Dynamic indices of preload depending on the heart-lung interaction require sinus rhythm and cannot be applied to patients with atrial fibrillation. PEEP-induced increase in central venous pressure (CVP) was shown to be a valid predictor of fluid responsiveness after cardiac surgery in patients with sinus rhythm, and was speculated to be of value in patients with rhythm other than sinus. The aim of this study is to assess the predictability of PEEP-induced increase in CVP and passive leg raising (PLR)-induced changes in stroke volume index (SVI) on fluid responsiveness in patients with atrial fibrillation following valvular heart surgery.

Inclusion Criteria:

1. age ≥20
2. atrial fibrillation patients who underwent elective valvular heart surgery

Exclusion Criteria:

1. age < 20
2. LV ejection fraction < 40%
3. any pulmonary disease
4. end stage renal disease
5. high intrabdominal pressure patient
6. contraindication of passive leg raising
7. deep vein thrombosis