Purpose: To investigate the effect of Quinapril (Q) or Losartan (L) or their combination on definite Diabetic Autonomic Neuropathy (DAN) and left ventricular systolic and diastolic function (LVF) over a period of 4 years.

Patients-methods: Fifty-nine patients with definite DAN [2 or more of the 4 Cardiovascular Reflex Tests (CRTs) were abnormal] were studied for 4 years. Patients were randomly allocated in 3 groups receiving A, 20 mg Q, B, 100 mg L and C, 20 mg Q +100 mg L respectively. CRTs analyzed with Mean Circular Resultant (MCR), Valsalva index, 30:15 ratio and postural hypotension. LV function was investigated with radionuclide ventriculography (RNV) at rest. Ejection fraction was used to assess LV systolic function, while peak filling rate, first third filling fraction, and atrial contribution to ventricular filling were used to investigate LV diastolic function. CRTs and RNV were performed at baseline and after 4 years.

Inclusion Criteria:

1. >18 years old
2. Diabetes mellitus
3. Diabetic autonomic neuropathy

Exclusion Criteria:

1. Coronary artery disease
2. Arterial hypertension
3. Heart failure with reduced ejection fraction LVEF<40%
4. Any contraindication to undergo radionuclide ventriculography