Left ventricular end-diastolic dimensions measured at the P wave and Q wave during a randomized, double-blind one-year follow-up study comparing the effect of atenolol vs. hydrochlorothiazide + amiloride on blood pressure in men with mild to moderate hypertension

Abstract

Echocardiographic measurement of left ventricular (LV) end-diastolic dimensions and mass (M) were made at baseline, at 3 and 12 months of a randomized trial comparing atenolol 50/100 mgod. and hydrochlorothiazide 25/ 50mg + amiloride 5mgod. (co-amiloride) in 100 men with mild to moderate hypertension. Data from 48 subjects controlled adequately on drug monotherapy and completing 12 months treatment are reported (31 randomized to atenolol and 17 to co-amiloride). Left ventricular mass was measured with the Penn convention at the R and P wave respectively. A significant reduction of LVM was noted after one year in both groups (p < 0.05) when measured at the R, but not at the P wave.

Measurements according to American Society of Echocardiography (ASE method) at the Q wave revealed a significant reduction of LV wall thickness (p < 0.01) and an increase of LV internal diameter (p < 0.01) with atenolol. In the co-amiloride group non-significant reductions of LV dimensions were observed. Principally similar changes were observed with measurements at the P wave (National Institute of Heart method) in both groups, but LV wall thickness was greater and LV internal diameter smaller than at the Q wave.

With similar effect on LVM, the mechanisms in reducing LVM were different between the two drugs. Left ventricular dimensions differed when assessed with the two methods applied, stressing the need for careful standardization in relation to the cardiac cycle in serial echocardiographic measurements.

Key Words:

• American Society of Echocardiography (ASE)
• M-mode echocardiography
• National Institute of Heart (NIH)