Arrythmias Flashcards
Discuss DDX of broad monomorphic complex tachycardia
VT
SVT with aberrancy due to bundle conduction abnormality
SVT with aberrancy due to additional conduction pathway WPW
List clinical features more suggestive of VT vs SVT
VT:
- Age>35
- Known structural heart disease
- Ischaemic heart disease
- Previous MI
- CCF
- Cardiomyopathy
- Family history fo sudden death
SVT
- previous ECG showing WPW
- previous ECG showing Bundle block of the same morphology
- Previous tachycardia terminated with vagal maneuvers
Discuss ECG features suggestive of VT
- Absence of typicall RBBB or LBBB morphology
- Extreme axis deviation (northwest +ve in avr, -ve in 1 and avl)
- Very broad complex
- AV dissociation
- Capture beats- occurs when the sinus node occasionally captures the ventricules in the midst of AV dissociation
- Fusion beats - occur when a sinus beat and ventricular beat occur at the same time producing a hybrid complex
- Positive or negative concordance - throughout the precordium the QRS show either entierly postive or entirely -ve complexes without RS
- Brugada sign - the distance from the onset of the QRS to the nadir of the S is >100
- Josephson sign - noctching near the nadir of the s wave
- RSR with a taller left rabbit ear
Discuss brugada criteria for distinguishing VT from SVT
Following in a step wise approach
- Absence of RS comples in the precordium
- RS >100
- AV dissociation
- Morphological criteria for VT both in v1-2 and 6
Discuss morhological cirteria in RBBB like morphology
V1-V2
- Smooth monophasic R wave
- Notched downslope to the r wave - the taller left rabbit ear
- a qr complex (small q tall r) in v1
V6
- QS complex - completely -ve with nil r wave
- R/S ratio < 1 ( indicates VT only if LAD is present)
Discuss morhpological criteria in LBBB like morphology
V1 and 2
- initial r wave >30-40 sec
- Notching or slurring of the s wave (josephines sign)
- RS interval (time from the R wave onset to s wave nadir) >60-70ms
V6
- QS wave
- QR wave (small q big r)
Discuss the Vereckei algorithm to differentiate VT from SVT
Most important point
- Dominant initial R wave in AVR –> VT
- Dominant terminal R wave in AVR (ie. following a qs) more likley SVT
Again stepwise algorith
1) AV dissociation
2) Initial R-wave in avR
3) QRS morphology unlike BBB of FB
4) v1/vt < or equal to 1
Discuss ECG features of RBBB
rSR pattern most noted in v1 and v2
Broad S wave in left ventricular leads
QRS greater than 120 ms in complete and <120 in incomplete
Describe ECG features of LBBB
Borad notched or slurred R wave in leads 1 avl, V5 and V6
-QRS >120
Describe ECG criteria for LAFB, LPFB
LAFB - Left axis without other cause
LPFB- Right axis without other cause
Describe ECG criteria for LAFB, LPFB
LAFB - Left axis without other cause
LPFB- Right axis without other cause
