The last two decades have witnessed the recognition of a significant relationship between the autonomic nervous system and cardiovascular mortality, including sudden cardiac death. Experimental evidence for an association between a propensity for lethal arrhythmias and signs of either increased sympathetic or reduced vagal activity has encouraged the development of quantitative markers of auton...

In 1981 a study on heart rate variability (HRV) and on the neural control of the heart was published in Science. Since then, the number of papers concerning this topic has increased exponentially. Some aspects of the relationship between HRV and the neural control of the cardiovascular system are now clear, for example: a decreased SDNN (a measure of variance) during a period of 24 hours is a w...

THE RHYTHM OF THE HEART has not only fascinated cardiologists but also inspired poets and musicians. Indeed, the periodic beat of the heart was used to define the speed of music. In music notation, the traditional Italian term “moderato” originally referred to one beat of the measure per walking pace (76–80 paces/min) or heartbeat ( 72 beats/min). The use of the heartbeat to define the speed of...