What is the medical term meaning condition of the heart being without a rhythm?

Apnea is the absence of breathing, but only for less than a few moments. If a patient has stopped breathing and does not restart breathing it is called respiratory arrest. Lack of spontaneous respiration is central apnea. Absence of spontaneous respiration means that the person's brainstem is not triggering them to take breaths. The medulla contains the respiratory center, and the respiratory center makes sure that the body is not ever breathing below 8 respirations per minute. A person with apnea is described as apneic.