Heart rate variability (HRV) is a useful diagnostic tool used in modern medicine to assess a variety of health conditions. Heart Rate Variability (HRV) uses a complex method using different frequencies to calculate the time or duration between each heart beat. Heart Rate Variability (HRV) is proven to be a reliable & reproducible method to quantify both activity & balance in both branches of the Autonomic Nervous System (parasympathetic & sympathetic nervous systems). HRV can assess a variety of physiological & pathological health factors including complications of diabetes, cardiovascular disease and identify risk of sudden cardiac death.
By definition, Heart rate variability (HRV) monitors the changes in the duration of each consecutive cardiac cycle. HRV can be measured by electrocardiogram (ECG) or via a pulse oximeter (photoplethsysmography or PTG). In the cases where ECG is used, the measurements are gathered based on R wave of the electrocardiogram. For PTG analysis, the arterial waveform is used to calculate the heart rate variability. Other names for Heart Rate Variability include HRV, R to R variability, heart period variability, cycle length variability & R to R period.
Heart Rate Variability (HRV) is used to quantify activivty of the autonomic nervous system. Autonomic Nervous System (ANS) testing is useful for assessing both physiological & pathological complications in diabetes & cardiovascular disease. Such complications include diabetic autonomic neuropathy, peripheral autonomic neuropathy, cardiac autonomic neuropathy, myocardial infarction & congestive heart failure (CHF).
HRV in normal healthy patients should vary greatly as the autonomic nervous system should precisely increase or decrease heart rate when needed. In patients with chronic disease, there a high association with the risk for sudden cardiac death and arrhythmias.
Heart Rate Variability (HRV) is strongly associated with cardiac arrhythmias. Sudden cardiac death from ventricular arrhythmia accounts for nearly 500,000 deaths each year in the US alone. HRV is also used for other diseases such as non-ischemic cardiomyopathy, heart failure, & unexplained causes of syncope. Low HRV can also be present in other diseases such as diabetes and neurological disorders.
Although Heart rate variability (HRV) has gone through periods of controversy as to its clinical significance, newer clinical studies published in the last 2 decades solidify the correlation of low HRV with increased mortality (especially in post MI patient populations). For more details on the clinical evidence, visit Clinical Studies.