Anemia and energy depletion: reply

Drs. Taegtmeyer and Sharma reiterate an important plausible biologic mechanism for the observed association between anemia and higher mortality in severe heart failure. As we also hypothesized (1), diminished oxygen-carrying capacity of anemic blood may necessitate higher cardiac output to meet systemic metabolic requirements; the concomitant increased neurohormonal activation may cause heart failure progression, producing a progressive cycle of metabolic–hemodynamic compromise. This hypothesis is supported by the inverse association between anemia and death due to progressive heart failure, rather than due to sudden death or other deaths (1). However, there are other potential explanations for the observed association between anemia and mortality in heart failure (1). We look forward to testing of this plausible metabolic–hemodynamic hypothesis in ongoing experimental and clinical trials.

• American College of Cardiology Foundation