Effect of hydration status on atrial and ventricular volumes and function in healthy adult volunteers

Background: Assessment of cardiac chamber volumes is a fundamental part of cardiac magnetic resonance (CMR) imaging. While the effects of inter- and intraobserver variability have been studied and have a recognized effect on the comparability of serial cardiac MR imaging studies, the effect of differences in hydration status has not been evaluated. Objective: To evaluate the effects of volume administration on cardiac chamber volumes. Materials and methods: Thirteen healthy adults underwent a baseline cardiac MR to evaluate cardiac chamber volumes after an overnight fast. They were then given two saline boluses of 10 ml/kg of body weight and the cardiac MR was repeated immediately after each bolus. Results: From the baseline scan to the final scan there was a significant increase in all four cardiac chamber end-diastolic volumes. Right atrial volumes increased 8.0%, from 61.1 to 66.0 ml/m2 (P<0.001), and left atrial volumes increased 10.0%, from 50.0 to 55.0 ml/m2 (P<0.001). Right ventricular volumes increased 6.0%, from 91.1 to 96.5 ml/m2 (P<0.001), and left ventricular volumes increased 3.2%, from 87.0 to 89.8 ml/m2 (P<0.001). Conclusion: Hydration status has a significant effect on the end-diastolic volumes of all cardiac chambers assessed by cardiac MR. Thus, hydration represents a “variable” that should be taken into account when assessing cardiac chamber volumes, especially when performing serial imaging studies in a patient.