113 Vol. 63, No. 3, September 2018 Original article Nocturnal blood pressure patterns in essential hypertensives: an over- looked cardiovascular burden H G W A P L Bandara 1 , U I Hewarathna 1 , R M S P Karunarathne 1 , T Kogulan 1 , N W Kodithuwakku 1 , A Jegavanthan 1 , K P Jayawickreme 1 , A W D T Ambagaspitiya 2 , M A H Siribaddana 1 , S R Jayawickreme 1 , C Hathlahawatte 1 , U Ralapanawa 2 (Index words: Ambulatory blood pressure monitoring, Abnormal nocturnal dipping, Nocturnal hypertension, Isolated nocturnal hypertension, Nocturnal hypotension) 1 Teaching Hospital Kandy, 2 Teaching Hospital Peradeniya, Sri Lanka. Correspondence: HGWAPLB, e-mail: <lakshmanbandara@gmail.com>. Received 23 July 2018 and revised version accepted 18 August 2018. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Abstract Introduction Understanding the diurnal variation of blood pressure (BP) is important in the management of hypertension. Objectives Primary objectives of the study were to analyse the pattern of nocturnal BP in patients with essential hypertension who are already on treatment. Methodology Cross-sectional descriptive study was conducted at cardiology unit Teaching Hospital Kandy, in 2015, in patients referred from the hypertensive clinic at Teaching Hospital Peradeniya. A consecutive sample of 100 essential hypertensives aged >18 years with stage I to III hypertension were included. Patients with a history of previous ischemic heart disease or cerebro-vascular events were excluded. Twenty-four-hour ambulatory blood pressure monitoring was performed in all patients after complete clinical evaluation. Results Sample size was 100. Mean age was 60.86 ± 8.73 years. Twenty eight were male. In the sample 32 had normal dipping patterns. Out of the 68 with abnormal dipping, 45 had sub-optimal dipping, 19 had reverse dipping and 4 had extreme dipping. There were 72 patients with nocturnal hypertension, of them 29 (39.7%) had isolated nocturnal hypertension. Conclusion A high prevalence of abnormal dipping, nocturnal hypertension and isolated nocturnal hyper- tension among our sample of patients with essential hypertension. Therefore, it is important to increase awareness and to consider ambulatory blood pressure monitoring to detect these abnormal nocturnal blood pressure variations. Introduction Hypertension is a characteristic feature of functional dysregulation of the cardiovascular system. It is one of the main contributors of cardiovascular morbidity and mortality [1]. Therefore, prevention of hypertension related complications require maintaining the therapeutic range of blood pressure (BP). Ambulatory Blood Pressure Monitoring provides a good indication of the variations in circadian BP rhythm [2]. Nocturnal BP which is an important parameter can be evaluated using ambulatory blood pressure monitoring. Dipping of BP is a feature of the diurnal pattern of BP. Dipping patterns of nocturnal BP have been described previously according to the degree of BP drop [3,4]. There is evidence that the non-dipping pattern of diurnal BP variation is associated with poorer prognosis of cardio- vascular events compared to those with normal dipping patterns [5]. Several studies have showed that more hypertensive end organ damage occur in patients with non-dipping patterns at night [6]. The novel clinical entity of isolated nocturnal hypertension (INH) is a new area of interest. These are people with elevated night-time BP with normal daytime BP [7]. This subgroup with isolated nocturnal hypertension have a higher incidence of target organ damage compared to nocturnal normotensives [7]. Since, patients with isolated nocturnal hypertension have lower or normal daytime BP, this group is not diagnosed and may present with end organ damage. The objective of this study was to identify the pattern of nocturnal BP in patients with essential hypertension who were already on treatment. Study aims to identify presence of non-dipping patterns, nocturnal hypertension and isolated nocturnal hypertension. Ceylon Medical Journal 2018; 63: 113-119 DOI: http://doi.org/10.4038/cmj.v63i3.8715