Remote ischemic conditioning has been shown to protect myocardium from ischemia-reperfusion injury during cardiac intervention or cardiac surgery. However, effect of beta-blocker, commonly used cardiovascular medication in patients with cardiac diseases such as hypertension or angina pectoris, on cardioprotective role of remote ischemic conditioning has not been well documented. The purpose of the study is to investigate the effect of beta-blocker on remote ischemic conditioning in healthy volunteers.

This study is prospective cross-over study investigating effect of beta-blocker on cardioprotective role of remote ischemic conditioning. Eleven male healthy volunteers are going to take oral beta-blocker (carvedilol, 12.5 mg once) or not before undergoing remote ischemic conditioning (consisting of 4 cycles of 5-min ischemia and subsequent 5-min reperfusion of upper arm), separated by 6-day wash-out period. To evaluate cardioprotective effect of remote ischemic conditioning, blood samples will be obtained before and after remote ischemic conditioning. Form the samples, human dialysate will be obtained and be perfused to rat heart through Langendorff apparatus before ischemia-reperfusion injury to the rat heart. Changes of infarct size of the rat heart will be compared between the beta-blocker and control groups.

Inclusion Criteria:

• Healthy male volunteer
• Not taking any medication

Exclusion Criteria:

• BMI < 18 kg/m2 or > 30 kg/m2
• Allergic history of any medication
• Baseline SBP > 150 mmHg or < 100 mmHg
• Baseline DBP > 100 mmHg or < 50 mmHg
• Strenuous exercise, excessive caffeine or alcohol, smoking 24 h prior to experiment
• Cannot undergoing remote ischemic conditioning for any reason
• Refuse to enroll