Related Experiment Video
Updated: Jul 26, 2026
Noninvasive Determination of Vortex Formation Time Using Transesophageal Echocardiography During Cardiac Surgery
Published on: November 28, 2018
Assessment of LV systolic function in atrial fibrillation using an index of preceding cardiac cycles
T Tabata1, R A Grimm, N L Greenberg
1Section of Cardiovascular Imaging, Department of Cardiology, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.
Insights
Assessing left ventricular (LV) systolic function during atrial fibrillation (AF) is challenging. A new index using preceding R-R intervals accurately estimates LV contractile function in AF, improving clinical assessment.
Area of Science:
- Cardiology
- Physiology
- Biomedical Engineering
Background:
- Clinical assessment of left ventricular (LV) systolic function is unreliable during atrial fibrillation (AF) due to beat-to-beat variability.
- Accurate evaluation of LV systolic function is crucial for patient management.
Purpose of the Study:
- To evaluate a novel index for estimating LV systolic function in AF.
- The index is based on the relationship between consecutive R-R intervals (R-R1 and R-R2).
Main Methods:
- LV Doppler stroke volume (SV), ejection fraction (EF), peak aortic flow rate (AoF), and dP/dt(max) were measured in 13 healthy dogs during induced AF.
- These parameters were correlated with the R-R1/R-R2 ratio.
Main Results:
- All measured LV systolic parameters (SV, EF, AoF, dP/dt(max)) demonstrated a strong positive linear relationship with the R-R1/R-R2 ratio (r values ranging from 0.65 to 0.75).
- Estimated LV systolic parameters at R-R1/R-R2 = 1 showed good agreement with measured average values.
- The index allows for accurate and reproducible evaluation of LV contractile function during AF.
Conclusions:
- The R-R interval ratio index provides a reliable method for assessing LV systolic function during AF.
- This approach overcomes the limitations of averaging multiple cardiac cycles for clinical assessment.
Abstract:
The clinical assessment of left ventricular (LV) systolic function during atrial fibrillation (AF) is unreliable and difficult because of beat-to-beat variability. We evaluated an index for the estimation of LV systolic function in AF that is based on the relationship between the preceding (R-R1) and prepreceding (R-R2) R-R intervals. LV Doppler stroke volume (SV), ejection fraction (EF), peak aortic flow rate (AoF) and the maximum value of the first derivative of the LV pressure curve (dP/dt(max)) were evaluated in 13 healthy open-chest dogs during triggered AF. All parameters showed a significantly strong positive linear relationship with the ratio of R-R1/R-R2 (r = 0.65, 0.74, 0.75, and 0.70 for SV, EF, AoF, and dP/dt(max), respectively). The calculated value of LV systolic parameters at R-R1/R-R2 = 1 in the linear regression line showed a good relationship and an agreement with the measured average value of the parameter over all cardiac cycles (SV, 12.1 vs. 12.8 ml; EF, 49.6 vs. 51.2%; AoF, 1.37 vs. 1.48 l/min; and dP/dt(max), 2,323 vs. 2,454 mmHg/s). Using the LV systolic parameters estimated at R-R1/R-R2 = 1 in the linear regression line allows the LV contractile function to be accurately and reproducibly evaluated during AF and obviates the less-reliable process of averaging multiple cardiac cycles.
Related Concept Videos
01:29Cardiac Cycle
During the cardiac cycle, blood flow through the heart is regulated entirely by changing pressure gradients. This sequence of events begins with the heart in a state of total relaxation, known as mid-to-late diastole, during which blood passively flows from...
01:30Dysrhythmias V: Evaluating Dysrhythmias