Common causes of sudden cardiac arrest for a few seconds are premature ventricular contractions, atrioventricular block and sick sinus node syndrome. 1. Premature ventricular contractions: Premature ventricular contractions occur when the heart beats early, and there is a compensatory interval before the heart beats early, which delays the next heartbeat and can be manifested as a sudden stoppage of the heart for a few seconds. 2. Atrioventricular block: If the atrioventricular node of the heart is diseased, so that the signaling pathway of the heart circuits is lagged, i.e., atrioventricular block, when the electrical signal of the heart is blocked, the heart will suddenly stop beating for a few seconds. 3. Sick sinus node syndrome: If the sinus node functions abnormally causing the heart to be unable to send out electrical signals according to the normal frequency, when there is a lag in the transmission of electrical impulses, it can cause the heart to suddenly stop beating for a few seconds. If the heart suddenly stops beating for a few seconds, you should go to the regular hospital in time to find out the cause of the disease, and under the guidance of a professional doctor to choose the appropriate method of treatment.