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[Assessment of abnormal left ventricular systolic blood flow in atrial fibrillation]
K Mawatari1, N Kuroiwa, J Sanada
1Second Department of Internal Medicine, Kagoshima University School of Medicine.
Insights
In atrial fibrillation, shorter preceding R-R intervals are linked to abnormal left ventricular blood flow ("back flow"). This back flow is associated with reduced ejection fraction and altered apical motion, impacting cardiac hemodynamics.
Area of Science:
- Cardiology
- Physiology
- Medical Imaging
Context:
- Hemodynamics in atrial fibrillation (AF) are known to vary with preceding R-R intervals.
- Previous methodological limitations hindered detailed blood flow dynamics assessment in AF.
- Pulsed Doppler echocardiography offers a method to investigate these dynamics.
Purpose:
- To assess blood flow dynamics in the left ventricle of patients with atrial fibrillation using pulsed Doppler echocardiography.
- To correlate observed blood flow patterns with preceding R-R intervals and left ventricular function.
Summary:
- Systolic "back flow" towards the left ventricular apex was observed in 14% of AF patients.
- This back flow occurred more frequently after shorter preceding R-R intervals and was linked to longer intervals when absent.
- Patients with back flow exhibited significantly reduced left ventricular ejection fraction and abnormal apical motion.
Impact:
- Identifies a specific abnormal blood flow pattern in atrial fibrillation.
- Highlights the relationship between R-R interval variability and adverse hemodynamic events.
- Provides insights into the mechanical consequences of irregular heart rhythms on ventricular function.
Abstract:
In atrial fibrillation, it is known that hemodynamics vary according to the preceding R-R intervals. However, the informations of blood flow dynamics have not been available because of the methodological limitations. In this study, blood flow dynamics of atrial fibrillation were assessed using pulsed Doppler echocardiography. The subjects were 160 consecutive patients with atrial fibrillation and without left ventricular asynergy. Using a commercially-available pulsed Doppler instrument (Aloka SSD-910), blood flow patterns in the left ventricle were investigated from the apical long-axis view. The results were as follows: 1. In 22 of the 160 cases (14%), systolic blood flow in the central or apical region of the left ventricle directed towards the apex (termed "back flow"). 2. In the cardiac cycle with "back flow", the preceding R-R interval was shorter; whereas it was longer when "back flow" was absent (591 +/- 103 vs 817 +/- 179 msec, p less than 0.01). Moreover, when a long R-R interval (PPI) followed by a short R-R interval (PI) was observed (greater PPI/PI ratios), the next beat showed distinct "back flow". 3. Left ventricular ejection fraction decreased significantly in patients with "back flow" compared to those without it (42 +/- 15 vs 66 +/- 12%, p less than 0.01). 4. On left ventriculography, the motion of the base of the heart was preserved; however, with "back flow", the motion of the apical area was abnormal, extending towards the apex along the longitudinal axis. 5. Left ventricular ejection flow at the outflow tract disappeared in 13 of the 22 cases with "back flow" in cardiac cycles with short preceding R-R intervals.(ABSTRACT TRUNCATED AT 250 WORDS)