Long QT Syndrome (LQTS) can affect anyone, even the young who are in the pink of health. LQTS is dangerous because it can strike without warning and cause sudden death. Take Mr Ted Wong* for example.

Long QT Syndrome (LQTS): A patient story

Mr Wong was in the pink of health and an all-round athlete who regularly ran marathons. So, when the 27-year-old lawyer suddenly slumped over at his desk one morning, his colleagues thought he was simply fooling around.

When he failed to respond to their nudges and calls after several minutes, they realised that he had stopped breathing. A colleague called for an ambulance while another started emergency cardiopulmonary resuscitation (CPR) on him.

When paramedics arrived, they tried to revive him. An electrocardiogram (ECG) done at the emergency department showed the presence of Long QT Syndrome (LQTS) – a disorder of the electrical activity that controls the heartbeat, and a known cause of sudden cardiac death in young, otherwise healthy people. Despite aggressive intervention by the medical team, Mr Wong unfortunately passed away.

Long QT syndrome (LQTS): Causes and risk factors

LQTS is usually inherited and can affect young victims. A check with the family revealed that Mr Wong’s father too had died of sudden cardiac death some years back.

Long QT syndrome (LQTS): What happens during an attack?

Victims develop sudden, uncontrollable and chaotic heart rhythms during exercise, when feeling strong emotions, or for no apparent reason. It is a known cause of collapse and sudden death in young athletes running marathons. If not corrected within a couple of minutes, these erratic heart rhythms can cause death.

Some people with LQTS experience symptoms such as palpitations, fainting spells or seizures, but many do not, and remain unaware they have the condition. Even if LQTS is diagnosed – often through ECG results during a routine check-up – there is currently no known cure for it.

Assoc Prof Philip Wong, Senior Consultant and Deputy Director of the National Heart Research Institute at National Heart Centre Singapore (NHCS), a member of the SingHealth group, said, “These dangerous heart rhythms can occur at any time and there need not be any specific trigger. Prolonged QT is a well-known cause of sudden cardiac death.”

Long QT syndrome (LQTS): How did it get its name?

The QT interval on an ECG indicates the time the heart takes to recharge before beginning its next contraction. In LQTS, the QT interval is prolonged as the electrical system controlling the heart’s rhythms takes longer to recharge. The delay may result in dangerous heart rhythms.

Long QT syndrome (LQTS) in Singapore

In Singapore, about 1 in 5,000 people have LQTS, said Prof Wong. “The incidence for LQTS is not as high as that of diabetes, which is one in five for those above the age of 50. But the difference is that diabetes is a chronic disease and doesn’t kill people suddenly, unlike LQTS which may affect the young in the prime of their lives,” he added.

How to prevent long QT syndrome (LQTS)?

The only way to prevent deaths in LQTS patients is for them to get an automated implantable cardioverter defibrillator implanted in their bodies.

The device monitors heart rhythms, and when it detects a dangerous one, delivers electrical shocks to reset the heart rate. However, this does not cure or correct the underlying cause of the condition.

*The patient's description is based on the typical profile of a patient with Long QT Syndrome.

Read on to find out about the latest research findings on cures for LQTS.

Ref: R14