Stress echo lab: contractility me too? Blood pressure analysis. One investigator records all blood pressures at rest and during exercise during the study. The blood pressure recording is made using a manometer sphygmomanometer and the diaphragm of a standard stethoscope. Echocardiography is performed using conventional two-dimensional echocardiography and tissue harmonic imaging and digitized on-line into a quad screen, cineloop format. Left ventricular end-systolic volumes are measured from apical four and two chamber view, using the biplane discs-method. To build the force-frequency relationship, the force is determined at each step as the ratio of the systolic pressure (cuff sphygmomanometer)/end-systolic volume index (biplane Simpson rule/body surface area).