Abstract
Introduction Palpitations occurring in specific body positions
are often reported by patients, but the effect of body position on
arrhythmia has received little research attention. We hypothesize that
resting body position can exert pro-arrhythmogenic effects in various
ways. For example, lateral body position is known to increase change
atrial and pulmonary vein dimensions. Methods This
observational study capitalizes on overnight polysomnography (PSG)
recordings from a tertiary sleep clinic. PSGs were retrieved based on
any mention of cardiac arrhythmia in the clinical report, irrespective
of primary sleep diagnosis and (cardiac) comorbidities. Every instance
of atrial ectopy was annotated and subgroups with a homogenous rate of
atrial ectopy were created based on the Dunn index. A generalized linear
mixed-effects model using age, sex, gender, sleep stage and body
position was used to analyse the total amount of atrial ectopy in each
combination of sleep stage and body position. Backward elimination was
then performed to select the best subset of variables for the model.
Results PSGs of 22 patients (14% female, mean age 61y) were
clustered and analysed. Body position, sleep stage, age or sex did not
have a significant effect on atrial ectopy in the subgroup with a low
rate of atrial ectopy (N=18). However, body position did significantly
affect the rate of atrial ectopy in the subgroup with a high rate of
atrial ectopy (N=4; 18%). Discussion In each individual with a
high rate of atrial ectopy, the rate of atrial ectopy was significantly
higher in either left or right decubital or supine position. Increase in
atrial wall stretch in lateral decubital position and obstructive
respiratory events in positional sleep apnea are two possible
pathophysiological mechanisms, while avoidance of a body position due to
symptomatic atrial ectopy in that position is an important limitation.
Conclusion In a selected cohort of patients with a high rate of
atrial ectopy during overnight polysomnography, the occurrence of atrial
ectopy is related to resting body position.