This 70-year-old man presents to the Emergency Department with episodic presyncope and weakness for the past several weeks. He has a history of paroxysmal atrial fibrillation, with mild symptoms during the past year:

• Sinus rhythm with a 6.28 second sinus pause and two junctional escape complexes

In view of the history of paroxysmal atrial fibrillation, a diagnosis of “tachycardia-bradycardia syndrome” (Sick Sinus Syndrome) was justified. The patient was admitted for pacemaker implantation.