Introduction: The importance of atrio-ventricular synchrony pacing in sinus rhythm patients is known. To identify patients in whom leadless pacemakers are able to guarantee this atrio-ventricular synchrony, we explored correlations among echocardiographic measures of left atrial (LA) size and function (doppler parameter and strain) with A4 amplitude in patients implanted with new generation Micra-AV device.
Methods: After implantation with Micra-AV system, patients underwent device interrogation to evaluate AV synchrony based on the sensing of atrial mechanics and echocardiographic exam to assess LA morphology and LA function.
Results: In the 21 studied patients (14 males, 72 ± 13 years), the A4 wave amplitude values inversely correlated with LA antero-posterior diameter, LA volume, LA contraction strain and LA conduit strain, while they were positively related with LA reservoir strain.
Discussion: Our results indicate a statistically significant relationship between morphological echocardiographic LA parameters and atrial contraction signal (A4), detected by leadless pacemakers and used to synchronize ventricular pacing with the atrium. Instantaneous LA function assessment obtained with LA strain provides incremental information over morphological parameters. LA strain evaluates atrial myocardial deformation during the whole cardiac cycle. We found higher value of A4 in patients that have grater absolute value of LAsr, LAscd and LAsct, that are simple and measurable parameters of LA functional capacity.
Conclusion: Preimplant echocardiographic evaluation of the atrial contractility may be useful in predicting adequate A4 sensing and consequently a good atrio-ventricular synchrony pacing. Echocardiography LA strain study seems promising in Micra-AV patient selection.
Keywords: 3-axis accelerometer; atrio-ventricular synchrony; left atrial echocardiographic assessment; left atrial strain.
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