This prospective study clarified changes in the mood states of Japanese patients with implantable cardioverter defibrillators as well as factors related to the mood states. Using a longitudinal repeated-measure design, 29 patients with implantable cardioverter defibrillators completed the Profile of Mood States-Short Form Japanese Version questionnaire before discharge and 1, 4, 7, and 13 months after implantation. One month after discharge, the mood states of the patients with implantable cardioverter defibrillators improved. From 7 to 13 months after discharge, moods deteriorated; 13 months after discharge, moods were equivalent to those at the time of discharge. No relationship with defibrillation experience was detected in this study, but employment, age, sex, and lack of experience of syncopal attack were factors related to poor mood states for patients with implantable cardioverter defibrillators. Therefore, Japanese patients with implantable cardioverter defibrillators with any factor deteriorating their mood state should be monitored so that their mood state does not deteriorate again between six months and one year after implantation
