Background: Arrhythmia symptoms are frequent complaints in children and often require a pediatric cardiology evaluation. Data regarding the clinical utility of wearable technologies are limited in children. We hypothesize that an Apple Watch can capture arrhythmias in children. Methods: We present an analysis of patients ≤18 years-of-age who had signs of an arrhythmia documented by an Apple Watch. We include patients evaluated at our center over a 4-year-period and highlight those receiving a formal arrhythmia diagnosis. We evaluate the role of the Apple Watch in arrhythmia diagnosis, the results of other ambulatory cardiac monitoring studies, and findings of any EP studies. Results: We identify 145 electronic-medical-record identifications of Apple Watch, and find arrhythmias confirmed in 41 patients (28%) [mean age 13.8 ± 3.2 years]. The arrythmias include: 36 SVT (88%), 3 VT (7%), 1 heart block (2.5%) and wide 1 complex tachycardia (2.5%). We show that invasive EP study confirmed diagnosis in 34 of the 36 patients (94%) with SVT (2 non-inducible). We find that the Apple Watch helped prompt a workup resulting in a new arrhythmia diagnosis for 29 patients (71%). We note traditional ambulatory cardiac monitors were worn by 35 patients (85%), which did not detect arrhythmias in 10 patients (29%). In 73 patients who used an Apple Watch for recreational or self-directed heart rate monitoring, 18 (25%) sought care due to device findings without any arrhythmias identified. Conclusion: We demonstrate that the Apple Watch can record arrhythmia events in children, including events not identified on traditionally used ambulatory monitors.

Background: With the advent of more intensive rhythm monitoring strategies, ventricular arrhythmias (VAs) are increasingly detected in Fontan patients. However, the prognostic implications of VA are poorly understood. We assessed the incidence of VA in Fontan patients and the implications on transplant-free survival. Methods: Medical records of Fontan patients seen at a single center between 2002 and 2019 were reviewed to identify post-Fontan VA (nonsustained ventricular tachycardia >4 beats or sustained >30 seconds). Patients with preFontan VA were excluded. Hemodynamically unstable VA was defined as malignant VA. The primary outcome was death and heart transplantation. Death with censoring at transplant was a secondary outcome. Results: Of 431 Fontan patients, transplant-free survival was 82% at 15 years post-Fontan with 64 (15%) meeting primary outcome of either death (n=16, 3.7%), at a median 4.6 (0.4–10.2) years post-Fontan, or transplant (n=48, 11%), at a median of 11.1 (5.9–16.2) years post-Fontan. Forty-eight (11%) patients were diagnosed with VA (90% nonsustained ventricular tachycardia, 10% sustained ventricular tachycardia). Malignant VA (n=9, 2.0%) was associated with younger age, worse systolic function, and valvular regurgitation. Risk for VA increased with time from Fontan, 2.4% at 10 years to 19% at 20 years. History of Stage 1 surgery with right ventricular to pulmonary artery conduit and older age at Fontan were significant risk factors for VA. VA was strongly associated with an increased risk of transplant or death (HR, 9.2 [95% CI, 4.5–18.7]; P <0.001), with a transplant-free survival of 48% at 5-year post-VA diagnosis. Conclusions: Ventricular arrhythmias occurred in 11% of Fontan patients and was highly associated with transplant or death, with a transplant-free survival of <50% at 5-year post-VA diagnosis. Risk factors for VA included older age at Fontan and history of right ventricular to pulmonary artery conduit. A diagnosis of VA in Fontan patients should prompt increased clinical surveillance.

BACKGROUND: To address the unmet need for a smaller pacemaker for babies, a specially modified implantable pulse generator was developed containing a Medtronic Micra subassembly in a polymer header connecting to a bipolar epicardial lead. The aim of this study was to report midterm follow-up data and outcomes of patients who underwent implantation of this device. METHODS: Deidentified data were collected from 12 of 15 sites in the United States implanting the pediatric implantable pulse generator between March 2022 and February 2024. All 29 patients at these 12 sites within this timeframe were included in the analysis. RESULTS: The median age at implant was 15 days (range, 0 days to 3 years, including 1 outlier). The median weight was 2.3 kg (range, 1.3–11.4 kg). Gestational age was 28.5 weeks to term, with 23 (79%) patients born prematurely. Of those with anatomic information, 25% had congenital heart disease. The average duration of implant was 325 days (73–808 days). The most recent lead impedance mean was 612 ohms (450–840 ohms), ventricular capture threshold mean was 1 V @ 0.4 ms (range, 0.38–2.75 V), and R-wave sensing mean was 12.5 mV (3.6–20 mV). There were 7 generator explants (24%), removed at 6.5 to 31 months of age. CONCLUSIONS: The pediatric implantable pulse generator can be safely implanted in neonates and infants. This multicenter report demonstrates that the devices remain stable, with effective pacing, normal electrical parameters, and battery longevity aligned with projections. This novel pediatric pacemaker provides a viable alternative to standard-size generators and addresses a vital unmet need for these small patients.