Final answer:
A lengthened Q-T interval on an ECG increases the risk of cardiac arrhythmias like Torsades de Pointes and ventricular fibrillation, which can disrupt blood circulation and potentially lead to sudden cardiac death.
Step-by-step explanation:
Lengthened Q-T Interval and Its Risks
A lengthened Q-T interval on an electrocardiogram (ECG) increases the risk of cardiac arrhythmias, which can be potentially life-threatening. The QT interval represents the time from the start of depolarization to repolarization of the ventricles, including the period of ventricular systole. When this interval is prolonged, it indicates that the ventricles are taking longer than normal to repolarize, which can lead to a type of arrhythmia called Torsades de Pointes, which may progress to ventricular fibrillation. Heart arrhythmias like these disrupt the normal rhythmic contractions of the heart, which can impair its ability to pump blood effectively. This can result in a sudden drop in blood pressure, fainting, and can even lead to sudden cardiac death if not promptly treated.
Factors like electrolyte imbalance, certain medications, and genetic conditions can lead to a lengthened QT interval. For instance, abnormal calcium ion levels can affect the QT interval, with high levels potentially shortening it and leading to a widened T wave on the ECG.