Atrial fibrillation (AF), an important cause of cardiac mortality and morbidity is the most common type of cardiac arrhythmia in clinical practice. Hypertensive individuals are at particular risk of development of atrial fibrillation. Renin-angiotensin-aldosteron system (RAS) which is activated in hypertension may be the underlying mechanism of AF among hypertensive patients.

Vitamin D deficiency has been shown to be involved in the pathogenesis of hypertension, cardiovascular disease and obesity. Increased RAS activity is one of the postulated mechanisms by which vitamin D deficiency may trigger the development of hypertension and various cardiovascular diseases. On the basis of these data we hypothesized that hypovitaminosis D might be associated with new-onset AF among patients with hypertension.

Inclusion Criteria:

• Hypertensive patients with new-onset AF

Exclusion Criteria:

Established coronary artery disease

• Heart failure
• Chronic obstructive pulmonary disease
• Diabetes mellitus
• Significant heart valve disease
• Hyperthyroidism
• Renal failure
• Any malignancy
• Acute infection
• Recent thoracic or abdominal surgery
• Under therapy of Vit D3

Hypertensive patients with new-onset AF. New onset AF was defined as AF identified for the first time by an electrocardiogram or ambulatory holter monitoring. Hypertension was defined as blood pressure ≥ 140/90 mmHg or a history of antihypertensive drug use.