Excluding a routine 12 lead electrocardiogram that takes a snapshot view of the hearts electrical signal, the most common tool for monitoring the heart rhythm is a Holter monitor. A Holter monitor is also called an ambulatory cardiac monitor. A Holter monitor records every heartbeat for 24 hours. It requires wearing multiple electrodes and carrying a recording system that is usually worn on a belt or on a holster strap. Such systems are relatively bulky and difficult to conceal in public venues. Also, their electrodes often disconnect, especially during sleep when the patient is unaware of electrode detachments that can occur when turning or during exercise. Moreover, they can't be worn during showering. These shortcomings notwithstanding, standard Holters remain the standard of care.