Final answer:
Isolated unifocal premature ventricular beats are a type of arrhythmia that occurs when an ectopic focus in the heart initiates an impulse earlier than usual. They can be caused by factors like localized ischemia, certain drugs, or autonomic nervous system stimulation. Chronic premature ventricular beats can lead to arrhythmias or fibrillation.
Step-by-step explanation:
Isolated unifocal premature ventricular beats are a type of arrhythmia, which is a deviation from the normal pattern of impulse conduction and contraction in the heart.
These premature ventricular beats occur when an ectopic focus, a region in the heart other than the SA node, initiates an impulse earlier than usual.
This can be caused by factors like localized ischemia, certain drugs, or stimulation by the autonomic nervous system. While occasional occurrences are generally non-life threatening, chronic premature ventricular beats can lead to arrhythmias or fibrillation.