Advanced 12 Lead ECG Interpretation
Information Covered:
- Lead systems and heart surfaces
- ECG rhythm analysis
- Value
- Limitations
- Heart surfaces
- Inferior
- Left lateral
- Precordial
- Acute signs of ischemia, injury and necrosispossible early identification of patients with acute myocardial infarction for intervention (thrombolysis PTCA)
- the role of out-of-hospital 12-lead ECG is not universally available but is appropriate in most EMS settings with proper medical oversight
- Advantages/ disadvantages
- ST segment elevation
- height, depth and contour
- ST (acute changes)
- anterior wall -- significant ST elevation in V1- V4 may indicate anterior involvement
- inferior wall -- significant ST elevation in II, III and aVF may indicate inferior involvement
- ST segment depression in eight or more leads
- ST segment elevation in aVR and V1
- Q waves
- depth, duration and significance
- greater than 5 mm, greater than .04 seconds
- may indicate necrosis
- may indicate extensive transient ischemia
- depth, duration and significance
- ECG rhythm analysis
- Cardiac arrhythmias
- Approach to analysis
- P wave
- configuration
- duration
- arial rate and rhythm
- P-R (P-Q) interval
- QRS complex
- configuration
- duration
- ventricular rate and rhythm
- S-T segment
- contour
- elevation
- depression
- Q-T interval
- duration
- implication of prolongation
- Relationship of P waves to QRS complexes
- consistent
- progressive prolongation
- no relationship
- T waves
- U waves
- P wave
- Interpretation of the ECG
- Origin of complex
- Rate
- Rhythm
- Clinical significance
- Arrhythmia originating in the sinus node
- Sinus bradycardia
- Sinus tachycardia
- Sinus arrhythmia
- Sinus arrest
- Arrhythmias originating in the atria
- Premature atrial complex
- Atrial (ectopic) tachycardia
- Re-entrant tachycardia
- Multifocal atrial tachycardia
- Atrial flutter
- Atrial fibrillation
- Atrial flutter or atrial fibrillation with junctional rhythm
- Atrial flutter or atrial fibrillation with pre-excitation syndromes
- Arrhythmias originating within the AV junction
- First degree AV block
- Second degree AV block
- Type I (Wenkebach)
- Type II/ infranodal (Classical)
- Complete AV block (third degree block)
- Arrhythmias sustained or originating in the AV junction
- AV nodal re-entrant tachycardia
- AV reciprocating tachycardia
- narrow
- wide
- Junctional escape rhythm
- Premature junctional complex
- Accelerated junctional rhythm
- Junctional tachycardia
- Arrhythmias originating in the ventricles
- Idioventricular rhythm
- Accelerated idioventricular rhythm
- Premature ventricular complex (ventricular ectopic)
- R on T phenomenon
- paired/ couplets
- multiformed
- frequent uniform
- "Rule of bigeminy" pertaining to precipitating ventricular arrhythmias
- Ventricular tachycardia
- Monomorphic and polymorphic
- Approach to analysis
- Ventricular fibrillation
- Ventricular standstill
- Asystole
- Abnormalities originating within the bundle branch system
- Incomplete or complete
- Right bundle branch block
- Left bundle branch block
- Differentiation of wide QRS complex tachycardia
- Potential causes
- supraventricular tachycardia with bundle branch block
- accessory pathways
- Differentiation
- physical evaluation
- Cannon “A” waves
- vary intensity of first heart tone
- beat to beat changes in blood pressure
- ECG differences
- aberration as a result of premature atrial complex
- identify PAC in previous ST segment or T wave
- sudden change in rate with bundle branch aberration
- concealed retrograde conduction
- right bundle branch refractoriness - may be time dependent
- compare with previous ECG, when available
- RBBB aberration - V1 – positive
- biphasic lead I with a broad terminal S-wave
- triphasic QRS in V4
- LBBB aberration - V1 – negative
- monophasic notched lead I
- slurred, notched or RSr’ in lead V4, V5, or V6
- Concordant precordial pattern
- totally negative precordial pattern is diagnostic of ventricular tachycarida
- totally positive precordial pattern is suggestive of ventricular tachycardia
- Preexisting BBB prior to onset of tachycardia (by history)
- aberration as a result of premature atrial complex
- Other considerations
- When in doubt:
- cardioversion when hemodynamic state is compromised or changing as evidenced
- When in doubt:
- physical evaluation
- Potential causes
- never use verapamil
- if hemodynamic state is stable - consider lidocaine
- Pitfalls
- age is not a differential
- slower rates may present with stable hemodynamic
- preexisting BBB prior to onset of the tachycardia
- Regularity
- monomorphic V-tach and SVT are usually very regular and SVT frequently is faster
- polymorphic V-tach is irregular
- Pulseless electrical activity
- Electrical mechanical dissociation
- Mechanical impairments to pulsations/ cardiac output
- Other possible causes
- Other ECG phenomena
- Accessory pathways
- Preexitation phenomenon
- Aberration versus ectopy
- ECG changes due to electrolyte imbalances
- Hyperkalemia
- Hypokalemia
- ECG changes in hypothermia
Content Creator: Ariel Wai
CAPCE Course Number: 20-EMTP-F3-7203
Total CE Hours: 1
Level: Advanced
EMT-CE uses the NEMSES guidelines as the foundation for every course outline.