Wolff–Parkinson–White syndrome is due to an extra pathway in the heart that is made up of electrical muscle tissue. This tissue allows the electrical impulse, which stimulates the heartbeat, to happen very rapidly. Right ventricular outflow tract tachycardia is the most common type of ventricular tachycardia in otherwise healthy individuals. This defect is due to an electrical node in the right ventricle just before the pulmonary artery. When the node is stimulated, the patient will go into ventricular tachycardia, which does not allow the heart to fill with blood before beating again. Long QT syndrome is another complex problem in the heart and has been labeled as an independent factor in mortality. There are multiple methods of treatment for these including cardiac ablations, medication treatment, or lifestyle changes to have less stress and exercise. Automaticity
Automaticity refers to a cardiac muscle cell firing off an impulse on its own. All of the cells in the heart have the ability to initiate an action potential; however, only some of these cells are designed to routinely trigger heartbeats. These cells are found in the conduction system of the heart and include the SA node, AV node, Bundle of His, and Purkinje fibers.
CMS prevalence rates reported from the study are summarised below:

Ethiopia [3600–4100 m]: 0%
Tibetan Plateau (Tibetans): 0.91–1.2%
Indian Himalayas [3000–4200 m]: 4–7%
Kyrgyzstan [3000–4200 m]: 4.6%
Tibetan Plateau (Han Chinese): 5.6%
La Paz, Bolivia [3600 m]: 6% to 8%
Bolivia: 8–10%
Cerro de Pasco, Peru [4300 m]: 14.8–18.2%

References
External links

^  Online calculator illustrating blood oxygen carrying capacity at altitude