Cardiac magnetic resonance imaging demonstrated that 29% of total stroke volume enters the atria during ventricular diastole and 68% during systole, independent of heart rate or heart size.
Observational (n=64)
In healthy humans at rest, approximately 70% of total stroke volume enters the atria during ventricular systole, driven by ventricular longitudinal contraction, independent of heart rate or heart size.
BACKGROUND: Whereas ventricular filling has been extensively studied and debated, atrial filling is less well characterized. Therefore, the aim of this study was to quantify atrial filling secured during ventricular diastole and systole, and to investigate whether atrial filling depends on heart rate (HR) and total heart volume (THV). METHODS: Thirty-two athletes (16 women) and 32 normal subjects (16 women) underwent cardiac magnetic resonance imaging. Cardiac volumes and atrioventricular plane displacement (AVPD) were determined. Longitudinal and radial contribution to stroke volume was calculated using planimetry and used to determine diastolic and systolic atrial filling. RESULTS: Atrial filling during ventricular diastole was 29 ± 10% of the total stroke volume, and during ventricular systole atrial filling was 68 ± 8% of the total stroke volume. There were no differences between groups of different HR (P = 0·70 and P = 0·41 for diastolic and systolic filling, respectively) or THV (P = 0·44 and P = 0·46 for diastolic and systolic filling, respectively). Systolic atrial filling was strongly correlated to longitudinal ventricular pumping (R = 0·76, P<0·001). CONCLUSION: This study demonstrated that in healthy humans at rest, approximately 30% of the total stroke volume enters the atria during ventricular diastole and approximately 70% during systole, independent of heart rate (HR) or heart size. The atria are filled through suction driven by ventricular longitudinal contraction which aspirates blood from the pulmonary and caval veins. As 70% of the atrial filling occurs during ventricular emptying, the heart volume remains relatively constant over the cardiac cycle, which minimizes pulling on surrounding tissues and therefore optimizes energy expenditure.
Steding‐Ehrenborg et al. (Wed,) conducted a observational in Healthy humans (n=64). Cardiac magnetic resonance imaging was evaluated on Atrial filling during ventricular diastole and systole. Cardiac magnetic resonance imaging demonstrated that 29% of total stroke volume enters the atria during ventricular diastole and 68% during systole, independent of heart rate or heart size.