Sudden death in childhood is a well recognised syndrome. There are reports of children between one and 12 years, otherwise healthy, suddenly collapsing and at times even dying. They may not have any known illness that may account for such a fatal event. In fact, even autopsy reports may not show any abnormality.

The commonest cause of such unexpected death among children is sudden onset of cardiac arrhythmia, when the heart’s electrical circuit suddenly becomes erratic, leading to a cardiac arrest.

This could be because of very fast or very slow heart rate. However, fast rate is more common. This causes sudden drop of blood pressure and the child suddenly turns blue and loses consciousness. It may lead to cardiac arrest.

There are two well-defined illnesses of electrical circuit of the heart. Long QT Syndrome and Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT). They often remain unknown and undiagnosed.

The first presentation may be sudden collapse of the child when he is 5.

This group of heart diseases, which may be sudden killers, are known as Channelopathy. In this disorder, the electrical channels inside the heart may be defective. Sudden exertion or any other stressful condition may trigger the channels, so the electrical circuit of the heart starts beating erratically fast, especially the ventricle. Then suddenly the heart stops.

CPVT is a disorder of sudden onset of fast heart rate because of ventricular arrhythmia (fast ventricular rate), leading to loss of consciousness without any structural disease of the heart.

This disease commonly affects children from five to 12 years. Boys are more prone to such an illness than girls. There are reports of genetic linkage of this disease which at times may remain unknown. Physical exertion or emotional stress, or exertion in extreme weather, may precipitate the event.

The best way to treat this condition is awareness. Health check-up at school can pick up such cases, provided society is aware of Sudden Arrhythmia Death Syndrome (SADS) in childhood. Simple ECG may detect the Long QT disorder and help treat this condition.

Any symptom of blackout among children must be investigated because it may be an early sign of SADS. Any child having history of sudden death in the family must have an ECG and Echocardiography. Children should have adequate hydration, food intake and avoid unusual physical exertion in extreme hot or cold.

Once diagnosed there are treatments by medication and in some situations, special pacemaker implantation.

SADS is a preventable disease. Once it is detected at an early stage, proper treatment is possible and the precious life of a child can be saved.

The author is director, Apollo Gleneagles Heart Institutes, Calcutta