Nocturnal nondipping and left ventricular hypertrophy in hypertension: an updated review

The classification of hypertensive subjects according to circadian blood pressure (BP) variations (i.e., dipping vs nondipping) is a useful means for reliable individual risk stratification and effective therapeutic decision-making. Increasing evidence, although not univocal, suggests that a reduced nocturnal BP fall relates to an excess of cardiovascular complications. The association between nondipping status with left ventricular hypertrophy (LVH) and its therapeutic implications are still debated; in this article we examined the studies published in the last decade on this controversial issue. The studies identified by a PubMed search were eligible for the analysis if they fulfilled the following criteria: full articles in English, published from 1 January 2000 to 31 December 2009, and inclusion of adult or elderly subjects. According to these criteria, 26 studies encompassing 3877 participants have been selected. A total of 17 studies for a total of 2497 subjects were positive for a link between nondipping and LVH, whereas the remaining nine studies were negative. Notably, three studies that accurately defined the nondipping status on the basis of two consistent ambulatory blood pressure monitoring sessions over a short time interval showed a significant association of this pattern with LVH; this suggests that a persisting nondipping pattern is associated with a more pronounced cardiac involvement. Preliminary data support the view that nondipping may be reverted to dipping by chronotherapy and by diuretics in salt-sensitive patients. Whether restoring the normal nocturnal BP dip in hypertensives with LVH regresses cardiac damage at present remains an untested hypothesis.