Perservative paroxysmal atrioventricular block: Cardiac syncope misdiagnosed as anxiety for more than 20 years

A 42-year-old woman was referred for cardiac diagnostic work-up of loss of recurrent consciousness over the past 25 years. She received medication with an anxiolytic, an antidepressant, and a neuroleptic drug. After a normal resting ECG, there were 112 episodes of paroxysmal atrioventricular block III° in her 24 h Holter recording with asystole for up to 27 s. The patient was symptomatic only once with dizziness due to an asystole of 8.8 s while she was awake in the early morning. After DDDR pacemaker implantation, the patient was asymptomatic during the following 2 years. This case illustrates the complex and not fully understood problem of paroxysmal AV block, in this instance neither intrinsic, nor phase 4 or vagally induced. It further reminds us to carefully clarify the cause of loss of consciousness consistently which may render prolonged ECG monitoring necessary also in patients without heart disease.