Effect of Right Ventricular Pacing on Cardiac Apex Rotation Assessed by a Gyroscopic Sensor

Abstract

To quantify cardiac apex rotation (CAR), the authors recently proposed the use of a Coriolis force sensor (gyroscope) as an alternative to other complex techniques. The aim of this study was to evaluate the effects of right ventricular (RV) pacing on CAR. A sheep heart was initially paced from the right atrium to induce a normal activation sequence at a fixed heart rate (AAI mode) and then an atrioventricular pacing was performed (DOO mode, AV delay ‫؍‬ 60 ms). A small gyroscope was epicardially glued on the cardiac apex to measure the angular velocity (Ang V). From AAI to DOO pacing mode, an increase (؉9.2%, p < 0.05) of the maximum systolic twisting velocity (Ang V MAX ) and a marked decrease (-19.9%, p < 0.05) of the maximum diastolic untwisting velocity (Ang V MIN ) resulted. RV pacing had negligible effects (-3.1%, p ‫؍‬ 0.09) on the maximum angle of CAR, obtained by integrating Ang V. The hemodynamic parameters of systolic (LVdP/dt MAX ) and diastolic (LVdP/dt MIN ) cardiac function showed slight variations (-3.8%, p < 0.05 and ؉3.9%, p < 0.05, respectively). Results suggest that cardiac dyssynchrony induced by RV pacing can alter the normal physiological ventricular twist patterns, particularly affecting diastolic untwisting velocity. ASAIO Journal 2007; 53: 304 -309.The importance of left ventricular (LV) torsional behavior as a sensitive indicator of cardiac performance has been previously demonstrated. 1-8 In systole, the LV apex rotates counterclockwise (as viewed from the apex), whereas the base rotates clockwise, creating a torsional deformation originating in the dynamic interaction of oppositely wound epicardial and endocardial myocardial fiber helices. This wringing motion has been quantified by using different methods such as radiographic tracking of myocardial markers, 9 -17 optical devices, 18 -20 and two-dimensional echocardiography. 21,22 In the past decade, tissue-tagging magnetic resonance imaging (tagged MRI) has enabled noninvasive measurement of LV myocardial deformation in three-dimensional space and prompted investigation of LV torsion in various cardiac diseases. [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] Recently, Doppler tissue imaging (DTI), which has been shown to accurately reflect myocardial velocity with better temporal resolution than MRI, has been proposed and validated as a novel noninvasive method for quantifying LV torsion in humans. 39 More recently, a newly developed speckle tracking imaging (STI) technique based on the appearance of speckle patterns within the tissue during two-dimensional ultrasound imaging was presented. Measurement of speckle motion, closely linked to tissue motion when small displacements are involved, is used for estimation of angle displacement about the central axis of the LV. 40,41 After our previous experiences with implantable cardiac devices equipped with hemodynamic sensors able to assess cardiac function 42-49 and investigations of the technological solutions offered by the market and described in scientific literature...

Determinants of left ventricular untwisting behaviour in patients with dilated cardiomyopathy: analysis by two-dimensional speckle tracking

“…Furthermore, precise assessment of systolic and diastolic function, and LV dyssynchrony can be simultaneously achieved 8. Marcelli et al reported that right ventricular pacing, which is known to cause LV dyssynchrony,9 altered diastolic untwisting velocity in sheep, suggesting a possible link between torsional behaviour and dyssynchrony 10. Therefore, we hypothesised that echocardiographic parameters, including LV dyssynchrony, could be associated with LV untwisting in addition to torsional deformation.…”

A Miniaturized MEMS Motion Processing System for Nuclear Medicine Imaging Applications

“…Accelerometer is very susceptible to earth gravity which makes it more prone to vibration/noise. Whereas, gyroscope is not affected by the gravity of earth and is insusceptible to axial and radial translational motions [14]. Additionally, gyroscope is an active sensor that consumes more power than accelerometer which is a passive sensor.…”

Implantable Sensors for Cardiac Function Monitoring

“…The results collected from preliminary evaluations on animals (73)(74)(75) demonstrated the feasibility of assessing cardiac rotation by means of a gyro sensor epicardially attached to the cardiac apex and its capability of detecting alterations of cardiac function experimentally induced (acute ischemia by coronary artery ligation, change in cardiac contractility by dobutamine infusion, and asynchronous cardiac contraction by pacing). Although this new sensor seems to have great potential in cardiac function monitoring, further animal evaluations are needed to confirm its long-term efficacy.…”