What is the Impact of Atrial fibrillation on blood pressure ? … It is also irregularly irregular !

Atrial fibrillation has a direct effect on systemic blood pressure as stroke volume swings from beat to beat because of changing  RR Interval ( preload ). The variation in systolic pressure actually reflects not only the changing stroke volume but also the enhanced contractility of the ventricle to the preload( Frank-Starling principle ). The net effect is reflected in the pulse as an irregularly irregular pulse (Both rate and volume /Amplitude).* However, In severely dysfunctional ventricles this variation in systolic  BP can be minimal. Also realize, If the preload is changing every beat, there is a considerable dynamism in the afterload as well because of ventricular arterial coupling. How to recognize ? As you record the BP by cuff, the Phase 1 Korotkoff sound floats up and down with each beat. If the variation in RR interval is huge one may get a beat-to-beat variation even up to 40 mmHg.We also know, AF can cause pulse drop /deficit intermittently. What happens to Korotkoff sound during pulse deficit? Obviously, there will be a loss of these phase 1 sounds, though the other phases of sound may be heard, which are generated by the previous cardiac cycle. So, measuring blood pressure in AF is not a clinically pleasant task. That’s why we are asked to record 3 times and take an average. Now coming to diastolic BP in AF. It’s a real hemodynamic riddle. Traditional teaching is, systolic BP is determined by cardiac output and diastolic BP by peripheral vascular...
Source: Dr.S.Venkatesan MD - Category: Cardiology Authors: Tags: Cardiology - Clinical Blood pressure in atrial fibillation cardiology research topic cardiology thesis topic pulse deficit Source Type: blogs