Final answer:
An extended period of time between the P wave and the QRS complex indicates a third-degree block.
Step-by-step explanation:
An extended period of time between the P wave and the QRS complex may indicate a third-degree block in the conduction of electrical signals in the heart.
In a third-degree block, there is no correlation between atrial activity (the P wave) and ventricular activity (the QRS complex).
This can be seen on an electrocardiogram (ECG) as a prolonged PR interval, which is the time interval between the start of the P wave and the start of the QRS complex.