Current Device Needs for Patients with Pediatric and Congenital Heart Disease.

Pediatric electrophysiologists believe that there is a paucity of pediatric-specific cardiac implantable electronic devices (CIEDs) available for their patients. Specific patient characteristics such as vascular size, intracardiac anatomy, and expected somatic growth limit the types of CIED implants possible for pediatric and congenital heart disease (CHD) patients. These patients demonstrate higher CIED-related complication rates compared with adults. As the number of pediatric and CHD patients who require CIEDs increases, so does the need for advocacy. Fortunately, collaboration among the Food and Drug Administration, industry, and pediatric societies has led to the improvement of regulations and support for clinical trials.

Outcomes After Development of Ventricular Arrhythmias in Single Ventricular Heart Disease Patients With Fontan Palliation.

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.

Arrhythmias in Williams Syndrome.

Williams syndrome (WS) is a congenital, multisystem disorder in which 80% of patients have cardiovascular abnormalities. Sudden cardiac death occurs 25 to 100 times more often in WS than in the general population, and cardiac repolarization is abnormal in WS. We sought to determine the prevalence of primary arrhythmias in patients with WS and whether QTc prolongation impacts arrhythmia risk. We retrospectively reviewed all patients with WS with ambulatory electrocardiogram (ECG) monitoring at our institution between October 2017 and January 2022. The primary outcome was the presence of arrhythmia. Predictors pre-determined for analysis included premature ventricular and atrial complex burden (%), degree of QTc change with varying heart rates, intervals and rhythm on 12-lead ECG, age, gender, symptomatology, and clinical and surgical history. A total of 74 patients (55% female, median age 8 years (3, 13) underwent 108 ambulatory monitors. Arrhythmias were present in 9 patients (12%). Within this group of 9 patients, 18/24 serial monitors were abnormal, and 3/9 patients (33%) had >1 arrhythmia type. Older age (p = 0.002) and symptoms (syncope, p = 0.005) were associated with arrhythmias. Arrhythmia was not associated with the degree of structural heart disease. Atrial tachycardia was the most identified arrhythmia (n = 6; 67% of patients with arrhythmias and 8% of the total cohort). The QTc abnormally increased with higher heart rates in all groups. There was a higher number of premature ventricular and atrial complexes per hour in patients with arrhythmias. In conclusion, atrial arrhythmias were the most common arrhythmia in patients with WS and routine ambulatory ECG and intermittent rhythm monitoring are indicated in WS, particularly given the high risk of sudden cardiac death in WS.