Contractility in tachycardia

  1. Hi, does somebody know how tachycardia affects contractility? I am confused between 2 possible answers that I can think of - related to B1-stimulation and decreased ventricular filling time. Any input will be very much appreciated. Thanks.
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    About gwapo

    Joined: Dec '05; Posts: 248; Likes: 37
    SRNA; from US
    Specialty: 7 year(s) of experience in ICU


  3. by   Biffbradford
    Vtach or sinus tach? Not that I have any answers after that, but it would depend if you're filling the chambers correctly or not.
  4. by   fiveofpeep
    My thought is that if you are tachy you have less filling time so you have less end-diastolic volume and thus less wall stretch, so according to Starling's law you would have less contractility.

    Frank-Starling Law
    Last edit by fiveofpeep on Jan 2, '12 : Reason: added EDV
  5. by   PetERNurse
    Beta-1 agonists will increase contractility and HR, but as the HR increases there is less time spent in diastole and therefore filling time is reduced. There is an optimal HR when using beta-1 agonists, and a HR above that will actually decrease CO (curve is parabolic).