Fig. 1
A Schematic illustration of pump function curves for normal and failing heart. Pressure and stroke volume axes are normalised to a scale of 100% for maximum pressure (at zero ejection) and maximum ejection (zero pressure load). In heart failure, the curve is flattened towards the volume axis, increasing the ejection sensitivity to pressure afterload. When the operating point moves from “1” to “2” due to a similar pressure increase (ΔP), the decrease in stroke volume (ΔV) is much greater in heart failure. B Schematic illustration of pulse pressure amplification between the aorta (aPP1) and brachial artery (bPP) for similar diastolic pressure (aDBP, bDBP), with the corresponding aortic systolic pressure (aSBP1). For reduction in heart rate (as occurs with beta-blockers), a similar bPP would correspond to a higher aortic pulse pressure (aPP2), hence giving a higher aortic systolic pressure (aSBP2). This difference (ΔSBP) can be a significant factor in analysing effects of arterial blood pressure in heart failure due to the increased pressure sensitivity of ventricular contractility and ejection (panel A), and if not taken into account it can be a potentially significant confounding factor in the analysis of cardiovascular risk. The effect will be masked if only bSBP is used in analyses where there are changes in pulse amplification. It can only be taken into account if aortic pressure is known
