Ticagrelor and Subacute Atrioventricular Block: Later It´s Possible

Ticagrelor is a potent, direct P2Y12 antagonist indicated in patients with acute coronary syndromes (ACS). This drug is usually well tolerated, but some patients experience serious adverse effects including ventricular pauses >3s. This side effect was usually transient and not associated with higher incidence of severe atrioventricular (AV) block. However, in last years some articles have described ACS patients with high-degree, life-threatening, AV block requiring drug discontinuation and, in some cases, pacemaker implantation. Usually those patients had previous conduction disturbances and bradyarrhythmia was detected hours to days after starting Ticagrelor therapy.

We describe one case of complete AV block following ticagrelor therapy detected long time after ACS. The patient had normal ECG before initiating Ticagrelor.

AV block was detected without symptoms in a Holter-ECG indicated for ventricular extrasystolia (12 months after ACS) under Bisoprolol plus Ticagrelor therapy. Bisoprolol was discontinuated but paroxysmal complete AV block unresolved after that.

The patient was then admitted to our hospital and Ticagrelor therapy was interrupted. During first 48 hrs only paroxysmal 2^nd degree AV block with narrow QRS was present, ECG monitoring during the next 48 hrs showed no AV block episodes.

Our experience suggests that conduction disturbances related to Ticagrelor therapy aren’t frequent and may be appreciated, in contrast with previous reports, long time after therapy starting and without pre-existing ECG abnormalities.

Further studies would help to detect and define the outcome of patients at higher risk of developing this complication.