Tiny leadless pacemaker safe in most patients

11th September 2015

A tiny leadless pacemaker put into the heart via a major artery in the leg appears to work well in the majority of patients, early research suggests.

The one centimetre Nanostim LP leadless pacemaker includes a battery, electronics and electrodes and goes into the right ventricle of the heart via a catheter. It is designed for patients who need just one chamber of the heart paced.

Leadless pacemaker

Researchers say the device appeared to function well in the majority of trial patients over its first six months of use but there were serious problems in one in 15 patients.

Dr Vivek Reddy, from the Mount Sinai School of Medicine in New York, told a European Society of Cardiology meeting that 504 out of 526 patients had the device implanted successfully and it met pre-specified pacing and sensing requirements in the large majority of patients.

The device has had a troubled history.   A study in Europe was halted last year after reports of six perforations including two that resulted in death.

It was suggested the problems related to the inexperience of those implanting the device as well as which patients were selected for it. The trial was stopped again earlier this year — again due to perforations —but has since restarted.

Researchers say the Nanostim device has various advantages over traditional pacemakers, which can have problems with leads into the heart and complications attached to having the device in a pocket under the skin.

At six months, the study showed device-related serious adverse events were seen in 6.7% of the patients, the researchers reported. These events included device dislodgement, cardiac perforations and pacing-issues requiring retrieval and device replacement.

It was said that though the adverse event rate was on the high side, it was good for something as new and as disruptive as this device, and cardiac perforations happened even with conventional pacemaker fitting.

There are still long term issues to be investigated including how long the device will work in the heart and how easy retrieval will be when it needs replacing.