BACKGROUND: Abnormality of left ventricular (LV) diastolic function is frequently the earliest indicator of LV dysfunction in many diseases, including coronary artery disease (CAD), and hypertension. Electrocardiography (ECG)-gated technetium (Tc) -99m tetrofosmin single-photon emission computed tomography (SPECT) has been reported to be a useful method for evaluation of LV function. OBJECTIVES: The purpose of this study is to assess the impact of hypertension on diastolic left ventricular function using ECG-gated Tc-99m tetrofosmin SPECT METHODS: Thirty consecutive patients with normal exercise myocardial perfusion and normal LV systolic function, were studied out of 233 patients underwent ECG-gated Tc-99m tetrofosmin SPECT at our institution between Jan 2012 and Dec 2013. Patients were divided into two groups according to the presence or absence of systemic hypertension (blood pressure > or = 140/90 mm Hg on > or = 3 measurements or treatment with antihypertensive medication). Parameters of diastolic LV function were assessed. Results: Of the studied 30 patients, 19/30 (63%) had hypertension. There was no difference with respect to age, gender, LV end-diastolic volume (EDV), LV end-systolic volume (ESV), and LV ejection fraction values obtained by quantitative gated SPECT between patients with and without hypertension. The first-third mean filling rate (1/3 MFR), peak filling rate (PFR) of patients with hypertension (1.22 ± 0.38, 2.83 ± 1.10 EDV/s) were significantly lower than those of patients without hypertension (1.54 ± 0.30, 2.90 ± 0.35 EDV/s) (P < 0.05), and the time to peak filling (TTPF) of patients with hypertension (199.42 ± 68.34 ms) was higher than TTPF of patients without hypertension (164.90 ± 36.39 ms). CONCLUSIONS: Quantitative ECG-gated Tc-99m tetrofosmin SPECT reveals that hypertensive patients with preserved global LV systolic function may have significant changes in diastolic LV function. Gated myocardial perfusion SPECT reports are always lacking in these changes in diastolic function. We recommend inclusion of such changes in diastolic function in gated myocardial perfusion SPECT reports that can help in proper management of hypertensive patients.