Amlodipine Versus Valsartan for Improvement of Diastolic Dysfunction Associated With Hypertension

Hypertensive patients are at increased risk of developing LV hypertrophy and myocardial fibrosis, which cause diastolic dysfunction. Because the activation of rennin-angiotensin-aldosterone system (RAAS) has been shown to induce LV hypertrophy and myocardial fibrosis, the RAAS may play a central role in the pathogenic process from hypertension to diastolic HF. Inhibitors of RAAS have been considered as a treatment option for these patients, and the angiotensin receptor blockers (ARB) have been of interest because they antagonize the effects of angiotensin II more completely. However, the Irbesartan in Heart Failure with Preserved Systolic Function (I-PRESERVE) trial reported that treatment with irbesartan did not reduce the risk of death or hospitalization for cardiovascular causes among 4,128 patients who had HF with a preserved LV ejection fraction. The degree of improvement of diastolic dysfunction was associated with the extent of systolic blood pressure reduction, whether a RAAS inhibitor or non-RAAS blood pressure lowering was used. Amlodipine is a potent and well-tolerated calcium channel blocker, and seems to be appropriate for achieving more aggressive systolic blood pressure target and improving diastolic dysfunction in hypertensive patients, because amlodipine is clinically very useful for controlling systolic blood pressure. Assessment of diastolic function by echocardiography will be helpful to determine whether addition of amlodipine or an ARB to standard therapy is more beneficial to hypertensive patients with diastolic dysfunction. The investigators hypothesize that amlodipine added to standard therapy will be superior to valsartan in improving diastolic dysfunction by lowering systolic blood pressure more effectively in hypertensive patients, and try to examine this hypothesis in a prospective, open-label, randomized comparison study using blinded echocardiographic evaluation for end point.