Cardiac catheterization: Coronary angiography will be performed to evaluate hemodynamic condition and to test for coronary artery disease. The LV filling pressure is continuously recorded (50 mm/s) by a 6-F pigtail catheter placed at the apex of the left ventricle and is taken from 3 to 5 end-respiratory cycles if patients can tolerate breath holding. The LV filling pressure value is calculated as the mean of at least 3 consecutive cardiac cycles. An LV filling pressure > 15 mmHg is considered elevated.