Strategy to achieve mitral isthmus flutter ablation by radiofrequency: the SHERIFF plan.

BACKGROUND: Achieving mitral isthmus (MI) block can be challenging. This prospective study evaluated the feasibility and efficacy of a systematic strategy comprising three consecutive steps to achieve MI block. METHODS: Twenty consecutive patients (mean (± SD) age 71.4 ± 6.98 years) undergoing ablation of perimitral atrial tachycardia (PMAT) between December 2019 and November 2021 were included. MI was ablated using a systematic strategy comprising up to three consecutive steps: (1) endocardial ablation from the superolateral mitral annulus to the left pulmonary veins; (2) additional epicardial ablation in the coronary sinus (CS) on the opposite side of the endocardial line; and (3) ablation of early activation sites between endocardial and epicardial breakthroughs. RESULTS: MI block was successfully achieved in 19/20 patients (95%). MI block after endocardial radiofrequency ablation alone (step 1) was observed in 7/20 patients (35%). Epicardial ablation within the CS on the other side of the endocardial line (step 2) resulted in bidirectional MI block in three more patients. Endocardial ablation of epicardial conduction was successful for nine additional patients (95% success). At the 12-month follow-up, five patients (25%) displayed recurrence of arrhythmia after a single procedure. One patient had electrical cardioversion for persistent atrial fibrillation. Four patients had a redo procedure for left atrial flutter and only two patients (10%) had conduction across the MI and showed recurrence of PMAT. No complications occurred. CONCLUSIONS: The three-step ablation strategy resulted in a high rate of acute and durable MI block. PMAT recurrence after a single procedure was 10% at 1-year follow-up.

Early pacemaker insertion after aortic valve replacement with an Edwards Intuity sutureless valve.

BACKGROUND: Postoperative conduction disorders are serious adverse events in patients undergoing aortic valve replacement, and may prolong the duration of hospitalization and require pacemaker insertion. AIM: Our aim was to evaluate the rate of pacemaker insertion after implantation of an Edwards Intuity sutureless aortic valve (Edwards Lifesciences, Irvine, CA, USA) compared with a standard surgical bioprosthesis. METHODS: This retrospective single-centre study included patients who underwent aortic valve replacement with an Intuity sutureless aortic valve or a standard bioprosthetic valve between 4 June 2014 and 27 June 2016. The main outcome criterion was the rate of postoperative pacemaker insertion. Secondary outcome criteria included the rate of new conduction disorders, the rate of atrial arrhythmia or paroxysmal conduction disorders, mortality and duration of hospital stay. RESULTS: Ninety-three patients received an Intuity sutureless aortic valve (median age 76 years, interquartile range 71-80 years), and 176 were implanted with a standard biological aortic valve (median age 73 years, interquartile range 68-79 years; P=0.007). The rate of postoperative pacemaker insertion, after adjustment, was 22.44% in the Intuity group and 5.66% in the standard aortic valve group (P=0.030). The main indications for postoperative pacemaker insertion were complete atrioventricular block and left bundle branch block with prolongation of the H-V interval. The rate of new postoperative left bundle branch block conduction disorders was significantly higher in patients implanted with an Intuity valve (odds ratio 5.28, 95% confidence interval 1.59 to 23.05; P=0.012). CONCLUSION: Higher rates of pacemaker insertion and new conduction disorders were observed in patients implanted with an Intuity sutureless bioprosthesis compared with those who received a standard surgical aortic valve.

Micra AV leadless pacemaker implantation after transcatheter aortic valve implantation.

BACKGROUND: Transvenous pacemaker (PM) implantation is a complication in patients undergoing transcatheter aortic valve implantation (TAVI). Recently, a second generation of leadless PMs able of atrioventricular (AV) synchronous pacing has been introduced and could be an alternative when ventricular pacing is required after TAVI. Real-world data on Micra AV after TAVI are still lacking. Our aim was to determine the per- and post-procedural outcomes in patients with Micra AV leadless PM implantation after TAVI. METHODS: A total of 20 consecutive patients underwent Micra AV leadless PM implantation after TAVI between November 2020 and June 2021. RESULTS: The main indication for ventricular pacing was high-degree AV block (55% of patients) and left bundle branch block (LBBB) associated with prolonged HV interval (45% of patients). At discharge, mean (SD) ventricular pacing threshold was 0.397 ± 0.11 V at 0.24 ms and ventricular impedance was 709.4 ± 139.1 Ω. At 1-month follow-up, 95% of patients were programmed in VDD pacing mode. Mean (SD) ventricular pacing threshold was 0.448 ± 0.094 V at 0.24 ms. In patients with ventricular> pacing > 90% (n = 5), mean AM-VP was 72.5% ± 8.3%. Pacing threshold at 1 month was not significantly different compared to discharge (p = .1088). Mean (SD) impedance was 631.0 ± 111.9 Ω, which remained stable at discharge (p = .0813). No procedural complications occurred during implantation. At 1-month follow-up, two patients displayed atrial under-sensing. CONCLUSIONS: Micra AV leadless PM implantation after TAVI is associated with a low complication rate and good device performance at 1-month post-implantation.

An improved window of interest for electroanatomical mapping of atrial tachycardia.

PURPOSE: Diagnosis of atrial tachycardia (AT) with 3D mapping system remains challenging due to fibrosis or previous ablation. This study aims to evaluate a new electroanatomical mapping annotation setting using a window of interest adjusted at the end of the P wave (WOIp wave) to identify the AT mechanism more accurately. METHODS: Twenty patients with successful ablation of left AT using navigation system CARTO3 were evaluated. Two maps for each patient were generated offline using either conventional settings of WOI (WOIconv.) or WOIp wave. Three investigators from two centres analysed the maps blindly. RESULTS: Mechanisms of AT were macroreentrant in 14/20 patients (70%) and focal in 6/20 (30%). WOIp wave resulted in a significant increase in the percentage of correct identification of the mechanism based on mapping alone (93.3 ± 13.7% vs 58.3 ± 33.9%; p = 0.0003) compared with WOIconv.. Diagnoses based on mapping were arrived at faster (27.8 ± 16.4 s vs 38.97 ± 13.64 s, respectively; p = 0.0231) and with a greater confidence in the diagnosis (confidence index 2.57 ± 0.45 vs 2.12 ± 0.45, respectively; p = 0.0024). With perimitral re-entry specifically "early meets late" was closer to the anatomical region of the mitral isthmus (15.9 ± 20.9 mm vs 48.77 ± 23.23 mm, respectively; p = 0.0028). CONCLUSIONS: This study found that electroanatomical mapping acquisition with a window of interest set at the end of the P wave improves the ability to diagnose the arrhythmia mechanism based on the initial map. It is particularly beneficial in identifying area of interest for ablation in perimitral AT.

Elimination of the negative component of the unipolar electrogram as a local procedural endpoint during paroxysmal atrial fibrillation catheter ablation using contact-force sensing: the UNIFORCE study.

PURPOSE: Elimination of the negative component of the unipolar atrial electrogram is a reliable indicator of the creation of a transmural lesion. Contact-force (CF) sensing technology has the potential to increase the durability of pulmonary vein isolation (PVI). In the present multicenter study, we assessed the 2-year sinus rhythm (SR) maintenance rate in patients with paroxysmal atrial fibrillation (PAF) after PVI guided by these two approaches. METHODS: Two hundred fifteen consecutive PAF patients (62.1 ± 10.1 years, 65 women) were prospectively enrolled. All patients underwent PVI under CARTO guidance according to a systematic contiguous "point-by-point" approach, using radiofrequency energy, and a CF externally irrigated ablation catheter with the goal of at least 10g (ideally 20g) of force. The ablation endpoint of each individual lesion was elimination of the negative component of the unipolar atrial signal. The procedural endpoint was PVI with bidirectional block. RESULTS: All PVs were successfully isolated. After 30 min of waiting time, 35 patients (16%) had PV reconnection and in all of them, the PVs were re-isolated. Two years after a single ablation procedure, 187 patients (87%) remained arrhythmia free, without anti-arrhythmic drugs. Of the 28 patients presenting with AF recurrence, 25 had PV reconnection and underwent repeat PVI while in the remaining 3 patients, all four PVs were isolated and extra-PV triggers were identified. There were six groin hematomas and one transient ischemic attack. CONCLUSIONS: Unipolar atrial signal analysis combined with CF sensing ensures a robust 2-year SR maintenance rate in the treatment of PAF. Clinical trial registration-URL: http://www.clinicaltrials.gov . Unique identifier: NCT02520960.

Complete atrioventricular block decreases left ventricular assist device flow rate.

A 52-year-old man, living at home, had been on left ventricular assistance for 15 months with a Novacor pump (Worldheart, Ottawa, ON, Canada). Following the onset of effort dyspnea that had recently become worse, he was admitted to the hospital. A review of the pump showed that its flow rate had significantly decreased. An electrocardiogram showed a third-degree atrioventricular block. A pacemaker was implanted and the patient became asymptomatic immediately afterwards. This clinical case report shows the importance of satisfactory right ventricle filling in these patients. Right ventricle filling can be impaired by conduction disorders.