Final answer:
A heart block refers to an arrhythmia with disrupted transmission of electrical signals from the SA node to the Purkinje fibers, with varying degrees of severity. Ectopic foci can cause arrhythmias, potentially leading to fibrillation. Chronic arrhythmias may require the implantation of an artificial pacemaker.
Step-by-step explanation:
The medical term describing an arrhythmia with interference in the normal transmission of electric impulses from the SA node to the Purkinje fibers is known as a heart block. There are different degrees of heart block, each representing a level of interference. A first-degree block involves a delay, while a third-degree or complete block shows no correlation between the atrial and ventricular contractions on an ECG.
An ectopic focus or ectopic pacemaker can cause a premature contraction, influencing these rhythms. When chronic, this can lead to a persistent arrhythmia leading to possible fibrillation, characterized by uncoordinated heartbeats. Chronic arrhythmias can be treated with artificial pacemakers to restore normal sinus rhythm.