Left ventricular wall thickness and plasma catecholamines in borderline and stable essential hypertension

It has been suggested that sympathetic overactivity has a pathogeneticrelevance to left ventricular hypertrophic development, evenapart from its effect on and in essential hypertension. To evaluate this possibility by echocardiographic and polygraphicmethods, we studied left ventricular wall thickness and functionand their possible relationship to plasma renin activity andplasma catecholamines in 11 normal subjects, 13 borderline hypertensivesand 11 stable hypertensives without radiological or electrocardiographicsigns of left ventricular hypertrophy. Compared with normal, borderline hypertensives showed an increasein interventricular septum (IVS) thickness (P < 0.01) andIVS/posterior wall (PW) thickness ratio (P < 0.01) togetherwith an increased supine and upright plasma norepinephrine (NE;P < 0.01); there was also a decreased pre-ejection period(PEP; P < 0.01), PEP/left ventricular ejection time ratio(P < 0.01) and total electromechanical systole (P < 0.05). In stable hypertensives, PW thickness was greater than it wasboth in normals (P < 0.01) and in borderline hypertensives(P < 0.01) and IVS thickness was higher than in normals (P< 0.05). Positive correlations between supine (P < 0.001), upright(P < 0.05) NE and both IVS thickness and IVS/PW thicknessratio were found in borderline but not in stable hypertensives. These results support the hypothesis recently put forward thatIVS hypertrophy may represent an early stage of essential hypertension-inducedLVH, which afterwards extends to the left PW; furthermore theresults suggest that the sympathetic overactivity may play arole in the IVS hypertrophy development in borderline hypertensives.