Using heart rate variability data to assess sudden death risk

We evaluated the relationship between heart rate variability and sudden death in a study of 6,693 consecutive patients who underwent 24-hour ambulatory electrocardiographic monitoring. Our data indicate that low variability (both short- and long-term) doubles the risk of sudden death independently from other risk factors. This finding supports the theory that patients with low parasympathetic activity have an increased risk of sudden death.