Swallow presyncope in an athletic patient caused by third-degree atrioventricular block.

Introduction Swallow syncope is a neurally mediated syncope. Multiple causes have been described in literature. A rare cause is arrhythmias. Only a limited amount of cases present the association of swallow syncope and third degree AV-block. Case presentation A 39-year-old man presented with episodes of presyncope while eating. Further medical history, physical examination, resting 12-lead ECG, cyclo-ergometry, transthoracic echocardiography and MRI of the heart were normal. 24 h Holter monitoring demonstrated high-grade third-degree atrioventricular (AV) block. The patient was scheduled for pacemaker implantation. Discussion Arrhythmia is a rare cause of swallow syncope. Reported arrhythmic causes are sinus bradycardia, sinoatrial block, atrioventricular block and complete atrial and ventricular asystole. Essential to the diagnosis is that (pre)syncope is preceded by swallowing and documentation of AV block on 24 h Holter monitoring. Treatment is guided by ESC guidelines which state that reflex syncope has a grade IIa recommendation for pacing, while current evidence suggests that asymptomatic vagally mediated AV block should not be treated until symptomatic.