Profound bradycardia with lidocaine during anesthesia induction in a silent sick sinus syndrome patient.

Sick sinus syndrome is caused by sinus node dysfunction that renders it unable to function as a pacemaker. Patients with sick sinus syndrome are often asymptomatic or have symptoms that are mild and nonspecific. Lidocaine (0.5 mg/kg) injection is used for reduction of pain associated with intravenous injection of propofol. Episodes of marked bradycardia with sinus arrest after prophylactic lidocaine injection are reported in a 69-y-old man with no apparent preoperative cardiac disease or electrocardiographic abnormality. Surgery was postponed, and he was later diagnosed with sick sinus syndrome.