Paeds Syncope Flashcards
Describe Brugada syndrome
Congenital condition due to NA channelopathy. Brugada symptoms can be transient or unsmasked by a host of things including
- Fever
- Ischaemia
- Drugs
- –Na channel blockers
- –A agonists
- –B blocker
- –CA blocker
- –Nitrates
- –Cholinergic stimulation
- – COcaine
- –ALcohol
- Hypokalaemia
- Hypothermia
- Post DC cardioversion
Describe Brugada type 1
Coved ST segment elevation of at greater than 2 mm in more than 1 of V1-3
Followed by -ve T-wave
Only sign that is potentially diagnositic - known as brugada sign
Describe Brugada pattern type 2
Type 2 has incomplete RBBB with greater than 2mm of st eleaveion
saddle
Describe Brugada patternt type 3
Can be either type 1 or 2 but with <2mm of elevation
Describe Brugada Syndrome
Brugada syndrome is Brugada pattern ECG with any of the following
- Documented ventricular fibrillation (VF) or polymorphic ventricular tachycardia (VT).
- Family history of sudden cardiac death at <45 years old .
- Coved-type ECGs in family members.
- Inducibility of VT with programmed electrical stimulation .
- Syncope.
- Nocturnal agonal respiration.
Discuss Management of Brugada Syndrome
The only proven therapy is an implantable cardioverter – defibrillator (ICD).
-Quinidine has been proposed as an alternative in settings where ICD’s are unavailable or where they would be inappropriate (eg: neonates).
Type 1 brugada can likley be discharged with EPS follow-up
Type 2-3 also
A japanese study of 98 people with Brugada sign were followed with 14000 others nil change in mortality seen
Discuss catecholaminerigic polymorhpic VT
Polymorphic VT is defined as a ventricular rhythm above 100 BPM with a continuously varying QRS morphology
Most are above 200 BPM, can cause HD instability, can deteriate into VF
History of Sudden cardiac death in the family
Typically begins in childhood to adolescence
Patients typically present after a physical or emotional stress with
-sudden cardiac death
- Syncope
-Seizure like activity
-Palpitations
Avoid stress
IACD
Propanalol
Describe the ECG of CPVT
Two types of polymorphic VT have been described in this condition
1) typical with continuing varying QRS morphology
2) Bidirectional VT
Bidirectional VT is generally pathognomic for digitalis intoxication but can also occur in CPVT both are thought ot be due to Ca overload leading to DADs
Discuss pre-excitation
Pre-excitation refer to early ventricular activation due to pathways that bypass the AV node
Can conduct antegrade towards the ventricle or retrograde towards the atria
Discuss ECG finding of WPW
Short PR <120
Delta wave
Wide QRS complex >110
ST segment and t-wave segment discordance
pseudo infarct pattern in up to 70% of cases
Type A: positive delta wave in all precordial leads with R/S > 1 in V1
Type B: negative delta wave in leads V1 and V2
IN retrograde only conduction nil ECG features will be seen as all APs are conducted throught the AV node – termed a concealed pathway
Discuss AVRT with orthodromic conduction
IN orthodromic ACRT conduction occurs throught the AV node
Narrow complex at a rate of 200-300 BPM
Can have QRS alternans
T-wave inversion common
St segment depression
Treatment depends on HD – if unstable shock the shit out of them
If stable as per SVT vagal maneuvers adenosine
Discuss AVRT with antedromic conduction
Antedromic AVRT conduction occurs through accessory pathway
Wide complex tachycard – 200-300 can be difficult to distinguish between this an VT
If seen in a child almost always re-entry with abherrency
Do not use AV nodal blockers as can detiorate into to VT/VF
Use flecanide or electicity
Discuss AF, aflut in WPW
Common occurs in 20% of patient with WPW for AF and 7% for A-flutter
Rate >200
Irregular if AF
Can have widecomplex if antedromic
QRS complex change in shape but does not alter axis as polymporphic VT would
Dont use AV nodal blockers as above
Flecanide or procainamide or shock
Discuss Mahaim type pre-excitation
Right sided accessory pathways connecting either AV node to ventricles, fascicles to ventricles, or atria to fascicles
ECG features:
Sinus rhythm ECG may be normal
May result in variation in ventricular morphology
Reentry tachycardia typically has LBBB morphology
Discuss ARVD
Second most common form of sudden cardiac death in young people after HOCM
Symptoms are caused by ventricular ectopic beats or sustained VT
Presenting complaint may be sudden cardiac death
if people survive often develop right sided heart failure
Discuss ECG finding of ARVD
ARVD is associated with characteristic ECG abnormalities:
- Epsilon wave (most specific finding, seen in 30% of patients)
- T wave inversion in V1-3 (85% of patients)
- Prolonged S-wave upstroke of 55ms in V1-3 (95% of patients)
- Localised QRS widening of 110ms in V1-3
- Paroxysmal episodes of ventricular tachycardia with LBBB morphology (e.g. right ventricular VT).
Described the epislon wave
Small positive deflection buried at the end of the QRS. Best seen in the precordial leads
Can use fontaine lead placement to exagerate epislon wave if present
Discuss imaging modalities of ARVD
ECHO can show dilated, hypokinetic right ventricle with prominent apical trabeculae and dilatation of the RV outflow tract
Cardiac MRI can be diagnostic of the condition showing fibrofatty infiltrate
Discuss risk assessment and management of ARVD
High risk groups
- family history of sudden death - 1st degree relative
- Recurrent arrythmias not suppressed by anti-arrythmics
- History of syncope due to cardiac arrest
Patient at high risk should all have IACD
THose without high risk features can trial antiarryhthmics such as b blockers or amioderone to suppress cathecholamine triggered VT
What is a long QT
QTc is prolonged if > 440ms in men or > 460ms in women
QTc > 500 is associated with increased risk of torsades de pointes
QTc is abnormally short if < 350ms
List causes of a long QT
1) Drugs -Amioderone -antipsychotics (haloperidol, droperidol, TCAs,) -Many antibiotics (erythromycin, fluconazole) -antiemetics (metoclopramide, ondansetron) -antidepressants ( SSRI)
2) genetic -cardiac ion channel mutation -long qt syndrome
3) Myocardial disease -MI -RF -cardiomyopathy
4) electorlyte abnormalities -low, ca, mg, k
Raised ICP
How do you caluculate a QTC
Bazett formula: QTC = QT / √ RR in seconds
Fridericia formula: QTC = QT / RR 1/3
Framingham formula: QTC = QT + 0.154 (1 – RR)
Hodges formula: QTC = QT + 1.75 (heart rate – 60)
Discuss management of long qt
beta-blockade avoidance of increased sympathetic tone cardiac pacing treat cause and avoid agents that will prolong the QT ICD
Discuss Short QTC
Patients are typically young and healthy, with no structural heart abnormalities; age at first presentation ranges from a few months to the sixth decade of life (median age = 30 years).
The most common initial presenting symptom is cardiac arrest (in one-third of cases); other patients may present with palpitations or syncope due to rapid atrial fibrillation or self-terminating ventricular arrhythmias.
Witnessed cardiac arrest within the first year of life and unexplained infant deaths have been observed in patients and families with SQTS, making it a possible cause of sudden infant death syndrome (SIDS).
Describe ECG of short QTC
Short QT interval
Lack of the normal changes in QT interval with heart rate
Peaked T waves, particularly in the precordial leads
Short or absent ST segments
Episodes of atrial or ventricular fibrillation
Management of short QTC
IACD however due to tall t -wave can given inappropriate shocks
Quinidine is medication of choice
Sotalol no good
Discuss RVOT
Monomorphic VTY originating from the outflow tract of the RV or occasionally the tricuspid annulus
ECG:
- LBBB morph
- inferior acis
- rs complex in V1 and R complex in V6
- precordial transition usually > v3 with the exception of spetal origin
- other general features of VT may also be present
RVOT Tachyacrdia is the most common form of idiopathic VT - whereby no strucutral heart disease, metabolic or electrolyte abnormalities or long QT can be found
The two most common froms are
1) repetitive unsustained monomorphic VT 60-90%
2) exercise induced sustained VT
Treatment
- Vagal manoeuvres or adenosine
- IV verapamil or beta blockers
