Single-beat method echocardiographic comparison of ventricular-arterial coupling in adults with and without Down syndrome

Adults with Down syndrome (Ds) demonstrate unique cardiovascular features, including smaller left ventricular volumes and lower blood pressure. Ventricular-arterial coupling (VAC), a key measure of cardiovascular efficiency, has not been previously studied in this adult population. Understanding VAC in adults with Ds may reveal compensatory mechanisms that maintain cardiac output despite distinct cardiovascular characteristics. This study used echocardiographic parameters to compare the VAC ratio of adults with and without Ds. Baseline echocardiographic data were collected from 28 adults with Ds and 18 adults without Ds (aged 18-35 yr), all of whom had low physical activity levels. The VAC ratio was calculated using the single-beat method. Adults with Ds had lower VAC ratios and diastolic blood pressure, faster preejection times, shorter normalized systolic durations, and a higher ejection fraction than adults without Ds. Adults with Ds exhibit distinct cardiovascular adaptations, including a lower VAC ratio and a shorter systolic duration, suggesting increased cardiac workload. Higher ejection fraction and faster preejection period indicate potential compensatory mechanisms to maintain cardiac output, whereas lower diastolic blood pressure may reduce coronary perfusion and preload. These findings demonstrate differences in cardiac function and timing in adults with Ds in this study.<b>NEW & NOTEWORTHY</b> This study reveals, for the first time, that adults with Down syndrome exhibit significantly lower ventricular-arterial coupling ratios, reflecting distinct cardiac timing and functional adaptations. These findings could indicate a compensatory mechanism to maintain cardiac output despite reduced diastolic pressure and smaller cardiac chambers, providing novel insight into the integrated cardiovascular physiology of adults with Down syndrome and its potential implications for exercise tolerance and long-term cardiovascular health.