ECG INTERPRETATION IN ACLS

 

Electrocardiogram (ECG) interpretation is a critical skill in Advanced Cardiovascular Life Support (ACLS). The ability to recognize life-threatening rhythms helps guide timely and appropriate interventions during cardiac emergencies.

🚨 Why It’s Important:
✅ ECG interpretation directs ACLS interventions (shock vs. no shock, pacing vs. medications).
✅ Helps differentiate between stable and unstable rhythms.
✅ Identifies reversible causes of cardiac arrest (Hs & Ts).

 

1️⃣ BASIC ECG COMPONENTS

✔️ P Wave: Atrial depolarization (contraction of the atria).
✔️ QRS Complex: Ventricular depolarization (contraction of the ventricles).
✔️ T Wave: Ventricular repolarization (recovery phase).
✔️ PR Interval: Time for electrical impulse to travel from the atria to the ventricles.
✔️ QT Interval: Total time for ventricular depolarization and repolarization.

🚑 Key Takeaway: Understanding these ECG components helps distinguish normal vs. abnormal rhythms!

 

2️⃣ KEY ACLS RHYTHMS & MANAGEMENT

🔹 1. Normal Sinus Rhythm (NSR)

✔️ HR: 60-100 bpm
✔️ Rhythm: Regular
✔️ P Wave: Present before each QRS
✔️ PR Interval: Normal (0.12-0.20 sec)
✔️ QRS Complex: Narrow (<0.12 sec)

✅ Management: No intervention required.

🔹 2. Sinus Bradycardia (HR < 60 bpm)

✔️ Rhythm: Regular
✔️ P Wave: Normal
✔️ PR Interval: Normal
✔️ QRS Complex: Normal

✅ Management (If Symptomatic)

  • Atropine 0.5 mg IV every 3-5 min (Max: 3 mg).
  • If Atropine is ineffective → Transcutaneous Pacing (TCP).
  • Consider Epinephrine (2-10 mcg/min IV infusion) or Dopamine (2-20 mcg/kg/min).

🚑 Key Takeaway: Treat only if symptomatic (hypotension, altered LOC, shock).

🔹 3. Sinus Tachycardia (HR > 100 bpm, Regular Rhythm)

✔️ P Wave: Normal
✔️ PR Interval: Normal
✔️ QRS Complex: Normal

✅ Management:

  • Identify & Treat the Underlying Cause (e.g., hypoxia, fever, pain, dehydration).
  • Avoid reflexive antiarrhythmic treatment unless unstable.

🚑 Key Takeaway: Sinus tachycardia is usually compensatory—fix the cause, don’t just lower the HR!

🔹 4. Atrial Fibrillation (AF) – “Irregularly Irregular”

✔️ Rhythm: Irregularly irregular
✔️ P Waves: Absent (fibrillatory waves)
✔️ QRS Complex: Normal (but irregular R-R intervals)

✅ Management:

  • Stable: Rate control with Beta-blockers (Metoprolol) or Calcium Channel Blockers (Diltiazem).
  • Unstable (Hypotension, altered LOC, HF): Immediate synchronized cardioversion (120-200 J).

🚑 Key Takeaway: AF increases stroke risk—assess for anticoagulation!

🔹 5. Atrial Flutter (Sawtooth Pattern)

✔️ Rhythm: Regular or irregular
✔️ P Waves: Sawtooth flutter waves (F-waves)
✔️ QRS Complex: Normal

✅ Management:

  • Stable: Rate control with Beta-blockers or Calcium Channel Blockers.
  • Unstable: Synchronized Cardioversion (50-100 J).

🚑 Key Takeaway: Atrial flutter can rapidly degenerate into AF—manage similarly!

🔹 6. Ventricular Tachycardia (VT) – “Wide QRS”

✔️ HR: >100 bpm
✔️ QRS Complex: Wide (>0.12 sec)
✔️ Types: Monomorphic (uniform QRS) or Polymorphic (varied QRS, e.g., Torsades de Pointes).

✅ Management:
✔️ Pulseless VT → Treat as Cardiac Arrest (CPR + Defibrillation).
✔️ Stable VT (with pulse) → Antiarrhythmic therapy (Amiodarone 150 mg IV over 10 min).
✔️ Unstable VT (Hypotension, shock) → Immediate Synchronized Cardioversion (100 J).

🚑 Key Takeaway: Always check for a pulse—Pulseless VT requires immediate defibrillation!

🔹 7. Ventricular Fibrillation (VF) – “Chaotic Electrical Activity”

✔️ Chaotic, disorganized ventricular rhythm.
✔️ No identifiable P waves, QRS complexes, or T waves.
✔️ Patient is pulseless and unresponsive.

✅ Management:
✔️ Immediate High-Quality CPR + Defibrillation (120-200 J biphasic).
✔️ Epinephrine 1 mg IV every 3-5 min.
✔️ Amiodarone 300 mg IV (if refractory VF after 3 shocks).

🚑 Key Takeaway: VF is ALWAYS a cardiac arrest rhythm—defibrillate ASAP!

🔹 8. Asystole (Flatline – No Electrical Activity)

✔️ No P waves, QRS complexes, or organized activity.
✔️ Patient is pulseless and unresponsive.

✅ Management (Non-Shockable Rhythm)

  • High-Quality CPR.
  • Epinephrine 1 mg IV every 3-5 min.
  • Identify & treat reversible causes (Hs & Ts).

🚑 Key Takeaway: Asystole = Poor survival rates. Focus on CPR & identifying reversible causes!

🔹 9. Pulseless Electrical Activity (PEA) – “ECG Without a Pulse”

✔️ Organized ECG activity (normal or abnormal rhythm) but NO pulse.

✅ Management (Non-Shockable Rhythm)

  • High-Quality CPR + Epinephrine 1 mg IV every 3-5 min.
  • Identify & Treat Reversible Causes (Hs & Ts).

🚑 Key Takeaway: Electrical activity ≠ perfusion. Always check for a pulse!

 

3️⃣ ECG INTERPRETATION IN ACLS ALGORITHMS


AlgorithmECG Role
Cardiac ArrestDetermines shockable (VF/pVT) vs. non-shockable (PEA/Asystole) rhythms.
BradycardiaIdentifies HR <60 bpm & guides pacing/medication use.
TachycardiaDifferentiates between narrow vs. wide QRS & stable vs. unstable tachycardia.

🚑 Key Takeaway: ECG interpretation directs ACLS interventions—treatment is rhythm-specific!

 

4️⃣ SUMMARY: MASTERING ACLS ECG INTERPRETATION

✔️ Recognize shockable (VF/pVT) vs. non-shockable (PEA/Asystole) rhythms.
✔️ Identify life-threatening bradycardia & tachycardia.
✔️ Use ECG to determine need for cardioversion, defibrillation, or pacing.
✔️ Always correlate ECG findings with the patient’s clinical status!

🚑 Takeaway: ACLS ECG interpretation is a critical skill—quick recognition leads to life-saving interventions!