Published in Heart, a journal of the British Cardiovascular Society, this study analyzed data from the Tromso Study—a large Norwegian research study started in 1974 to investigate risk factors for heart disease. Using surveys and health exams, the Tromso Study has collected information from thousands of Norwegian adults about various heart conditions, including atrial fibrillation (AFib).
AFib is a common type of irregular heartbeat that causes reduced blood flow to the body. While there are a number of well established risk factors for AFib, such as high blood pressure and diabetes, recent studies have found an association between an enlarged heart and increased risk for AFib. However, most of these studies were small and only followed patients for a short period of time.
To learn more, researchers analyzed data from more than 2,400 participants in the Tromso Study. On average, participants were 62 years old at the start of the study and were followed for 16 years, providing health information through periodic surveys. Participants also underwent echocardiograms, which use moving pictures to assess the size, shape and function of the heart. For the purposes of this study, researchers looked at the size of participants’ left atrium, which is one of the four chambers of the heart. An enlarged left atrium has been linked to AFib, as it can prevent the heart from pumping blood properly and may increase risk for an irregular heartbeat.
Based on tests results, researchers found that 19% of study participants had AFib; most were men. Individuals with a moderately enlarged left heart chamber were 60% more likely to have AFib than those with a normal heart size. Those with a severely enlarged left atrium were more than four times more likely to have AFib than those with normal heart chambers.
Findings confirm that an enlarged left atrium is an independent risk factor for AFib, similar to risk factors like obesity and diabetes. Although further research is needed to better understand the association between heart size and AFib, authors hope findings can help identify patients at risk for AFib or those at risk for complications from AFib, such as stroke and heart failure.
Afib is a common condition affecting roughly 2.7 million Americans. Although AFib significantly increases risk for stroke, healthy lifestyle choices, medication and other treatments can help reduce risk for complications. Addressing risk factors for AFib like high blood pressure can also go a long way in reducing risk for developing this condition. The more we know about risk factors that put us at increased risk for AFib, the more we can do to reduce risk for complications.