Wave reflection in hypertensive left ventricular hypertrophy

Wave reflection in the arterial circulation is an important contributor to systolic blood pressure, ventricular load and regional blood flow. Wave Intensity Analysis is a novel non-invasive technique which measures energy transport in the cardiovascular system and also allows regional pulse wave velocity and both forward and reflected pressure waves to be determined. The aim of this study was to determine differences in these haemodynamic parameters in hypertensive subjects associated with the presence or absence of left ventricular hypertrophy (LVH). Thirty-five untreated hypertensive subjects were studied. Sixteen had echocardiographic LVH (10 men, age 54±7 years, BP 174±27 / 102±18, left ventricular mass index (LVMI) 156±48 g/m2). The remainder (15 men & 4 women, age 51±8 years, BP 156±19 / 93±10) had a mean LVMI of 109±15 g/m2. Pressure and flow velocity were recorded non-invasively at 200Hz in the right common carotid artery using applanation tonometry and pulsed wave Doppler. Carotid pulse wave velocity (c), peak forward pressure (P+), peak backward pressure (P- ) and cardiac systolic wave power (dI+c1) were calculated using custom written software in the Matlab environment. Reflected cardiac systolic wave energy from the body travelling up the carotid (Ec+) and reflected wave energy from the head (Ec- ) were also determined. The results (Table) indicate that the presence of LVH is associated with changes in arterial haemodynamics including increased pulse wave velocity and enhanced wave reflection, particularly from the body. It is possible that these abnormalities are related to the the development of LVH. Data in the table are presented as means (95% CI). p≤0.05, not significant. Data in the table are presented as means (95% CI). p≤0.05, not significant.