Ventricular wall stress and wall shear stress homeostasis predicts cardiac remodeling during pregnancy: A modeling study

Uncertainty in cardiovascular digital twins despite non-normal errors in 4D flow MRI: Identifying reliable biomarkers such as ventricular relaxation rate

Cardiovascular digital twins and mechanistic models can be used to obtain new biomarkers from patient-specific hemodynamic data. However, such model-derived biomarkers are only clinically relevant if the uncertainty of the biomarkers is smaller than the variation between timepoints/patients. Unfortunately, this uncertainty is challenging to calculate, as the uncertainty of the underlying hemodynamic data is largely unknown and has several sources that are not additive or normally distributed. This violates normality assumptions of current methods; implying that also biomarkers have an unknown uncertainty. To remedy these problems, we herein present a method, with attached code, for uncertainty calculation of model-derived biomarkers using non-normal data. First, we estimated all sources of uncertainty, both normal and non-normal, in hemodynamic data used to personalize an existing model; the errors in 4D flow MRI-derived stroke volumes were 5-20 % and the blood pressure errors were 0 ± 8 mmHg. Second, we estimated the resulting model-derived biomarker uncertainty for 100 simulated datasets, sampled from the data distributions, by: 1) combining data uncertainties 2) parameter estimation, 3) profile-likelihood. The true biomarker values were found within a 95 % confidence interval in 98 % (median) of the cases. This shows both that our estimated data uncertainty is reasonable, and that we can use profile-likelihood despite the non-normality. Finally, we demonstrated that e.g. ventricular relaxation rate has a smaller uncertainty (∼10 %) than the variation across a clinical cohort (∼40 %), meaning that these biomarkers have clinical potential. Our results take us one step closer to the usage of model-derived biomarkers for cardiovascular patient characterization.

A Very Late Atrial Septal Erosion After an Ostium Secundum Percutaneous Closure

Complications after device closure of ostium secundum defects are rare but possible. We present a very late erosion of the interatrial septum after a percutaneous closure of an ostium secundum defect. Identification of early clinical and imaging clues associated with this condition is fundamental for a timely diagnosis and treatment. (Level of Difficulty: Intermediate.).

Tricuspid annular disjunction can be isolated and even arrhythmogenic. A cardiac magnetic resonance study

Mitral annular disjunction is related to increased arrhythmogenic risk; in a certain percentage of cases, mitral annular disjunction is associated with tricuspid annular disjunction. While the prognostic implications of mitral annular disjunction have been well established, there is still little data to define this aspect regarding the tricuspid annular disjunction. We present a case of a patient admitted for life-threatening ventricular arrhythmias that occurred during endurance sporting activity, who was found to have isolated tricuspid annular disjunction, not associated with mitral annular disjunction. Based on several factors, including the morphology and axis of QRS of the ventricular arrhythmic activity, and its behavior, including the response to antiarrhythmic treatment, and in keeping with the finding of edema and late gadolinium enhancement at the basal segment of the right ventricle free wall on cardiac magnetic resonance imaging, a direct relation between tricuspid annular disjunction and ventricular arrhythmias was highly conceivable. Control after three months showed almost complete remission of the previously described and persistence of LGE at the level of the basal segment of the free wall of the right ventricle, so giving strength to the hypothesis of an event related to increased acute RV free wall stress, secondary to high-intensity physical activity, established on a framework of chronic wall stress, as represented by LGE, similarly to what happens for mitral valve prolapse. To the best of our knowledge, this is the first case of a legitimately conceivable direct relation between tricuspid annular disjunction and ventricular arrhythmias.