Systematic Approach (6 Steps):

Rate – Regular: 300 Rule (300 ÷ # large boxes between R waves).
Irregular: 6-Second Strip Method (R waves in 6 seconds × 10).

Rhythm – Regular or irregular?

P Wave – Present before every QRS?

PR Interval – Normal: 0.12–0.20 sec (3–5 small boxes).

If the R is far from P → first-degree block.

QRS Complex –

Narrow (<0.12 sec): supraventricular origin (normal pathway).

Wide (>0.12 sec): ventricular origin or bundle branch block.

Mnemonic: Narrow = Normal, Wide = Worry.

Interpretation – Identify rhythm and appropriate intervention.

Key Rhythms & Interventions:

Normal Sinus Rhythm (NSR): 60–100 bpm, consistent P before QRS. → Routine monitoring.

Atrial Fibrillation: Irregularly irregular, no P waves, wavy baseline. → Stroke prevention with anticoagulants (warfarin or DOACs).

Ventricular Tachycardia (V-tack): Fast + wide complexes. → Check for pulse first!

Pulse + stable → Amiodarone.

Pulse + unstable → Cardioversion.

No pulse → Defibrillate.

Ventricular Fibrillation (V-fib): Total chaos. → Defibrillate immediately.

Mnemonic: “V-fib = Defib.”

Asystole (Flatline): No electrical activity. → CPR + Epinephrine, confirm in 2nd lead.

Rule: Confirm before you code.

Pulseless Electrical Activity (PEA): Electrical activity without a pulse. → CPR + Epinephrine, find reversible H’s and T’s.

Third-Degree (Complete) Heart Block: P’s and QRS march independently. → Immediate pacing.

Mnemonic: “If P’s and Q’s don’t agree → 3rd-degree.”

Shockable vs Non-Shockable:

Shockable: V-fib, Pulseless V-tack.

Non-Shockable: Asystole, PEA.
💡 Nursing Pearl: “If there’s chaos, shock. If it’s flat, compress.”

NCLEX Tip:
Always check for a pulse before paddles — treat the patient, not the monitor.

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