ECG Interpretation Essentials for Nurses

Oct 5, 2024

ECG Interpretation for Nurses

Overview

  • ECG interpretation is essential for nurses.
  • Focus on understanding different heart rhythms: normal sinus rhythm, sinus bradycardia, sinus tachycardia, atrial fibrillation, atrial flutter, ventricular tachycardia, ventricular fibrillation, asystole, PEA, and AV heart blocks.

Normal Sinus Rhythm

  • Originates from the SA node (sinoatrial node).
  • Characteristics:
    • P waves: present, upright, < 0.12 seconds.
    • Atrial rhythm: regular, 60-100 bpm.
    • PR interval: 0.12-0.20 seconds.
    • QRS complex: one per P wave, < 0.12 seconds.
    • QT interval: 0.36-0.44 seconds.
    • T wave: normal, round, upright.
    • ST segment: flat.
  • Monitor to prevent deviations (e.g., atrial fibrillation, heart blocks).

Sinus Bradycardia

  • Rate: < 60 bpm, regular.
  • Causes: "SLOW RATES"
    • S: Sick sinus syndrome
    • L: Low thyroid hormone
    • O: Older adult
    • W: Weak/damaged heart muscles
    • R: Raised intracranial pressure
    • A: Athletes
    • T: Toxicity (e.g., beta blockers, calcium channel blockers, digoxin)
    • E: Electrolyte imbalances
    • S: Stimulation of vagal response
  • Treatment:
    • Assess symptoms (hypotension, SOB, chest pain).
    • Treatment involves addressing the cause, medication (AID: Atropine, Dopamine, Epinephrine), and possible pacemaking.

Sinus Tachycardia

  • Rate: > 100 bpm, regular.
  • Causes: "TACHY HEARTS"
    • T: Temperature elevation
    • A: Aerobics (exercise)
    • C: Cardiac disease
    • H: Hyperthyroidism
    • Y: Yelp (pain)
    • H: Hemorrhage/hypovolemic shock
    • E: Emotional stress/fear
    • A: Anemia
    • R: Respiratory conditions
    • T: Therapeutic (medications)
    • S: Stimulants (nicotine, alcohol, cocaine, caffeine, amphetamines)
  • Treatment: Identify and treat cause, medication (beta blockers, calcium channel blockers), possible antipyretics or pain medication.

Atrial Fibrillation (AFib)

  • Characteristics:
    • Irregular fibrillatory waves (F waves), no distinct P waves.
    • Ventricular rhythm: irregular, can be normal or fast (> 100 bpm).
  • Causes: Heart surgery, valve problems, CAD, lung conditions.
  • Treatment:
    • Stable: Monitor and control rate.
    • Unstable: Synchronized cardioversion, anticoagulation, possible TEE.
    • Medications: Diltiazem, Adenosine, Amiodarone, anticoagulants (Warfarin).
    • Procedures: Ablation.

Atrial Flutter

  • Characteristics:
    • Flutter waves with sawtooth appearance.
    • Ventricular rate: can be regular or irregular.
  • Causes: Heart valve problems, MI, overactive thyroid.
  • Treatment: Control rate with medications, prevent blood clots, possible synchronized cardioversion or ablation.

Ventricular Tachycardia (VTach)

  • Characteristics:
    • Wide, bizarre QRS complexes (> 0.12 seconds).
    • Ventricular rate: 100-250 bpm, regular.
  • Causes: Electrolyte imbalances, MI, medication toxicity, heart disease.
  • Treatment:
    • Stable: Antiarrhythmics (Amiodarone), possible cardioversion.
    • Unstable: Synchronized cardioversion.
    • No pulse: CPR, defibrillation, epinephrine.

Ventricular Fibrillation (VFib)

  • Characteristics:
    • Chaotic, rapid rhythm, no organized ECG waveform.
  • Causes: Severe heart disease, electrolyte imbalances, hypoxia, drug overdose.
  • Treatment: Immediate CPR, defibrillation, epinephrine, ACLS protocol.

Asystole

  • Characteristics: Flat line, no ECG waveform.
  • Causes: Untreated lethal rhythms, severe cardiac events.
  • Treatment: Confirm asystole, CPR, epinephrine, investigate causes (H's and T's).

Pulseless Electrical Activity (PEA)

  • ECG shows organized rhythm but no pulse.
  • Causes: Hypoxia, hypovolemia, electrolyte imbalance, thrombosis.
  • Treatment: CPR, epinephrine, identify underlying cause.

AV Heart Blocks

First Degree

  • Characteristics: Prolonged PR interval (> 0.20 seconds).
  • Causes: MI, medications.
  • Treatment: Monitor, adjust medications.

Second Degree Type 1 (Mobitz I/Wenckebach)

  • Characteristics: Progressive PR lengthening, dropped QRS.
  • Causes: MI, medications, increased vagal tone.
  • Treatment: Monitor, atropine if symptomatic.

Second Degree Type 2 (Mobitz II)

  • Characteristics: Constant PR interval, dropped QRS complexes.
  • Causes: MI, structural damage.
  • Treatment: Temporary pacing, possibly permanent pacemaker.

Third Degree (Complete Heart Block)

  • Characteristics: Independent atrial and ventricular rhythms.
  • Causes: Severe heart disease, congenital.
  • Treatment: Atropine, pacing, permanent pacemaker.