Listen to your heart

NZ researchers aim to improve understanding of a dangerous form of irregular heartbeat that often goes undetected.

- NICKY PELLEGRINO

A trial fibrillation (AF) is especially common among older adults. It is estimated that about 60,000 New Zealanders have been diagnosed and more remain unaware they have the condition. This is concerning because AF increases the risk of suffering a stroke and heart failure, and it has been linked to dementia.

In a healthy person, electrical signals keep the heart rate at a steady rhythm. With AF, those electrical signals are chaotic and this results in the heartbeat becoming irregular, which means blood is not pumped efficiently.

The causes of atrial fibrillation aren't always clear, although some lifestyle factors play a part, including long-term heavy drinking and being overweight. Often, the first sign is the sensation of heart palpitations or a racing "fluttering" heartbeat and, at the beginning, episodes may come and go, lasting for minutes, hours or a few days. But in many cases, this progresses to persistent AF.

Exactly how that affects blood flow to the brain is being investigated by researchers in Auckland. They are using MRI scans to measure exactly what is happening to the blood and how it affects the structure of the brain.