Aim: Micra AV represents a leadless endocardial pacing system able to detect atrial contractions providing atrioventricular synchrony. A reduction of myocardial contractility may be detected in case of first-degree atrioventricular block (AVB). Materials & methods: In six patients with first-degree AVB (PQ interval ≥220 msec) was evaluated the left ventricle global longitudinal strain (LV GLS) by speckle tracking (ST) echocardiography during single-lead atrial sensing ventricular pacing (VDD) stimulation as compared with spontaneous rhythm (SR), 24-48 h after Micra AV implantation. Results: A statistically significant difference between the two modalities was observed (LV GLS during SR: -14.7% [interquartile range (IQR) 5.5], LV GLS during VDD pacing: -16.1% [IQR 5.2]; p value = 0.041). Conclusion: Our preliminary results suggest an improvement of myocardial contractility with VDD pacing as compared with SR.
Keywords: Micra AV; VDD pacing; atrioventricular block; global longitudinal strain; leadless pacemaker; speckle tracking echocardiography.
What is this article about? The Micra AV is an electronic device placed in the heart chambers capable to supply the electrical activity of the heart. A reduction of cardiac contractility may be observed in patients with electrical disorders of the heart. What were the results? In six patients affected by electrical cardiac disorders, we observed an improvement of cardiac contractility using Micra AV as compared with the spontaneous electrical activity of the heart. What do the results of the study mean? The results of this study suggest that in patients carrying this electronic device should be preferred a specific modality of activation of the device as compared with the spontaneous electrical activity of the heart in order to improve the contractility of the cardiac walls.