What is the significance of ectopic pacemakers?

Heart rhythm. The heart rhythm is being generated in a different spot than usual (usually from the high right atrium in the sinus node). If your rate is normal & the rhythm is regular, it would have no significance and you wouldn't even know about it unless you have an ekg. The overall condition of your heart determines the significance, not the rhythm, per se.
None in majority. In the great majority of patients, ectopic beats whether they are from the atria or the ventricles, do not have prognostic value. While patients with heart disease are more likely to have these, just having the beats is not a sign of heart disease (all walnuts are round, but not every round thing is a walnut).