What is the difference between complete right bundle branch block and incomplete right bundle branch block?

Duration. A complete right bundle branch block has a qrs duration of 120 milliseconds or more, an incomplete rbbb is less than 120 milliseconds.
EKG diagnosis. On the EKG if the qrs (electrical wave cause by the heart muscle depolarizing) is 0.12 seconds or greater, it is by definition complete. Less that that would be incomplete. Complete implies that there is no conduction at all and incomplete that it is just delayed. However, that number is somewhat arbitrary.

Related Questions

Would it be possible that a rbbb (right bundle branch block) cause a heart murmur?

No. But there are conditions that can both cause a heart murmur and a rbbb (for example, pulmonic stenosis or an atrial or ventricular septal defect). Read more...
No. A rbbb is a pattern seen in the ECG where the electrical impulse is delay or interrupted as it spread along the heart. Prevalence increase with age. At 80 y/o close to 10% people can have it. Somewhat benign but an evaluation need to be done to r/o heart and lung conditions. Conditions like copd, cad, myocarditis, valvular heart disease, and other structural heart conditions. Read more...