Figure 4.

Triple‐risk hypothesis of SUNDS. We propose that SUNDS occurs when 3 factors coincide: a vulnerable young person carrying susceptible variants; stressors caused by environmental or social factors; and finally a disturbance in action potential production and propagation in nocturnal sleep. The final pathway of SUNDS is commonly accepted as lethal ventricular arrhythmia. Cardiac structural changes may also be potential but unnecessary structure substrates for SUNDS. Whether the structural changes are a primary cause or a secondary change is still unknown. Certain associations between potential structure substrate, genetic risk factors, and impaired action potential production and propagation have yet to be demonstrated (dashed arrow). AP indicates action potential; REM, rapid eye movement; SUNDS, sudden unexplained nocturnal death syndrome.