ECG Flashcards
Bipolar Leads
I,II & III
Augmented Bipolar Leads
AVL, AVF, AVR
Monopolar Leads
V1-6
VT
A tachycardia originating from the ventricles which is life-threatening as it can lead to VF and asystole
It can be Monomorphic (all beats the same) or polymorphic (variations in wave shape). This should be treated with cardioversion if they still have a pulse or defibrillated if in pulseless VT
VF
The uncoordinated fibrillation of the heart. This is most common defibrillatible rhythm. It looks crazy, with smaller, more variable waves than VT
AF
The most common arrhythmia, may be asmyptomatic or associated with fainting, palpitations,chest pain, CHF and increased stroke risk
ECG will show no P waves and pulse is irregular
Flutter
An arrhythmia which is characterized by an atrial reentrant rhythm producing a ‘saw-tooth’ pattern instead of P waves which can be type I (240-340 beats) or type II (340-440). The ventricles contract at 3:1 or 4:1, and can be counterclockwise (common) where flutter waves are negative in II, III & AVR, or clockwise which is positive
Wolf-parkinson-white Syndrome
There is an abnormal accessory pathway causing early ventricular depolarisation (delta wave) but rarely causes sudden cardiac death. May present as SVT. Can be cured with catheter ablation
STEMI
An MI with cell death as opposed to angina
Will show inverted T waves, pathological Q waves & ST elevation.
NSTEMI
An MI which is not as serious as a STEMI and shows inverted T waves, pathological Q waves & ST depression
PE changes
S1, Q3, T3 –> rarely seen due to right ventricle strain. S wave in lead I & a Q wave and inverted T wave in III
LBBB
WiLiaM - RSR wave in V6 & qRs in V1 due to damage to the left branch of the bundle of his causing the left ventricle to contract slower
RBBB
MaRroW - RSR wave in V1 & qRs in V6 due to damage to the left branch of the bundle of his causing the left ventricle to contract slower
Signal Averaged ECG
Averages and amplifies abnormal low-amplitude signals after the QRS, and is useful for looking for ventricular arrhythmia’s after an MI
SVT
A tachycardic rhythm originating from above the AV node. They often come on and resolve spontaneously, with SOB, pounding in the chest, dizziness and LOC. They typically present at 150-270bpm. Unlike VT they are narrow complex
Digoxin Toxicity
Presents with a ‘scooped out’ ST segment across the ECG and N+V, confusion and seeing yellow/green halos around light/colour vision disturbance.
Torsades de Pontes
Polymorphic VT in the context of prolonged resting QT interval
Acute Pericarditis
Can be normal (ureamic pericarditis) but may show saddle-shaped ST elevation throughout the ECG, possibly with low voltage throughout
Axis Deviation
Mean direction of current in the heart.
Normally I and II are positive
In left axis deviation II is negative
In right axis deviation I is negative
1st Degree Heart Block
A fixed prolongation of the PR interval above 200ms due to disease or increased vagal tone (athletes)
2nd Degree Heart Block, Moditz type 1, Wenkebach phenomenon
A progressive prolongation of the PR interval causing a missed 3rd/4th beat, giving a missed beat. This gives strings of 3 to 4 sinus beats with increasing distance between them
2nd Degree Heart Block, Moditz type 2
A intermittent failure of conduction leading to ‘dropped beats’ which are not preceded or followed by changes in the PR interval
3rd Degree Heart Block
A total failure for impulses to conduct from the atria, leading to total dissociation between the P waves and the QRS
PR interval
120-200ms, up to 5 small squares
QRS complex
120ms, 3 small squares
QT interval
440ms in males, 460ms in females
Drug causes of torsades de pointes
Anti-arrythmics Amiodarone Methadone Lithium Chloroquine Erythromycin Amphetamine
Hypokalaemia ECG changes
P wave is wider and taller Prolonged PR T wave flat and inverted ST depression Prominent U waves (precordial leads) Long QU interval SVT
ECG changes in hypothermia
Bradyarrhythmias J waves (Osborne waves) Prolonged PR, QRS and QT intervals Shivering artefact Ventricular ectopics VT/VF/asystole
Treatment of rate controlled atrial fibrillation
Beta blockers
Rate limiting CCBs
Digoxin second line
Treatment of rhythm controlled atrial fibrillation
Sotalol
Amiodarone
Flecainide
