title: Atrial signal amplitude measurements in VDD systems according to body position.
abstract: Single lead VDD pacing is an established therapy in patients with AV block. Body position may influence the amplitude of the atrial signal recorded through the floating atrial electrode. This study analyzed the degree of posture related variation in the signal amplitude of floating atrial electrodes in 63 patients (mean age 72 +/- 21 years) implanted with a VDD system. The average atrial amplitude in the supine position was 1.59 +/- 1.15 mV and decreased significantly in the sitting position (1.37 +/- 1.08, P < 0.014), right decubitus (1.33 +/- 0.83, P < 0.007), and the abdominal position (1.24 +/- 0.86, P < 0.001). The left side decubitus showed a nonsignificant increase in atrial amplitude (1.66 +/- 1.02, P < 0.64). Body position significantly affects P wave amplitude and may be the cause of intermittent atrial undersensing. P wave amplitude measurement in different body postures should be performed in cases where suspected atrial undersensing occurs.
authors.affiliation: Department of Cardiology, Rabin Medical Center, Petah Tikva, Tel Aviv University, Sackler Faculty of Medicine, Tel Aviv, Israel.
authors.forename: Jairo
authors.initials: J
authors.lastname: Kuzniec
authors.forename: Gregory
authors.initials: G
authors.lastname: Golovchiner
authors.forename: Alexander
authors.initials: A
authors.lastname: Mazur
authors.forename: Alexander
authors.initials: A
authors.lastname: Battler
authors.forename: Boris
authors.initials: B
authors.lastname: Strasberg
mesh_terms: D000368:Aged; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D006325:Heart Atria / Q000503:physiopathology*; D006801:Humans; D008297:Male; D010138:Pacemaker, Artificial; D011187:Posture / Q000502:physiology*