Expert consensus document on automated diagnosis of the electrocardiogram: The task force on automated diagnosis of the electrocardiogram in Japan part 3: Inappropriate internal processing in the automatic diagnosis of electrocardiograms and its problems.

Computer diagnosis of electrocardiograms is widely used to provide useful information in clinical practice and medical checkups. However, it is common for users to be confused by the inappropriate diagnosis. We illustrate some examples of inappropriate automatic diagnoses and discuss the actual situation of inappropriate automatic processing and its problems.

Age-dependent contribution of intrinsic mechanisms to sinoatrial node function in humans.

Average beat interval (BI) and beat interval variability (BIV) are primarily determined by mutual entrainment between the autonomic-nervous system (ANS) and intrinsic mechanisms that govern sinoatrial node (SAN) cell function. While basal heart rate is not affected by age in humans, age-dependent reductions in intrinsic heart rate have been documented even in so-called healthy individuals. The relative contributions of the ANS and intrinsic mechanisms to age-dependent deterioration of SAN function in humans are not clear. We recorded ECG on patients (n = 16 < 21 years and n = 23 41-78 years) in the basal state and after ANS blockade (propranolol and atropine) in the presence of propofol and dexmedetomidine anesthesia. Average BI and BIV were analyzed. A set of BIV features were tested to designated the "signatures" of the ANS and intrinsic mechanisms and also the anesthesia "signature". In young patients, the intrinsic mechanisms and ANS mainly contributed to long- and short-term BIV, respectively. In adults, both ANS and intrinsic mechanisms contributed to short-term BIV, while the latter also contributed to long-term BIV. Furthermore, anesthesia affected ANS function in young patients and both mechanisms in adult. The work also showed that intrinsic mechanism features can be calculated from BIs, without intervention.

Pulmonary vasodilator therapies in pulmonary arterial hypertension associated with CHD: a systematic review and network meta-analysis.

The optimal treatment strategy using pulmonary vasodilators in pulmonary arterial hypertension associated with CHD (PAH-CHD) remains controversial. We aimed to compare the efficacy and safety of pulmonary vasodilators in PAH-CHD. PubMed and EMBASE databases were searched through May 2022 and a network meta-analysis was conducted. The primary outcomes were mean difference of changes in 6-minute walk distance, NYHA functional class, and N-terminal pro-brain natriuretic peptide. The secondary outcomes included pulmonary vascular resistance, mean pulmonary arterial pressure, and resting oxygen saturation. We identified 14 studies, yielding 807 patients with PAH-CHD. Bosentan and sildenafil were associated with a significant increase in 6-minute walk distance from baseline compared with placebo (MD 48.92 m, 95% CI 0.32 to 97.55 and MD 59.70 m, 95% CI 0.88 to 118.53, respectively). Bosentan, sildenafil, and combination of bosentan and sildenafil were associated with significant improvement in NYHA functional class compared with placebo (MD -0.33, 95% CI -0.51 to -0.14, MD -0.58, 95% CI -0.75 to -0.22 and MD -0.62, 95% CI -0.92 to -0.31, respectively). Bosentan and sildenafil were also associated with significant improvements in secondary outcomes. These findings were largely confirmed in the subgroup analysis. Various adverse events were reported; however, serious adverse event rates were relatively low (4.8-8.7%), including right heart failure, acute kidney injury, respiratory failure, hypotension, and discontinuation of pulmonary vasodilators. In conclusion, bosentan and sildenafil were the most effective in improving prognostic risk factor such as 6-minute walk distance and NYHA class. Overall, pulmonary vasodilators were well tolerated in PAH-CHD.

Longitudinal Cardiac Outcomes of Multisystem Inflammatory Syndrome in Children: A Systematic Review and Meta-Analysis.

There is a paucity of longitudinal data on cardiac outcomes in multisystem inflammatory syndrome in children (MIS-C) associated with COVID-19. We aimed to investigate the longitudinal cardiovascular outcomes in MIS-C. PubMed and EMBASE were searched through May 2022. Observational studies were included, reporting mid-term (≥ 3 months) outcomes in children (aged < 21) with MIS-C. Data were extracted by two researchers. Longitudinal outcomes were synthesized by a one-group meta-analysis using a random-effects model. Eleven studies with a follow-up period (3 months to 1 year) were identified, including 547 MIS-C patients. The mortality was 2.5% (95% CI 1.3-4.9). The majority of left ventricular (LV) systolic dysfunction present in 46.8% (95% CI 32.7-61.3) in the acute phase resolved by 3 months, and the prevalence of LV systolic dysfunction was 1.7% (95% CI 0.5-5.7) and 2.1% (95% CI 0.8-5.4) at 3 month and 6 month follow-up, respectively. Additionally, the persistent LV systolic dysfunction in the small population was mild. However, coronary abnormalities such as coronary artery dilatation or aneurysms, seen in 23.7% (95% CI 17.7-31.1) at baseline, persisted in 4.7% (95% CI 1.5-14.3) at 3 months and 5.2% (95% CI 3.0-8.9) at 6 months. Mitral regurgitation (MR), which was observed in 56.6% (95% CI 27.7-81.6) at baseline, also persisted in 7.5% at 6 months. In conclusion, our study demonstrated largely favorable cardiac outcomes, suggesting resolution of LV systolic dysfunction in the majority of cases. However, coronary abnormalities and MR persisted in a subset of patients at mid-term follow-up.

Extracorporeal Membrane Oxygenation in Children With COVID-19: A Systematic Review and Meta-Analysis.

OBJECTIVES: The indication, complications, and outcomes of extracorporeal membrane oxygenation (ECMO) in children with COVID-19-related illnesses remain unelucidated. Our study aimed to investigate the characteristics and outcomes of ECMO in children with COVID-19-related illnesses. DATA SOURCES: We searched PubMed and EMBASE databases in March 2022. STUDY SELECTION: We retrieved all studies involving children (age ≤ 18 yr) with COVID-19-related illnesses who received ECMO. DATA EXTRACTION: Two authors independently extracted data and assessed the risk of bias. Mortality, successful weaning rate, and complications while on ECMO were synthesized by a one-group meta-analysis using a random-effect model. Meta-regression was performed to explore the risk factors for mortality. DATA SYNTHESIS: We included 18 observational studies, four case series, and 22 case reports involving 110 children with COVID-19-related illnesses receiving ECMO. The median age was 8 years (range, 10 d to 18 yr), and the median body mass index was 21.4 kg/m 2 (range, 12.3-56.0 kg/m 2 ). The most common comorbidities were obesity (11% [7/63]) and congenital heart disease (11% [7/63]), whereas 48% (30/63) were previously healthy. The most common indications for ECMO were multisystem inflammatory syndrome in children (52% [47/90]) and severe acute respiratory distress syndrome (40% [36/90]). Seventy-one percent (56/79) received venoarterial-ECMO. The median ECMO runtime was 6 days (range, 3-51 d) for venoarterial ECMO and 11 days (range, 3-71 d) for venovenous ECMO. The mortality was 26.6% (95% CI, 15.9-40.9), and the successful weaning rate was 77.0% (95% CI, 55.4-90.1). Complications were seen in 37.0% (95% CI, 23.1-53.5) while on ECMO, including stroke, acute kidney injury, pulmonary edema, and thromboembolism. Corticosteroids and IV immunoglobulin therapies were associated with lower mortality. CONCLUSIONS: The mortality of children on ECMO for COVID-19 was relatively low. This invasive treatment can be considered as a treatment option for critically ill children with COVID-19.

Efficacy of SubcutAneous implantable cardioVErter-defibrillators in ≤18 year-old CHILDREN: SAVE-CHILDREN registry.

BACKGROUND: In adult patients, subcutaneous implantable cardioverter defibrillators (S-ICDs) have been reported to be non-inferior to transvenous ICDs with respect to the incidence of device-related complications and inappropriate shocks. Only a few reports have investigated the efficacy of S-ICDs in the pediatric field. This study aimed to investigate the utility and safety of S-ICDs in patients ≤18 years old. METHODS: This study was a multicenter, observational, retrospective study on S-ICD implantations. Patients <18 years old who underwent S-ICD implantations were enrolled. The detailed data on the device implantations and eligibility tests, incidence of appropriate- and inappropriate shocks, and follow-up data were assessed. RESULTS: A total of 62 patients were enrolled from 30 centers. The patients ranged in age from 3 to 18 (median 14 years old [IQR 11.0-16.0 years]). During a median follow up of 27 months (13.3-35.8), a total of 16 patients (26.2%) received appropriate shocks and 13 (21.3%) received inappropriate shocks. The common causes of the inappropriate shocks were sinus tachycardia (n = 4, 30.8%) and T-wave oversensing (n = 4, 30.8%). In spite of the physical growth, the number of suitable sensing vectors did not change during the follow up. No one had any lead fractures or device infections in the chronic phase. CONCLUSIONS: Our study suggested that S-ICDs can prevent sudden cardiac death in the pediatric population with a low incidence of lead complications or device infections. The number of suitable sensing vectors did not change during the patients' growth.

Paradoxical Continuous Left-to-Right Ductal Shunt during Circulatory Collapse due to Ductal Closure in an Infant with Duct-Dependent Systemic Circulation.

Duct-dependent systemic circulation is accompanied by a right-to-left ductal shunt, at least during systole. Although observations of paradoxical continuous left-to-right shunts in duct-dependent systemic circulation have been reported, the mechanism remains unclear. We report a continuous left-to-right ductal shunt throughout the cardiac cycle during the initial recovery phase from circulatory collapse and right ventricular (RV) dysfunction due to ductal closure in an infant with hypoplastic left heart and severe aortic coarctation. Further recovery improved his RV function and changed the ductal flow from continuous left-to-right to bidirectional, which is usually seen in duct-dependent systemic circulation. Marked RV dysfunction may contribute to the continuous left-to-right ductal shunt. A continuous left-to-right ductal shunt should not be used to rule out duct-dependent systemic circulation.

Ablation characteristics and incidence of steam pops with a novel, surface temperature-controlled ablation system in an ex vivo experimental model.

BACKGROUND: A novel irrigation catheter (QDOT MICRO™) has been introduced, which enables a surface temperature-controlled ablation combined with tip cooling. However, the detailed description of its complex behavior and effect on the incidence of pops and lesion formation remains elusive. This study aimed to systematically investigate the ablation characteristics, feedback behavior, and incidence of steam pops in a simplified ex vivo swine model. METHODS: Using swine ventricular tissue perfused with saline at 37°C, we systematically created lesions with 4×3 combinations of the wattage (20, 30, 40, and 50 W) and contact force (CF, 10, 30, and 50 g). Ablation was continued for either 120 s or until a steam pop occurred and repeated 10 times with each setting. The lesion geometry, ablation index, feedback dynamics, and conditions underlying the steam pops were measured and analyzed. RESULTS: Steam pops occurred particularly frequently in combinations of a low CF and high power (10 g vs. 30 g+50 g [p < .0001]; 40 W+50 W vs. 20 W+30 W [p < .0001]). Failure to activate a feedback process was associated with a 5.1 times higher incidence of steam pops (21/109 vs.11/11, [95% CI 3.499-7.716], p < .0001). The wattage feedback was particularly evident with a high CF (30 and 50 g) and high initial wattage (40 and 50 W). The average delivered wattage at 27 W predicted the occurrence of steam pops. CONCLUSION: The temperature-controlled ablation with the QDOT MICRO™ demonstrated a complex feedback behavior, which contributed to a reduced incidence of steam pops and prolonged lead time to the pops.

Successful Ablation of a Biatrial Tachycardia from the Superior Vena Cava after a Senning Operation for Complete Transposition of the Great Arteries.

The Senning operation used to be widely performed for an intracardiac repair in a complete transposition of the great arteries. During the long-term follow-up, supraventricular tachycardia (SVT) is often observed because of the complex suture lines. The typical mechanism of a Senning-related SVT is cavo-tricuspid isthmus-dependent atrial flutter. On rare occasions, complex SVTs (e.g., biatrial tachycardia (BiAT)) whose diagnosis and treatment are challenging, may occur. We report a rare case of a BiAT following a Senning operation that was successfully ablated from the superior vena cava, and the local activation time histogram module (CARTO3 V7 module [Biosense Webster, Irvine, CA, USA]) was crucial for analyzing the complex circuit.

Control of Heart Rate in Infant and Child Tachyarrhythmia With Reduced Cardiac Function Using Landiolol (HEARTFUL)　- Results of a Prospective, Multicenter, Uncontrolled Clinical Study.

BACKGROUND: The prospective Control of HEART rate in inFant and child tachyarrhythmia with reduced cardiac function Using Landiolol (HEARTFUL) study investigated the effectiveness and safety of landiolol, a short-acting ß1 selective blocker, in children.Methods and Results: Twenty-five inpatients aged ≥3 months to <15 years who developed supraventricular tachyarrhythmias (atrial fibrillation, atrial flutter, supraventricular tachycardia, and inappropriate sinus tachycardia) were treated with landiolol. The primary endpoint, the percent of patients with a reduction in heart rate ≥20% from the initial rate of tachycardia, or termination of tachycardia at 2 h after starting landiolol, was achieved in 12/25 patients (48.0%; 95% CI 28.4-67.6), which exceeded the predetermined threshold (38.0%). At 2 h after starting landiolol administration, heart rate had decreased by ≥20% in 45.8% (11/24) and recovery to sinus rhythm was achieved in 40.0% (6/15) of the patients. Adverse reactions (ARs) occurred in 24.0% (6/25) of patients, and the study was discontinued in 4.0% (1/25) of the patients; however, none of these ARs were considered serious. The most common AR was hypotension (20.0% [5/25] of patients). CONCLUSIONS: The HEARTFUL study has demonstrated the efficacy of landiolol, by reducing heart rate or terminating tachycardia, in pediatric patients with supraventricular tachyarrhythmias. Although serious ARs and concerns were not identified in this study, physicians should be always cautious of circulatory collapse due to hypotension.

A novel mechanism of sudden infant death syndrome during atrioventricular reentrant tachycardia: a case report.

Background: Although orthodromic atrioventricular reentrant tachycardia (AVRT) using retrograde conduction through an accessory pathway (AP) is a common manifestation of Wolff-Parkinson-White (WPW) syndrome, a rare yet critical consequence is sudden cardiac arrest in a few patients. This fatal event used to be reported as a result of rapid atrioventricular conduction of atrial fibrillation via an AP. Case summary: A 3-month-old infant with WPW syndrome had AVRT accompanied by global cardiac ischaemia, apparently caused by a rapid ventricular rate itself that degenerated into ventricular fibrillation during the AVRT. Discussion: Our case suggested that orthodromic AVRT may be sufficient to cause WPW-related sudden cardiac death (SCD) or sudden infant death syndrome via fatal ischaemia and ventricular arrhythmias even when the effective refractory period of an antegrade AP conduction is long or even when an antegrade AP is not present. It is possible that an AP ablation in those who have a history of a fast orthodromic AVRT would be useful to prevent SCD in addition to symptom control.