Short QT or Short QT Syndrome (SQTS) is a congenital abnormality in the electrical activity within the musculature of the heart. In order to understand where the name comes from we must, therefore, first look at the electrocardiogram (ECG).
The ECG is a representation of the electrical activity in the heart. As the heart beats, the electrical activity is recorded from electrodes placed at specific places on the human body. This electrical activity is translated into wave patterns on paper, which contains a lot of information about the overall condition of the heart. Among such conditions are old or new heart attack, enlargement of the chambers of the heart, irregularities in the heart rhythm and important to our discussion, the presence of Short QT.
A normal ECG as the one shown below has multiple wave forms that come in clusters and each cluster representing a single heart beat:
An ECG usually represents 12 different recordings of the same heart beats with each recording (or lead) distinguished by numbers or letters (For instance lead I or lead V4). The following figure shows a single heart beat in a single lead:
The heart is made up of four chambers. Two of these chambers are the right and left atria (the upper chambers). From there the blood is pumped down in the two lower chambers (right and left ventricle). The electrical activity in the atria is separate from the electrical activity in the ventricles and is represented by the earliest wave in the ECG called the P-wave. The electrical activity in the ventricles is represented by the next wave (or waves) called the QRS wave(s). Finally there is a T wave signifying the end of a heartbeat.
This basic understanding about the ECG will help with the understanding in the next section: What Is A QT