Reply to: Two Ripples in a Pond: The Subtleties of Mapping Observations in Localizing

Left atrial appendage occlusion (LAAO) has emerged as an important therapy for patients with atrial fibrillation at risk for stroke who are not good candidates for long-term oral anticoagulation. Transesophageal echocardiography (TEE) has an important and foundational role in preprocedural left atrial appendage assessment, intraprocedural guidance and device deployment, and post-procedural evaluation in follow-up. Recent studies have evaluated intracardiac echocardiography (ICE) as a primary intraprocedural imaging modality without the need for TEE. The use of ICE offers promise of expedited patient care, reduced procedural complexity, and reduced costs. Observational reports of ICE for LAAO highlight significant variability in procedural technique, including but not limited to ICE catheter placement and position as well as the type and number of intracardiac views. Integration with concomitant electroanatomic mapping provides additional information to the operator regarding the orientation of the ICE catheter to the atrial geometry and can be used to optimize views and avoid perforation. It also allows for more precise near-field delineation of transseptal access. This review characterizes a standardized approach for harnessing ICE based off four anatomic views (aortic, mitral, left superior pulmonary vein, and inferior). These views optimize the unique vantage points of left atrial ICE as opposed to attempting to replicate the transesophageal windows. The focus on complementary and orthogonal angles allows for more precise device placement and assessment for device positioning and peri-device leak.

Background: The Micra Coverage with Evidence Development (CED) Study is a novel comparative analysis of Micra (leadless VVI) and transvenous single-chamber ventricular pacemakers (transvenous VVI) using administrative claims data. Objective: To compare chronic complications, device reinterventions, heart failure hospitalizations, and all-cause mortality after 3 years of follow-up.  Methods: U.S. Medicare claims data linked to manufacturer device registration information were used to identify Medicare beneficiaries with a de novo implant of either a Micra VR leadless VVI or transvenous VVI pacemaker from March 9, 2017-December 31, 2018. Unadjusted and propensity score overlap-weight adjusted Fine-Gray competing risk models were used to compare outcomes at 3 years.   Results: Leadless VVI patients (N=6,219) had a 32% lower rate of chronic complications and a 41% lower rate of reintervention compared with transvenous VVI patients (N=10,212) (chronic complication hazard ratio [HR] 0.68; 95% CI, 0.59-0.78; reintervention HR 0.59; 95% CI 0.44-0.78). Infections rates were significantly lower among patients with a leadless VVI (<0.2% versus 0.7%, P<0.0001). Patients with a leadless VVI also had slightly lower rates of heart failure hospitalization (HR 0.90; 95% CI 0.84-0.97). There was no difference in the adjusted 3-year all-cause mortality rate (HR 0.97; 95% CI, 0.92-1.03).  Conclusion: This nationwide comparative evaluation of leadless VVI versus transvenous VVI de novo pacemaker implants demonstrated that the leadless group had significantly fewer complications, reinterventions, heart failure hospitalizations, and infections than the transvenous group at 3 years, confirming that the previously reported shorter-term advantages associated with leadless pacing persist and continue to accrue in the medium-to-long-term.