Reduced heart rate predicts early CHF death

HRV test targets funds, patients to benefit

A test measuring daily swings in heart rate may help identify individuals with congestive heart failure (CHF) who are at the highest risk of dying from the condition within a year, British researchers found. The heart rate variability (HRV) test will allow physicians to target extra treatment to the 40% of patients most likely to benefit, saving the money not used to treat low-risk patients. HRV tests can be used in conjunction with other measurements such as chest X-ray, blood tests or heart ultrasound examinations.

The test measures HRV, the amount by which the heart rate changes from slow to fast in one 24-hour period. "The less the heart rate varies over 24 hours, the more likely a person will die of congestive heart failure," wrote James Nolan of St. James’ University Hospital in Leeds.

Nolan and colleagues gathered data on more than 400 patients who exhibited stable signs and symptoms of CHF for at least three months. Most of the patients, 97%, were being treated with a diuretic, and 82% were being treated with an ACE inhibitor. Heart electrical activity was recorded by holter monitors on participants who were followed for an average of 482 days after their monitoring. Fifty-four deaths occurred during this time, with a total death rate of 9.5%.

Patients with the lowest HRV, whose fastest heart rate was not much different from their slowest heart rate, were three times more likely to die than individuals with the highest HRV. Low HRV may be due to a defect in the autonomic nervous system. The annual death rate of people with the lowest HRV was 51.4%, compared to 5.5% for those with the highest HRV. People whose HRV was between the two extremes had an annual death rate of 12.7%.

Reference

1. Nolan J, Batin PD, Andrews R, et al. Prospective Study of Heart Rate Variability and Mortality in Chronic Heart Failure. Circulation 1998; 98:1,510-1,516.