Study design
Observational study in four European centres. We included all patients
aged over 18 with confirmed diagnosis of HCM undergoing a catheter
ablation for AF. According to the guidelines of the European Society of
Cardiology [2], HCM was defined as a wall thickness ≥15 mm in one or
more left ventricular myocardial segments (on either echocardiogram or
cardiac magnetic resonance imaging) that is not explained solely by
loading conditions. Participants needed to be on effective oral
anticoagulation (VKA, apixaban, edoxaban, rivaroxaban, or dabigatran)
for at least 30 days before the procedure to be considered for
inclusion. Patients on VKA had a target INR of 2-3. Peri-procedure
interruption or continuation of the oral anticoagulants, with or without
heparin bridging, was based on the local protocol of each centre at the
time of the ablation. In patients elected to VKA interruption with
heparin bridging, the VKA was substituted 3 days before the procedure
with enoxaparin 100 IU/kg twice a day or dalteparin 200 IU/kg daily. All
patients provided written informed consent prior to the procedure. The
study complied with the Declaration of Helsinki and the research
protocol was approved by the local ethics or audit committees.