ECG Tutorial: Rhythm Recognition Review – the systematic approach Rhythm – the hardest part!...
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Transcript of ECG Tutorial: Rhythm Recognition Review – the systematic approach Rhythm – the hardest part!...
ECG Tutorial: Rhythm Recognition
• Review – the systematic approach
• Rhythm – the hardest part!– Again – be systematic– Mind your p’s & q’s & follow the rules!
• The Approach – Tachy –vs- Brady
• Examples
• Quiz
ECG Tutorial: Rhythm Recognition
• My systematic approach:– Rate
– Rhythm– Axis– Intervals (PR, QRS, QTc)– Blocks / Hypertrophy / Enlargement– Segments (PR, ST)– Waves (Q-waves, T-waves)– Ectopy– Compare to old ECG
Rhythm Recognition
• Golden rule: mind your ‘p’s (& ‘q’s’)• Step I – Is it fast or slow?
– Tachycardia = >100
– Bradycardia = < 60
• Step II – Is it sinus rhythm or not?– 2 questions (rules):
• ‘p’ with every QRS complex?
• Upright ‘p’ in I, II & aVF?
– Yes to BOTH = sinus origin (nice job!)
Tachycardias: The ‘Down & Dirty’
• Common• Need to recognize the ‘bad boys’!
– ACLS, etc…
• 2 questions– Is the QRS narrow (<=0.12 second or 2.5 small boxes)
or wide? • “Wide complex Tachycardia”-vs-“Narrow Complex
Tachycardia”
– Is the rhythm regular or irregular?
Sinus Arrythmia-Typically a normal finding – esp. in younger, fit individuals
-Due to changes in autonomic tone during inspiration
Tachycardias: DDx(Rule of 3’s!)
• Narrow Complex & Regular:– Sinus Tachycardia– Atrial Flutter– Other supraventricular Tachycardia (SVT)
• AVNRT (A-V nodal reentrant tachycardias)• Atrial reciprocating tachycardia (from pre-
excitation, ex: WPW)• Ectopic atrial tachycardia• Other uncommon causes
Sinus Tachycardia…but why?
• Physiologic (#1)– Response to exercise
– Stress, anger, etc.. (‘fight or flight’)
• Other causes:– Fever– Hyperthyroidism– Effective volume depletion,
hypotension– Sepsis, Shock– Anemia– PE– CHF– Drugs (stimulants)– Drug withdrawal (ETOH)– Pheochromocytoma
Suspect A-flutter:•Narrow complex tachycardia
•‘F’ (flutter waves) = rate of 300 (“sawtooth”)
•Ventricular rate = 150 bpm
Other Narrow Complex Tachycardiaa - AVNRT
NSR Premature Atrial Complex (PAC)
-Regular, Narrow-complex tachycardia w/rate: 120-220
-‘p’ buried or after QRS (usually) & inverted (retrograde) in leads I, II & aVF
-Most common non-fib/flutter SVT
Ectopic Atrial Tachycardia
• Regular narrow complex tachycardia
• Originates outside of the AV node
• Constant ‘p’ wave morphology
• Constant P-R intervals
• Use the “rule of sinus rhythm” & mind your ‘p’s’
Tachycardias: DDx
• Narrow Complex & IR-regular:– Atrial Fibrillation (“irregularly irregular”)– Atrial Flutter with variable A-V block– MAT (Multifocal Atrial Tachycardia)– Other Supraventricular tachycardias with
variable AV block
Atrial Fibrillation
• The most common arrythmia in older patients• ECG:
– Absent ‘p’-waves
– “fibrillatory waves” – vary in appearance
– Irregularly irregular R-R intervals
– Typically narrow complex QRS (unless aberrant conduction)
• Bundle Branch Blocks / other blocks
• Re-entry (WPW)
– Rate > 100 = “rapid ventricular response” (RVR)
MAT – Multifocal Atrial Tachycardia
• Narrow complex, irregularly irregular• You’re thinking A-fib, but…
– You see clearly conducted ‘p’-waves– ‘p’-waves are not all the same
• You see 3 different ‘p’-wave morphologies • “Multifocal”• Varying P-P & R-R intervals
– Associated with lung disease (COPD), theophylline, hypertension, etc…
Narrow Complex Tachycardias - Review
• Regular:– Sinus Tachycardia– Atrial Flutter– Other “SVT”
• AVNRT (A-V nodal reentrant tachycardias)
• Atrial reciprocating tachycardia (from pre-excitation, ex: WPW)
• Ectopic atrial tachycardia
• Others (uncommon)
• IR-regular:– Atrial Fibrillation
(“irregularly irregular”)– Atrial Flutter with
variable A-V block
– MAT (Multifocal Atrial Tachycardia)
– Others
Wide Complex Tachycardias (WCT)
• A Big Deal…may require emergent treatment!• A limited Differential Diagnosis
– Ventricular Tachycardia (VT)– NOT Ventricular Tachycardia:
• SVT w/aberrant conduction (Aberrancy)• SVT w/pre-excitation (ie-WPW)
– What is “aberrancy”?
• Assume Ventricular Tachycardia until proven otherwise– Esp. in a patient over 40 years old
Wide Complex Tachycardia
• Rate > 100 bpm
• QRS duration > 0.12 seconds
• Again– Regular –vs- Irregular
Wide Complex Tachycardia
• Regular– Ventricular Tachycardia– A REGULAR SVT w/Aberrant conduction
• Sinus tachycardia
• A-flutter
• AVNRT
• Atrial Tachycardia
Wide Complex Tachycardia
• IR-Regular– Ventricular Fibrillation– An IR-Regular SVT w/Aberrant conduction
• Atrial fibrillation
• Aflutter with variable AV block
• MAT
– Special Case: WPW & A-fib
V-Tach –vs- SVT w/Aberrancy
• Assume V-T until proven otherwise– Treatment for SVT can kill a patient in VT– Treatment for VT usually won’t kill a patient in
SVT– Criteria – Brugada, others (beyond our scope)
• AV dissociation, increased age, CV risk factors = VT
• Fusion / Dresler beats = VT
Bradyarrythmias
• I. Pauses– #1 cause of a pause is a non-conducted PAC
• II. Early, weird-looking beats: PVC –vs- PAC– PVC
• Wide complex• Compensatory pause
– PAC• Narrow, no compensatory pause
Bradyarrythmias
• I. Problem is sinus or at the AV node– Sinus:
• Sinus bradycardia• Sinus Arrest
– AV Node:• 1st Degree AV block• 2nd Degree
– Mobitz I (Wenkebach)– Mobitz II
• 3rd Degree AVB
2nd degree Mobitz I (Wenkebach)
-lengthening PR interval…then…dropped beat
-“Group Beating” = Wenkeback until proven otherwise
-Block at AV node
-Normal in young patients (high vagal tone)
-Think Meds (B-blockers, CCBs)
2nd degree Mobitz II-Constant PR interval…then dropped beat
-Block always BELOW AV node (more serious)
-Never normal
-Likely needs a pacemaker
3rd degree (complete) heart block
-A-V dissociation is present
-‘p’ waves “march” out
-Atrial rate > ventricular rate**
-“Escape” rhythm
-Clinical settings
-Likely needs a pacemaker