title: Novel method of predicting the optimal atrioventricular delay in patients with complete AV block, normal left ventricular function and an implanted DDD pacemaker.
abstract: BACKGROUND
  The optimal atrioventricular (AV) delay setting is important for achieving optimal AV synchrony in patients with an implanted DDD pacemaker. Using pulsed Doppler echocardiography is the most common method of predicting the optimal AV delay, but it is a complicated and time-consuming method. Therefore, an automatic optimizing function of the AV delay at different atrial rates is desirable for achieving a favorable hemodynamic state. This study aimed to predict the optimal AV delay using phonocardiography.
  
  
  RESULTS
  The amplitude of the first heart sound (S1) recorded on the phonocardiogram was measured with different AV delays in 6 patents with complete AV block, normal left ventricular function and an implanted DDD pacemaker. The correlation between the amplitude of S1 and the length of the AV delay was a cubic curve (y=974.15x(3)-23.084x(2)-8.0074x+0.7495, R2=0.9511). The length of the AV delay at the inflection point of the curve showed a significant positive correlation with the optimal AV delay determined by pulsed Doppler echocardiography (R=0.9254, P<0.01).
  
  
  CONCLUSIONS
  This study demonstrated a novel simple method of predicting the optimal AV delay using phono-cardiography.
authors.affiliation: Department of Medical Science and Cardiorenal Medicine, Yokohama City University School of Medicine, Yokohama, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Miki
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Ishikawa
authors.forename: Kohei
authors.initials: K
authors.lastname: Matsushita
authors.forename: Youhei
authors.initials: Y
authors.lastname: Yamakawa
authors.forename: Katsumi
authors.initials: K
authors.lastname: Matsumoto
authors.forename: Shinichi
authors.initials: S
authors.lastname: Sumita
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Uchino
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kimura
authors.forename: Satoshi
authors.initials: S
authors.lastname: Umemura
mesh_terms: D000368:Aged; D054537:Atrioventricular Block / Q000503:physiopathology* / Q000628:therapy; D018619:Echocardiography, Doppler, Pulsed / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D010138:Pacemaker, Artificial; D010701:Phonocardiography / Q000379:methods*; D011237:Predictive Value of Tests