A normal resting heart rate ranges from 60 to 100 beats per minute (ref. 1). In atrial fibrillation, the heart beats irregularly and can exceed 400 beats per minute (ref. 7). When the heart beats too rapidly, blood may pool in the atrium, increasing the likelihood of clot formation, which can in turn cause a stroke. This mechanism accounts for 20%–30% of all strokes and raises the overall risk fivefold (ref. 2).

Although regular medical check‑ups are essential, atrial fibrillation can still go undetected because it does not always present consistently. Many people remain undiagnosed, as the risk of atrial fibrillation increases with age and its symptoms are often subtle or mistaken for other conditions. Signs to be aware of include palpitations, chest pain, dizziness, a general feeling of fatigue and shortness of breath.

This is because the upper chambers of the heart do not pump blood effectively, which can lead to blood pooling and clot formation (ref. 5). If a clot develops, it may travel through the heart and circulate elsewhere in the body. Should it block a cerebral artery, it can obstruct blood flow to the brain and cause a stroke.

Hypertension and atrial fibrillation can occur in the same individual. In fact, one medical study found that high blood pressure increased the risk of atrial fibrillation by 50% in men and 40% in women (ref. 6). Furthermore, high blood pressure was identified as the fourth most significant risk factor, after heart failure, ageing, and heart valve disease.