ECG Interpretation for Nursing

Overview

Understanding ECG rhythms is crucial in nursing.
This lecture covers important heart rhythms: Normal Sinus Rhythm, Sinus Bradycardia, Sinus Tachycardia, Atrial Fibrillation, Atrial Flutter, Ventricular Tachycardia, Ventricular Fibrillation, Asystole, Pulseless Electrical Activity (PEA), and Heart Blocks.

Origin: SA Node (sinoatrial node).
Characteristics:
- P waves present before every QRS complex, upright and <0.12 seconds.
- Atrial & Ventricular Rate: 60-100 bpm, regular.
- PR Interval: 0.12-0.20 seconds. (>0.20 suggests a heart block)
- QRS Complex: <0.12 seconds.
- T waves: Normal, round, upright after each QRS.
- QT Interval: 0.36-0.44 seconds
- ST Segment: Flat (isoelectric).
Management: Monitor patient, ensure no deviation from rhythm.

Origin: SA Node; slow rhythm (<60 bpm).
Characteristics:
- Same as normal sinus but slower rate.
- PR Interval: 0.12-0.20 seconds.
- QT Interval may be longer at slower rates.
Causes: SLOW RATES mnemonic
- Sick Sinus Syndrome
- Low thyroid hormone
- Older adult
- Weak heart muscles
- Raised intracranial pressure
- Athlete
- Toxicity (beta blockers, calcium channel blockers, digoxin)
- Electrolyte imbalances
- Stimulation of vagal response.
Management:
- Symptomatic: Emergency response, medications (atropine, dopamine, epinephrine), temporary or permanent pacemaker.
- Asymptomatic: Monitor patient.

Origin: SA Node; fast rhythm (>100 bpm).
Characteristics:
- Same as normal sinus but faster rate.
- PR Interval: 0.12-0.20 seconds.
- QT Interval may be shorter at faster rates.
Causes: TACHY HEARTS mnemonic
- T: Temperature elevation (fever)
- A: Aerobics (exercise)
- C: Cardiac disease (e.g., congestive heart failure)
- H: Hyperthyroidism
- Y: Yelp (pain)
- H: Hemorrhage or hypovolemic shock
- E: Emotional stress/fear
- A: Anemia
- R: Respiratory conditions
- T: Therapeutic medications (atropine, albuterol, etc.)
- S: Stimulants (nicotine, caffeine, alcohol, etc.)
Management:
- Identify and treat underlying cause.
- May need cardiac tests (stress test, echocardiogram, Holter monitor), labs, and medications (beta blockers, calcium channel blockers).
- Medications: Beta blockers, calcium channel blockers.

Description: Atria not beating properly, blood pooling causing risk of clot formation.
Characteristics:
- No P waves; F waves (irregular, fine or coarse).
- Atrial rate: >400 bpm (irregular).
- QRS Complex: <0.12 seconds.
- Ventricular rhythm: Irregular; rate >100 bpm (uncontrolled), <100 bpm (controlled).
- Cannot measure PR or QT interval.
Causes: Post-heart surgery, heart valve problems, CAD, MI, pericarditis, lung conditions, sleep apnea.
Management:
- Stable (Controlled): Monitor and manage rate.
- Unstable (Uncontrolled): Synchronized cardioversion, pharmacological cardioversion, TEE for blood clot check, long-term anticoagulation, Beta blockers, calcium channel blockers, ablation.

Description: Abnormal electrical signal causing rapid atrial contraction.
Characteristics:
- No P waves; Flutter waves (sawtooth appearance).
- Atrial rate: ~300 bpm, regular.
- QRS Complex: <0.12 seconds; rhythm can be regular or irregular.
- Cannot measure PR or QT interval.
Causes: Heart valve problems, MI, heart surgery, hyperthyroidism.
Management:
- Medications: Calcium channel blockers (Diltiazem), Beta blockers (Propranolol), Digoxin, antiarrhythmics (Amiodarone).
- Prevent blood clots: Anticoagulants (Warfarin).
- Synchronized cardioversion, ablation procedure for persistent symptoms.

Description: Fast, abnormal rhythm originating from ventricles.
Characteristics:
- Hallmark: Wide, bizarre QRS complexes (>0.12 seconds).
- Ventricular rate: 100-250 bpm, regular.
- No identifiable P waves or PR intervals.
Types: Monomorphic (same throughout), Polymorphic including Torsades de Pointes (varied appearance).
Causes: Electrolyte imbalances, MI, medication toxicity, cardiac disease.
Management:
- Stable: Antiarrhythmic medication (Amiodarone), synchronized cardioversion.
- Unstable: Synchronized cardioversion, CPR, defibrillation, epinephrine, amiodarone, lidocaine, airway support.
- Polymorphic V-tach (Torsades): Magnesium sulfate, avoid QT-prolonging medications.
- Long-term: Implanted cardioverter-defibrillator (ICD).

Description: Chaotic, disorganized rhythm originating from ventricles.
Characteristics:
- No P waves, QRS complexes, or T waves.
- Appearance: Coarse or fine fibrillatory waves.
Causes: Severe heart disease, MI, electrolyte imbalances, hypoxia, drug overdose.
Management: Immediate CPR, defibrillation, epinephrine, amiodarone, lidocaine, airway support, implanted ICD post-resuscitation.

Description: No cardiac activity or contraction; flat line on ECG.
Characteristics:
- No P waves, QRS complexes, or T waves.
- Flat line on ECG.
Causes: Progression from lethal rhythms (V-tach/V-fib), hypothermia, hypoxia, toxins, thrombosis, etc.
Management: Confirm asystole, immediate CPR, epinephrine, airway support, check for reversible causes (H's and T's).

Description: Organized electrical activity on ECG, but no pulse or breathing in patient.
Causes: Hypoxia, hypovolemia, electrolyte imbalances, thrombosis, trauma, cardiac disease.
Management: Immediate CPR, epinephrine, airway support, identify and treat underlying cause.

Description: Progressive lengthening of PR interval until a QRS complex is dropped.
Causes: MI, increased vagal tone, medications.
Management: Monitor, adjust medications, treat underlying cause, atropine or temporary pacing if symptomatic.

Description: No coordination between P waves and QRS complexes, independent rhythms.
Causes: Congenital, severe heart disease, MI, heart valve issues, medication toxicity.
Management: Emergency response, atropine, temporary pacing, permanent pacemaker.