Defining the blanking period, using continuous ECG monitoring, after cryoballoon pulmonary vein isolation.

BACKGROUND: Pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation (AF) ablation. A blanking period (BP) of 3 months is used in clinical trials and practice. However, the optimal BP duration after PVI remains undefined. OBJECTIVE: The aim of this study was to objectively define, using continuous monitoring by an implantable loop recorder, the optimal BP duration after cryoballoon PVI. METHODS: We enrolled consecutive patients who had cryoballoon PVI and an implantable loop recorder. We determined the time of the last confirmed episode of AF within the blanking period. This was then correlated with AF recurrence in the first year after ablation. RESULTS: There were 210 patients (66 ± 9 years; 138 [66%] male; 116 [55%] paroxysmal AF; CHA2DS2-VASc score, 2.5 ± 1.6). We defined 4 distinct groups based on the last AF episode within the BP: no AF days 0-90 (n = 96 [46%]) and last AF 0-30 days (n = 46 [22%]), 31-60 days (n = 18 [9%]), and 61-90 days (n = 50 [24%]). After the 3-month BP, 101 (48%) patients had AF recurrence at 160 ± 86 days. Compared with patients with no AF in the BP, those with recurrent AF and AF burden >0% 30 days after ablation had a significantly greater AF recurrence during long-term follow-up (P = .001). CONCLUSION: Our data show that the approximately one-third of patients in whom AF occurs and who have a burden of >0% after the first month that follows PVI are at significantly higher risk of long-term recurrent AF. We therefore suggest that the blanking period be limited to a month after cryoballoon PVI.

Results from the prospective, multicenter AMBULATE-CAP trial: Reduced use of urinary catheters and protamine with hemostasis via the Mid-Bore Venous Vascular Closure System (VASCADE® MVP) following multi-access cardiac ablation procedures.

INTRODUCTION: Manual compression (MC), historically the most common method to achieve hemostasis after percutaneous vascular procedures, is time consuming, requires prolonged bedrest, and is uncomfortable for patients and clinicians. Recent studies demonstrate the efficacy and safety of vascular closure devices and suggest shorter times to hemostasis and patient ambulation compared with MC. The current study evaluated the feasibility of the VASCADE® venous vascular closure system (VVCS) while allowing for urinary catheter (UC) elimination, and elimination of protamine and/or same calendar day discharge (SCDD). METHODS AND RESULTS: In this prospective, multicenter trial, patients were enrolled and assigned to the following groups: no UC, no protamine, and/or SCDD (no co-enrollment in no protamine and SCDD). After completing the catheter-based cardiac procedure, access sites were closed using the VVCS. Outcomes included final hemostasis (all sites) without major access site-related complications at 30 days, rates of access site closure-related complications, device success, and study group success. All 168 patients had hemostasis without major access site-related complications through 30 days. In the no UC group, 160 out of 164 (97.6%) patients did not receive a UC. Additionally, 39 out of 41 (95.1%) patients received heparin without protamine reversal and no access site bleeding-related ambulation delays, and 18 out of 18 (100%) patients were discharged on the same day. There were no major access site closure-related complications, few minor complications, and adverse events were generally mild and well managed. CONCLUSION: The VVCS was effective for achieving hemostasis following catheter-based procedures; access site closure-related complications and adverse events were well managed.

Incidence and Predictors of Very Late Recurrence of Atrial Fibrillation Following Cryoballoon Pulmonary Vein Isolation.

BACKGROUND: A very late recurrence (VLR) of atrial fibrillation (AF) is considered present when the first recurrence of AF occurs ≥12 months following ablation. Prior studies characterizing VLR have not used an implantable loop recorder for ECG monitoring. Thus, it is unknown whether VLR truly occurs or whether these patients have simply had unrecognized AF. Our objective was to assess the incidence and predictors of VLR in patients who underwent cryoballoon pulmonary vein isolation alone, had an implantable loop recorder, and were confirmed AF free for at least 1 year. METHODS: We enrolled consecutive patients with paroxysmal or persistent AF who underwent cryoballoon pulmonary vein isolation and had an implantable loop recorder implanted <3 months post-ablation. Patients free of AF 1 year post-ablation were followed prospectively for recurrent AF. All AF episodes were adjudicated. RESULTS: We included 188 patients (66±10 years; 116 [62%] men; 102 [54%] paroxysmal AF; CHA2DS2-VASc, 2.6±1.7). After 1 year post-pulmonary vein isolation, 93 (49%) patients remained AF free. During subsequent follow-up, 30 (32%) patients had VLR of AF. The only independent risk factor for VLR was an elevated CHA2DS2-VASc score (hazard ratio, 1.317 [95% CI, 1.033-1.6979]; P=0.026). Patients with CHA2DS2-VASc score ≥4 represented a quarter of the population and were at the highest risk. CONCLUSIONS: Our data using implantable loop recorders for continuous ECG monitoring post-AF ablation show that VLR occurs in a third of patients after an apparently successful cryoballoon pulmonary vein isolation procedure. Additional strategies are needed to ensure long-term freedom from AF recurrences in these high-risk patients.

Incidence, duration, pattern, and burden of de novo atrial arrhythmias detected by continuous ECG monitoring using an implantable loop recorder following ablation of the cavotricuspid isthmus.

Background: Following cavotricuspid isthmus (CTI) ablation, many patients with atrial flutter (AFL) are diagnosed with atrial fibrillation (AF). The incidence, duration, pattern, and burden of AF remain undefined. These may have implications for the management of these patients. Objective: To classify the incidence, duration, pattern, and burden of AF/AFL using an implantable loop recorder (ILR) after CTI ablation. Methods: We enrolled consecutive patients with CTI-dependent AFL, no known history of AF, and CHA2DS2-VASc ≥ 2. An ILR was implanted before or within 90 days of ablation. The time to first AF/AFL, pattern, duration, and burden of longest AF/AFL were determined. Five distinct AF/AFL cohorts were identified: no AF/AFL and those with recurrences of isolated, clustered, frequent, or persistent AF/AFL. Results: Fifty-two patients (81% male; 73 ± 9 years; CHA2DS2-VASc 3.7 ± 1.2) were followed for 784 (interquartile range [IQR] 263, 1150) days. AF/AFL occurred in 44 (85%) patients at 64 (IQR 8, 189) days post-CTI ablation and was paroxysmal in 31 (70%) patients (burden 0.6% [IQR 0.1, 4.8]). AF/AFL was isolated (n = 5, 11%), clustered (n =7, 16%), frequent (n =19, 43%), and persistent (n =13, 30%). The longest AF episode was <24 hours in 27 (61%) patients. Conclusion: Following CTI ablation in AFL patients, although AF/AFL occurs in most patients, the burden is low and episodes were <24 hours in the majority of patients. Additional studies are needed to determine whether long-term electrocardiographic monitoring can help guide management of patients undergoing CTI ablation.

The Efficacy of His Bundle Pacing: Lessons Learned From Implementation for the First Time at an Experienced Electrophysiology Center.

OBJECTIVES: This study sought to evaluate the clinical and procedural characteristics impacting outcomes during implementation of a His bundle pacing (HBP) program in a real-world setting. BACKGROUND: Right ventricular pacing is associated with an elevated risk of heart failure, but device reprogramming and upgrades have significant challenges. HBP has emerged as an alternative and is reported to be highly successful in the hands of highly experienced centers. METHODS: All patients referred for permanent pacemaker implantation at the Valley Hospital (Ridgewood, New Jersey) between October 2015 and October 2017 were evaluated; a subset of 24% was selected for HBP. RESULTS: Permanent HBP was feasible with an acute implant success rate of 75%. HBP in the presence of bundle branch block (64% vs. 85%; p = 0.05) or complete heart block (56% vs. 83%; p = 0.03) was significantly less successful. The pattern of atrioventricular block in combination with bundle branch block (BBB) further affects outcomes. HBP is highly successful across the spectrum of atrioventricular block pattern severity in the absence of BBB. In the presence of BBB, Mobitz II AV block and complete heart block significantly attenuated HBP success compared with Mobitz I atrioventricular block (62% vs. 100%; p = 0.02). A rising threshold was observed in 30%, and 8% required lead intervention. CONCLUSIONS: HBP was feasible and readily learned with a high implant success in the hands of experienced electrophysiologists without prior exposure to the technique. BBB and atrioventricular block pattern appears to affect success. The technique is limited by a high rate of rising thresholds and lead intervention. These data have important implications for patient selection.

Correlation of QT interval correction methods during atrial fibrillation and sinus rhythm.

The calculation of the corrected QT interval (QTc) is particularly problematic in patients during atrial fibrillation (AF). The aims of this study were to compare the QTc calculated using Bazett's formula in AF and sinus rhythm (SR) and determine whether alternative methods for QT correction were superior to Bazett's, in an effort to define the optimal method for QT correction in patients with AF. We evaluated consecutive patients with persistent AF admitted for initiation of dofetilide. The QT interval was corrected according to the following formulas: Bazett's, Fridericia, and Framingham. We compared the QTc interval on the last electrocardiogram in AF to the first electrocardiogram in SR. The cohort included 54 patients (age 60 ± 10 years, 80% men) with persistent AF for a median of 36 months. Bazett's overestimated QTc during AF compared with SR (464 ± 34 vs 445 ± 38 ms, p = 0.008); in contrast, Framingham underestimated it (385 ± 48 vs 431 ± 40 ms, p <0.001, respectively). However, there was no significant difference between the QTc interval in AF and SR when assessed by Fridericia (435 ± 33 vs 440 ± 35 ms, p = 0.46). There were 24 dofetilide dose reductions based on Bazett's QTc; this would have been avoided in 33% of patients had Fridericia been used. In conclusion, the commonly used Bazett's formula leads to an overestimation of the QTc during AF. This may result in unnecessary reduction in antiarrhythmic doses and thus drug efficacy. These data suggest that the Fridericia most closely approximates the QTc during AF to QTc during SR.