Cardiac kinematic parameters computed from video of in situ beating heart

Abstract

Mechanical function of the heart during open-chest cardiac surgery is exclusively monitored by echocardiographic techniques. However, little is known about local kinematics, particularly for the reperfused regions after ischemic events. We report a novel imaging modality, which extracts local and global kinematic parameters from videos of in situ beating hearts, displaying live video cardiograms of the contraction events. A custom algorithm tracked the movement of a video marker positioned ad hoc onto a selected area and analyzed, during the entire recording, the contraction trajectory, displacement, velocity, acceleration, kinetic energy and force. Moreover, global epicardial velocity and vorticity were analyzed by means of Particle Image Velocimetry tool. We validated our new technique by i) computational modeling of cardiac ischemia, ii) video recordings of ischemic/reperfused rat hearts, iii) videos of beating human hearts before and after coronary artery bypass graft, and iv) local Frank-Starling effect. In rats, we observed a decrement of kinematic parameters during acute ischemia and a significant increment in the same region after reperfusion. We detected similar behavior in operated patients. This modality adds important functional values on cardiac outcomes and supports the intervention in a contact-free and non-invasive mode. Moreover, it does not require particular operator-dependent skills.

Artificial Intelligence Supports Decision Making during Open-Chest Surgery of Rare Congenital Heart Defects

“…We applied Vi.Ki.E. in the field of myocardial ischemia [21] and complex congenital heart diseases such as Tetralogy of Fallot (ToF) [22,23], which is the most common RV pathology representing 7-10% of the congenital cardiac defects [24]. Interestingly, in our most recent work on ToF [23], we observed a promising correlation between the before surgery Vi.Ki.E.…”

“…As for the intraoperative evaluation of the RV, our group has introduced and validated an innovative and contactless imaging technique named Vi.Ki.E. (Video Kinematic Evaluation) [21]. Briefly, the technique consists of recording hightemporal resolution videos of the epicardial movement of the exposed beating heart to calculate kinematic parameters before and after surgery.…”

Numerical evaluation of cardiac mechanical markers as estimators of the electrical activation time

“…The numerical simulations presented are based on the strongly coupled electromechanical model developed in our previous works, 26,34 which takes into account the bidomain representation of the cardiac tissue, mechanoelectric (ie, stretch‐activated channels) and geometric feedbacks, transversely isotropic strain energy function for the description of passive mechanics and detailed membrane and excitation‐contraction coupling models. The outcomes of our electromechanical solver, in particular in terms of strain waveforms and pressure‐volume loop, have been validated by a comparison with experimental data in our previous works 35,36 …”

“…stretch-activated channels) and geometric feedbacks, transversely isotropic strain energy function for the description of passive mechanics and detailed membrane and excitation-contraction coupling models. The outcomes of our electro-mechanical solver, in particular in terms of strain waveforms and pressure-volume loop, have been validated by a comparison with experimental data in our previous works [26,20].…”

Altered Mitochondrial Metabolism and Mechanosensation in the Failing Heart: Focus on Intracellular Calcium Signaling

“…Arrhythmia is a macroscale phenomenon; the mechanisms herein described (mitochondria relocation, and MiCa i initiation and propagation) at single cell levels can be transposed to the mechanically induced arrhythmia encountered in vivo (triggered activity, commotio cordis, or calcium alternans) [ 74 , 75 , 76 ]. Indeed, a similar hydrojet pressure approach on in vivo beating rat hearts can induce an AV block when the jet is delivered on top of the pulmonary cone [ 77 ]. Thus, as abnormal Ca 2+ waves underline arrhythmias, what we described here in terms of mitochondria relocation and Ca 2+ handling may be involved as a novel arrhythmogenic substrate.…”