Final answer:
In ventricular tachycardia, abnormal electrical signals in the ventricles can cause a rapid heart rate, as seen on an electrocardiogram (ECG) due to increased frequency of QRS complexes.
Step-by-step explanation:
In ventricular tachycardia, abnormal electrical signals in the ventricles cause the heart to behave erratically, often resulting in a very fast heart rate. The normal heart rhythm is established by the heart's natural pacemaker cells in the sinoatrial (SA) node. However, in ventricular arrhythmias like ventricular tachycardia, the electrical signals become abnormal, potentially compromising the heart's ability to pump blood effectively. An electrocardiogram (ECG) commonly shows an increase in the frequency of QRS complexes, indicating this rapid heart rate.