ECG - Interpretation ARRYTHMIA THEORY 1 Flashcards
Normal Sinus rhythm
– Intrinsic rate of 60 to 100 beats/minute
– Regular, with minimal variation between R-R intervals
– P wave is present, upright, and precedes each QRS
complex.
- Normal PR interval; 3-5 small squares/ 0.04s - 0.12s
Sinus Bradycardia
SINO ATRIAL (SA Node) Dysrhythmia
– Rate of less than 60 beats/minute
– Rhythm is regular.
– Treatment focuses on the patient’s tolerance to the bradycardia
Sinus Tachycardia
SINO ATRIAL (SA Node) Dysrhythmia
- rate of > 100bpm
- rhythm is regular
- increases the work of the heart
- treatment is related to the underlying cause
HOW TO SPOT SINUS TACHYCARDIA ON AN ECG:
- rhythm is regular with a rate of 100-160bpm
- P WAVE is NORMAL
- PR INTERVAL is NORMAL
- QRS COMPLEX DURATION is NORMAL
- BPM IS FAST
Sinus Arrhythmia
SINO ATRIAL (SA Node) Dysrhythmia
- Slight variation of a sinus rhythm
- bainbridge reflex; a cardiovascular reflex that increases the heart rate in response to increased stretching of the right atrium and/or inferior vena cava.
- Increases SV and Blood pressure
- findings are normal in children and young adults.
How to spot Sinus Arrythmia on an ECG?
Look for variation in the time in between consecutive P waves (P-P interval)
P-P interval:
This signifies the time taken for a full cycle of the heart beating takes to occur. If P-P interval is irregular, Sinus Arrhythmia could be indicated.
Also look for difference in time between each QRS complex, irregular differences indicate sinus arrhythmia.
Sinus Arrest
SINO ATRIAL (SA Node) Dysrhythmia
- SA node fails to initiate an impulse
- SA node then resumes normal functioning
- occasional episodes of sinus arrest are insignificant
- TREATMENT: based on the overall HR and tolerance to sinus arrest; are they symptomatic, displaying red flags etc.
How to spot Sinus Arrest on an ECG?
- look for a missing beat (PQRST cycle)
- rest of the rhythm will usually be regular
Premature Atrial Complex (PAC)
ATRIAL DYSRHYTHMIA
- Existence of a particular complex within another rhythm
- AKA: also know as atrial ectopic
- Occurs earlier in time than the next expected sinus complex
- TREATMENT: not usually indicated
How to spot Premature Atrial Complex (PAC) on an ECG?
-PREMATURE and ABNORMALLY shaped P wave on the PAC
- Rhythm is irregular when a PAC occurs
- underlying rhythm is regular
Supraventricular Tachycardia (SVT)
ATRIAL DYSRHYTHMIA
- occurs in the Pacemaker site above the ventricles (AV)
- HR generally above 150bpm
- TREATMENT: medication or electrical cardioversion or pacing
How to spot Supraventricular Tachycardia (SVT) on an ECG?
- The P WAVE is LOST in the preceding (before) T WAVE due to the fast heart rate
- the rhythm is regular
Atrial Flutter
ATRIAL DYSRHYTHMIA
- Atria contract at a rate too rapid for the ventricles to match
- known as a flutter (F WAVES)
- can have variable ratio of F wave:QRS COMPLEX —> (1:1 , 2:1 , 3:1 etc)
- can be regular or irregular
-TREATMENT: medication or electrical Cardioversion
How to spot Atrial Flutter on an ECG?
- VENTRICULAR rate is LESS than ATRIAL rate
- look out for SAW TOOTH flutter waves
Atrial Fibrillation
ATRIAL DYSRHYTHMIA
- Rhythm in which the atrial fibrillation or quiver, WITHOUT organised contraction
- Cells depolarise independently
How to spot Atrial Fibrillation on an ECG?
- the P WAVE is replaced by ERRATIC FIBRILLATORY WAVES.
- IRREGULARLY- IRREGULAR rhythm.
Junctional AV Rhythm
JUNCTIONAL RHYTHM
- AKA: junctional “escape rhythm”
- allows the heart to “escape” from stopping completely
- regular rate of 40-60bpm
- OCCURS when AV node or the bundle of his take over as the hearts pacemaker, instead of the SA node, often caused by SA mode dysfunction.
TREATMENT: pacemaker
How to spot Junctional AV Rhythm on an ECG?
- P waves are absent or inverted, before or after the QRS
- QRST is normal
Accelerated Junctional Rhythm
JUNCTIONAL RHYTHM
- Junctional Rhythm with a rate exceeding the normal range of 60bpm
- less than 100bpm
How to spot accelerate Junctional rhythm on an ECG?
- P waves are absent or inverted, before or after the QRS
- regular BPM of 60-100
- ESSENTIALLY SAME AS JUNCTIONAL (AV) RHYTHM BUT HEART RATE IS WITHIN NORMAL PARAMETERS
