**Abstract**

Isolated systolic hypertension (ISH) is a major contributor to cardiovascular disease morbidity and mortality worldwide, however, diagnosis of ISH is mainly dependent on conventional blood pressure (BP) techniques. Studies that have used ambulatory blood pressure monitoring (ABPM) were only limited to 24-hour BP. To date ambulatory isolated BP subtypes have never been identified. Therefore, the prevalence of ambulatory subtypes of ISH unknown. Conventional and ambulatory BP was measure in 549 participants and based on the results, they were stratified into ISH subtypes (Conventional, Daytime, Night-time and 24-hour ISH). Participants further underwent measurements of pulse wave velocity (PWV) and left ventricular mass index (LVMI) to determine the extent of arterial stiffness and left ventricular hypertrophy. We further assessed whether the target organ changes are associated with any ISH subtype. The prevalence of Conventional ISH (ISHC), 24-hour ISH (ISH24), Night-time ISH (ISHN) and Daytime ISH (ISHD) was 7.5%, 7.1%, 7.7% and 7.5% respectively. Compared to normotensives, all ISH subtypes had higher PWV and LVMI. These target organ changes were similar to those observed in hypertensives. Our results indicate that isolated systolic hypertension, whether conventional or ambulatory, is as detrimental as hypertension on cardiovascular target organs.

**Keywords:** hypertension, hypertrophy, ambulatory nocturnal, conventional, cardiovascular
