Abstract 4369718: Right atrial contraction function measured by echocardiography predicting atrioventricular synchrony for Micra-AV leadless pacemaker

Background: Micra-AV leadless pacemaker could achieve atrioventricular synchrony (AVS) by sensing atrial mechanics. However, Micra-AV showed low atrial tracking capability and AVS percentage in some patients. Objectives: Echocardiographic parameters were testified to predict AVS of Micra-AV, which could potentially facilitate to screen suitable patients for Micra-AV. Methods: Patients with atrioventricular block and indicated for Micra-AV were included. Ultrasonic speckle tracking imaging was used to assess atrial contraction/conduit/reservoir strain. Early diastolic (E) and atrial systolic (A) peak flow velocities, early diastolic (E') and atrial systolic (A') tissue Doppler velocities at mitral or tricuspid annulus were measured. AVS was defined as AV interval ≤ 300ms by Holter monitor. Results: 60 patients diagnosed with atrioventricular block were included. For AVS with 70% and above, tricuspid E/A ratio < 1.62 (OR = 3.237, 95% CI: 1.495 to 7.012, p = 0.003) and right atrial contraction strain < -3.3% (OR = 3.794, 95% CI: 1.718 to 7.765, p = 0.001) were verified as potent predictor. For AVS with 80% and above, tricuspid E/A ratio < 1.48 (OR = 6.571, 95% CI: 2.998 to 15.02, p < 0.001) and right atrial contraction strain < -4.8% (OR = 7.667, 95% CI: 3.441 to 16.81, p < 0.001) were verified as potent predictor. Nonetheless, left atrial parameters failed to attain statistical significance. Conclusions: Right atrial echocardiographic parameters are predominant over left ones in relevancy of AVS. Tricuspid E/A and right atrial contraction strain showed great potency to predict AVS independently in Micra-AV.