High efficiency single-catheter workflow for radiofrequency atrial fibrillation ablation in the QDOT catheter era.

BACKGROUND: High-power short-duration (HPSD) ablation may improve the consistency and efficiency of pulmonary vein isolation (PVI). The novel QDOT Micro™ catheter (Biosense Webster, Inc.) with temperature feedback and microelectrodes aims to enhance PVI efficiency and safety. This study wants to evaluate the feasibility, safety, and efficiency of a standardized single-catheter workflow for PVI using QDOT (Q-FLOW). METHODS: The Q-FLOW includes single transeptal access, radiofrequency encircling of the PVs using a power of 50 W in a temperature/flow-controlled mode, and validation of the circles with microelectrodes. A 1:1 propensity-matched cohort of patients treated with conventional power-controlled ablation using a circular mapping catheter (CMC-FLOW) was used to compare procedural and clinical outcomes. RESULTS: A total of 150 consecutive atrial fibrillation patients (paroxysmal 67%, persistent 33%) were included. First-pass isolation rate was 86%. Procedural time, X-ray time, and dose were significantly lower for the Q-FLOW vs the CMC-FLOW (67.2 ± 17.9 vs 88.3 ± 19.2 min, P < 0.001; 3.0 ± 1.9 vs 5.0 ± 2.4 min, P < 0.001; 4.3 ± 1.9 vs 6.4 ± 2.3 Gycm2, P < 0.001). Complications were numerically but not significantly lower in the Q-FLOW group (2 [1.3%] vs 7 [4.7%], P = 0.091). There was no difference in arrhythmia recurrence at 12 months (atrial arrhythmia-free survival rate, 87.5% vs 84.4%, P = 0.565). CONCLUSION: A streamlined single-catheter workflow for PVI using QDOT was feasible and safe, resulting in a high rate of first-pass isolation and a low complication rate. The Q-FLOW further improved the efficiency of PVI compared to the standard CMC-FLOW, without difference in the 12-month outcome.

Transcatheter Aortic Valve Implantation and Cardiac Conduction Abnormalities: Prevalence, Risk Factors and Management.

Over the last decades, transcatheter aortic valve implantation (TAVI) or replacement (TAVR) has become a potential, widely accepted, and effective method of treating aortic stenosis in patients at moderate and high surgical risk and those disqualified from surgery. The method evolved what translates into a noticeable decrease in the incidence of complications and more beneficial clinical outcomes. However, the incidence of conduction abnormalities related to TAVI, including left bundle branch block and complete or second-degree atrioventricular block (AVB), remains high. The occurrence of AVB requiring permanent pacemaker implantation is associated with a worse prognosis in this group of patients. The identification of risk factors for conduction disturbances requiring pacemaker placement and the assessment of their relation to pacing dependence may help to develop methods of optimal care, including preventive measures, for patients undergoing TAVI. This approach is crucial given the emerging evidence of no worse outcomes for intermediate and low-risk patients undergoing TAVI in comparison to surgical aortic valve replacement. This paper comprehensively discusses the mechanisms, risk factors, and consequences of conduction abnormalities and arrhythmias, including AVB, atrial fibrillation, and ventricular arrhythmias associated with aortic stenosis and TAVI, as well as provides insights into optimized patient care, along with the potential of conduction system pacing and cardiac resynchronization therapy, to minimize the risk of unfavorable clinical outcomes.

Robotic magnetic navigation-guided catheter ablation establishes highly effective pulmonary vein isolation in patients with paroxysmal atrial fibrillation when compared to conventional ablation techniques.

INTRODUCTION: Pulmonary vein isolation (PVI) is a pivotal part of ablative therapy for atrial fibrillation (AF). Currently, there are multiple techniques available to realize PVI, including: manual-guided cryoballoon (MAN-CB), manual-guided radiofrequency (MAN-RF), and robotic magnetic navigation-guided radiofrequency ablation (RMN-RF). There is a lack of large prospective trials comparing contemporary RMN-RF with the more conventional ablation techniques. This study prospectively compared three catheter ablation techniques as treatment of paroxysmal AF. METHODS: This multicenter, prospective study included patients with paroxysmal AF who underwent their first ablation procedure. Procedural parameters (including procedural efficiency), complication rates, and freedom of AF during 12-month follow-up, were compared between three study groups which were defined by the utilized ablation technique. RESULTS: A total of 221 patients were included in this study. Total procedure time was significantly shorter in MAN-CB (78 ± 21 min) compared to MAN-RF (115 ± 41 min; p < .001) and compared to RMN-RF (129 ± 32 min; p < .001), whereas it was comparable between the two radiofrequency (RF) groups (p = .062). A 3% complication rate was observed, which was comparable between all groups. At 12-month follow-up, AF recurrence was observed in 40 patients (19%) and was significantly lower in the robotic group (MAN-CB 19 [24%], MAN-RF 16 [23%], RMN-RF 5 [8%] AF recurrences, p = .045) (multivariate hazard ratio of RMN-RF on AF recurrence 0.32, 95% confidence interval: 0.12-0.87, p = .026). CONCLUSION: RMN-guided PVI results in high freedom of AF in patients with paroxysmal AF, when compared to cryoablation and manual RF ablation. Cryoablation remains the most time-efficient ablation technique, whereas RMN nowadays has comparable efficiency with manual RF ablation.

Juvenile-onset multifocal atrial arrhythmias, atrial standstill and compound heterozygosity of genetic variants in TAF1A: sentinel event for evolving dilated cardiomyopathy-a case report.

Background: Juvenile onset of extensive atrial electromechanical failure, including atrial standstill, is a rare disease entity that may precede ventricular cardiomyopathy. Genetic variants associated with early-onset atrioventricular (AV) cardiomyopathy are increasingly recognized. Case summary: A 16-year-old patient presented with atrial brady- and tachyarrhythmias and concomitant impaired atrial electromechanical function (atrial standstill). The atrial phenotype preceded the development of a predominantly right-sided AV dilated cardiomyopathy with pronounced myocardial fibrosis. A His-bundle pacemaker was installed for high-degree AV conduction block and sinus arrest. Using familial-based whole-exome sequencing, a missense mutation and a copy number variant deletion (compound heterozygosity) of the TAF1A gene (involved in ribosomal RNA synthesis) were identified. Discussion: Juvenile onset of severe atrial electromechanical failure with atrial arrhythmias should prompt deep pheno- and genotyping and calls for vigilance for downstream cardiomyopathic deterioration.

Re-implantation after extraction of a cardiac implantable electronic device.

Background: With increasing cardiovascular implantable electronic device (CIED) implantations, growing number of extractions of leads and devices are noted, mainly for complications such as infection and lead dysfunction. The optimal timing for re-implantation remains uncertain. We  investigated the time to eventual re-implantation of CIEDs in the University Hospitals Leuven, Belgium.Methods: All consecutive patients, referred for extraction between January 2005 and December 2016, were analysed for the timing of eventual re-implantation.Results: Two-hundred and forty-three patients were included. Mean follow-up was 77 ± 37 months. Global re-implantation rate was 89.3%: 100% for lead dysfunctions versus 80.7% following infections. Median time to re-implantation (TTR) was 0 [0-111] days and 8.5 [0-3025] days, respectively (p < .001). Globally 0 [0-3025] days. Re-implantation was performed in 83.2% of pacemaker patients, compared to 95.8% of defibrillator patients (p < .001). Median TTR was 4 [0-3025] days and 0 [0-345] days, respectively (p < .001). In AV-block related pacemaker indications, 90% were re-implanted, compared to 78% for symptomatic indications (p = .09). Median TTR was 2 [0-3025] and 6 [0-2047] days, respectively (p = .02). Re-implantation was performed in 96.7% of defibrillator patients with a secondary prevention indication, compared to 94.7% with primary prevention indication (p = .59). Median TTR was 0 [0-164] and 0 [0-345] days, respectively (p = .472).Conclusions: Ten percent of CIEDs is not re-implanted after extraction. CIEDs are re-implanted more often and earlier after extraction for lead dysfunction than after extraction for infectious reasons. Pacemakers are re-implanted less and later than defibrillators. Re-implantation is performed faster in stronger clinical CIED indications.