Post tachycardia sinus pause

ECG: At the beginning of the tracing, atrial activity is irregular, very rapid and disorganized; it corresponds to a conducted AF with complete right bundle branch block (QRS > 120 ms, rsR’ pattern in V1, wide and slurring S wave in V6); atrial arrhythmia is reduced with evidence of a post-tachycardia sinus pause of more than 2 seconds; resumption of normal sinus activity with the same pattern of right bundle branch block.

Comments: This type of tracing corresponds to a variant of atrial disease, associating episodes of atrial fibrillation and pauses occurring only at the time of the end of arrhythmia. The palpitations were related to episodes of paroxysmal atrial fibrillation, and the syncopes with the occurrence of post-tachycardia pauses. There are two possible strategies to prevent the occurrence of syncope in this setting. The first is to consider that the post-tachycardia pause is merely the consequence of the arrhythmia and that treatment should target atrial fibrillation. One study showed that in this type of patient, ablation of the pulmonary veins enabled to avoid arrhythmia recurrence while also allowing to suppress syncope. The second strategy is to consider that the post-tachycardia pause reflects the presence of a sinus node dysfunction revealed at the reduction hence justifying pacemaker implantation.

Take-home message: The occurrence of a post-tachycardia pause after an episode of atrial arrhythmia should be considered in a patient with atrial fibrillation or flutter and syncope.