Accurate Measurement of Both Main Components of Heart Rate Variability Can Be Applied Routinely Clinically

One century ago, the critical role of the Autonomic Nervous System (ANS) in health and disease was prophesized. In 1990, Heart Rate Variability (HRV = Sympathetic-tone [S] + Parasympathetictone [P]) was 1st used in clinical cardiology. Emphasizing the reduction in HRV was associated with a poor prognosis in all major cardiovascular illness. In 2000, HRV was included in Sudden Cardiac Death (SCD) risk stratification. There are over 350,000 SCDs/yr. in the USA. High S and critically low P are associated with increased mortality, life-threatening ventricular arrhythmias, congestive heart failure (CHF), and acute coronary syndromes (ACSs). Two common autonomic dysfunctions are Sympathetic Withdrawal (SW, an abnormal alpha-adrenergic response to head-up postural change underlying Orthostatic dysfunction) and Parasympathetic Excess (PE, an abnormal cholinergic response to stress, amplifying the stress response, as in difficult to manage blood pressure (BP), blood glucose, hormone levels, or Anxiety syndromes). Both SW and PE contribute significantly to the worldwide pandemic of uncontrolled Hypertension (HTN). Both result in ......