Cathrin Theis

The second generation of transcatheter pacing systems, called Micra AV, can provide atrioventricular (AV) synchronous pacing via a new pacing algorithm relying on sensing mechanical atrial contraction. Several novel programming parameters were introduced to enable AV synchronous pacing, including an A3 window and A4 window as well as a conduction mode switch and an activity mode switch. In addition to several automated features, manual programming optimization of some of the novel parameters is key to improving AV synchrony. A solid knowledge of the features and their programming is essential for electrophysiologists implanting or following patients with Micra AV devices. Differences in programming optimization might partially explain the high variability of AV synchrony published in real-world data reports. This article reviews the key programming parameters of Micra AV. Subsequently, optimal programming recommendations for defined patient profiles are presented. Those were established by consensus within an expert panel comprised of 11 European electrophysiologists from high-volume Micra AV centres. The patient profiles were (1) high degree AV block and slow sinus rhythm; (2) high degree AV block and fast sinus rhythm; and (3) intermittent AV block. The panel recommended to evaluate the mechanical atrial activity on transthoracic echocardiography prior to implant. It was also agreed that Auto A3 Threshold and Tracking Check should be turned off in all patients, AV conduction mode switch should be turned off in all patients with high degree AV block, and the lower rate should be programmed to 50 bpm with exceptions based on individual clinical assessment. Future studies will be useful to evaluate the strength of those recommendations to improve the AV synchrony.

Background An effective therapy of persistent atrial fibrillation beyond pulmonary vein isolation remains unsatisfactory. Targeting endocardial low-voltage areas represents an approach of substrate modification. This prospective, randomized study investigated the efficacy of ablation of low-voltage areas versus PVI and additional linear ablations in patients with persistent atrial fibrillation in terms of single-procedure arrhythmia-free outcome and safety. Methods and results A total number of 100 patients undergoing de-novo catheter ablation for persistent AF were randomized in a 1:1 ratio into two different treatment arms: group A: pulmonary vein isolation (PVI) and, if low-voltage areas were present, a substrate modification. Group B: PVI and, if atrial fibrillation persisted, additional ablations, such as linear ablation and/or ablation of non-PV triggers. A total of 50 patients were randomized into each group without significant differences in baseline characteristics. During a mean follow-up of 17.64 ± 4.5 months after a single procedure, 34 (68%) patients of group A were free of arrhythmia recurrence versus 28 (56%) patients in group B (p = ns). In group A, 30 (60%) patients did not show endocardial fibrosis and received solely PVI. Both procedures were performed with a low number of complications; no pericardial effusion or stroke were seen in either group. Conclusions A significant proportion of patients with persistent atrial fibrillation do not show low-voltage areas. A total of 70% of the patients receiving solely PVI did not show any recurrence of atrial fibrillation, and therefore, extensive additional ablation should be avoided in de-novo patients. Graphical Abstract

Background: The single procedure success rates of durable pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation (AF) vary between 80% and 90%. This prospective, randomized study investigated the efficacy of cryoballoon PVI (CBA) versus PVI with radio‐frequency (RF)‐energy following the CLOSE protocol (ablation index [AI], interlesion distance ≤6 mm, surround flow catheter) in terms of single‐procedure arrhythmia‐free outcome and safety.Methods and Results: A total number of 150 patients undergoing de novo catheter ablation for paroxysmal AF were randomized to two different treatment arms. In group A patients, PVI was performed with the 23 or 28 mm cryoballoon (Artic Front™ Balloon in conjunction with an Achieve Mapping Catheter, Medtronic Inc.). The ablation procedure in group B was performed with RF‐energy, using AI and following the CLOSE protocol. PVI using AI incorporates stability, contact force (CF), time, and power. The CLOSE protocol combines AI and ≤6 mm interlesion distance using a surround flow catheter (Biosense Webster Thermocool STSF). A total of 75 patients were randomized into each group without significant differences in baseline characteristics. During a mean follow‐up of 12 ± 4.5 months after a single procedure, 64 (85.33%) patients of group A were free of arrhythmia recurrence versus 65 (86.67%) patients in group B (p = ns). A total of 14 patients (group A: 7 [9.33%]; group B: 7 [9.33%]; p = ns) underwent a redo‐procedure. No significant difference between both groups was observed in terms of PV recovery (group A: 4 [5.33%] vs. group B: 3 [4%]; p = ns). In two patients of group A and four patients of group B, the PVs were durably isolated, whereas the patients had AF recurrence caused by extra‐PV AF sources. Two patients of each group had continued paroxysmal AF but did not undergo redo‐procedure. Patients of group A showed significantly more AF recurrence during the blanking period of 3 months (group A: 14 [18.67%] vs. group B: 6 [8%]; p < .05). With regard to the procedural data, the procedure time was significantly shorter in group A (70.53 ± 16.13 vs. 115.35 ± 15.38; p < .01); the flouroscopy time and dose area product showed no significant differences (Table 2). Both procedures were performed with a low number of complications; no pericardial effusion was seen in either group; in group A two patients had a significant hematoma of the groin with the need for surgical repair.Conclusions: Cryoballoon PVI and PVI using ablation index following the CLOSE protocol are equally efficient in achieving durable PV isolation. In this study, cryoballoon ablation led to significantly more AF recurrence during the blanking period.

Background The single procedure success rates of durable pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation (AF) varies between 80 and 90 %. This prospective, randomized study investigated the efficacy of Cryoballoon PVI (CBA) versus pulmonary vein isolation with RF-energy following the CLOSE protocol in terms of single-procedure arrhythmia-free outcome and safety. Methods and results A total number of 150 patients undergoing de-novo catheter ablation for paroxysmal AF were randomized to two different treatment arms in a 1:1 fashion. In group-A patients, PVI was performed with the Cryoballoon (Articfront Balloon, Medtronic Inc). The ablation procedure in group B was performed with RF-energy (CARTO 3, Biosense Webster Thermocool STSF), following the CLOSE protocol. During a mean follow-up of 12  4.5 months after a single procedure, 64 (85.33 %) patients of group A were free of arrhythmia recurrence versus 65 (86.67 %) patients in group B (p=ns). A total of 14 patients (group A: 7 (9.33 %) group B: 7 (9.33 %); p=ns) underwent a redo-procedure. No significant difference between both groups was observed in terms of PV recovery (group A: 4 (5.33 %) vs. group B: 3 (4 %); p=ns). Patients of group A showed significantly more AF recurrence during the blanking period of three months (group A: 14 (18.67 %) versus group B: 6 (8 %); p<0.05. Conclusions Cryoballoon PVI and PVI using ablation index following the CLOSE protocol are equally efficient in achieving durable PV-isolation. Cryoballoon ablation leads to significantly more AF recurrence during the blanking period.

Background: After tricuspid valve (TV) surgery due to tricuspid regurgitation (TR), patients needing a permanent pacemaker often receive an epicardial lead implantation. This may result in delayed recovery from open‐chest surgery and increased postoperative risk. Leadless pacemaker (LPM) implantation may represent a valuable option.Methods and Results: A total of 14 consecutive patients underwent LPM implantation (Micra Transcatheter Pacing System, Medtronic, Minneapolis, MN) early after TV surgery. The pacing indication in those patients was atrial fibrillation with a slow atrio‐ventricular (AV) conduction or atrial fibrillation and a concomitant AV block III. Three patients already had a pacemaker prior to surgery, which was explanted during TV repair. Three patients received a valve replacement with a bioprosthesis, while the remaining eight patients received a TV repair. All procedural data and device measurements during and after LPM implantation were recorded. Transthoracic echocardiography was performed prior and post LPM implantation, showing no changes in TV or bioprosthesis performance. The device measurements were within an adequate range: threshold: 0.83 ± 0.34 V @ 0.24 ± 0 ms, impedance: 480 ± 58.88 ohm, and R‐wave: 10.10 ± 3.60 mV. LPM implantation was successful in all patients with a mean procedural time of 32 ± 11.8 minutes, fluoroscopy time of 3.71 ± 3.15 minutes, and dose‐area product of 536.67 ± 811.26 cGy/m².Conclusions: Implantation of an LPM early after TV surgery is a feasible option. LPM implantation does not affect TV or bioprosthesis performance in transthoracic echocardiography.