Does left atrial epicardial conduction time reflect atrial fibrosis and the risk of atrial fibrillation recurrence after thoracoscopic ablation? Post hoc analysis of the AFACT trial.

OBJECTIVES: To determine the association between left atrial epicardial conduction time (LAECT), fibrosis and atrial fibrillation (AF) recurrence after thoracoscopic surgical ablation of persistent AF. SETTING: Single tertiary care centre in the Netherlands. PARTICIPANTS: Patients with persistent AF from the randomised Atrial Fibrillation Ablation and Autonomic Modulation via Thoracoscopic Surgery (AFACT)-trial were included. Patients eligible for thoracoscopic AF ablation were included, full inclusion and exclusion criteria were previously published. All patients underwent thoracoscopic ablation, encompassing pulmonary vein isolation with an additional roof and trigone lesion. In patients with conduction block across the roof and trigone lesion, LAECT was measured. LAECT was defined as the time to local activation at one side of the roofline on pacing from the opposite side. Collagen fibre density was quantified from left atrial appendage histology. OUTCOME MEASURES: Primary outcome: AF recurrence during 2 years of follow-up. RESULTS: 121 patients were included, of whom 35(29%) were women, age was 60.4±7.8 and 51% (62) had at least one AF recurrence during 2 years of follow-up. LAECT was longer in patients with versus without AF recurrence (182±43 ms vs 147±29 ms, p<0.001). LAECT was longer in older patients, in patients with a higher body mass index (BMI) and in patients using class IC antiarrhythmic drugs. LAECT was shorter in patients with higher collagen fibre density. A previously failed catheter ablation, LAECT and BMI were independently associated with AF recurrence. CONCLUSION: LAECT is correlated with collagen fibre density and BMI and is independently associated with AF recurrence in patients with persistent AF. In these patients, LAECT appears to reflect substrate characteristics beyond clinical AF type and left atrial volume. TRIAL REGISTRATION NUMBER: NCT01091389.

Anticoagulant bridging in left-sided mechanical heart valve patients.

BACKGROUND: In preparation for an invasive procedure with a high bleeding risk, patients with a mechanical heart valve temporarily have to discontinue their anticoagulant therapy and are usually bridged with either intravenous unfractionated heparin (UFH) or subcutaneous low-molecular-weight heparin (LMWH). In this study we retrospectively analyzed the safety of UFH versus LMWH as bridging strategy in left-sided mechanical heart valve patients. METHODS: We performed a retrospective multicenter study in four surgical centers in The Netherlands. Patients with a mechanical heart valve implantation bridged from January 2010 until January 2015 were included. The cumulative incidence of adverse events in the 30days following the procedure was recorded. Main outcomes were major bleeding according to International Society on Thrombosis and Haemostasis (ISTH) criteria, symptomatic thromboembolism, and mortality. RESULTS: In total, 238 (174 aortic, 42 mitral, 22 aortic+mitral) bridging episodes were included. The incidence of major bleeding was 16 (19%) events in the UFH group versus 29 (19%) events in the LMWH group (p=0.97). Incidences of thromboembolism were 2 (2.4%) versus 1 (0.6%). The incidence of death was 1 (1.2%) patient in the UFH group versus 3 (1.9%) patients in the LMWH group. More than 50% of all bleeding complications were categorized as a major bleeding. CONCLUSIONS: Bridging anticoagulation in patients with aortic and mitral mechanical valves is associated with considerable risk, but no difference was apparent between UFH and LMWH strategy. The rate of thromboembolism and death was low with either strategy and the vast majority of adverse events were bleedings.