Masked hypertension and echocardiographic left ventricular hypertrophy: an updated overview

Masked hypertension (MH) is an emerging clinical entity predisposing to subclinical organ damage and to increased cardiovascular risk. We sought to review the recent literature focusing on the association between MH and echocardiographic left ventricular hypertrophy (LVH). A MEDLINE search was performed in order to identify relevant papers using the key words such as 'masked hypertension', 'ambulatory hypertension', 'left ventricular hypertrophy', 'cardiac damage', 'target organ damage', 'left ventricular dysfunction'. Full articles published in English language in the last decade, namely from 1 December 1999 to 31 July 2011, reporting studies in adult or elderly individuals, were considered. Checks of the reference lists of selected papers complemented the electronic search. A total of 13 studies, including 966 patients with MH (sample size range 17-222 patients, mean age range 30-70 years; men 71%) and 2640 controls with sustained normotension, controlled hypertension, and white coat hypertension were considered. The prevalence of LVH, defined according to six criteria, ranged from 7 to 66% in MH and from 0.4 to 42% in non-MH counterparts (average 29 vs. 9%, P<0.01). In conclusion, available evidence linking a selective blood pressure elevation outside office to echocardiographic LVH in clinically normotensive individuals is supported by limited evidence. Further studies are needed to expand our knowledge in this area and to explore the beneficial effects of antihypertensive treatment on subclinical cardiac damage in patients with MH.