Figure 8

Methodology of the force-frequency curve with pacemaker stress echo in normal subject. On the left, from upper to lower rows: heart rate from external programming of permanent pacemaker (first row); systolic blood pressure by cuff sphygmomanometar (second row); left ventricular end-systolic apical four (4C) and the two (2C) chamber view (third and fourth row); end-systolic volume calculated with biplane Simpson method (fifth row). An increased heart rate is accompanied by an increased systolic pressure with smaller end-systolic volumes (normal up sloping FFR).