Telemonitoring in chronic heart failure. In this scenario a patient with DCM has the FFR monitored through the sensor built FFR in baseline conditions (week 1) and during beta-blockade titration (weeks 2 to 9). The force-frequency relation of these diseased hearts exhibits a flat or negative slope at contraction frequencies above about 100 bpm. Therapy with beta blockers has proved effective in cardiomegaly regression, however patients do not respond uniformly. The bradycardic action of beta blockers reduces the number of daily working phases of the heart in the negative part of the force-frequency relationship. To optimize chronic heart failure therapy, monitoring the patient's FFR enables the effectiveness of therapies to be verified. By monitoring in accordance with this new sensor, not only can positive or negative decompensation changes as a result of certain events be determined, but also the variation in the force-frequency curve over twenty-four hours, days or weeks. A three-dimensional diagram could be determined which for each heart rate not only indicates the instantaneous force value but also enables the variation of said value with time to be monitored.