The clinical characteristics of sudden cardiac arrest in asymptomatic patients with congenital heart disease

Machine Learning-Based Cardiac Arrest Prediction for Early Warning System

The early warning system detects early and responds quickly to emergencies in high-risk patients, such as cardiac arrest in hospitalized patients. However, traditional early warning systems have the problem of frequent false alarms due to low positive predictive value and sensitivity. We conducted early prediction research on cardiac arrest using time-series data such as biosignal and laboratory data. To derive the data attributes that affect the occurrence of cardiac arrest, we performed a correlation analysis between the occurrence of cardiac arrest and the biosignal data and laboratory data. To improve the positive predictive value and sensitivity of early cardiac arrest prediction, we evaluated the performance according to the length of the time series of measured biosignal data, laboratory data, and patient data range. We propose a machine learning and deep learning algorithm: the decision tree, random forest, logistic regression, long short-term memory (LSTM), gated recurrent unit (GRU) model, and the LSTM–GRU hybrid model. We evaluated cardiac arrest prediction models. In the case of our proposed LSTM model, the positive predictive value was 85.92% and the sensitivity was 89.70%.

Prediction of In-Hospital Cardiac Arrest Using Shallow and Deep Learning

Sudden cardiac arrest can leave serious brain damage or lead to death, so it is very important to predict before a cardiac arrest occurs. However, early warning score systems including the National Early Warning Score, are associated with low sensitivity and false positives. We applied shallow and deep learning to predict cardiac arrest to overcome these limitations. We evaluated the performance of the Synthetic Minority Oversampling Technique Ratio. We evaluated the performance using a Decision Tree, a Random Forest, Logistic Regression, Long Short-Term Memory model, Gated Recurrent Unit model, and LSTM–GRU hybrid models. Our proposed Logistic Regression demonstrated a higher positive predictive value and sensitivity than traditional early warning systems.

Importance of electrocardiographic markers in predicting cardiac events in children

ECG is a common diagnostic tool in medical practice. Sudden cardiac death (SCD) is a rare but devastating event. The most common cause of SCD in the young is a primary arrhythmic event, which is often produced by malignant ventricular arrhythmia. Several electrocardiographic markers for ventricular repolarization and depolarization have been proposed to predict this arrhythmic risk and SCD in children. Although many of these parameters can easily be used in clinical practice, some of them need specific techniques for interpretation. In this review, we summarized the current knowledge regarding the clinical importance and the ability of these ECG parameters to predict adverse cardiac events in the pediatric population.

Forns Index is a predictor of cardiopulmonary bypass time and outcomes in Fontan conversion

Recent reports suggested that cardiopulmonary bypass (CPB) time is one of the risk factors for postoperative complications after Fontan conversion. Although Fontan conversion may be performed for the patients with hepatic fibrosis after initial Fontan procedure, there is no predictive indicator regarding the liver function associated with hemostasis which can affects CPB time. Thirty-one patients who underwent Fontan conversion using the same surgical procedure (extracardiac conduit conversion with right atrium exclusion) were enrolled. In multivariate analyses including age at Fontan conversion, interval from initial Fontan to conversion, hemodynamic data such as right atrial pressure, ventricular end-diastolic pressure, and cardiac index, hepatic data such as platelet count, prothrombin time international normalized ratios, serum total bilirubin, hyaluronic acid levels, five known indices for hepatic fibrosis (Forns Index, APRI, FIB4, FibroIndex, and MELD-XI), and liver stiffness measured by ultrasound elastography, only the Forns Index remained independently associated with the CPB time (P < 0.01) and blood transfusions (plasma transfusions and platelet concentrations: P < 0.01 for both). The cutoff level for Forns Index to predict the prolonged CPB time (exceeding 240 min) was 4.85 by receiver-operating characteristic curve (area under the curve 0.823, sensitivity 76.9%, and specificity 72.2%). Three patients with Forns Index > 7.0 had poor outcomes with long CPB time and massive blood transfusions in contrast with the other 28 patients. In conclusion, Forns Index could serve as a practical predictor of CPB time and is associated with blood transfusion volume in Fontan conversion.

Long-term follow-up of Fontan completion in adults and adolescents

BACKGROUND

The Fontan procedure is rarely performed in adults and adolescents in the present era. We review our results with the Fontan procedure in adolescents and young adults.

METHODS

Between 1974 and 2010, 79 consecutive patients underwent the Fontan procedure at an age ≥ 15 years (mean age at Fontan operation, 20.3 years ± 4.5 years). Forty-five patients underwent atriopulmonary connection, 11 underwent the Bjork procedure, and 23 underwent total cavopulmonary connection.

RESULTS

Ten hospital deaths (HDs) and/or early Fontan takedowns (TDs) occurred. The median follow-up period was 18.2 years (range, 0.6-37.6 years). The estimated freedom from death or TD rates was 79.7% at 5 years, 77.0% at 10 years, 73.9% at 15 years, and 63.9% at 20 years. Age was not a predictor of HD and/or TD. Freedom from death or TD after 1998 was 69.1% at 5 years, 69.1% at 10 years, and 69.1% at 15 years, and before 1997 was 82.3% at 5 years, 79.0% at 10 years, 75.5% at 15 years, and 65.1% at 20 years; there were no significant differences between the two groups. In 19 late-death patients, nine (47.4%) experienced sudden death. Among these patients, five had known arrhythmias before sudden death.

CONCLUSIONS

In patients who were ≥15 years old, the surgical results of the Fontan operation were acceptable. Approximately half of the late deaths were sudden deaths, mainly occurring 10-20 years postoperatively.

Significance of right atrial tension for the development of complications in patients after atriopulmonary connection Fontan procedure: potential indicator for Fontan conversion

Elevated right atrial (RA) pressure and progressive RA dilation are thought to play pivotal roles in the development of late complications after atriopulmonary connection (APC) Fontan surgery. However, no clear cut-off value for RA pressure or RA volume has been determined for stratifying the risk of developing Fontan complications. We hypothesized that RA tension, which incorporates information about both RA pressure and volume, might help predict the risk of developing complications. We retrospectively studied 51 consecutive APC Fontan patients (median postoperative period 14 years). RA tension was computed from the RA pressure and RA radius, which was calculated from RA volume measured by RA angiography. The correlation between the cardiac catheterization hemodynamic data and the complications of APC Fontan was investigated. Of the 51 patients, 28 had complications, including liver fibrosis (n = 28), arrhythmia (n = 8), protein-losing enteropathy (n = 1), and RA thrombosis (n = 1). Among the hemodynamic data, RA volume and RA tension, but not RA pressure, were significantly higher in patients with complications than in those without (P = 0.004 and P = 0.001, respectively). The cut-off level for RA tension to predict Fontan complications was 26,131 dyne/cm by receiver operating characteristic curve (area under the curve 0.79, sensitivity 71.4%, and specificity 73.9%). The present study demonstrated the significance of RA tension rather than high venous pressure for the development of Fontan complications. Amid the uncertainty about clinical outcomes, the present results, subject to further validation, may contribute to the indications for Fontan conversion.

Transcatheter closure of atrial septal defect protects from pulmonary edema: septal occluder device gradually reduces LR shunt

A 56-year-old woman was diagnosed as atrial septal defect (ASD) with pulmonary hypertension; pulmonary blood flow/systemic blood flow (Qp/Qs) of 2.3, pulmonary artery pressure (PAP) of 71/23(39) mmHg and diastolic dysfunction of left ventricle. PAP was improved after medical therapy; therefore, transcatheter ASD closure was performed. Seven days later, left-sided heart failure occurred, however, the improvement of Qp/Qs (1.7) and PAP of 51/21(32) was confirmed. Diuretic therapy was introduced which led to further decrease of PAP 40/12(25) and Qp/Qs (1.1). Because of gradual decrease of Qp/Qs, this patient appeared to be protected from acute pulmonary edema.

Assessing utility of exercise test in determining exercise prescription in adolescent and adult patients with repaired tetralogy of fallot

Parameters from cardiopulmonary exercise test (CPET) are useful prognostic factors for patients with repaired tetralogy of fallot (TOF). Its application in exercise prescription remains unclear. This study sought to define its role. We made current exercise recommendations in repaired TOF patients according to European Society of Cardiology (ESC) guideline, which were based on ventricular function, pressure/volume load, pulmonary artery pressure, hypoxemia and arrhythmic burden both at rest and during exercise. CPET parameters (peak oxygen consumption, oxygen uptake efficiency plateau, and E/CO₂ slope), along with cardiothoracic ratio, ventricular arrhythmia, QRS duration and NYHA functional status, were used to calculate "score to exercise". 112 repaired TOF adolescent and adult aged 32.6 ± 10.8 (14.05- to 56.99-year-old, median 30.1) years received exercise recommendations by ESC guideline, which suggested high, moderate and low intensity sports for 45 (40.2 %), 45 (40.2 %), and 22 (19.6 %) patients, respectively. The optimal cut-off values were 67 and 77 % for peak VO₂, 86 and 100 % for OUEP, 22 and 28 for E/CO₂ slope to correlate to the exercise intensity recommendation. But, individual CPET parameter had low consistency (41-46 %) in making decisions of exercise intensity compared to ESC recommendations. Using the "score to exercise", the consistency rate could be increased to 74.1 %. With "score to exercise" recommended exercise intensity, follow-up result revealed no adverse event related to sports. Individual CPET parameter did not correlate well to the exercise recommendation from ESC. We proposed a scoring system, "score to exercise", which incorporates three CPET parameters with cardiothoracic ratio, ventricular arrhythmia, QRS duration and NYHA functional status. Score to exercise is easy to be assessed and provides useful information for exercise recommendation in patients with repaired TOF.

Single center experience of aortic bypass graft for aortic arch obstruction in children

The purpose of this study is to access the outcomes of aortic bypass graft placement in children. This is a retrospective review of all children having aortic bypass graft placement for aortic arch obstruction for the first time between 1982 and 2013 at a single institution. The actuarial survival and the freedom from aortic arch reoperation were calculated and compared between the groups. Seventy consecutive children underwent aortic bypass graft placements. The median age and body weight at the operation were 14 days and 3.6 kg. There were 7 early deaths, 6 late deaths, and 7 heart transplants during the median follow-up of 10.8 years (0.0-31.5 years). The actuarial transplant free survival was 64.7 % at 20 years and the freedom from aortic arch reoperation was 50.5 % at 10 years. Between the children younger than 1 year old and older than 1 year old, there were significant differences in actuarial transplant free survival (56.4 vs. 100 % at 15 years, p = 0.0042) and in the freedom from aortic arch reoperation (18.7 vs. 100 % at 10 years, p < 0.001). The children who received aortic bypass graft larger than 16 mm in size had no aortic arch reoperation at 15 years. The aortic bypass graft placement for aortic arch obstruction can be done with low mortality and morbidity for children who can receive bypass graft larger than 16 mm in size. However, it should be avoided for the neonates and infants except selected situations.

A novel cardiac ryanodine receptor gene (RyR2) mutation in an athlete with aborted sudden cardiac death: a case of adult-onset catecholaminergic polymorphic ventricular tachycardia

Sudden cardiac death (SCD) in athletes <35 years of age are mostly due to congenital or acquired cardiac malformations or hypertrophic cardiomyopathy. However, ion channelopathies such as catecholaminergic polymorphic ventricular tachycardia (CPVT) or long-QT syndromes, which are less frequently observed, are also potential pathogenesis of SCD in young athletes. CPVT is an inherited arrhythmia that is induced by physical or emotional stress and may lead to ventricular fibrillation syncope or SCD. Here, we report a case of athlete woman with adult-onset CPVT and aborted SCD who has a novel missense mutation (K4392R) in the cardiac RyR2 gene.

Decreased tricuspid regurgitation following percutaneous closure of congenital perimembranous ventricular septal defect: immediate and 6-month echocardiographic assessment

As a common concomitant performance and the most frequent complications of transcatheter perimembranous ventricular septal defect (VSD) closure, tricuspid regurgitation (TR) has rarely been concerned. From January 2008 to December 2012, a total of 70 patients (men: 33, women: 37; mean age: 30.0 ± 17.1 years) with at least mild TR before VSD closure were examined in 508 consecutive congenital perimembranous VSD patients to investigate the outcomes of TR. After VSD closure, the jet area decreased from 3.4 ± 2.5 to 1.2 ± 2.5 cm(2) (p < 0.001); however, no significant decrease was found in 3 patients (mean age 59.7 ± 2.5 years) with severe TR (12.0 ± 1.2 versus 11.2 ± 3.2 cm(2), p = 0.668). Compared to the early outcome after VSD closure, the jet area detected by TTE at 6-month follow-up had further decreased (1.2 ± 2.5 versus 0.9 ± 2.2 cm(2), p < 0.001). In 6 patients, a slight residual shunt was detected immediately after VSD closure and diminished in 3 patients at 6-month follow-up. The hemolysis occurred in one of these six patients and recovered after 3 days. In conclusion, functional TR was ameliorated after percutaneous VSD closure, although persistent abundant TR was common in patients with severe TR before procedure.