Flashcards in Electrophysiology Deck (131)
What is the definition of short RP interval?
What causes SVT with abnormal p waves with short RP interval
Atrial tachycardia with AV nodal conduction delay
What are the differentials for SVT with retrograde p waves with a long RP interval
AVRT with slow accessory pathway
What are retrograde p waves on ECG?
Inverted p waves in inferior leads
What are the differentials for SVT with abnormal p waves with a long RP interval
Uncommonly from atypical AVNRT
What are the important ECG features to assess in SVT?
P wave morphology
What is the most common side for antidromic AVRT?
Left sided as needs 4cm between AV node and bypass tract
What is the acute arrhythmic management of orthodromic AVRT?
1. Modified Vagal
4. Beta Blocker/Procainamide
What is the acute arrhythmic management of antidromic AVRT?
If known to be AVRT then adenosine, verapamil, IV beta blockers
What is the medical treatment for recurrent AVRT?
What are the contraindications to flecainide?
Structural heart disease
Ischaemic heart disease
What are the contraindications to propafenone?
Chronic airways disease
What are the contraindications to procainamide?
What is the rate of stroke when cardioverting AF of >48 hours without preceding anti-coagulation?
What are the ECG features which increase the likelihood of VT?
Capture beat, fusion beat
Positive of negative concordance in chest leads
Absence of typical RBBB/LBBB
What is brugada sign? What does it indicate
Distance from start of QRS to nadir of S wave is 100ms
More likely VT
What is Josephson sign?
Notching near nadir of s wave, likely VT
What does an RSR with a taller left rabbit ear indicate?
Specific for VT
What is the use of the Vereckei Algorithm?
Used to diagnose VT over SVT with aberancy
Describe the steps of the Vereckei Algorithm?
1. AV Dissociation
2. Initial R wave in AVR
3. Atypical BBB pattern
4. Vi/Vt <1
Yes to any of these is VT
Describe the steps of the Brugada Algorithm?
1. Absence of RS complex in all precordial leads
2. R to S intercal >100ms in one precordial lead
3. AV dissociation
4. Morphology criteria for VT present in V1 and V6
What are the morphological criteria for RBBB morphology VT in the chest leads?
Smooth monophasic R wave
Notched downslope of R wave (taller left rabbit ear)
qR complex in V1
negative QS complex
R/S ratio <1 (small R big S)
What are the morphological criteria for LBBB morphology VT in the chest leads?
R wave >30-40ms
Notching of S wave
RS interval >60-70ms
QS wave (highly specific)
qR pattern (small q large R)
What is ohms law formula?
Voltage = current * resistance
What is the resistance aimed for at pacemaker lead tips?
What is the purpose for high resistance in pacemaker leads?
Preserve battery life
What is the typical amplitude ranges for signals recorded from atrial and ventricular leads?
1.5-5 and 5-25mV
What occurs if the atria and ventricular signals have amplitudes lower than the respective amplitude ranges?
Undersensing and potential inappropriate delivery of pacing pulses
Yield of holter monitor in syncope?
Useful to fund cardiologists’ Ferrari’s