What is sudden cardiac death (SCD)? In a recent presentation, Dr Leslie Lam from The Cardiac Centre tells us that it is a sudden, unexpected death caused by loss of heart function. Is this natural death due to cardiac cause heralded by an abrupt loss of consciousness within one hour of the onset of symptoms?

In sudden cardiac death there may be a pre-existing cardiac disease. The time and mode of death from SCD is totally unexpected.

Sudden cardiac death happens to 0.1-0.2% of adults over 35 years of age, in a year. 60-85% of SCD in this group is due to underlying coronary artery disease. Other causes include hypertrophic cardiomyopathy, congestive cardiomyopathy and myocarditis.

In young people, however, the causes of SCD are slightly different. 36% of SCD is due to hypertrophic cardiomyopathy, 19% due to congenital coronary anomalous and 10% due to mildly increased cardiac mass. The remaining 35% is a result of other causes (ruptured aorta, tunnelled LAD, aortic stenosis, myocarditis, dilated cardiomyopathy, arrhythrnogenic right ventricular dysplasia , mitral valve prolapse, coronary artery disease, Wolff Parkinson White Syndrome, prolonged QT interval syndrome, short QT syndrome, Brugada syndrome, Idiopathic VT/VF and complete heart block).

The Management of Sudden Cardiac Arrest Itself

The management of SCA is to call for help immediately, perform immediate Cardio Pulmonary Resuscitation (CPR) if possible and early admission to the hospital.

Management of Sudden Cardiac Death Survival (Secondary Prevention)

• Look for reversible transient factors, e.g. acute heart attack, underlying structure heart disease, dilated hypertrophic cardiomyopathy, impaired left ventricular function.
  
  
• Be mindful of high-risk sub-groups such as prolonged QT interval, Brugada syndrome, set a need for revascularisation if associated with coronary artery disease.

Primary Prevention of Sudden Cardiac Death in the Younger Age Group

Unless there is a family history of SCD, it is not feasible to screen everyone for underlying heart disease. The causes stated previously would have to be excluded. Primary prevention would involve an ECG, Treadmill Stress Test, 2D Echo examination of the heart and if necessary Electrophysiological Study (EPS). When the cause is identified then it is possible to prevent SCD in some cases.

SCD is a major cause of mortality and may be preventable to a certain extent. Its successful prevention, however, needs a multi-level approach at the primary, secondary and tertiary level.