Flashcards in Electrophysiology Deck (131)
What is the significance of agonal nocturnal breathing in a patient with suspected cardiac arrhythmia?
Equivalent of syncope/ventricular arrhythmia. ?aborted event
How does fever influence Brugada?
Reduction in sodium current resulting in predisposition to ventricular arrhythmia
What is the diagnostic criteria for type 1 Brugada Syndrome?
- Type 1 Brugada pattern (V1 or V2) at rest or with flecainide challenge
- type 1 Brugada pattern with
- first degree block, LAD
- atrial fibrillation
- late potentials, fragmented qrs, st-t wave alternans with VEB
- absence of structural heart disease
- absence of coronary artery disease
What is the definition of “symptomatic” in patients with Brugada?
Inducible VT on EP
Nocturnal agonal respiration
Family history of SCD <45 years
Family history Type 1 Brugada pattern
What is the definition of Type 2 Brugada?
1. Type 2 Brugada pattern
2. Conversion to Type 1 with flecainide challenge
3. Additional feature listed below
- inducible VT on EP
- family history SCD <45
- family history of Type 1 ECG
- agonal respiration
- unexplained syncope
What is the evaluation of suspected Brugada Syndrome?
In the setting of wide complex tachycardia, what are the features suggestive of VT over SVT with aberrant conduction?
Positive or negative concordance in QRS in chest leads
No mans land axis (pos aVR and neg aVF and lead 1)
RSR pattern with taller left rabbit ear
Absence of typical LBBB or RBBB pattern
How do you risk assess people with Brugada pattern without symptoms?
Cardiac imaging - echo/MRI
Drug Challenge if Type 2
Signal averaged ECG
Consider EP study in Type 1 asymptomatic patients
Genetic testing if mutation identified in family
What are the indications for Flecanide challenge in those with Type 2 brugada pattern?
Family history of SCD<45 years
Family history of Type 1 pattern
No family history, recommend against challenge
What is the sensitivity of flecainide drug challenge in patients with Type 2 Brugada for Type 1 pattern?
What are the indications to stop a drug challenge for ?Brugada?
Type 1 brugada pattern
>2mm increase in ST elevation with Type 2
Ventricular premature beats
QRS widening >30%
What is the rate of sustained ventricular arrhythmia following drug challenge?
What is the duration of ECG monitoring post Flecainide challenge for Brugada?
30min if IV
4 hours if oral
ECG at 90 min is useful
VT on exertion makes you suspicious of what diseases?
What proportion of patients with Brugada pattern ECG with inducible VT on EP studies will develop and arrhythmic event?
What is the management of Brugada Syndrome?
1. Treat pyrexia
2. ICD implantation
3. Antiarrrhythmics indicated if refusing ICD or multiple shocks (quinidine or amiodarone)
4. Avoid sodium channel blockers (apart from quinidine)
5. Catheter ablation - if recurrent events
6. Family Testing
What is the family testing in a patient with Brugada Syndrome?
ECG and clinical history
If negative for repeat assessment every 1-2 years as may still develop disease
What are the rates of complications with ICD placement over 6 years?
37% inappropriate shock
30% lead issues
What is the incidence of AF >30s in patients in sinus with mitral stenosis on holter?
What is the rate of TIA/stroke?
What are the ecg features of RVOT VT?
Rightward axis (positive inferior leads)
Physiology of typical slow fast AVNRT
Atrial premature beat allows slow pathway conduction while fast is refractory.
Slow pathway then is able to conduct through to the fast pathway resulting in AVNRT
Which has the shorter refractory period, slow or fast pathway of AVN?
Slow pathway - short refractory period
Fast pathway - long refractory period
What are the potential triggers for AVNRT?
nicotine, alcohol, stimulants, exercise
ECG features of Typical AVNRT
P waves close to QRS (commonly after)
Retrograde P waves
ECG features of Atypical AVNRT
Very late retrograde p waves often shortly before the next QRS
What is the modified valsalva?
Exhaling against a closed glottis for 15 seconds
Followed by supine re-positioning with passive leg raise for 15 seconds
What is the adenosine dose for a patient with SVT with orthotopic heart transplant
What is the acute arrhythmic management of AVNRT?
1. Modified valsalva twice
2. Adenosine if no contraindication
3. IV beta blockers of calcium channel blocker
Long term management of recurrent AVNRT
1. Patient education on modified valsalva and pill in pocket
2. Chronic suppressive therapy with anti arrhythmics
3. Catheter ablation 95% success