Which kind of memory is disrupted by electroconvulsive therapy?

Short term memory.: Electroconvulsive therapy for depression has been given a scary reputation in movies, but it is actually an effective therapy which is appropriate in some cases of severe depression. Patients frequently have some memory loss surrounding the time of the procedure, and those memories are not recovered. However, electroconvulsive therapy is not thought to produce progressive memory loss.

Dr Fox agreed

Retrograde Amnesia: Memory loss w/ ECT is more likely to impair recent memories than ingrained ones. The more "fresh" the memory, the more likely it may be lost. It is not entire loss of memory, but rather "holes" in your memory. For example, you may remember who attended your recent birthday party, but have no recollection of any gifts. Unilateral electrode placement affects memory more than right unilateral.