Autonomic nerve function is involved in both blood pressure (BP) regulation and the pathogenesis of coronary artery spasm(CAS), but few studies have been published about the relationship between CAS and effect of BP lowering drugs in patients with hypertension. The purpose of this study is to investigate the incidence of CAS, atrioventricular (AV) block and effect of BP lowering drugs on CAS in hypertensive patients treated with BP lowering agents. The investigators will register consecutive patients who underwent coronary angiography with an acetylcholine (Ach)-induced provocation test. The investigators will include hypertensive patients who were taking antihypertensive drugs, and exclude patients who had a documented history of cardiovascular disease or who were not treated with antihypertensive agents. CAS is defined as >70% luminal narrowing on Ach provocation and /or concurrent chest pain. The study population will be divided into quartiles of rising systolic BP and diastolic BP. The incidence of Ach-induced CAS according to each systolic BP/diastolic BP quartile will be evaluated.

A total of consecutive patients in the CAS registry of the Cardiovascular Center at Korea University Guro Hospital and who had resting chest pain without significant coronary lesions (luminal narrowing <50%) underwent a provocation test with Ach infusion during coronary angiography from November 2004 to May 2012 will be reviewed. Among them, patients with documented cardiovascular disease and/or any other serious medical condition, such as an increased serum creatinine level (>2mg/dl), will be excluded. Patients will be excluded due to incomplete data. The investigators will register hypertensive patients who are currently using antihypertensive medications. The study population will be divided into quartiles based on rising systolic BP, diastolic BP, and pulse pressure. CAS+chest pain(CP) means>70% luminal narrowing on Ach provocation test. and/or concurrent typical chest pain.

BP was measured with a noninvasive BP monitoring device with the patient lying on the angiographic table after a five-minute rest (Patient monitoring system, NP 30:Philips, Amsterdam, The Netherlands). The first reading was discarded, and the mean of the next two consecutive readings was used. Next, coronary angiography was performed. Hypertension is defined as systolic BP ≥140mmHg and/or diastolic BP ≥90mmHg on at least two consecutive readings in the outpatient clinic. Patients taking antihypertensive medications are also categorized as hypertensives. Other Risk factors for CAS examined in this study include hyperlipidemia (total cholesterol level ≥200mg /dl or current medication with lipid-lowering drugs), diabetes (fasting blood glucose≥126mg /dl, and/or glycated Hemoglobin A1c level more than 6.5% or current use of medications), current smoker (active smoking within the past 12 months), and current alcohol user (at least 1 alcohol drinking a week).

Inclusion Criteria:

• Hypertensive patients who are treated with antihypertensive drugs have resting chest pain without significant coronary lesions(luminal narrowing <50%) underwent a provocation test with Ach infusion during coronary angiography.

Exclusion Criteria:

• Patients with documented cardiovascular disease and/or any other serious medical condition, such as an increased serum creatinine level(>2mg/dl), patients with incomplete data, or patients who were not treated with antihypertensive agents

A total of 5,304 consecutive patients in the CAS registry of the Cardiovascular Center at Korea University Guro Hospital