The erythrocyte sedimentation rate in congestive heart failure. BACKGROUND AND METHODS. Physicians have long believed that the erythrocyte sedimentation rate is low in patients with congestive heart failure, but this concept is based on a misinterpretation of the results in a single report published in 1936. To reevaluate this concept in the modern era, we measured the sedimentation rate in 242 patients who were referred for treatment of chronic heart failure. RESULTS. The sedimentation rate was low (less than 5 mm per hour) in only 24 patients (10 percent) but was increased (above 25 mm per hour) in 50 percent. Patients with low or normal sedimentation rates (less than or equal to 25 mm per hour) had more severe hemodynamic abnormalities than patients with elevated rates: lower cardiac index (mean +/- SEM, 1.7 +/- 0.1 vs. 2.0 +/- 0.1 liters per minute per square meter of body-surface area) and higher mean right atrial pressure (mean +/- SEM, 12 +/- 1 vs. 9 +/- 1 mm Hg) (both P less than 0.0001). New York Heart Association functional class IV symptoms were present in 66 percent of the patients with a low or normal sedimentation rate, as compared with 42 percent of those with elevated rates (P less than 0.0001). After one to three months of therapy, patients whose sedimentation rates decreased showed little hemodynamic or clinical response to treatment, whereas both cardiac performance and functional status improved in patients whose rates increased (P less than 0.02 for the comparison between groups). The sedimentation rate was correlated with the plasma fibrinogen level (r = 0.64, P = 0.0025), and changes in the sedimentation rate during treatment were correlated inversely with changes in mean right atrial pressure (r = -0.57, P = 0.0002). During long-term follow-up, patients with low or normal sedimentation rates had a worse one-year survival than patients with elevated rates (41 vs. 66 percent, P = 0.01). CONCLUSIONS. These data indicate that the erythrocyte sedimentation rate is correlated with the severity of illness in patients with chronic heart failure. Because of its lack of discriminatory power, however, the test is of limited value in the clinical management of this disorder. 