🔍 ECG Arrhythmia - Sample Images + Identification Guide (Cath Lab Nursing)

 Below is a clean, nursing-friendly explanation of ECG arrhythmia samples, identification, and interpretation, along with sample ECG images for educational use in Cath Lab settings.

1. Normal ECG for Reference

Key Features

• HR: 60–100 bpm
• P wave before each QRS
• PR interval: 0.12–0.20 sec
• QRS < 0.12 sec
• Regular rhythm

2. Common Arrhythmias With Sample Images:

A. Atrial Fibrillation (AF / A-Fib)

Identification

• No visible P waves
• Irregularly irregular R–R intervals
• Baseline: fibrillatory waves
• Ventricular rate may be fast, normal, or slow

Cath Lab Nursing Importance

• Risk of thromboembolic stroke
• Used for cardioversion, Watchman device, ablation

B. Atrial Flutter

Identification

• “Saw-tooth” flutter waves (F waves)
• Atrial rate ~250–350 bpm
• Ventricular conduction often 2:1 or 4:1

Cath Lab Use

• Ablation at CTI (cavo-tricuspid isthmus)
• Anticoagulation management

C. Ventricular Tachycardia (VT)

Identification

• Wide QRS > 0.12 sec
• Regular fast rhythm (120–250 bpm)
• No P waves or AV dissociation

Cath Lab Relevance

• Emergency: shocks, antiarrhythmics
• For EP study, ablation candidates
• May deteriorate into VF

D. Ventricular Fibrillation (VF)

Identification

• Chaotic, irregular waveform
• No identifiable QRS, P, or T waves
• NOT compatible with life

Cath Lab

• Immediate defibrillation
• Often seen during PCI complications

E. Supraventricular Tachycardia (SVT)

Identification

• Narrow QRS
• Regular rate 150–250 bpm
• P waves often hidden

Cath Lab

• Adenosine use
• AVNRT/AVRT ablation

F. Complete Heart Block (3rd-Degree AV Block)

Identification

• P–P interval regular
• R–R interval regular
• No relationship between P and QRS
• Escape rhythm (ventricular)

Cath Lab

• Temporary pacing
• Permanent pacemaker implantation

3. Quick Nursing Checklist (Cath Lab ECG Interpretation)

Before Procedure

✔ Confirm electrode placement

✔ Remove chest hair if needed

✔ Check lead II and V5 especially

During Procedure

✔ Watch for ischemic changes (ST depression/elevation)

✔ Watch for arrhythmias during contrast injection

✔ Communicate immediately to cardiologist

After Procedure

✔ Document start time, arrhythmias, interventions

✔ Monitor for reperfusion arrhythmias

✔ Check pacing thresholds if pacemaker used

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4. References (Legitimate & Evidence-Based)

American Heart Association (AHA) — ECG Basics
European Society of Cardiology (ESC) Guidelines 2023
Heart Rhythm Society (HRS) — Arrhythmia Standards
Cleveland Clinic: Arrhythmia Interpretation
Mayo Clinic: ECG & Cardiac Monitoring Resources
StatPearls (NIH): ECG Rhythms & Arrhythmias