Dexmedetomidine is a selective α2 adrenergic agonist that can be considered a primary anesthetic, an adjuvant to propofol or inhalational anesthetics. Dexmedetomidine mediate its cardiovascular effect through activation of receptors in central and peripheral nervous system. The classic cardiovascular response of dexmedetomidine is the biphasic with initial shorten-increase in blood pressure followed by long-lasting decrease in BP and HR. There were several reports about these hemodynamic changs of dexmedetomidine, but not the evaluation of direct cardiac function of patients who was preexisted diastolic dysfunction. The purpose of this study is to evaluate the effects of dexmedetomidine as an anesthetic adjuvant in diastolic dysfunction by using the echocardiography.

Inclusion Criteria:

The inclusion criteria included patients who estimated lateral e' velocity <10 cm/s or septal e' velocity <8 cm/s from the mitral annuli and averaged E/e' ≧ 9 in preoperative echocardiographic evaluation. For patients of old age (> 60 yr) who did not undergo preoperative echocardiographic evaluation, written consent was obtained and TTE was performed to evaluate presence of diastolic dysfunction; patients with diastolic dysfunction, as previous defined, were included and those without were excluded

1. Above 40 years of age.
2. American Society of Anesthesiologists (ASA) Physical Status II, III.
3. Preserved systolic function (Ejection fraction > 50%)

Exclusion Criteria:

The exclusion criteria included patients who estimated lateral e' velocity >10 cm/s or septal e' velocity >8 cm/s from the mitral annuli, and averaged E/e' ≦ 8 in preoperative echocardiographic evaluation.

1. severe functional liver or kidney disease
2. diagnosed HF (LV ejection fraction <50% , or wall motion abnormality)
3. arrhythmia or received treatment with antiarrythmic drug .
4. severe bradycardia(HR < 45 bpm) and AV block 6. pathologic esophageal lesion (esophageal stricture or varix ) 7. pregnancy 8. severe chronic obstructive lung disease.