Abstract Introduction Patients (pts) with osteoporosis (OP) have an increased 10-year cardiovascular death risk. Low bone mineral density (BMD) observed in OP may be associated with arrhythmic presentation of cardiovascular diseases (CVD). Few studies assessed the relationship between OP and arrhythmia. Aim Arrhythmias assessment in pts with OP. Methods A total of 103 postmenopausal female pts (mean age 69 +/- 7), consulted by endocrinologist, were divided into 2 groups according to BMD (assessed by dual energy X-ray absorptiometry). BMD measurements, expressed as T-score (T-sc), were taken from the femoral neck (T-sc Neck), entire total hip (T-sc TH) and/or spine (T-sc L2-L4, L1-L4). Arrhythmia was evaluated using 24-hour Holter-ECG monitoring (HM). Major osteoporotic and total hip fracture risks (MOFR and THFR, respectively) were assessed by the FRAX scale. We compared 51 pts with OP (T-sc ≤ -2.5), with 52 matched controls without OP, including 44 pts with osteopenia (T-sc > -2.5). There were no significant differences between the groups regarding the history of stroke, myocardial infarction, coronary artery disease or arterial hypertension. Exclusion criteria included heart failure NYHA >II and/or LVEF <36%, acute coronary syndrome within the last 6 months, severe valvular disease, cardiac implantable electronic device. Results There was a trend towards a greater number of supraventricular and ventricular arrhythmias in the OP group compared to the controls. Arrhythmic burden was significantly correlated with BMD measures: correlations were observed between 24-hour ventricular ectopic beats (VEB) count with T-sc Neck (r=-0.20, p=0.04), with T-sc TH (r=-0.22, p=0.03). The number of supraventricular ectopic beats (SVEB) in HM was also correlated with BMD parameters: T-sc Neck (r=-0.21, p=0.03), T-sc TH (r=-0.23, p=0.02). Multivariate analysis (linear regression model) revealed that age and T-sc TH were independently related with ectopy: age (0.07; CI: 0.01 - 0.13, p=0.03) and T-sc TH (-0.58; CI: -1.07 - -0.08, p=0.02) were predictors for VEB, and SVEB were related to age (0.07; CI: 0.03 - 0.12, p<0.01) and, with borderline significance with T-sc TH (-0.34; CI: -0.699 - 0.012, p=0.058). Ectopic beats count was also positively correlated with osteoporotic fracture risk: VEB with THFR (r=0.206, p=0.04) and SVEB with MOFR (r=0.21, p=0.04). Conclusions The study showed an increased arrhythmia burden as detected in HM in pts with OP. Beside the T-sc TH, age was identified as an independent factor of increased SVEB / VEB. The main significant negative correlations were observed between the number of VEB / SVEB and BMD in femur (T-sc Neck, T-sc TH). Ectopic beats count was also positively correlated with osteoporotic fracture risk: VEB with THFR and SVEB with MOFR.