Key result
The ratio of slope to peak ejection velocity at an RR interval of 1 second (Slope/Vpe-1) for preceding RR intervals of 0.6 to 1.0 seconds was significantly higher in atrial fibrillation patients with LV dysfunction compared to those with normal LV function (0.46 vs 0.26, p=0.001).
Why the study?
New parameters representing left ventricular function independent of irregular RR intervals in atrial fibrillation were needed to quantitatively evaluate LV function.
Can new parameters derived from the relationship between RR intervals and LV performance quantitatively evaluate LV function in patients with atrial fibrillation?
Cross-Sectional (n=18)
No
Can new parameters derived from the relationship between RR intervals and LV performance quantitatively evaluate LV function in patients with atrial fibrillation?
Absolute Event Rate: 0.46% vs 0.26%
p-value: p=0.001
New parameters derived from the relationship between RR intervals and LV outflow peak ejection velocity may be useful for quantitatively evaluating LV function in patients with atrial fibrillation.
This study was designed to obtain new parameters representing left ventricular (LV) function independent of irregular RR intervals in atrial fibrillation (AF). AF patients were divided into Normal (n=9) and LV Dysfunction (n=9) groups. The relations between LV outflow peak ejection velocity (Vpe) and preceding (RR-1) or prepreceding RR intervals (RR-2) were obtained using logarithmic equations, from which the squared correlation coefficient (r2), slope, Vpe at RR-1 or RR-2=1 sec (Vpe-1), and the ratio of slope to Vpe-1 (Slope/Vpe-1) were calculated. Among the parameters between RR-1 and Vpe, Slope/Vpe-1 was higher in LV Dysfunction group than in Normal group (p=0.05). When only coordinates with RR-1 from 0.6 to 1 sec were included, Slope/Vpe-1 (p=0.001) was higher in LV Dysfunction group than in Normal group. Among the parameters between RR-2 and Vpe, Slope/Vpe-1, slope, and r2 were different between the two groups. In multivariate analysis, Slope/Vpe-1 between RR-2 and Vpe was only independent parameter. However, Slope/Vpe-1 between RR-1 and Vpe in the coordinates with RR-1 from 0.6 to 1 sec had the highest discriminating power. New parameters derived from the relations between RR intervals and LV performance might be useful to evaluate LV function quantitatively in AF.
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Ko et al. (2005) conducted a cross-sectional in Atrial Fibrillation (n=18). Left ventricular dysfunction vs. Normal left ventricular function was evaluated on Slope/Vpe-1 in the relation between RR-1 and Vpe (coordinates with RR-1 from 0.6 to 1 sec) (p=0.001). The ratio of slope to peak ejection velocity at an RR interval of 1 second (Slope/Vpe-1) for preceding RR intervals of 0.6 to 1.0 seconds was significantly higher in atrial fibrillation patients with LV dysfunction compared to those with normal LV function (0.46 vs 0.26, p=0.001).
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