Cardiology Flashcards
How to work out rate in ECG
300/ Number of squares in R-R interval
how long should p wave be?
120-200ms
Prolonged PR interval indicates
AV block
Shortened PR interval indicates ? What other feature of this condition do you often see on ecg
atrial impulse to ventricles quicker i.e. accessory pathway
associated with delta wave (slurred QRS upstroke) in Wolff Parkinson White
QRS normal length ?
80-120ms
Where is the j point
where S waves meets ST segment
When is ST elevation significant?
> 1mm in 2 or more limb leads
or >2mm in 2 or more chest leads
What is the t wave?
ventricular repolarisation
When is a t wave “tall” what could this mean?
> 5mm in limb AND >10mm in chest
associated hyperacute STEMI and hyperkalaemia
Inverted T wave is normal where?
V1 and lead III
Inverted t waves association?
ischaemia, PE, BBB
What is sinus bradycardia
<60bpm
every P wave is followed by a QRS
Physiological causes of sinus bradycardia?
Pathological?
Physiological: athletes, young due to *high resting vagal tone (vagal activity is continuous)
Pathological: acute MI, drugs (BB, dig, amiodarone), hypothyroid, hypothermia, sick sinus, raised ICP
When do you treat bradycardia
<40bpm / symptomatic
Mx of symptomatic bradycardia
IV atropine - anticholinergic, i.e. muscarinic antagonist, reduces vagal tone
Temporary pacing wire
What is sick sinus syndrome? Causes ?
Result of dysfunction of SA node with impairment of ability to generate impulse
Normally idiopathic fibrosis of node
ischaemia
digoxin toxicity
Causes of AV block
MI/ischemia (inferior)
SLE
myocarditis
(lyme disease endocarditis, degeneration of HIS-PURKINJE, drugs (digoxin, BB, CCB))
1st degree heart block is?
PR > 0.2s, PR constant, every P followed by QRS
2nd degree heart block?
Intermittent failure of conduction from atria to ventricles. Some P are not followed by QRS
Mobitz type I (Wenckebach) failure at level of AV node.
PR interval progressively lengthens and is then blocked.
Mobitz type II intermittent failure of P wave conduction.
PR interval is constant + prolonged. Fixed PR interval, dropped QRS waves2:1 block or 3:1 block
What is 3rd degree heart block? Usual cause?
Complete failure conduction atria to ventricles
myocardial fibrosis
Name 3 causes of RBBB
Rheumatic heart disease
RVH
IHD, myocarditis, cardiomyopathy, degenerative disease conduction system
Name 2 changes on ECG of RBBB
MarroW
QRS > 0.12s
Secondary R wave in V1, V2 - RSR’ [Seconary R in RBBB]
Deep, wide slurred S wave in I, V5, V6
LBBB associated conditions. Name 2
Coronary artery disease, hypertensive heart disease, dilated cardiomyopathy, anterior infarction
Name 2 ECG changes in LBBB
WilliaM
Wide QRS > 0.12s
Absent Q in V5, V6
Broad R in I, V5, V6
Deep S in V1, V2 [Long S in LBBB]