What is the primary cause of cardiac arrest for a patient struck by lightning?

The primary cause of cardiac arrest in a patient struck by lightning is often asystole. When a person is struck by lightning, the electric current can interfere with the heart's electrical system, leading to a disruption in the normal rhythm. In many cases, this disruption results in asystole, which is a state where there is no electrical activity in the heart, leading to a cessation of effective heart contractions and, subsequently, blood circulation.

Asystole suggests that the heart has completely stopped beating, which is a critical emergency requiring immediate resuscitation efforts, such as CPR and advanced cardiac life support. The electric shock from the lightning not only affects the heart but can additionally cause serious injuries to other organ systems and lead to various complications.

Other potential issues, like hypoxia, depression of body functions, or obstruction of coronary circulation, typically arise secondary to asystole or the effects of the electric shock, rather than being the primary immediate cause. Thus, asystole is recognized as the most direct and evident immediate consequence of a lightning strike that leads to cardiac arrest.