Final answer:
Widening of the Q-T interval and the appearance of a U wave following a flattened T wave indicate abnormalities in the electrical activity of the heart, specifically related to repolarization.
Step-by-step explanation:
Widening of the Q-T interval and the appearance of a U wave following a flattened T wave indicate abnormalities in the electrical activity of the heart, specifically related to repolarization. These changes on an ECG can be seen in conditions such as long QT syndrome, electrolyte imbalances (such as hypokalemia or hypercalcemia), or certain medications.
In long QT syndrome, the QT interval (which measures the time it takes for the ventricles to repolarize) is longer than normal. This can increase the risk of life-threatening arrhythmias. The U wave is an additional, small wave that follows the T wave and represents delayed repolarization of the ventricles.
In summary, widening of the Q-T interval and the appearance of a U wave following a flattened T wave on an ECG are indicative of abnormalities in ventricular repolarization, which may be associated with conditions like long QT syndrome or electrolyte imbalances.