Heart rate variability as a predictor of mortality in patients with AA and AL amyloidosis

AIMS: Patients with AA and AL amyloidosis have a limited life-expectancy. The aim of this study was to investigate whether heart rate variability can predict mortality in these patients. METHODS AND RESULTS: Twenty-two recently diagnosed patients with AA and 23 patients with AL amyloidosis were included. Fifteen patients (5 AA, 10 AL) died within 1 year. Twenty-four hour Holter recording was performed to quantify the mean of all normal to normal RR-intervals (mean NN) and the standard deviation of all normal to normal RR-intervals (SDNN). The SDNN predicted 1-year mortality in the total group of patients with amyloidosis. The median SDNN was 73 ms. In patients with an SDNN < or =73 ms, the risk of dying within 1 year was found to have increased 3.5-fold (P=0.0036; 95% CI 1.1-11.0). An SDNN < or =50 ms, a predictor of mortality in other patient groups, increased the risk of dying within 1 year 22-fold (P=0.0001; 95% CI 5.4-90.4). In contrast to patients with AA amyloidosis, in the subgroup analysis of patients with AL amyloidosis the SDNN remained a predictive parameter (SDNN < or =50 ms: risk ratio 11.5, 95% CI 2.4-56.2, P=0.0025). CONCLUSION: The SDNN is a strong predictor of short-term mortality in patients with AL amyloidosis.