Background-The effect of moderate left ventricular systolic dysfunction (LVSD) on ventricular/vascular coupling and the aortic pressure waveform (AoPW) has been well described, but the effect of severe LVSD has not. Methods and Results-We used noninvasive, high-fidelity tonometry of the radial artery and a mathematical transfer function to generate the AoPW in 25 treated patients with LVSD (mean LV ejection fraction, 24Ϯ8.8%; range, 11% to 40%; 21 patients Ͻ30%). Pulse wave analysis of the AoPW was used to characterize ventricular/vascular coupling and compared with pulse wave analysis performed in 25 normal subjects matched for age, gender, height, body mass index, and heart rate.