Background: Patients with AF and likelihood of bleeding can undergo left atrial appendage occlusion (LAAO) as an alternative method of stroke prophylaxis. Short-term anti-thrombotic drugs are used post-procedure to offset the risk of device-related thrombus, evidence for this practice is limited. Objectives: To investigate optimal post-implant antithrombotic strategy in high bleeding-risk patients. Methods: Patients with AF and high-risk for both stroke and bleeding undergoing LAAO were advised their peri-operative drug therapy by a multi-disciplinary physician panel. Those deemed to be at higher risk of bleeding from anti-thrombotic drugs were assigned to minimal treatment with no antithrombotics or aspirin-alone. The remaining patients received standard care (STG)with a 12week course of dual-antiplatelets or anticoagulation post-implant. We compared mortality, device-related thrombus, ischemic stroke and bleeding events during the 90 days post-implant and long-term. Event-free survival was assessed using Kaplan-Meier survival analysis, with logrank testing for statistical significance. Results: 75 pts underwent LAAO of whom 63pts(84%) had a prior serious bleeding event. The 42pts on minimal treatment were older(74.3±7.7vs71.2±7.2) with higher HASBLED score (3.6±0.9vs3.3±1.2) than the 33pts having standard care. There were no device-related thrombi or strokes in either group at 90 days post-procedure; STG had more bleeding events (5/33vs0/42,p=0.01) with associated deaths (3/33vs0/42,p=0.05). During long-term follow up (median 2.2yrs), all patients transitioned onto no antithrombotic drugs (43pts(61%)) or a single-antiplatelet (29pts(39%)). There was no evidence of early minimal treatment adversely affecting long-term outcomes. Conclusions: Short-term anti-thrombotic drugs may not be needed after LAAO implant in patients with high bleeding risk and could be harmful. Larger, prospective studies would be warranted to test these findings.

Aims: A prolonged PR interval may adversely affect ventricular filling and therefore cardiac function. AV delay can be corrected using right-ventricular-pacing (RVP) but this induces ventricular dyssynchrony, itself harmful. Therefore, in intermittent heart-block, pacing-avoidance algorithms are often implemented. We tested His-bundle pacing (HBP) as an alternative. Methods: Out-patients with a long PR interval(>200ms) and intermittent need for ventricular pacing were recruited. We measured within patient differences in high-precision haemodynamics between AV-optimized RVP, and HBP, as well as a pacing-avoidance algorithm [Managed Ventricular Pacing (MVP)]. Results We recruited 18 patients. Mean left ventricular ejection fraction was 44.3±9%. Mean intrinsic PR interval was 266±42ms and QRS duration was 123±29ms. RVP lengthened QRS duration(+54 ms, 95%CI 42 to 67ms, p<0.0001) whilst HBP delivered a shorter QRS duration than RVP(-56 ms, 95%CI -67 to -46ms, p<0.0001). HBP did not increase QRS duration(-2ms 95%CI -8 to 13ms, p=0.6). HBP improved acute systolic blood pressure by mean of 5.0 mmHg(95%CI 2.8 to 7.1mmHg, p<0.0001) compared to RVP and by 3.5 mmHg(95%CI 1.9 to 5.0mmHg, p=0.0002) compared to the pacing avoidance algorithm. There was no significant difference in haemodynamics between RVP and ventricular pacing avoidance (p=0.055). Conclusions HBP provides better acute cardiac function than pacing avoidance algorithms and RVP, in patients with prolonged PR intervals. HBP allows normalisation of prolonged AV delays (unlike pacing avoidance) and does not cause ventricular dyssynchrony (unlike RVP). Clinical trials may be justified to assess whether these acute improvements translate into longer term clinical benefits in patients with bradycardia indications for pacing.