Dual-chamber cardiac pacing provides distinct advantages over single-chamber systems, namely atrioventricular synchrony, improved cardiac output, and prevention of pacemaker syndrome. Providing nursing care to patients with dual-chamber pacemakers demands an understanding of basic cardiac pacing and of the unique features of dual-chamber systems. This knowledge is essential in evaluating pacemaker function, relating it to the patient's condition, and intervening appropriately in the face of complex paced rhythms.