Correcting bias in cardiac geometries derived from multimodal images using spatiotemporal mapping.

Cardiovascular imaging studies provide a multitude of structural and functional data to better understand disease mechanisms. While pooling data across studies enables more powerful and broader applications, performing quantitative comparisons across datasets with varying acquisition or analysis methods is problematic due to inherent measurement biases specific to each protocol. We show how dynamic time warping and partial least squares regression can be applied to effectively map between left ventricular geometries derived from different imaging modalities and analysis protocols to account for such differences.

MITEA: A dataset for machine learning segmentation of the left ventricle in 3D echocardiography using subject-specific labels from cardiac magnetic resonance imaging.

Segmentation of the left ventricle (LV) in echocardiography is an important task for the quantification of volume and mass in heart disease. Continuing advances in echocardiography have extended imaging capabilities into the 3D domain, subsequently overcoming the geometric assumptions associated with conventional 2D acquisitions. Nevertheless, the analysis of 3D echocardiography (3DE) poses several challenges associated with limited spatial resolution, poor contrast-to-noise ratio, complex noise characteristics, and image anisotropy.

Atrial fibrillation cardiac radioablation target visibility on magnetic resonance imaging.

Magnetic resonance imaging (MRI) guided cardiac radioablation (CR) for atrial fibrillation (AF) is a promising treatment concept. However, the visibility of AF CR targets on MRI acquisitions requires further exploration and MRI sequence and parameter optimization has not yet been performed for this application. This pilot study explores the feasibility of MRI-guided tracking of AF CR targets by evaluating AF CR target visualization on human participants using a selection of 3D and 2D MRI sequences.

Right Ventricular Flow Vorticity Relationships With Biventricular Shape in Adult Tetralogy of Fallot.

Remodeling in adults with repaired tetralogy of Fallot (rToF) may occur due to chronic pulmonary regurgitation, but may also be related to altered flow patterns, including vortices. We aimed to correlate and quantify relationships between vorticity and ventricular shape derived from atlas-based analysis of biventricular shape. Adult rToF ( = 12) patients underwent 4D flow and cine MRI imaging.

MRI-guided cardiac-induced target motion tracking for atrial fibrillation cardiac radioablation.

Background And Purpose: Atrial fibrillation (AF) cardiac radioablation (CR) challenges radiotherapy tracking: multiple small targets close to organs-at-risk undergo rapid differential cardiac contraction and respiratory motion. MR-guidance offers a real-time target tracking solution. This work develops and investigates MRI-guided tracking of AF CR targets with cardiac-induced motion.

Cardiac radioablation for atrial fibrillation: Target motion characterization and treatment delivery considerations.

Purpose: The safe delivery of cardiac radioablation (CR) for atrial fibrillation (AF) is challenged by multi-direction target motion, cardiac rate variability, target proximity to critical structures, and the importance of complete target dose coverage for therapeutic benefit. Careful selection of appropriate treatment procedures is therefore essential. This work characterizes AF cardiac radioablation target motion and target proximity to surrounding structures in both healthy and AF participants to guide optimal treatment technique and technology choice.

Cardiac output as a predictor in congenital heart disease: Are we stating the obvious?

Background: Significant pulmonary regurgitation, declining right-sided ejection fraction, increased right ventricular (RV) volumes as well as left ventricular (LV) dysfunction have all been identified as predictors of poor outcomes in patients with congenital heart disease (CHD). The prognostic value of the cardiac output (CO) in these patients however has never been studied.

Methods: All consecutive ambulatory adult patients with CHD referred for magnetic resonance imaging (MRI) at the Montreal Children's Hospital between June 2007 and May 2009 were included.

The role of echocardiography in Staphylococcus aureus bacteraemia at Auckland City Hospital.

Aims: Current guidelines recommend echocardiography in all episodes of Staphylococcus aureus bacteraemia (SAB). This study aimed to determine whether a very low-risk group of patients with SAB could be found in whom echocardiography was of no incremental diagnostic value for the diagnosis of infective endocarditis.

Methods: Using the ANZCOSS dataset, we identified 574 eligible episodes of adult SAB at Auckland District Health Board (ADHB) between 2007 and 2012, and retrospectively obtained additional microbiological and clinical data.

Prognostic significance of left atrial appendage "sludge" in patients with atrial fibrillation: a new transesophageal echocardiographic thromboembolic risk factor.

Background: When stratifying thromboembolic risk to patients with atrial fibrillation (AF), left atrial appendage (LAA) thrombus is currently the only echocardiographic index that absolutely contraindicates cardioversion. The aim of this study was to identify the predictors of LAA "sludge" and its impact on subsequent thromboembolism and survival in patients with AF.

Methods: A total of 340 patients (mean age, 66 ± 12 years; 75% men) who underwent transesophageal echocardiography to exclude LAA thrombus before electrical cardioversion or radiofrequency pulmonary vein isolation) for AF were retrospectively studied.

Diagnosis of pulmonary hypertension in the congenital heart disease adult population impact on outcomes.

Objectives: The aim of this study was to assess the impact of the diagnosis of pulmonary hypertension (PH) on mortality, morbidity, and health services utilization (HSU) in an adult congenital heart disease (CHD) population.

Background: Although PH is a well-recognized complication of CHD, population-based studies of its significance on the survival and functional capacity of patients are uncommon.

Methods: A retrospective longitudinal cohort study was conducted in an adult CHD population with 23 years of follow-up, from 1983 to 2005.

Role of Transesophageal Echocardiography Compared to Computed Tomography in Evaluation of Pulmonary Vein Ablation for Atrial Fibrillation (ROTEA study).

Background: Computed tomography (CT) is the gold standard for assessing pulmonary vein (PV) anatomy and stenosis after ablation for atrial fibrillation (AF), but radiation exposure can be a concern. Transesophageal echocardiography (TEE) provides anatomic and functional assessment of the PVs, although no study has prospectively compared findings on TEE with those on CT.

Methods: The Role of Transesophageal Echocardiography Compared to Computed Tomography in Evaluation of Pulmonary Vein Ablation for Atrial Fibrillation (ROTEA) study was a prospective, single-blinded observational study of patients with paroxysmal or persistent AF undergoing ablation.

Influence of concentric left ventricular remodeling on early mortality after aortic valve replacement.

Background: Severe left ventricular (LV) hypertrophy increases risk for adverse outcome after aortic valve replacement. Whether LV geometry influences mortality risk after aortic valve replacement is unclear. And, whether LV mass or relative wall thickness (RWT) better predicts risk for adverse postoperative outcomes is unknown.