More on Ivabradine in Tachycardia with Paraganglioma

To the Editor: Malaza et al. (March 28 issue) 1 describe the benefit of ivabradine administration in a patient with catecholamine-induced tachycardia and metastatic paraganglioma. However, further data on hemodynamic variables before and after ivabradine treatment were lacking. Previous investigations have attempted to detect the hemodynamic effects of ivabradine in counteracting the undesirable tachycardia that is related to exogenous catecholamines. Vitale and colleagues 2 found a significant heart-rate–lowering response to ivabradine, which was associated with increased cardiac index, stroke-volume index, and mixed venous oxygen saturation in a series of patients with sinus tachycardia that had been induced by inotropic agents after cardiac . . .