Anatomy for right ventricular lead implantation

Israel C, Tribunyan S, Yen Ho S, Cabrera JA. Anatomy for right ventricular lead implantation. Herzschrittmachertherapie + Elektrophysiologie. 2022;33(3):319-326.**Abstract** To understand the position of a pacing lead in the right ventricle and to correctly interpret fluoroscopy and intracardiac signals, good anatomical knowledge is required. The right ventricle can be separated into an inlet, an outlet, and an apical compartment. The inlet and outlet are separated by the septomarginal trabeculae, while the apex is situated below the moderator band. A lead position in the right ventricular apex is less desirable, last but not least due to the thin myocardial wall. Many leads supposed to be implanted in the apex are in fact fixed rather within the trabeculae in the inlet, which are sometimes difficult to pass. In the right ventricular outflow tract (RVOT), the free wall is easier to reach than the septal due to the fact that the RVOT wraps around the septum. A mid-septal position close to the moderator band is relatively simple to achieve and due to the vicinity of the right bundle branch may produce a narrower paced QRS complex. Special and detailed knowledge is necessary for His bundle and left bundle branch pacing.**Zusammenfassung** Um die Position einer Schrittmacherelektrode im rechten Ventrikel zu verstehen und Fluoroskopie sowie intrakardiale Signale richtig interpretieren zu können, sind gute anatomische Kenntnisse erforderlich. Der rechte Ventrikel kann in einen Einflusstrakt, einen Ausflusstrakt und einen apikalen Bereich unterteilt werden. Ein- und Ausflusstrakt werden durch die septomarginalen Trabekel voneinander getrennt, der apikale Bereich liegt unterhalb des Moderatorbands. Eine Elektrodenlage im rechtsventrikulären Apex ist nicht zuletzt aufgrund des dort dünnen Myokards nicht günstig und oft gar nicht einfach zu erreichen; die Elektrodenspitze bleibt leicht in den Trabekeln des Einflusstrakts hängen, die manchmal schwer zu passieren sind. Im rechtsventrikulären Ausflusstrakt (RVOT) ist die freie Wand einfacher zu erreichen als die septale, da der RVOT sich um das Septum herumwindet. Eine mittseptale Position nahe dem Moderatorband ist relativ leicht zu erreichen und erzielt durch die Nähe zum rechten Schenkel oft einen schmaleren stimulierten QRS-Komplex. Spezielle und detaillierte anatomische Kenntnisse sind für eine His-Bündel- und Linksschenkelstimulation erforderlich

Atrial Fibrillation in Patients with Embolic Stroke of Undetermined Source during 3 Years of Prolonged Monitoring with an Implantable Loop Recorder

Kitsiou A, Rogalewski A, Kalyani M, et al. Atrial Fibrillation in Patients with Embolic Stroke of Undetermined Source during 3 Years of Prolonged Monitoring with an Implantable Loop Recorder. Thrombosis and Haemostasis. 2021;121(06):826-833.Background: Undocumented atrial fibrillation (AF) is suspected as a main stroke cause in patients with embolic stroke of undetermined source (ESUS), but its prevalence is largely unknown. This prospective study therefore aimed at delineating the prevalence of AF in patients with ESUS using continuous cardiac monitoring by implantable loop recorder (ILR) with daily remote interrogation over a period of 3 years and its clinical consequences, including recurrent stroke. Methods: In consecutive patients with an ESUS diagnosis after complete work-up, an ILR was implanted and followed by daily remote monitoring until AF was detected or a follow-up of at least 3 years was completed. Additionally, the ILR was interrogated in-hospital in 6-month intervals. Results: A total of 123 patients (74 male, mean age 65 ± 9 years) were enrolled and completed the 3 years study period. AF was detected in 51 patients (41.4%). In 43 of the 51 AF positive patients (84%) oral anticoagulation was established. Recurrent strokes occurred in 18 patients (14.6%) of this ESUS population, 9 of these patients being AF positive (17.6% of the AF-positive patients) and 9 being AF negative (12.5% of AF-negative patients). Patients with AF were slightly older than patients without AF (63.1 ± 8.8 vs. 67.5 ± 9.6 years, p = 0.12). Other parameters such as CHA2DS2-VASc score, infarct localization, micro- and macroangiopathy, carotid or aortic plaques, or stroke recurrence were not significantly different between groups. Conclusion In ESUS patients, early implantation of an ILR with cardiac monitoring and remote transmission over a 3-year period detected AF in 41.4% and resulted in oral anticoagulation in 84% of these patients