Assessment of Antitachycardia Pacing in Primary Prevention Patients: The APPRAISE ATP Randomized Clinical Trial.

Importance: The emergence of novel programming guidelines that reduce premature and inappropriate therapies along with the availability of new implantable cardioverter-defibrillator (ICD) technologies lacking traditional endocardial antitachycardia pacing (ATP) capabilities requires the reevaluation of ATP as a first strategy in terminating fast ventricular tachycardias (VTs) in primary prevention ICD recipients. Objective: To assess the role of ATP in terminating fast VTs in primary prevention ICD recipients with contemporary programming. Design, Setting, and Participants: This global, prospective, double-blind, randomized clinical trial had an equivalence design with a relative margin of 35%. Superiority tests were performed at interim analyses and the final analysis if equivalence was not proven. Patients were enrolled between September 2016 and April 2021 at 134 sites in 8 countries, with the last date of follow-up on July 6, 2023. Patients were required to have an indication for a primary prevention ICD, including left ventricular ejection fraction less than or equal to 35%. Interventions: Patients were randomized in a 1:1 ratio to receive ATP plus shock vs shock only. Main Outcomes and Measures: The primary end point was time to first all-cause shock. Secondary end points included time to first appropriate shock, time to first inappropriate shock, all-cause mortality, and the composite of time to first all-cause shock plus all-cause mortality. Results: A total of 2595 patients were randomized (mean age, 63.9 years; 22.4% were females). At a mean follow-up of 38 months, first all-cause shock occurred in 129 participants in the ATP plus shock group and 178 participants in the shock only group. The hazard ratio (HR) for the primary end point was 0.72 (95.9% CI, 0.57-0.92), with P = .005 for superiority of the ATP plus shock group over the shock only group. During follow-up in an intention-to-treat analysis, the total shock burden per 100 patient-years was not statistically different, at 12.3 and 14.9, respectively (P = .70). Conclusions and Relevance: The use of a single burst of ATP prior to shock in primary prevention ICD recipients with modern ICD detection programming prolonged the time to first all-cause ICD shock. Trial Registration: ClinicalTrials.gov Identifier: NCT02923726.

Effects of Atrioventricular Optimization on Left Ventricular Reverse Remodeling With Cardiac Resynchronization Therapy: Results of the SMART-CRT Trial.

BACKGROUND: The role of atrioventricular optimization (AVO) to improve cardiac resynchronization therapy outcomes remains controversial. Previous post hoc analyses of a multicenter trial showed that measures of electrical dyssynchrony (right ventricular-left ventricular [LV] or LV electrical delay durations) are associated with patients who benefit from AVO. METHODS: This was a global, multicenter, prospective, randomized trial of de novo cardiac resynchronization therapy implant patients with an right ventricular-LV duration ≥70 ms to determine whether AVO results in greater reverse remodeling. Patients were randomized 1:1 for either an AVO algorithm (SmartDelay) that determines atrioventricular delay and pacing chamber, biventricular or LV only, or a fixed atrioventricular delay of 120 ms with biventricular pacing. Paired echocardiograms performed at baseline and 6 months were evaluated. The primary end point was echocardiographic cardiac resynchronization therapy response, defined dichotomously as a >15% reduction in LV end-systolic volume. RESULTS: A total of 310 patients (n=120 women) were randomized and had completed 6 months of follow-up. The echocardiographic cardiac resynchronization therapy response rate did not statistically differ between the groups (SmartDelay, 74.8%; fixed, 67.7%; P=0.17). Analyses of prespecified secondary end points demonstrated significant improvements in the absolute (median: SmartDelay, -41.0 mL; fixed, -33.0 mL; P=0.01) and relative change in LV end-systolic volume (SmartDelay, -38.3%; fixed, -27.8%; P=0.03) for patients with SmartDelay optimization. Similar results were observed for the relative improvement in LV ejection fraction (SmartDelay, 46.7%; fixed, 32.1%; P=0.050); absolute improvement in LV ejection fraction trended to be higher with SmartDelay (P=0.06). CONCLUSIONS: Analysis of reverse remodeling parameters demonstrated that AVO via SmartDelay, relative to the nonoptimized fixed atrioventricular delay comparator group, improved absolute and relative changes in LV function in patients with longer right ventricular-LV duration. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT03089281.

Cardiovascular implantable electronic device implantation with uninterrupted dabigatran: comparison to uninterrupted warfarin.

BACKGROUND: While continuation of oral anticoagulation (OAC) with warfarin may be preferable to interruption and bridging with heparin for patients undergoing cardiovascular implantable electronic device (CIED) implantation, it is uncertain whether the same strategy can be safely used with dabigatran. OBJECTIVE AND METHODS: To determine the risk of bleeding and thromboembolic complications associated with uninterrupted OAC during CIED implantation, replacement, or revision, the outcomes of patients receiving uninterrupted dabigatran (D) were compared to those receiving warfarin (W). RESULTS: D was administered the day of CIED implant in 48 patients (age 66 ± 12.4 years, 13 F and 35 M, 21 ICDs and 27 PMs), including new implant in 25 patients, replacement in 14 patients, and replacement plus lead revision in 9 patients. D was held the morning of the procedure in 14 patients (age 70 ± 11 years, 4 F and 10 M, 5 ICDs and 9 PMs). W was continued in 195 patients (age 60 ± 14.4 years, 54 F, and 141 M), including new implant in 122 patients, replacement in 33 patients, and replacement plus lead revision or upgrade in 40 patients. Bleeding complications occurred in 1 of 48 patients (2.1%) with uninterrupted dabigatran (a late pericardial effusion), 0 of 14 with interrupted D, and 9 of 195 patients (4.6%) on W (9 pocket hematomas), P = 0.69. Fifty percent of bleeding complications were associated with concomitant antiplatelet medications. CONCLUSIONS: The incidence of bleeding complications is similar during CIED implantation with uninterrupted D or W. The risks are higher when OAC is combined with antiplatelet drugs.

Catheter ablation of a posteroseptal accessory pathway in a case with congenital long QT syndrome.

A 23-year-old woman with pre-excitation who was resuscitated from ventricular fibrillation underwent electrophysiologic testing. Successful catheter ablation of a left posteroseptal accessory pathway was achieved. Though the JT and JTc intervals as well as QT and QTc intervals were prolonged before and one day after the ablation, they normalized within about 5 hours after the ablation. This case demonstrated that in a patient with pre-excitation and long QT syndrome (LQTs), the JTc interval was useful for diagnosing LQTs and a longer follow-up of the JTc interval after the ablation was necessary in order not to miss the diagnosis of LQTs.