Background: Although pulmonary vein isolation (PVI) is an effective treatment strategy for patients with paroxysmal atrial fibrillation (AF), it is associated with limited success rates in patients with persistent AF (PersAF). In this context the left atrial appendage (LAA) was recently identified as a target of catheter ablation especially in PVI non-responders. Although effective, this strategy may cause electromechanical dissociation and was therefore assumed to be associated with an increased risk of thromboembolism despite oral anticoagulation (OAC). Since RF based LAAI showed increased rates of thromboembolism and stable LAAI is difficult to achieve in some cases, Cryoballoon-based LAAI might offer a valuable option to achieve safe and durable LAAI. Recently the fourth generation cryoballoon (CB4, Arctic Front Advance Pro, Medtronic) was introduced. Additionally, the 40% shorter tip potentially increases the safety profile as well as efficacy of CB-based LAAI.

Objective: To assess safety and efficacy on CB2 vs CB4 based LAAI.

Methods: Cryoballoon based PVI and LAAI was performed in 20 patients with PersAF and long-standing PersAF. The first 10 consecutive patients were treated by the second-generation cryoballoon (CB2) the last 10 patients were treated by the CB4. LAAI was performed by utilizing a bonus freeze protocol (freezing time 300 seconds + another 300 seconds after LAAI).

Results: Stable LAAI was achieved after a mean of 2.6+/- 1.7 cryoballoon applications with a mean minimal temperature of -52+/-6 °C. Unless one phrenic nerve palsy (5.6%) of the left phrenic nerve no further periprocedural complications occurred. Successful LAAI was performed in 19/20 (95%). TEE after 6 weeks detected LAA thrombus in 3/10 (30%) patients (CB2 group) and 3/10 patients (30%) (CB4 group), p = 0.99. Successful LAA-closure was performed in 16/20 patients (80%) after a mean of 75+/-59 days. The LAA was durable isolated in 8/9 patients (89%, CB2) and 6/8 patients (75%, CB4), p=0.56). AF recurrence after 6 weeks was 1/10 (10%, CB2) and 3/9 (33%, CB4), p=0.26.

Conclusions: Here we used – to our knowledge – for the first time a CB4 for LAAI, followed by a combined check for LAAI and LAA-closure after 6 weeks, compared to the CB2. LAAI was successfully isolated by both cryo-balloons in the majority of patients. Hence the use of newest cryo-balloon generation for LAAI seems a safe and successful procedure compared to earlier balloon generations. However, a relatively high rate of LAA-Thrombus was detected after LAAI. Therefore, LAA closure is mandatory in this population.