Frank-Starling mechanism contributes modestly to ventricular performance during atrial fibrillation

Zoran B. Popović, Hirotsugu Yamada, Kent A. Mowrey, Youhua Zhang, Don W. Wallick, Richard A. Grimm, James D. Thomas, Todor N. Mazgalev*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

Objectives: The aim of this study was to assess whether Frank-Starling mechanism has an independent effect on left ventricular (LV) performance in atrial fibrillation (AF). Background: Ventricular performance in AF depends on variable contractility through the interval-force mechanism based on the ratio of preceding and pre-preceding RR intervals (RRp/RRpp). The impact of end-diastolic volume (EDV) variability, through the Frank-Starling mechanism, is not well understood. Methods: We induced AF in 16 open chest dogs. RR intervals, LV pressure, LV volume, and aortic flow were collected for > 400 beats during rapid AF (ventricular cycle length 292 ± 66 ms). In six of the dogs, additional data were collected while average ventricular cycle length was prolonged from 258 ± 34 ms to 445 ± 80 ms by selective vagal nerve stimulation of the AV node. Results: The relations of maximal LV power (LVPower) and peak LV pressure derivative (dP/dt) versus RRp/RRpp were fitted to the equation y = A * (1 - EXP (RRp/RRppmin - RRp/RRpp)/C) and the residuals (RES) of these relations were analyzed. LVPower and dP/dt strongly correlated with RRp/RRpp (r2 = 0.67 ± 0.12 and 0.66 ± 0.12, P > .0001 for all correlations). Importantly, RES-LVPower and RES-dP/dt showed linear correlation with EDV (r2 = 0.20 ± 0.14 and r2 = 0.24 ± 0.17, P < .01 for all correlations). In the six dogs with slowed average ventricular rate, the slope of both residual relationships (RES-LVPower vs EDV and RES- dP/dt vs EDV) decreased (P < .03 for both). Conclusions: The Frank-Starling mechanism contributes to ventricular performance in AF independently of the interval-force effects of the beat-to-beat variability in cardiac contractility. The Frank-Starling mechanism is sensitive to the average ventricular rate.

Original languageEnglish (US)
Pages (from-to)482-489
Number of pages8
JournalHeart Rhythm
Volume1
Issue number4
DOIs
StatePublished - Oct 1 2004

Keywords

  • Atrial fibrillation
  • Contractility
  • Frank-Starling mechanism
  • Hemodynamics
  • Preload
  • Tachyarrhythmia

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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