Final answer:
A QT interval greater than 0.44 seconds signifies prolonged repolarization of the ventricles, which increases the risk of ventricular fibrillation, necessitating further medical evaluation.
Step-by-step explanation:
The importance of a QT interval greater than 0.44 seconds is indicative of prolonged repolarization. This abnormality can be associated with an increased risk of ventricular fibrillation, a potentially life-threatening heart rhythm problem. The QT interval on an electrocardiogram (ECG) represents the time from the start of ventricular depolarization to repolarization, encompassing the ventricular systole phase. A prolonged QT interval can be a sign of an underlying cardiac issue, making it important for further evaluation and management to prevent serious complications like arrhythmias. The QT interval is affected by various factors including electrolyte imbalances, such as abnormal calcium ion levels and the use of certain medications like calcium channel blockers.