Absence of an impact of emotional distress on the perception of intracardiac shock discharges.

The pain of transvenous cardioversion shocks in awake patients is an important clinical problem. It is unknown whether psychological factors modulate any observed variation in pain perception. Thirty-seven patients with chronic atrial fibrillation (AF; mean age 61.9 years, 29 men, 8 women) were consecutively included in the study. Pain perception of a low energy test shock (60V, 0.1J) during internal cardioversion was assessed immediately following the stimulus. Before treatment anxiety, depression, somatization were evaluated. The intracardiac shock was perceived as hypalgesic in 15 (41%) patients, as normalgesic in 10 (27%), and as hyperalgesic in 10 (32%) patients. Pain threshold was significantly lower in patients in which AF was accidentally diagnosed (p < 0.029). Age, sex, and the level of education were equally distributed over the three pain groups. The hyperalgesic pain threshold was not associated with anxiety, depression, or the patients' tendency to amplify benign bodily sensations. This study discloses a wide range of perceived pain intensity caused by a homogenous intracardiac stimulation. Anxiety and depression do not amplify perception of intracardiac shocks. Sensory gating mechanisms may play a more important role in the level of intracardiac shock perception than distressing affective factors.