances (e.g., too much or too little potassium)
  • Early sign of heart attack

💡 If the T wave looks “hyper-acute,” it may mean the heart attack is just starting.

6. ✅ QT Interval

• This is the total time the ventricles take to contract and relax.
• Measured from start of QRS to end of T wave.
• Normal duration: about 0.40 seconds.
• A longer QT interval can mean:
  • Risk of sudden death due to abnormal rhythms.