Search results
Results From The WOW.Com Content Network
The QT interval is a measurement made on an electrocardiogram used to assess some of the electrical properties of the heart.It is calculated as the time from the start of the Q wave to the end of the T wave, and approximates to the time taken from when the cardiac ventricles start to contract to when they finish relaxing.
Intermittent QT prolongation, or intermittent prolongation of the QTc (corrected QT interval) on the ECG (electrocardiogram) is noted. The implications of intermittent QTc prolongation predispose to life-threatening cardiac electrical instability (and this is therefore a more critical condition than constant QTc prolongation).
So we have a QT of 400 milliseconds divided by the square root of 0.66 seconds over 1 second, which is 400 milliseconds divided by 0.81, which is unitless, and we get a corrected QT interval of 493 milliseconds, which is greater than 440, so actually, a 400 milliseconds QT interval at 90 beats per minute is considered long.
Long QT syndrome (LQTS) is a condition affecting repolarization (relaxing) of the heart after a heartbeat, giving rise to an abnormally lengthy QT interval. [7] It results in an increased risk of an irregular heartbeat which can result in fainting, drowning, seizures, or sudden death. [1]
Corrected QT interval (QTc) The QT interval is measured from the beginning of the QRS complex to the end of the T wave. Acceptable ranges vary with heart rate, so it must be corrected to the QTc by dividing by the square root of the RR interval. A prolonged QTc interval is a risk factor for ventricular tachyarrhythmias and sudden death.
Romano–Ward syndrome is principally diagnosed by measuring the QT interval corrected for heart rate (QTc) on a 12-lead electrocardiogram (ECG). Romano–Ward syndrome is associated with a prolonged QTc, although in some genetically proven cases of Romano–Ward syndrome this prolongation can be hidden, known as concealed Long QT syndrome. [13]
Andersen–Tawil syndrome, also called Andersen syndrome and long QT syndrome 7, is a rare genetic disorder affecting several parts of the body. The three predominant features of Andersen–Tawil syndrome include disturbances of the electrical function of the heart characterised by an abnormality seen on an electrocardiogram (a long QT interval) and a tendency to abnormal heart rhythms ...
qt: quart: q.v. which see (from Latin quod vide); as much as you please (from Latin quantum vis) q.wk. also qw: weekly (once a week) This page was last ...