Background—In arterial hypertension, left ventricular hypertrophy (LVH) includes myocyte hypertrophy and fibrosis, which leads to LV diastolic dysfunction and, finally, heart failure. In spontaneously hypertensive rats, myocardial fibrosis was regressed and LV diastolic function was improved by treatment with the angiotensin-converting enzyme inhibitor lisinopril. Whether this holds true for patients with hypertensive heart disease was addressed in this prospective, randomized, double-blind trial.

Methods and Results—A total of 35 patients with primary hypertension, LVH, and LV diastolic dysfunction were treated with either lisinopril (n=18) or hydrochlorothiazide (HCTZ; n=17). At baseline and after 6 months, LV catheterization with endomyocardial biopsy, Doppler echocardiography with measurements of LV peak flow velocities during early filling and atrial contraction and isovolumic relaxation time, and 24-hour blood pressure monitoring were performed. Myocardial fibrosis was measured by LV collagen volume fraction and myocardial hydroxyproline concentration. With lisinopril, collagen volume fraction decreased from 6.9±0.6% to 6.3±0.6% (P<0.05 versus HCTZ) and myocardial hydroxyproline concentration from 9.9±0.3 to 8.3±0.4 μg/mg of LV dry weight (P<0.00001 versus HCTZ); this was associated with an increase in the early filling and atrial contraction LV peak flow velocity ratio from 0.72±0.04 to 0.91±0.06 (P<0.05 versus HCTZ) and a decrease in isovolumic relaxation time from 123±9 to 81±5 ms (P<0.00002 versus HCTZ). Normalized blood pressure did not significantly change in either group. No LVH regression occurred in lisinopril-treated patients, whereas with HCTZ, myocyte diameter was reduced from 22.1±0.6 to 20.7±0.7 μm (P<0.01 versus lisinopril).

Conclusions—In patients with hypertensive heart disease, angiotensin-converting enzyme inhibition with lisinopril can regress myocardial fibrosis, irrespective of LVH regression, and it is accompanied by improved LV diastolic function.