The correlation of coronary microvascular function and body composition with cardiopulmonary exercise capacity will be assessed in patients with heart failure with preserved ejection fraction.

We will select the patients with chest pain or ischemic symptoms with non-obstructive coronary artery disease (<50% stenosis) in coronary angiography and preserved ejection fraction (≥50%) in echocardiography. All patients will undergo body composition analysis and adenosine stress echocardiography with the evaluation of coronary artery blood flow by Doppler echocardiography and maximal oxygen consumption (VO2 max) by cardiopulmonary exercise test (CPET). Left ventricular end-diastolic pressure will be assessed during coronary angiography. Coronary flow reserve (CFR) is defined as the ratio of peak to baseline mean diastolic velocity of coronary blood flow. The correlation of CFR and body composition with cardiopulmonary exercise capacity will be assessed.

Inclusion Criteria:

• Age 20 to 80
• Typical/atypical chest pain or ischemic symptoms including dyspnea
• No significant coronary artery stenosis (>50% stenosis) in coronary angiography or computed tomography
• Left ventricular ejection fraction ≥50%

Exclusion Criteria:

• More than moderate valvular heart disease
• Congenital heart disease
• Chronic renal failure (estimated glomerular filtration rate <30 ml/min/1.73m2) or end-stage renal failure undergoing hemodialysis or peritoneal dialysis
• Asthma, chronic obstructive pulmonary disease and primary pulmonary hypertension
• Receiving anticancer drugs
• Vasculitis associated with autoimmune diseases
• Patients with difficulty in performing exercise load evaluation (treadmill, bicycle ergometer)
• Atrial fibrillation
• Atrioventricular block with more than second degrees, symptomatic bradycardia, cryo-node failure syndrome, Wolff-Parkinson-White (WPW) patients