Palpitations, which the investigators described as "frequent" in the total study group, increased the risk of AF in women by 62% (a hazard ratio of 1.62) and in men by 91% (HR 1.91).
The investigators also examined separately the predictors for palpitations and for AF (in order to exclude any common overlapping risk factors). This analysis found that for palpitations (but not for AF) several significant risk factors were related to lifestyle, while the most prominent risk factors for AF were biological (such as age, blood pressure, height, body mass index and diabetes). And although height, antihypertensive treatment and coronary heart disease were found to be risk factors for both palpitations and AF, the investigators nevertheless concluded "that palpitations are probably causally associated with atrial fibrillation".
"Although the occurrence of palpitations was assessed before a diagnosis of AF and the association remained significant even after adjustment for other AF risk factors, we cannot conclude with certainty that the association is causal," said first author Dr Audhild Nyrnes from the Department of Community Medicine, University of Troms, Norway. "However, in this case it is not unreasonable to propose a causal relationship. 'Palpitations' are used subjectively to describe irregular heart beats or accelerated heart rate, and it is likely that a proportion of palpitations also represent cases of irregular heart rhythm, which is a main characteristic of AF."
A much cited US study of 190 patients presenting to hospital with palpitations concluded that cardiac arrhythmias were diagnosed in 40%, with the remainder of varied - or unknown - cause.(3) This and other studies suggest that palpitations can represent heterogeneous mechanisms, with highly different clinical implications.
"However," said Dr Nyrnes, " palpitations per s
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