title: Acute electromechanical effects of atrioventricular coupled pacing in patients with heart failure.
abstract: BACKGROUND
  Postextrasystolic potentiation (PESP) is a property of cardiac tissue whereby two closely timed depolarizations cause the subsequent contraction to be of increased magnitude.
  
  
  RESULTS
  Ten subjects were studied in a single-blind study to evaluate the safety and performance of an atrioventricular coupled pacing (A-VCP) algorithm to produce sustained PESP among subjects with moderate heart failure. The primary end points were algorithm safety, patient perception, and cardiac function. The effects of A-VCP on cardiac function were assessed by comparing echocardiographic parameters before and after 15 to 20 minutes of A-VCP. A-VCP produced no arrhythmic episodes, ejection fraction increased by 8 ejection fraction points (31%) (P < or = .001), end-systolic volume decreased by 10% (P < or = .05), and a trend toward increasing end-diastolic volume was observed (P = .084). Stroke volume increased by 43% (P < or = .001), and the pulse rate decreased by 41% (P < or = .001) during A-VCP. This resulted in decreased cardiac output of 15% (P < or = .05). Six of the 10 subjects felt no effects from A-VCP, and four subjects felt a change with A-VCP turned on.
  
  
  CONCLUSIONS
  Short-term A-VCP was found to be safe and well tolerated in a majority of patients. Hemodynamic effects were mixed with improved ejection fraction and stroke volume but decreased cardiac output.
authors.affiliation: Robert Wood Johnson Medical School, New Brunswick, New Jersey, USA.
authors.forename: Ronald
authors.initials: R
authors.lastname: Freudenberger
authors.forename: Mark
authors.initials: M
authors.lastname: Aaron
authors.forename: Steve
authors.initials: S
authors.lastname: Krueger
authors.forename: Melody
authors.initials: M
authors.lastname: Labeau
authors.forename: Karen
authors.initials: K
authors.lastname: Kleckner
authors.forename: Ruth Nicholson
authors.initials: RN
authors.lastname: Klepfer
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D018619:Echocardiography, Doppler, Pulsed; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000000981:diagnostic imaging* / Q000401:mortality / Q000628:therapy*; D006334:Heart Function Tests; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011336:Probability; D011446:Prospective Studies; D018570:Risk Assessment; D012720:Severity of Illness Index; D016037:Single-Blind Method; D013318:Stroke Volume / Q000502:physiology; D015996:Survival Rate; D016896:Treatment Outcome