Ticagrelor-associated ventricular pauses: A case report and literature review

We present a case of symptomatic ventricular pauses in a patient loaded with ticagrelor post-percutaneous coronary intervention (PCI) for non-ST elevation acute coronary syndrome (NSTEACS) and review the literature relating to ticagrelor and its brady-arrhythmic potential. Case summary A 59-year-old female presented to our hospital with NSTEACS and received an oral load of ticagrelor 180 mg following PCI to her mid-left circumflex coronary artery.

Three hours after, four pauses were observed on telemetry over a 20 min period, the longest being 18.5 s in duration. Ticagrelor was ceased and clopidogrel commenced in place. No arrhythmic events were recorded on loop recorder interrogation following ticagrelor discontinuation.

Discussion The exact mechanism of ticagrelor-induced brady-arrhythmia is unclear, although inhibition of adenosine reuptake is proposed as likely due to structural similarities between ticagrelor and adenosine. In the setting of acute coronary syndrome treated with ticagrelor, extracellular adenosine concentrations are amplified by the ischaemic milieu with myocardial adenosine release and blunted cellular reuptake. This leads to enhanced agonism of adenosine A1 receptors, causing negative chronotropy and dromotropy.

This case report highlights ticagrelor’s brady-arrhythmic potential even in the absence of baseline conduction disease or concurrent confounding medications.