Prediction of functional coronary stenosis by computed tomography-derived fractional flow reserve in surgical revascularization.

Objectives: The aims of this study were (1) to compare computed tomography-derived fractional flow reserve (CT-FFR) values with graft patency and (2) to establish the cut-off value of CT-FFR for predicting competitive graft flow after coronary artery bypass grafting (CABG).

Methods: Of the 77 patients who underwent isolated CABG with an in situ internal thoracic artery (ITA)-based composite graft and who were also evaluated by preoperative cardiac CT, CT-FFR values were obtained in 74 patients. Early postoperative angiograms were performed in all 74 patients.

A Simple Method for Automatic 3D Reconstruction of Coronary Arteries From X-Ray Angiography.

Automatic three-dimensional (3-D) reconstruction of the coronary arteries (CA) from medical imaging modalities is still a challenging task. In this study, we present a deep learning-based method of automatic identification of the two ends of the vessel from X-ray coronary angiography (XCA). We also present a method of using template models of CA in matching the two-dimensional segmented vessels from two different angles of XCA.

Electrophysiological significance of the interatrial conduction including cavo-tricuspid isthmus during atrial fibrillation.

Key Points: The interatrial conduction, including Bachmann's bundle, the posterior septal conduction, the anterior septal conduction, and the cavo-tricuspid isthmus, contributes to the maintenance mechanisms of atrial fibrillation in a 3D biatrial model. The interatrial conduction ablation including a cavo-tricuspid isthmus ablation significantly affects the wave dynamics of atrial fibrillation (AF) and facilitates the AF termination or atrial tachycardia conversion of the AF after the circumferential pulmonary vein isolation. Additional cavo-tricuspid isthmus ablation after the circumferential pulmonary vein isolation improves long-term rhythm outcome after clinical AF catheter ablation.

Effectiveness of atrial fibrillation rotor ablation is dependent on conduction velocity: An in-silico 3-dimensional modeling study.

Background: We previously reported that stable rotors are observed in in-silico human atrial fibrillation (AF) models, and are well represented by a dominant frequency (DF). In the current study, we hypothesized that the outcome of DF ablation is affected by conduction velocity (CV) conditions and examined this hypothesis using in-silico 3D-AF modeling.

Methods: We integrated 3D CT images of left atrium obtained from 10 patients with persistent AF (80% male, 61.

Influence of LVAD function on mechanical unloading and electromechanical delay: a simulation study.

This study hypothesized that a left ventricular assist device (LVAD) shortens the electromechanical delay (EMD) by mechanical unloading. The goal of this study is to examine, by computational modeling, the influence of LVAD on EMD for four heart failure (HF) cases ranging from mild HF to severe HF. We constructed an integrated model of an LVAD-implanted cardiovascular system, then we altered the Ca transient magnitude, with scaling factors 1, 0.

Physiome approach for the analysis of vascular flow reserve in the heart and brain.

This work reviews the key aspects of coronary and neurovascular flow reserves with an emphasis on physiomic modeling characteristics by the use of a variety of numerical approaches. First, we explain the definition of fractional flow reserve (FFR) in coronary artery and introduce its clinical significance. Then, computational researches for obtaining FFR are reviewed, and their clinical outcomes are compared.

Ganglionated plexi stimulation induces pulmonary vein triggers and promotes atrial arrhythmogenecity: In silico modeling study.

Background: The role of the autonomic nervous system (ANS) on atrial fibrillation (AF) is difficult to demonstrate in the intact human left atrium (LA) due to technical limitations of the current electrophysiological mapping technique. We examined the effects of the ANS on the initiation and maintenance of AF by employing a realistic in silico human left atrium (LA) model integrated with a model of ganglionated plexi (GPs).

Methods: We incorporated the morphology of the GP and parasympathetic nerves in a three-dimensional (3D) realistic LA model.

Numerical simulation of motion-induced dynamic noise in a ubiquitous ECG application.

Wearable ubiquitous biomedical applications, such as ECG monitors, can generate dynamic noise as a person moves. However, the source of this noise is not clear. We postulated that the dynamic ECG noise has two causes: the change in displacement of the heart during motion and the change in the electrical impedance of the skin-gel interface due to motion-induced deformation of the skin-gel interface.