To answer properly, interpolated PVC's are PVC's that happen without a compensatory pause. This is because they trigger early enough and the usual R-R interval is long enough that the next sinus beat can still conduct. In normal PVCs, the PVC itself blocks conduction from the AV node to the ventricles, missing the usual sinus beat and hence the compensatory pause.
Interpolated PVCs are not immediately dangerous but studies show frequent interpolated PVCs are more likely to lead to cardiomyopathies.
PVCs, premature ventricular contractions, are common and in most cases are benign in the setting of someone without other heart problems. Unless you are having very frequent PVCs and they are leading to symptoms you shouldn't have to do anything about them.