Assessment of relationship between acid reflux and heartburn using receiver operating characteristic curves.

Arguments proposed in this article may explain why a subgroup of patients, having so-called "functional heartburn," does not respond to acid inhibition therapy [19,20]. It is highly likely that acid is not the cause of heartburn in this group of subjects. These conclusions are supported further by observations of Wiener et al [2] and Howard et al [21], who found that a subgroup of patients with high SI have a negative Bernstein test, which suggests that the presence of acid in the esophagus at the time of spontaneous heartburn may be coincidental and does not reflect a cause-and-effect relationship between the two. The motor events responsible for the occurrence of acid reflux (longitudinal muscle contraction of the esophagus [SEC] associated with transient LES relaxation) may be the cause of heartburn sensation.