Long Q-T Syndrome (LQTS)

Is an infrequent, hereditary disorder of the heart's electrical rhythm that can occur in otherwise-healthy people. It usually affects children or young adults.

When the heart contracts, it emits an electrical signal. This signal can be recorded on an electrocardiagram (ECG or EKG) and produces a characteristic waveform.

The different parts of this waveform are designated by letters -- P, Q, R, S and T. The Q-T interval represents the time for electrical activation and inactivation of the ventricles, the heart's lower chambers. 

A doctor can measure the time it takes for the Q-T intrerval to occur (in fractions of a second), and can tell if it occurs in a normal amount of time. If it takes longer than normal, it's called a prolonged Q-T interval.

Brugada Syndrome

Is a heredity condition which affects the electrical conduction system of the heart, causing an abnormal heart rhythm.

In some cases, Bugada syndrome can be life-threatening and may take effect with little warning.