A pacemaker similar to the size of a nickel can be implanted in patients to restore the heart's normal rhythm, when it is unable to pump enough oxygen-rich blood, experts have said.

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 rate.

Houston Methodist Hospital in Texas is now offering a US Food and Drug Administration (FDA) approved Micra Transcatheter Pacing System (TPS) -- the world's smallest pacemaker for patients with bradycardia, a condition characterized by a slow heart rate, usually fewer than 60 beats per minute.

The device is the size of a large vitamin, and unlike traditional pacemakers, it does not require cardiac wires (leads) or a surgical "pocket" under the skin to deliver a pacing therapy.

"The device is small enough to be delivered through a catheter and implanted directly into the heart, providing a safe alternative to conventional pacemakers without the complications associated with leads," said Paul Schurmann, Managing Director at Houston Methodist Hospital.

"The device also allows us to automatically adjust pacing therapy based on a patient's activity levels and another positive is the battery can last up to 10 years," added Schurmann.

Micra TPS was designed with a unique feature that enables it to be permanently turned off so it can remain in the body and a new device can be implanted without risk of electrical interaction.