Based on accumulating evidence showing that impaired cardiac energetic metabolism plays important role in the mechanism of cardiac diastolic dysfunction,the study is designed to evaluate whether metabolic modulator treatment with trimetazidine could have beneficial effects on patients with coronary heart disease(CHD) and ventricular diastolic dysfunction.This study is a prospective,randomised,open-label trial to assess the efficacy of trimetazidine treatment in improving diastolic function in CHD patients with diastolic dysfunction.

The primary objective of this trial is to determine whether the 24-week trimetazidine therapy, as an adjunct to routine treatment for CHD, would improve diastolic function in patients with ischemic heart disease compared to the routine treatment.

Inclusion Criteria:

• Aged between 50 and 79 years,male or female (without pregnancy).
• Diagnosed CHD by coronary angiography,with stenoses in main bifurcations less than 70% after PCI treatment.
• Left ventricular ejection fraction(LVEF) more than 50% assessed by ultracardiography.
• Characteristics of diastolic dysfunction by ultracardiography (more than 2 criteria as following):(1)Average E/e'>14,(2)Septal e' velocity <7 cm/s or lateral e' velocity <10 cm/s,(3)Tricuspid regurgitation (TR) velocity >2.8m/s,(4)Left atrium (LA) volume index >34ml/m2.
• Not yet being treated by trimetazidine.
• Provided informed consent.

Exclusion Criteria:

• Acute heart failure or acute exacerbation of chronic heart failure.
• LVEF less than 50% at admission or in the past.
• History of malignant tumor or life expectancy under 12 months.
• Acute myocardial infarction or unstable angina pectoris within 3 months.
• Scheduled coronary artery bypass grafting therapy within 6 months.
• Diagnosed or considered valvular heart disease, hypertrophic cardiomyopathy,restrictive cardiomyopathy or pericardium diseases.
• Significant hepatic impairment (Serum glutamate-pyruvate transaminase more than 3 times normal upper limit) or severe renal dysfunction (eGFR≤30 ml/min/1.73m2).
• Known or considered Parkinson's Disease.
• Known hypersensitivity or intolerance to trimetazidine.
• Pregnancy and lactation period.
• Any disorder which, in the opinion of the investigator, might jeopardise subject's safety or compliance with the protocol.
• Participation in another clinical trial within the past 30 days.