Noninvasive evaluation of left ventricular force−frequency relationships by measuring carotid arterial wave intensity during exercise stress

Background and purpose Estimation of the contractility of the left ventricle during exercise is important in drawing up a protocol of cardiac rehabilitation. It has been demonstrated that color Doppler- and echo tracking-derived carotid arterial wave intensity is a sensitive index of global left ventricular (LV) contractility. We assessed the feasibility of measuring carotid arterial wave intensity and determining force−frequency (contractility−heart rate) relations (FFRs) during exercise totally noninvasively.