Muhammad Rizwan Afzal

Implantable cardioverter-defibrillators (ICDs) are life-saving devices used to prevent sudden cardiac death. Two newer types of ICDs—the extravascular ICD (EV-ICD) and the subcutaneous ICD (S-ICD)—offer alternatives to traditional transvenous ICDs. Additionally, efforts are being made to introduce defibrillation and pacing interventions through a single device called the modular cardiac rhythm management system (mCRM). This review compares the EV-ICD and S-ICD based on currently available clinical data, focusing on their safety and performance. Additionally, we review modular ICD systems, which integrate leadless pacing with defibrillation. We conducted a comprehensive literature search of PubMed and ScienceDirect, focusing on articles demonstrating the clinical outcomes of EV-ICDs and S-ICDs as well as modular systems. However, we found that sufficient studies are not available to determine the clinical efficacy and safety outcomes of EV-ICDs and the mCRM. Additionally, comparative studies between EV-ICDs and S-ICDs are still required to determine their relative roles in the field of electrophysiology, with the goal of empowering clinicians to understand these emerging technologies to support better patient care decision-making.

Background: There is a paucity of data regarding the optimal timing of left atrial appendage closure (LAAC) and whether scheduling delays increase the risk for adverse outcomes. Objectives: This study sought to assess the incidence and predictors of adverse events among patients awaiting LAAC. Methods: This single‐center retrospective study assessed all patients who underwent LAAC from January 2017 to March 2020. The primary study endpoints were the rate and characteristics of adverse events occurring from the time of initial shared decision to pursue LAAC until the time of LAAC. Adverse events were defined as clinically significant bleeding or anemia, thromboembolic complications, or death. Patients were censored after successful closure or the first adverse event. Results: Two hundred and sixty‐five patients underwent LAAC with demographics notable for age 73.5 ± 8.1 years, 98 (37%) females, left ventricular ejection fraction 52.3% ± 10.4%, CHA ₂ DS ₂ ‐VASc 4.8 ± 1.4, and HAS‐BLED 3.2 ± 1.2. Median time from shared decision to insurance approval and insurance approval to LAAC were 18 (IQR 28) and 44 (IQR 40) days, respectively. Seventeen (6%) patients suffered an adverse event, including 15 (88%) cases of bleeding or anemia and 2 (12%) cases of thromboembolism. Multivariate analysis demonstrated that increased time to LAAC (odds ratio [OR] 1.31, 95% confidence interval [CI] [1.15, 1.50], p < 0.001) and higher HAS‐BLED score (OR 1.67, CI [1.11, 2.59], p = 0.017) were associated with significantly increased risk for adverse events. Conclusion: Prolonged time to LAAC and higher HAS‐BLED score portend an increased risk for adverse events while awaiting LAAC. Expedited closure is warranted in high‐risk patients.

Snaring via a Femoral Approach to Facilitate Transvenous Lead Extraction of an Infected Right Ventricular Lead Jailed by a Bioprosthetic Tricuspid Valve

Introduction: Among patients with non‐valvular atrial fibrillation (AF) and percutaneous left atrial appendage closure (LAAC) undergoing direct current cardioversion (DCCV), the need for and use of LAA imaging and oral anticoagulation (OAC) is unclear.Objective: The purpose of this study is to evaluate the real‐world use of transesophageal echocardiography (TEE) or cardiac computed tomography angiography (CCTA) before DCCV and use of OAC pre‐ and post‐DCCV in patients with AF status post percutaneous LAAC.Methods: This retrospective single center study included all patients who underwent DCCV after percutaneous LAAC from 2016 to 2022. Key measures were completion of TEE or CCTA pre‐DCCV, OAC use pre‐ and post‐DCCV, incidence of left atrial thrombus (LAT) or device‐related thrombus (DRT), incidence of peri‐device leak (PDL), and DCCV‐related complications (stroke, systemic embolism, device embolization, major bleeding, or death) within 30 days.Results: A total of 76 patients with AF and LAAC underwent 122 cases of DCCV. LAAC consisted of 47 (62%), 28 (37%), and 1 (1%) case of Watchman 2.5, Watchman FLX, and Lariat, respectively. Among the 122 DCCV cases, 31 (25%) cases were identified as “non‐guideline based” due to: (1) no OAC for 3 weeks and no LAA imaging within 48 h before DCCV in 12 (10%) cases, (2) no OAC for 4 weeks following DCCV in 16 (13%) cases, or (3) both in 3 (2%) cases. Among the 70 (57%) cases that underwent TEE or CCTA before DCCV, 16 (23%) cases had a PDL with a mean size of 3.0 ± 1.1 mm, and 4 (6%) cases had a LAT/DRT on TEE resulting in cancellation. There were no DCCV‐related complications within 30 days.Discussion: There is a widely varied practice pattern of TEE, CCTA, and OAC use with DCCV after LAAC, with a 6% rate of LAT/DRT. LAA imaging before DCCV appears prudent in all cases, especially within 1 year of LAAC, to assess for device position, PDL, and LAT/DRT.

Introduction: Insertable cardiac monitors (ICMs) are commonly used to diagnose cardiac arrhythmias. False detections in the latest ICM systems remain an issue, primarily due to inaccurate R‐wave sensing. New discrimination algorithms were developed and tested to reduce false detections of atrial fibrillation (AF), pause, and tachycardia episodes in ICMs.Methods: Stored electrograms (EGMs) of AF, pause, and tachycardia episodes detected by Abbott Confirm Rx™ ICMs were extracted from the Merlin.net™ Patient Care Network, and manually adjudicated to establish independent training and testing datasets. New discrimination algorithms were developed to reject false episodes due to inaccurate R‐wave sensing, P‐wave identification, and R–R interval patterns. The performance of these new algorithms was quantified by false positive reduction (FPR) and true positive maintenance (TPM), relative to the existing algorithms.Results: The new AF detection algorithm was trained on 5911 EGMs from 744 devices, resulting in 66.9% FPR and 97.8% TPM. In the testing data set of 1354 EGMs from 119 devices, this algorithm achieved 45.8% FPR and 97.0% TPM. The new pause algorithm was trained on 7178 EGMs from 1490 devices, resulting in 70.9% FPR and 98.7% TPM. In the testing data set of 1442 EGMs from 340 devices, this algorithm achieved 74.4% FPR and 99.3% TPM. The new tachycardia algorithm was trained on 520 EGMs from 204 devices, resulting in 57.0% FPR and 96.6% TPM. In the testing data set of 459 EGMs from 237 devices, this algorithm achieved 57.9% FPR and 96.5% TPM.Conclusion: The new algorithms substantially reduced false AF, pause, and tachycardia episodes while maintaining the majority of true arrhythmia episodes detected by the Abbott ICM algorithms that exist today. Implementing these algorithms in the next‐generation ICM systems may lead to improved detection accuracy, in‐clinic efficiency, and device battery longevity.

Background: Transesophageal echocardiography (TEE) and cardiac computed tomography angiography (CCTA) are currently utilized for left atrial appendage closure (LAAC) planning. During the recent global iodine contrast media shortage in 2022, cardiac magnetic resonance imaging (CMR) was utilized for the first time for LAAC planning. This study sought to assess the utility of CMR versus TEE for LAAC planning. Methods: This single center retrospective study consisted of all patients who underwent preoperative CMR for LAAC with Watchman FLX or Amplatzer Amulet. Key measures were accuracy of LAA thrombus exclusion, ostial diameter, depth, lobe count, morphology, accuracy of predicted device size, and devices deployed per case. Bland-Altman Analysis was used to compare CMR versus TEE measurements of LAA ostial diameter and depth. Results: 25 patients underwent preoperative CMR for LAAC planning. A total of 24 (96%) cases were successfully completed with 1.2 +/- 0.5 devices deployed per case. Among the 18 patients who underwent intraoperative TEE, there was no significant difference between CMR versus TEE in LAA thrombus exclusion (CMR 83% vs. TEE 100% cases, p = .229), lobe count (CMR 1.7 +/- 0.8 vs. TEE 1.4 +/- 0.6, p = .177), morphology (p = .422), and accuracy of predicted device size (CMR 67% vs. TEE 72% cases, p = 1.000). When comparing the difference between CMR and TEE measurements, Bland-Altman analysis demonstrated no significant difference in LAA ostial diameter (CMR-TEE bias 0.7 mm, 95% CI [-1.1, 2.4], p = .420), but LAA depth was significantly larger with CMR versus TEE (CMR-TEE bias 7.4 mm, 95% CI [1.6, 13.2], p = .015). Conclusions: CMR is a promising alternative for LAAC planning in cases where TEE or CCTA are contraindicated or unavailable.

Approaches for Successful Implantation of Cardiac Implantable Devices in Patients with Persistent Left Superior Vena Cava

Background: Insertable cardiac monitors (ICMs) are essential for ambulatory arrhythmia diagnosis. However, definitive diagnoses still require time‐consuming, manual adjudication of electrograms (EGMs).Objective: To evaluate the clinical impact of selecting only key EGMs for review.Methods: Retrospective analyses of randomly selected Abbott Confirm Rx™ devices with ≥90 days of remote transmission history were performed, with each EGM adjudicated as true or false positive (TP, FP). For each device, up to 3 “key EGMs” per arrhythmia type per day were prioritized for review based on ventricular rate and episode duration. The reduction in EGMs and TP days (patient‐days with at least one TP EGM), and any diagnostic delay (from the first TP), were calculated versus reviewing all EGMs.Results: In 1000 ICMs over a median duration of 8.1 months, at least one atrial fibrillation (AF), tachycardia, bradycardia, or pause EGM was transmitted by 424, 343, 190, and 325 devices, respectively, with a total of 95 716 EGMs. Approximately 90% of episodes were contributed by 25% of patients. Key EGM selection reduced EGM review burden by 43%, 66%, 77%, and 50% (55% overall), while reducing TP days by 0.8%, 2.1%, 0.2%, and 0.0%, respectively. Despite reviewing fewer EGMs, 99% of devices with a TP EGM were ultimately diagnosed on the same day versus reviewing all EGMs.Conclusion: Key EGM selection reduced the EGM review substantially with no delay‐to‐diagnosis in 99% of patients exhibiting true arrhythmias. Implementing these rules in the Abbott patient care network may accelerate clinical workflow without compromising diagnostic timelines.