The world's smallest pacemaker, which is about as big as a large vitamin capsule and provides the most advanced pacing technology, has been successfully implanted for the first time in a patient in the US. Scientists said, the pacemaker is for patients with bradycardia, a condition characterised by a slow heart rate, usually fewer than 60 beats per minute.<br/><br/>The Micra Transcatheter Pacing System, recently approved by the US Food and Drug Administration, is a new type of heart device that provides patients with the most advanced pacing technology at one-tenth the size of a traditional pacemaker and is the only leadless pacemaker approved for use in the US.<br/><br/>Pacemakers are the most common way to treat bradycardia to help restore the heart's normal rhythm and relieve symptoms by sending electrical impulses to the heart to increase the heart<br/>rate.