Sudden death is always an unexpected and devastating occurrence. The normal electrophysiological behavior of the human heart is determined by an ordered propagation of excitatory stimuli that result in slow repolarization and a rapid depolarization, thereby, generating action potential in each myocyte. Hence, mutations in or involving cardiac ion channels result in an abnormal propagation or action potential formation, leading to cardiac arrhythmias. Despite the worrisome impact of sudden cardiac death, and sudden infant death syndrome in the society resulting from such arrhythmias, knowledge of the underlying cellular mechanism is poor, and treatment is consequently and continuously limited. This chapter aims to focus on the role of basic science (current diagnostic and therapeutic options) in investigating primary electrical cardiac diseases as a paradigm for cardiac arrhythmias, concentrating on the long-QT syndrome, Brugada syndrome, and catecholaminergic polymorphous ventricular tachycardia. Also, the underlying pathology and physiology of ion channel diseases are described associated with sudden infant death syndrome to provide a clinical perspective of cardiac channelopathies about sudden infant death syndrome. The learning objectives of the chapter would enable practicing physicians/clinicians in the field to:
I. Recognize risk factors, signs, and symptoms that should prompt suspicion of a congenital arrhythmia syndrome,
II. Explain the treatment options, list measures to prevent sudden cardiac death and sudden infant death syndrome, and
III. Finally, describe what can be achieved with molecular genetic diagnostic tests and thereby, comfortably list the difficulties and limitations of interpreting genetic results.