[Future cardiac pacemakers – technical visions].

Cardiac pacemakers are routinely used for the treatment of bradyarrhythmias. Contemporary pacemakers are reliable and allow for a patient specific programming. However, pacemaker replacements due to battery depletion are common (~25 % of all implantation procedures) and bear the risk of complications. Batteryless pacemakers may allow overcoming this limitation. To power a batteryless pacemaker, a mechanism for intracorporeal energy harvesting is required. Such a generator may consist out of subcutaneously implanted solar cells, transforming the small amount of transcutaneously available light into electrical energy. Alternatively, intravascular turbines may harvest energy from the blood flow. Energy may also be harvested from the ventricular wall motion by a dedicated mechanical clockwork converting motion into electrical energy. All these approaches have successfully been tested in vivo. Pacemaker leads constitute another Achilles heel of contemporary pacemakers. Thus, leadless devices are desired. Miniaturized pacemaker circuits and suitable energy harvesting mechanisms (incorporated in a single device) may allow catheter-based implantation of the pacemaker in the heart. Such miniaturized battery- and leadless pacemakers would combine the advantages of both approaches and overcome major limitations of today’s systems.

Ätiologie des Hirninfarkts

Das pathogenetische Verständnis bei zerebralen Durchblutungsstörungen wächst. Durch die moderne Diagnostik gelingt eine immer genauere Abgrenzung verschiedener Ursachen von Hirninfarkten. Ursächlich kommen ein embolischer Gefässverschluss, eine lokale Thrombusbildung oder seltener eine hämodynamische Insuffizienz aufgrund eines vorgeschalteten Strömungshindernisses in Betracht. Die häufigste Emboliequelle stellt allerdings das Herz dar. Ziel der Abgrenzung ist eine ätiologische Zuordnung und die adäquate Therapie.