More than 2 million mostly older Americans have the heart rhythm disorder known as atrial fibrillation, which greatly increases their risk for stroke, heart failure, and death.
Researchers followed about 2,000 Norwegian men for an average of 30 years, during which time 270 developed atrial fibrillation.
Men whose systolic blood pressure (the upper number) was in the high-normal range at the start of the study were 50% more likely than men with normal blood pressure to develop the heart rhythm condition.
An earlier study in women who were followed for an average of 14 years also showed high-normal blood pressure to be associated with a higher risk for atrial fibrillation.
In the United States, high blood pressure is defined as a systolic reading of 140 or higher and a diastolic reading of 90 or more.
High-normal blood pressure, also known as prehypertension, is generally defined as having a systolic reading of between 120 and 139 and/or a diastolic reading of 80 to 89.
Atrial fibrillation is characterized by an irregular -- and sometimes rapid -- heartbeat resulting when the two upper chambers and two lower chambers of the heart are not contracting in sync.
Symptoms can include heart palpitations, shortness of breath, general weakness, or no symptoms at all.
In an effort to determine if the earlier findings in women also applied to men, researcher Irene Grundvold, MD, and colleagues from Norway’s Oslo University Hospital analyzed data from a study of men who were in their 40s and 50s when first examined in the early- to mid-1970s.
The men were followed for up to 35 years.
The study revealed that:
Men with systolic blood pressure readings of 140 or higher when they entered the study had a 60% increased risk of developing atrial fibrillation over the next three decades, compared to men with systolic readings below 128.
Men with systolic readings of 128 to 138 at at the start of the study had a 50% increase in risk.
Men with diastolic readings of 80 or higher were 79% more likely than those with lower diastolic blood pressure to develop atrial fibrillation over the next three decades.