Cardiac syncope is extremely rare but potentially fatal.
24% incidence in subsequent cardiac arrest – 10 Australian youths die suddenly every week due to SADS (Sudden Arrhythmic Death Syndrome).
These deaths are rare, but preventable. We see a lot more cases with warning symptoms than deaths. We need to recognise the importance of the identification of cardiac syncope to prevent death.
- Cardiac arrest
A retrospective study at RCH, Melbourne 2012 demonstrated that syncope was leading cause for presentation of new diagnosis of conduction disorders and VT.
A simple faint has:
- Warning symptoms (felt faint)
- Provoking factors (hot, tired stressed, hungry, emotion, full stomach etc)
- Standing up at the time
- Pale before & during event
- May jerk limbs especially if not laid down
- No headache or post-ictal behaviour
- Past history of faints
Cardiac syncope has:
- Relationship to exercise
- No warning symptoms
- Higher incidence of injuries
- Pale during event
- Rapid recovery
- Previous history of blackouts, shortness of breath or chest tightness during exertion, or palpitations
- Family history of young death
The causes of SADS can be classified as follows:
Structural heart disease
- Cardiomyopathies (HOCM, DCM, RCM, ARVC)*
- Congenital heart disease (abnormal valves, chambers, or anomolous coronary arteries, from birth)
- Re-entrant tachycardias
- Long / short QT Syndrome (natural or iatrogenic)
- CPVT (Catecholaminergic Polymorphic Ventricular Tachycardia)
In the next post we will look at some examples of these on ECGs…
*HOCM = hypertrophic obstructive cardiomyopathy
DCM = dilated cardiomyopathy
RCM = restrictive cardiomyopathy
ARVC = arrhythmogenic right ventricular cardiomyopathy (AKA arrhythmogenic right ventricular dysplasia – ARVD)