Sudden death is an event that has always remained a mystery to us. In Greek mythology, Atropos, the oldest of the three goddesses of destiny, is the one responsible for cutting the thread of life, which was spun by her youngest sister Klotho and measured by Lachesis, the third of the Fates. The name “Atropos” translates to something like “the Inevitable”. Fateful and inevitable is what sudden cardiac death has felt like to us up until this very day. It is a relatively rare event overall. However, it can particularly affect adolescents and adults with congenital heart disease (ACHD).

Sudden Cardiac Death Is a Particularly Tragic Incident

Thanks to significant advancements in pediatric cardiology and pediatric heart surgery, the number of adult patients with congenital heart disease has been increasing continuously in the past decades. Numerous achievements in medical care such as, for instance, the detection and treatment of heart rhythm disorders in the field of electrophysiology, facilitate a largely “normal” life. However, at the same time, heart rhythm disorders and cases of sudden heart-related death occur more frequently in certain patients with congenital heart disease.

Sudden cardiac death is perceived as being particularly tragic because of its being unexpected. Patients who are suddenly torn from life and their family were doing well subjectively. The risk of sudden cardiac death can hardly be anticipated since so far, a first-time sudden cardiac death (SDC) has not even been able to be predicted by a mathematical risk assessment. By an implantable cardioverter defibrillator (ICD), which is quite frequently implanted for prevention, adolescents and adults with congenital heart disease, in particular,are exposed to disproportionate side effects. The complication rate is high.

Diagnoses with an Increased Risk of SCD

According to the current state of research, there are three diagnosis groups that are particularly associated with an increased SCD risk. As a recent study investigating patients who had suffered sudden cardiac death found, 19 percent of these patients had transposition of the great arteries (TGA) after atrial switch surgery, 16 percent had tetralogy of Fallot (TOF) after corrective surgery and 13 percent had a so-called left-side outflow tract obstruction (LVOTO). According to that, almost half of the studied cases of sudden death (48 percent) were patients that belonged to one of these three diagnosis groups.

Risk Increases Depending on Patient Age

According to medical literature, the yearly SCD risk is 0.19 percent for TOF patients, 0.49 percent for TGA patients after atrial switch and 0.54 percent for patients with LSOTO. This means that, within five years, one out of 100 patients with TOF will die of sudden cardiac death, while one out of 100 patients with TGA after atrial switch or with LSOTO will suffer such an event within two years. In addition, depending on patient age and other clinical characteristics, the yearly risk increases to up to 0.9 percent, which means roughly one sudden cardiac death per year in TOF patients.

Register Creates Research Basis for Risk Assessment

One sudden cardiac death is still one too many. However, the available models for risk stratification are only of limited suitability to the identification of at-risk patients for preventative intervention. In single medical institutions, SDC in patients with congenital heart disease occurs too rarely to allow for creating bases for valid research. As a result, there is a lack of science-based evidence for a precise risk assessment.

We would like to change that with a Europe-wide register. The ATROPOS Register includes the anonymized data from all patients in Europe with TGA after atrial switch, TOF or LSOTO, who deceased due to sudden cardiac death or who survived such an event. In doing so, it creates the basis for a systematic and quick identification of the risk factors involved. In a next step, we will compare the clinically relevant data of patients deceased due to sudden cardiac death with medical data of patients with similar clinical patterns of the same age group in case control studies.

AI-Based Prevention

In a third step, we will utilize the possibilities of artificial intelligence. Based on the scientifically identified risk factors, so-called deep learning algorithms will be trained to warn the treating physicians, thus facilitating improved diagnostics and prevention that will then allow for targeted medical intervention. We assume that the development of new practical risk models on a large data basis will facilitate a preventive treatment for avoiding SCD. Sudden cardiac death would then be a preventable fate.

Europe-wide Participation

The project is supervised by the EMAH-Center at the Klinik fuer Kardiologie III (department of cardiology III): Center for Congenital and Acquired Heart Defects (EMAH) at Muenster University Hospital. We are calling on physicians from all over Europe to get involved in the data collection for this register and to include any relevant cases that they know of.

The research project is supported by the ESC Working Group Grown-up Congenital Heart Disease EuroGUCH  and the European Heart Rhythm Association EHRA.