For the first time ever, a transcatheter pacemaker was implanted at the Clinic for Cardiology Pneumology and Angiology at the University Hospital Düsseldorf (German: Klinik für Kardiologie, Pneumologie und Angiologie des Universitätsklinikums Düsseldorf), which is directly inserted into the heart as a fully self-contained system using minimally invasive surgery. It signifies substantial progress in the medical treatment of patients with cardiac pacemakers.
Miniaturized cardiac pacemaker
The fundamental difference between the Micra (Medtronic GmbH) transcatheter pacemaker and traditional cardiac pacemakers is that this tiny device is able to do without an electrode and is inserted into the heart via the femoral vein. By comparison, it is only one-tenth of the size, merely weighs 1.75 grams, is 26 millimeters long and 6.7 millimeters in diameter. This equates to roughly the size of a large vitamin capsule. "This is the actual engineering masterpiece," says PD Dr. Dong-In Shin, Director of the Rhythmology Department. "The device exhibits all functions and scope of a unicameral pacemaker. The capsule-sized pacemaker is even safe to use in MRI scanners up to 3 Tesla."
With the help of a catheter, the transcatheter pacemaker is first inserted via the femoral vein – the vena femoralis –into the superior vena cava that flows directly into the heart and is then positioned inside the right ventricle of the heart. It is subsequently being tested and programmed with an external device. "The transcatheter pacing system has a passive fixation mechanism," explains Shin. "This means that the moment the capsule is being detached from the catheter, nitinol anchors expand. They are made of very soft metal. The internal wall of the right ventricle is interspersed with tiny trabeculae, tiny fibers or rather muscle fibers, and the transcatheter pacing system attaches itself to it." The mini cardiac pacemaker then delivers the necessary electrical impulses to the heart wall.