AbuRmilah, Anan

Background: Many cardiac implantable devices have the capability of monitoring the volume status in patients with heart failure by tracking the intra-thoracic impedance changes over time measured by OptiVol fluid index. Objective: The aim of this study is to evaluate the association between the intra-thoracic impedance measured by OptiVol fluid index and the onset of tachyarrhythmias. Methods: We searched Medline and EMBASE databases through January 2021 looking for studies evaluating intra-thoracic impedance measured by OptiVol with either ventricular tachycardia/ventricular fibrillation (VT/VF) or atrial tachycardia/atrial fibrillation (AT/AF). After extracting the data from each study, we calculated the odds ratio with 95% confidence intervals using RevMan 5 software. Results: Ten studies met our inclusion criteria with a total of 118,504 patients were included in our analysis. Seven studies measured VT/VF included 94,816 patients and 5 studies measured AT/AF included 23,688 patients. Two studies measured both AT/AF and VT/VF. The odds ratio for developing VT/VF with OptiVol fluid index crossing a threshold of 60 Ω-days was 1.55 (95% CI 1.35, 1.78) (P<0.00001) and for developing AT/AF was 1.79 (95% CI 1.43, 2.24) (P<0.00001) {Figure1} Conclusion: The decrease in intra-thoracic impedance measured by OptiVol fluid index threshold crossing of 60 Ω-days is associated with higher risk for developing new onset AT/AF and VT/VF. Key Words: intra-thoracic impedance; OptiVol; tachyarrhythmia Figure1: Forest Plot for risk of developing VT/VF Figure: Forest Plot for risk of developing AT/AF