Relationship between left ventricular mass, uremia, hypertension and vagal tachycardic reserve.

I read with interest the article by Mircoli et al. [1] describing the relationship between left ventricular mass, uremia, hypertension and vagal tachycardic reserve. Overall, this paper is an important confirmation of a larger study [2] showing a relationship between left ventricular posterior wall and relative wall thickness and the heart rate response to deep breathing, which is an accepted measure of the parasympathetic control of heart rate. In that study, parasympathetic dysfunction and left ventricular hypertension were strongly linked to nocturnal hypoxemia, a very frequent problem in uremic patients [3]. The blunted tachycardic response to atropine (including the age-dependency of the phenomenon) in dialysis patients was also well documented in the 1980s in a study including 45 dialysis patients and 30 age-matched healthy controls [4].