Question

What is the path of conduction for single ventricular foci and multiple ventricular foci?

Answer 1

Ectopic foci are strange pacemaker web sites within the coronary heart (outside of the SA node) that display automaticity. Their pacemaker activity, however, is typically suppressed (overdrive suppression) by way of the higher charge of the SA node. They can manifest inside the atria or ventricles.

Ectopic foci can purpose additional beats (observed as premature beats) or take over the regular pacemaker activity of the SA node. These ectopic pacemakers can lead to either tachycardia or bradycardia depending upon their vicinity and surrounding electrical conditions. Example, ectopic foci in the ventricle when coupled with a reentry pathway can precipitate ventricular tachycardia. In third degree AV nodal block, a ventricular rhythm nevertheless takes place due to the fact of the expression of generally latent ectopic pacemaker sites inside the ventricle. These ectopic ventricular pacemakers generally produce a rhythm (30-40 beats/minutes); this resting price is tons slower than that generally produced by the SA node (60-100 beats/min).

When an ectopic foci drives the rhythm of the heart, the unfold of depolarization normally does no longer comply with the normal, fast conducting pathways within the heart. Because of this, the depolarization wave takes longer to unfold throughout the myocardium. This usually reasons a form alternate in QRS complex and prolongs its duration (>0.10 sec) because extra time is required for the whole ventricle to turn out to be depolarized.