Reversible complete atrioventricular block caused by aortic bicuspid valve calcification with severe aortic stenosis: a case report.

Background: The aetiology of secondary complete atrioventricular blocks includes ischaemia, cardiac sarcoidosis, electrolyte imbalance, drug use, rheumatic fever, and infections such as Lyme disease and endocarditis. Diagnosis is important since some of these causes are reversible. Although several studies have reported on aortic valve calcification causing complete atrioventricular blocks, no study has described improvement of complete atrioventricular blocks by removal of the calcification. Case summary: A 42-year-old man with syncope had a Mobitz type II atrioventricular block, an alternating bundle branch block, and severe aortic stenosis. We identified a 10 s paroxysmal complete atrioventricular block with pre-syncope and performed pacemaker implantation. Electrocardiography-gated computed tomography confirmed that the calcification had reached the muscular septum. 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) revealed significant FDG uptake with high CT value of calcification in basal interventricular septum. The calcification in the septum was removed carefully, and aortic valve replacement was performed. The atrioventricular conduction capacity improved post-surgery. During the 1-year follow-up, the patient reported dramatic improvement in exercise capacity. We also noted an improvement of <0.1% in the right ventricular pacing burden. Discussion: Complete atrioventricular blocks occur in patients with aortic stenosis accompanied by severe calcification of the aortic valve, which are visualized comprehensively by echocardiography. Electrocardiography-gated computed tomography and FDG-PET enabled detailed evaluation of the extent of calcification and pre- and post-operative tissue inflammation. Hence, we suspected that the calcification in the septum was causing complete atrioventricular block. Moreover, clinicians should recognize that aortic valve calcification with aortic stenosis can cause complete atrioventricular blocks.

Efficacy of Computed Tomography-Based Evaluation of Myocardial Extracellular Volume Combined With Red Flags for Early Screening of Concealed Cardiac Amyloidosis in Patients With Atrial Fibrillation.

BACKGROUND: The prevalence of transthyretin amyloid cardiomyopathy (ATTR-CM) in atrial fibrillation (AF) patients remains unclear. We explored the efficacy of computed tomography-based myocardial extracellular volume (CT-ECV) combined with red flags for the early screening of concealed ATTR-CM in AF patients undergoing catheter ablation.Methods and Results: Patients referred for AF ablation at Oita University Hospital were prescreened using the red-flag signs defined by echocardiographic or electrocardiographic findings, medical history, symptoms, and blood biochemical findings. Myocardial CT-ECV was quantified in red flag-positive patients using routine pre-AF ablation planning cardiac CT with the addition of delayed-phase cardiac CT scans. Patients with high (>35%) ECV were evaluated using technetium pyrophosphate (99 mTc-PYP) scintigraphy. A cardiac biopsy was performed during the planned AF ablation procedure if 99 mTc-PYP scintigraphy was positive. Between June 2022 and June 2023, 342 patients were referred for AF ablation. Sixty-seven (19.6%) patients had at least one of the red-flag signs. Myocardial CT-ECV was evaluated in 57 patients because of contraindications to contrast media, revealing that 16 patients had high CT-ECV. Of these, 6 patients showed a positive 99 mTc-PYP study, and 6 patients were subsequently diagnosed with wild-type ATTR-CM via cardiac biopsy and genetic testing. CONCLUSIONS: CT-ECV combined with red flags could contribute to the systematic early screening of concealed ATTR-CM in AF patients undergoing catheter ablation.

Cardiomyopathy with an LMNA Genetic Variant Affecting Three Consecutive Generations: A Case Series.

We report the case of a family afflicted with cardiac laminopathy who showed atrial fibrillation (AF) and complete atrioventricular block across three generations. Implantable cardioverter defibrillators (ICDs) implantation, or cardiac resynchronization therapy (CRT) were delivered to the three patients (proband; 61 years old, proband's mother: 84 years old, and proband's daughter; 38 years old) to prevent sudden cardiac death or suppress heart failure progression. A novel frameshift mutation (LMNA Exon 9: c.1550dupA;p. N518Efs*34) was found in all three cases through genetic testing, and this mutation may potentially result in the relatively late appearance of a phenotype of left ventricular systolic dysfunction.

R-R' interval in the left bundle branch block predicts long-term outcomes after cardiac resynchronization therapy by estimating greater mechanical dyssynchrony and viable myocardium.

BACKGROUND: Typical left bundle branch block (LBBB) shows 2 peaks of the R wave, which reflect activation reaching the interventricular septum (R) and posterolateral wall (R') sequentially. OBJECTIVE: The purpose of this study was to investigate the relationship among R-R' interval (RR'), mechanical dyssynchrony, extent of viable myocardium, and long-term outcomes in cardiac resynchronization therapy (CRT) candidates. METHODS: The study enrolled 49 patients (34 men; mean age: 69 ± 11 years) with LBBB who received CRT. The LBBB definition used requires the presence of mid-QRS notching in leads V1, V2, V5, V6, I, and aVL. Baseline evaluations were QRS duration (QRSd) and RR' measured from the 12-lead electrocardiogram; eyeball dyssynchrony (apical rocking and septal flash) and opposing-wall delay by speckle tracking from echocardiography, and extent of viable myocardium assessed by thallium-201 single-photon emission computed tomography. Primary outcomes included the combination of all-cause death and heart failure-related hospitalization. RESULTS: RR' predicted volumetric response better than QRSd (area under the curve 0.73 vs 0.67, respectively). The long RR' group (≥48 ms) revealed more frequent eyeball dyssynchrony and significantly greater radial (SL) and circumferential dyssynchrony (AP and SL) and %viable segment than the short RR' group. In multivariate regression analysis, only RR' ≥48 ms was independently associated with higher event-free survival rates following CRT (hazard ratio 0.21; P = .014). CONCLUSION: These findings suggest that RR' in complete LBBB was associated with mechanical dyssynchrony, extent of viable myocardium, and long-term outcomes following CRT.

Remission of Cardiac Sarcoidosis after the Administration of Methotrexate as First-line Drug Therapy.

A 54-year-old woman developed new-onset heart failure and was diagnosed with cardiac sarcoidosis. An implantable cardioverter-defibrillator with biventricular pacing was implanted before immunosuppressive therapy to prevent sudden death. The patient refused oral steroids because she disliked their specific side effects and potential adverse events with long-term use; therefore, methotrexate was chosen as an alternative first-line drug. Nine months after starting oral therapy, 18F-fluorodeoxyglucose-positron emission tomography revealed remission of sarcoidosis, disappearance of heart failure symptoms, marked improvement in cardiac contractility, and a reduced frequency of ventricular arrhythmias.

Innovations in online classes introduced during the COVID-19 pandemic and their educational outcomes in Japan.

BACKGROUND: The novel coronavirus disease (COVID-19) pandemic emerged in Japan in February 2020, forcing the adoption of online education by university medical schools across Japan. The advantages and disadvantages of online education have been studied in Japan; however, the educational outcome of online classes conducted during the COVID-19 pandemic has not been completely evaluated. In this study, we examined the relationship between lecture format (e.g., face-to-face or online) and performance of third-year university students in their organ-specific cardiovascular course examination. METHODS: This retrospective, nonclinical, and noninterventional comparative educational study included 550 third-year medical students who took a cardiovascular course between April 2018 and May 2022. Cardiovascular coursework was conducted in-person in 2018 and 2019, online in 2020 and 2021, and again in-person in 2022. The course comprised 62 lecture and 2 problem-based learning (PBL) sessions. A quiz was set up in advance on Moodle based on all lectures conducted in 2021 and 2022. A written examination was administered at the end of the course to evaluate the knowledge of students. The student online course evaluation questionnaires were administered in 2020 and 2021. Examination scores and proportion of failures in each year were compared. RESULTS: The mean examination scores were significantly higher in 2021 and 2022 than in 2018, 2019, and 2020 (p < 0.05). Univariate and multivariate analyses adjusted for the class type, online quiz, and PBL revealed that only online quiz was significantly associated with better examination results (p < 0.05). A student course evaluation survey indicated that the online format did not interfere with the students' learning and was beneficial. CONCLUSIONS: The introduction of online classes into medical education due to the COVID-19 pandemic was as effective as face-to-face classes owing to learning management system and other innovations, such as online quizzes. Online education may confer more benefits when provided in a combination with face-to-face learning after COVID-19 pandemic.

Empagliflozin Suppresses the Differentiation/Maturation of Human Epicardial Preadipocytes and Improves Paracrine Secretome Profile.

Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce epicardial adipose tissue (EAT) in humans, enhancing cardioprotective effects on heart failure and atrial fibrillation. We investigated the direct effect of the SGLT2 inhibitor empagliflozin on human primary epicardial adipocytes and preadipocytes. SGLT2 is primarily expressed in human preadipocytes in the EAT. The expression levels of SGLT2 significantly diminished when the preadipocytes were terminally differentiated. Adipogenesis of preadipocytes was attenuated by empagliflozin treatment without affecting cell proliferation. The messenger RNA levels and secreted protein levels of interleukin 6 and monocyte chemoattractant protein 1 were significantly decreased in empagliflozin-treated adipocytes. Coculture of human induced pluripotent stem cell-derived atrial cardiomyocytes and adipocytes pretreated with or without empagliflozin revealed that empagliflozin significantly suppressed reactive oxygen species. IL6 messenger RNA expression in human EAT showed significant clinically relevant associations. Empagliflozin suppresses human epicardial preadipocyte differentiation/maturation, likely inhibiting epicardial adipogenesis and improving the paracrine secretome profile of EAT, particularly by regulating IL6 expression.

Usefulness of Prehospital 12-Lead Electrocardiography System in ST-Segment Elevation Myocardial Infarction Patients in Oita　- Comparison Between Urban and Rural Areas, Weekday Daytime and Weekday Nighttime/Holidays.

BACKGROUND: We have reported that a prehospital 12-lead electrocardiography system (P-ECG) contributed to transport of suspected acute coronary syndrome (ACS) patients to appropriate institutes and in this study, we compared its usefulness between urban and rural areas, and between weekday daytime and weekday nighttime/holiday.Methods and Results: Consecutive STEMI patients who underwent successful primary percutaneous coronary intervention after using P-ECG were assigned to the P-ECG group (n=123; 29 female, 70±13 years), and comparable STEMI patients without using P-ECG were assigned to the conventional group (n=117; 33 females, mean age 70±13 years). There was no significant difference in door-to-reperfusion times between the rural and urban cases (70±32 vs. 69±29 min, P=0.73). Door-to-reperfusion times in the urban P-ECG group were shorter than those in the urban conventional group for weekday nighttime/holiday (65±21 vs. 83±32 min, P=0.0005). However, there was no significance different between groups for weekday daytime. First medical contact to reperfusion time (90±22 vs. 105±37 min, P=0.0091) in the urban P-ECG group were significantly shorter than in the urban conventional groups for weekday nighttime/holiday, but were not significantly different between the groups for weekday daytime. CONCLUSIONS: P-ECG is useful even in urban areas, especially for patients who develop STEMI during weekday nighttime or while on a holiday.

Role of polyunsaturated fatty acids in Japanese patients with coronary spastic angina.

BACKGROUND: n-3 polyunsaturated fatty acids (PUFAs) reduce the risk of ischemic heart disease. However, there are few reports of a relationship between n-3 PUFAs and coronary spastic angina (CSA). This study aimed to assess the age-dependent role of serum levels of fatty acid in patients with CSA. METHODS AND RESULTS: We enrolled 406 patients who underwent ergonovine tolerance test (ETT) during coronary angiography for evaluation of CSA. All ETT-positive subjects were diagnosed as having CSA. We categorized the patients by age and results of ETT as follows: (1) young (age ≤ 65 years) CSA-positive (n = 32), (2) young CSA-negative (n = 134), (3) elderly (age > 66 years) CSA-positive (n = 36), and (4) elderly CSA-negative (n = 204) groups. We evaluated the serum levels of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), arachidonic acid, and dihomo-gamma-linolenic acid. In the young groups, the serum levels of EPA (64.3 ±â€¯37.7 µg/mL vs. 49.4 ±â€¯28.8 µg/mL, p = 0.015) and DHA (135.7 ±â€¯47.6 µg/mL vs. 117.4 ±â€¯37.6 µg/mL, p = 0.020) were significantly higher in the CSA-positive group than in the CSA-negative group, respectively. However, this was not the case with elderly groups. In the multivariate analysis in young groups, the serum levels of EPA (p = 0.028) and DHA (p = 0.049) were independently associated with the presence of CSA, respectively. CONCLUSION: Our results suggested that the higher serum levels of EPA and/or DHA might be involved in the pathophysiology of CSA in the young population but not in the elderly population.

Association between interatrial septum adiposity and atrial fibrillation: transesophageal echocardiography imaging and autopsy study.

Recent clinical evidence has suggested that interatrial septal (IAS) adiposity contributes to atrial fibrillation (AF). The present study aimed to confirm the usefulness of transesophageal echocardiography (TEE) to estimate IAS adiposity in patients with AF. The histological IAS analysis based on autopsy samples sought to clarify characteristics that underlie the contribution of IAS adiposity to AF. The imaging study analyzed the TEE results in patients with AF (n = 184) in comparison with transthoracic echocardiography (TTE) and computed tomography (CT) results. The autopsy study histologically analyzed IAS in subjects with (n = 5) and without (n = 5) history of AF. In the imaging study, the ratio of interatrial septum adipose tissue (IAS-AT) volume per epicardial adipose tissue (EpAT) volume was greater in patients with persistent AF compared (PerAF) to those with paroxysmal AF (PAF). Multivariable analysis revealed that both TEE-assessed IAS thickness and TTE-assessed left atrial dimension were predicted by CT-assessed IAS-AT volume. In the autopsy study, the histologically-assessed IAS section thickness was greater in the AF group than that in the non-AF group and was positively correlated with the IAS-AT area percentage. In addition, the size of adipocytes in IAS-AT was smaller, compared to EpAT and subcutaneous adipose tissue (SAT). IAS-AT infiltrated into the IAS myocardium, as if adipose tissue split the myocardium (designated as myocardial splitting by IAS-AT). The number of island-like myocardium pieces as a result of myocardial splitting by IAS-AT was greater in the AF group than in the non-AF group and was positively correlated with the IAS-AT area percentage. The present imaging study confirmed the usefulness of TEE to estimate IAS adiposity in patients with AF without radiation exposure. The autopsy study suggested that the myocardial splitting by IAS-AT may contribute to atrial cardiomyopathy leading to AF.

Interatrial conduction time is associated with left atrial low voltage area and predicts the recurrence after single atrial fibrillation ablation.

Background: Interatrial conduction time (IACT) prolongs in fibrotic left atrium. We tested the hypothesis that IACT is related to left atrial low voltage area (LVA) and predicts the recurrence after single atrial fibrillation (AF) ablation. Methods: One hundred sixty-four consecutive AF patients (79 non-paroxysmal) who underwent initial ablation in our institute were analyzed. IACT and LVA were defined as interval from the onset of P-wave to the basal left atrial appendage (P-LAA) activation, and area with bipolar electrogram < 0.5 mV covering over 5% of the total left atrial surface area during sinus rhythm, respectively. Pulmonary vein antrum isolation, non-PV foci ablation, and atrial tachycardia (AT) ablation were performed without substrate modification. Results: LVA was frequently identified in patients with prolonged P-LAA ≥ 84 ms (n  = 28) compared with patients with P-LAA < 84 ms (n  = 136). Patients with P-LAA ≥ 84 ms were older (71 ± 10 vs. 65 ± 10 years, p  = .0061), and had more frequent non-paroxysmal AF (75% vs. 43%, p  = .0018), larger left atrial diameter (43.5 ± 4.5 vs. 39.3 ± 5.7 mm, p  = .0003), and higher E/e' ratio (14.4 ± 6.5 vs. 10.5 ± 3.7, p  < .0001) compared with P-LAA < 84 ms patients. After a mean follow-up period of 665 ± 153 days, Kaplan-Meier curve analysis showed that AF/AT recurrences was more frequently observed in patients with prolonged P-LAA (Log-rank p  = .0001). Additionally, univariate analysis revealed that P-LAA prolongation (OR = 1.055 per 1 ms, 95% CI: 1.028-1.087, p  < .0001) and the existence of LVA (OR = 5.000, 95% CI: 1.653-14.485 p  = .0053) were predictors of AF/AT recurrences after single AF ablation. Conclusions: Our results suggested that prolonged IACT as measured by P-LAA was associated with LVA and predicts AT/AF recurrence after single AF ablation.

Vagal response is involved in the occurrence of ventricular fibrillation in patients with early repolarization syndrome.

BACKGROUND: Patients with early repolarization syndrome (ERS) and Brugada syndrome (BruS) have comparable clinical symptoms. In both conditions, ventricular fibrillation (VF) is experienced often near midnight or in the early morning hours when the parasympathetic tone is augmented. However, differences between ERS and BruS regarding the risk of VF occurrence have recently been reported. The role of vagal activity remains especially unclear. OBJECTIVE: The goal of this study was to determine the relationship between VF occurrence and autonomic nervous activity in patients with ERS and BruS. METHODS: We enrolled 50 patients with ERS (n = 16) and BruS (n = 34) who received an implantable cardioverter-defibrillator. Of these, 20 patients (5 ERS and 15 BruS) experienced VF recurrence (recurrent VF group). We investigated baroreflex sensitivity (BaReS) with the phenylephrine method and heart rate variability using Holter electrocardiography in all patients to estimate autonomic nervous function. RESULTS: In both patients with ERS and BruS, there was no significant difference in heart rate variability between the recurrent VF and nonrecurrent VF groups. However, in patients with ERS, BaReS was significantly higher in the recurrent VF group than in the nonrecurrent VF group (P = .03); this difference was not evident in patients with BruS. High BaReS was independently associated with VF recurrence in patients with ERS according to Cox proportional hazards regression analyses (hazard ratio 1.52; 95% confidence interval 1.031-3.061; P = .032). CONCLUSION: Our findings suggest that in patients with ERS, an exaggerated vagal response, as represented by increased BaReS indices, may be involved in the risk of VF occurrence.

Multiple accessory pathways coexisting with a persistent left superior vena cava: a case report.

BACKGROUND: Wolff-Parkinson-White syndrome is characterized by a short PR interval (delta-wave), long QRS complex, and the appearance of paroxysmal supraventricular tachycardia. Patients with Wolff-Parkinson-White syndrome usually have one accessory pathway, whereas cases with multiple accessory pathways are rare. Persistent left superior vena cava is a vascular anomaly in which the vein drains into the right atrium through the coronary sinus at the junction of the left internal jugular and subclavian veins due to abnormal development of the left cardinal vein. The simultaneous presence of multiple accessory pathways and persistent left superior vena cava has not been reported before. CASE PRESENTATION: A 56-year-old Japanese man with a 5-year history of palpitations was referred for radiofrequency catheter ablation due to increased frequency of tachycardia episodes in the previous 2 months. Persistent left superior vena cava was confirmed by transthoracic echocardiography and computed tomography. An electrophysiological study revealed that the accessory pathways were located in the left lateral wall, anterolateral wall, and posteroseptal region. They were completely ablated with radiofrequency energy application. CONCLUSIONS: We reported an extremely rare case of a patient with multiple accessory pathways and persistent left superior vena cava. Our case may suggest a potential embryological relationship between the multiple accessory pathways and persistent left superior vena cava.

A Case Report of Acute Cardiac Tamponade Creation in a Macaque: Echo-Guided Catheter Manipulation to Perforate Coronary Artery.

Although acute cardiac tamponade is one of the major problems in clinical practice, a suitable animal model is still lacking. We tried to create acute cardiac tamponade in macaques by echo-guided catheter manipulation. A 13-year-old male macaque was anesthetized, and a long sheath was inserted into the left ventricle via the left carotid artery under the guidance of transthoracic echocardiography. The sheath was then inserted into the orifice of the left coronary artery to perforate the proximal site of the left anterior descending branch. A cardiac tamponade was successfully created. Injection of diluted contrast agent into the pericardial space via a catheter made it possible to clearly distinguish between the hemopericardium and the surrounding tissues on postmortem computed tomography. This procedure did not need an X-ray imaging system during catheterization. Our present model would help us examine the intrathoracic organs in the presence of acute cardiac tamponade.

Predictors of outcome after catheter ablation for atrial fibrillation: Group analysis categorized by age and type of atrial fibrillation.

BACKGROUND: The outcome of catheter ablation could probably differ among patients with atrial fibrillation (AF), depending on age and AF type. We aimed to investigate the difference in predictors of outcome after catheter ablation for AF among the patient categories divided by age and AF type. METHODS AND RESULTS: A total of 396 patients with AF (mean age 65.69 ± 11.05 years, 111 women [28.0%]) who underwent catheter ablation from January 2018 to December 2019 were retrospectively analyzed. We divided the patients into four categories: patients with paroxysmal AF (PAF) or persistent AF (PeAF) who were 75 years or younger (≤75 years) or older than 75 years (>75 years). Kaplan-Meier survival analysis demonstrated that patients with PAF aged ≤75 years had the lowest AF recurrence among the four groups (log-rank test, p = .0103). In the patients with PAF aged ≤75 years (N = 186, 46.7%), significant factors associated with recurrence were female sex (p = .008) and diabetes (p = .042). In the patients with PeAF aged ≤75 years (N = 142, 35.9%), the only significant factor associated with no recurrence was medication with a renin-angiotensin system inhibitor (p = .044). In the patients with PAF aged >75 years (N = 53, 14.4%), diabetes was significantly associated with AF recurrence (p = .021). No significant parameters were found in the patients with PeAF aged >75 years (N = 15, 4.1%). CONCLUSIONS: Our findings indicate that the risk factors for AF recurrence after catheter ablation differed by age and AF type.

Adolescent Persistent Atrial Fibrillation Concomitant with Pectus Excavatum.

A 19-year-old man with pectus excavatum developed symptomatic persistent atrial fibrillation (AF). He had no remarkable medical history or comorbidities and had not exercised intensely during childhood. Electrical cardioversion and pre-treatment with amiodarone for two months failed to maintain sinus rhythm. Computed tomography before ablation revealed compression of the right and left atria between the sternal bone and vertebral bodies. Voltage mapping revealed that the right and left atrial voltages were preserved within the normal limit. However, radiofrequency catheter ablation successfully eliminated recurrent persistent AF. No recurrence was observed during eight months of follow-up.

Risk stratification of ventricular fibrillation in patients with symptomatic Brugada syndrome using pharmacological tests.

BACKGROUND: Brugada syndrome (BrS), which is characterized by J-point elevation in right precordial leads of a 12-lead electrocardiogram, is associated with the occurrence of ventricular fibrillation (VF). However, risk stratification of VF in patients with BrS remains challenging. OBJECTIVE: The aim of this study was to identify a risk predictor of VF in patients with BrS using pharmacological tests. METHODS: Twenty-one consecutive patients with BrS and a history of documented spontaneous VF (n = 16) or syncope presumed to be caused by lethal ventricular arrhythmia (n = 5) were enrolled. J-wave changes in response to intravenous verapamil, propranolol, and pilsicainide were separately assessed. RESULTS: During the median follow-up period of 86.0 months, 8 patients had VF recurrence (recurrence group) and 13 patients did not have VF recurrence (non-recurrence group). Intravenous propranolol injection induced significant J-wave augmentation (i.e., increase in amplitude >0.1 mV) in the inferior and/or lateral leads in the recurrence group compared to the non-recurrence group (p = .048 and p = .015, respectively). Kaplan-Meier analysis revealed that VF recurrence is significantly higher in patients with BrS and J-wave augmentation due to intravenous propranolol than in patients without J-wave augmentation (p = .014). CONCLUSION: The study results show that propranolol-induced J-wave augmentation is involved in the risk of VF in patients with BrS. The results suggest that early repolarization patterns in response to pharmacological tests may be useful for risk stratification of VF in patients with symptomatic BrS.

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.