title: Relation Between RR Intervals and Early Diastolic Mitral Annular Velocities in Atrial Fibrillation.
abstract: OBJECTIVE
  Irregular RR intervals in atrial fibrillation (AF) make beat-to-beat changes in left ventricular (LV) systolic performance. Early diastolic mitral annular velocity (E') is one of the well-established parameters for evaluating LV diastolic function. The relation between RR intervals and E's is unknown. The aim of this study was to observe the influence of continuous changes in RR interval on the parameter for diastolic function in AF.
  
  
  METHODS
  Echocardiography was performed in 117 patients with AF. E' was adjusted for the effect of pre-preceding RR interval (RR-2) using the logarithmic equation between RR-2 and E'. The logarithmic equation between adjusted E' and preceding RR interval (RR-1) was calculated.
  
  
  RESULTS
  The slope in the relation between RR-1 and E' varied from -2.5 to 2.6. The slope was lower (more likely negative) in patients with higher ratio of early diastolic mitral flow velocity (E) to E' (r=-0.21, p=0.023), ischemic heart disease (IHD, r=0.21, p=0.026), and higher systolic blood pressure (r=-0.19, p=0.046). When patients were divided into these 3 groups on the basis of slope, the lowest slope group (<-0.55, n=39) was associated with higher E'/E (p=0.004) and IHD (p=0.018) compared with the highest slope group (>0.57, n=39). The slope with regards to the relationship between RR-2 and E' also varied from -3.4 to 3.1.
  
  
  CONCLUSIONS
  Changes in RR intervals had variable effects on E's according to clinical variables in AF.
authors.affiliation: Division of Cardiology, Department of Internal Medicine, College of Medicine, Chung-Ang University, Seoul, Korea.
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Kim
authors.forename: Young Hwan
authors.initials: YH
authors.lastname: Choi
authors.forename: Cheol Won
authors.initials: CW
authors.lastname: Hyeon
authors.forename: Jun Hwan
authors.initials: JH
authors.lastname: Cho
authors.forename: Kyung Joon
authors.initials: KJ
authors.lastname: Kim
authors.forename: Wang-Soo
authors.initials: WS
authors.lastname: Lee
authors.forename: Kwang Je
authors.initials: KJ
authors.lastname: Lee
authors.forename: Sang-Wook
authors.initials: SW
authors.lastname: Kim
authors.forename: Tae Ho
authors.initials: TH
authors.lastname: Kim
authors.forename: Chee Jeong
authors.initials: CJ
authors.lastname: Kim
keywords: Atrial fibrillation; Electrocardiography; Heart rate; Pulsed Doppler echocardiography; Ventricular function, left