A statistical analysis of many of these risk factors determined that approximately 50% of all cardiac arrests occur in 10% of the population perceived to be at greatest risk due to aggregate harm of multiple risk factors demonstrating that cumulative risk of multiple comorbidities exceeds the sum of each risk individually.Previous adverse cardiac events, non-sustained ventricular tachycardia (NSVT), syncope, and left ventricular hypertrophy (LVT) have been shown to predict sudden cardiac death in children. Current cigarette smokers with coronary artery disease were found to have a two to threefold increase in the risk of sudden death between ages 30 and 59. Furthermore, it was found that former smokers risk was closer to that of those who had never smoked.Functional changes in the heart such as reduced ejection fraction or cardiac arrhythmia have been shown to increase the risk of cardiac arrest and act independently from the risk factors previously mentioned. Conditions that produce these functional changes can be acquired following previous cardiac injury, or inherited through familial history of arrhythmogenic disorders. : 828

Causes and mechanisms
Sudden cardiac arrest (SCA), or sudden cardiac death (SCD), occur when the heart abruptly begins to beat in an abnormal or irregular rhythm (arrhythmia). Without organized electrical activity in the heart muscle, there is no consistent contraction of the ventricles, which results in the hearts inability to generate an adequate cardiac output (forward pumping of blood from heart to rest of the body).
Dermatopathia pigmentosa reticularis (DPR) is a rare, autosomal dominant congenital disorder that is a form of ectodermal dysplasia. Dermatopathia pigmentosa reticularis is composed of the triad of generalized reticulate hyperpigmentation, noncicatricial alopecia, and onychodystrophy. : 856  DPR is a non life-threatening disease that largely affects the skin, hair, and nails. It has also been identified as a keratin disorder. Historically, as of 1992, only 10 cases had been described in world literature; however, due to recent advances in genetic analysis, five additional families studied in 2006 have been added to the short list of confirmed cases. Signs and Symptoms (Presentation)
Symptoms include lack of sweat glands, thin hair, brittle nails, mottled skin, and lack of fingerprints. It is also characterized by a widespread, early-onset reticulate hyperpigmentation. Those affected may also have adermatoglyphia, abnormal epithelial differentiation, palmoplantar hyperkeratosis of the palms and soles, acral dorsal blistering, as well as hypohidrosis or hyperhidrosis.DPR is very similar to the related Naegeli-Franceschetti-Jadassohn syndrome (NFJS). Both cause an affected person to lack fingerprints, as well as present a lace-like pattern of hyperpigmentation and hyperkeratosis of the palms of the hands and soles of the feet. DPR is distinguished from NFJS by the duration of hyperpigmentation and lack of dental abnormalities. Since these differences are very slight and relatively minimal, researchers recommend that NFJS and DPR be considered a single disorder. Molecular Genetics
The disease interval for DPR was found to harbor 230 genes associated with the condition.