What rhythm is prolonged QT?
Long QT syndrome (LQTS) is a heart rhythm condition that can potentially cause fast, chaotic heartbeats. These rapid heartbeats might trigger you to suddenly faint. Some people with the condition have seizures. In some severe cases, LQTS can cause sudden death.
What does the QT wave represent?
The QT interval on the ECG is measured from the beginning of the QRS complex to the end of the T wave (see ECG components). It represents the time it takes for the ventricles of the heart to depolarize and repolarize, or to contract and relax.
Why is QT important?
The QT interval on the electrocardiogram (ECG) has gained clinical importance, primarily because prolongation of this interval can predispose to a potentially fatal ventricular arrhythmia known as torsades de pointes.
What causes Q waves?
The usual cause of Q wave irregularities is a previous heart attack (MI – myocardial infarction) resulting in dead heart muscle tissue or thickening of the heart muscle possibly from insufficient blood flow to the heart.
What are inferior Q waves?
Inferior q waves on ECG indicate possible prior inferior wall myocardial infarction ( heart attack ). To be significant, the q wave must be at least 25% or more in amplitude compared to following r wave, and be 1 mm wide. If it does not meet these criteria, it is a “borderline” q wave, and is less likely to indicate a prior heart attack.
What can a significant Q wave indicate?
A pathologic Q wave Pathologic Q waves are a sign of previous myocardial infarction. They are the result of absence of electrical activity. A myocardial infarction can be thought of as an elecrical ‘hole’ as scar tissue is electrically dead and therefore results in pathologic Q waves.
What is the definition of a Q wave?
Q waves are a marker of electrical silence, which, when pathological, implies full thickness death of myocardium, which happened a long time ago. They are negative because they are effectively windows through which can be seen the opposite side of the heart, in which depolarisation will be moving away from the electrode.