Ventricular Region Research Articles

Significance of left posterior extension of early repolarization in patients with J-wave syndrome

J waves in the inferior or lateral leads are characteristic electrocardiographic (ECG) changes in patients with early repolarizationsyndrome (ERS). However, the presence of J waves in the left posterior region has not yet been evaluated. The purpose of this study was to clarify the significance of J waves in the posterior left ventricle using leads V7-V9 and a body surface mapping (BSM) system. Forty patients diagnosed with ERS were included. All patients exhibited J waves in either the contiguous inferior, lateral, or posterior leads. We evaluated the incidence of J waves in the inferolateral and posterior leads using a 15-lead ECG with synthesized V7-V9 and an 87-lead BSM. Additionally, we assessed the arrhythmogenicity of the posterior regions based on the morphology ofthe premature ventricular complexes (PVCs) associated with ventricularfibrillation (VF). J waves were observed in the lateral, inferior, and posterior leads of 26 (65%), 31 (78%), and 39 (97%) patients, respectively. J waves were found only in the posterior leads of 5 patients. BSM was evaluated in 9 patients, all of whom exhibited a positive area on the posterior region. PVCs associated with VF were recorded in 5 patients. Among patients with inferolateral and posterior J waves, all except 1 patient who displayed left bundle branch block morphology showed PVCs originating from the posterior left ventricular region. Posterior J waves are common in ERS patients. This abnormality can be detected using leads V7-V9 and the BSM system and may be associated with arrhythmogenesis.

COVID-19 as a potential trigger for refractory arrhythmias and electrical storm in a patient with dilated cardiomyopathy: a case report

Arrhythmias occur both in the acute coronavirus disease 2019 (COVID-19) and in the post-acute period, which may be associated with the long-term SARS-CoV-2 persistence. In a case report, patient with primary dilated cardiomyopathy, an implanted cardioverter-defibrillator, recurrent ventricular arrhythmias, and an electrical storm are presented. The patient was repeatedly hospitalized in a city hospital, where electrical cardioversion, antiarrhythmic therapy, radiofrequency ablation of recurrent ventricular tachycardia regions, including emergency ("lifesaving") combined catheter radiofrequency destruction of the electrical storm substrate, was performed. Subsequently, against the background of ongoing postoperative therapy, massive pulmonary embolism (PE) suddenly developed, which led to the death. Autopsy established that the cause of the patient’s death was massive pulmonary embolism; SARS-CoV-2 and enterovirus was detected in the myocardium. Based on an autopsy study, the patient was diagnosed with primary dilated cardiomyopathy with secondary active chronic lymphocytic myocarditis.

A method of motion estimation of segmental ventricular wall with tracking of ultrasonic echocardiogram

BackgroundUltrasonic echocardiography is commonly used for monitoring myocardial dysfunction. However, it has limitations such as poor quality of echocardiography images and subjective judgment of doctors.MethodsIn this paper, a calculation model based on optical flow tracking of echocardiogram is proposed for the quantitative estimation motion of the segmental wall. To improve the accuracy of optical flow estimation, a method based on confidence-optimized multiresolution(COM) optical flow model is proposed to reduce the estimation errors caused by the large amplitude of myocardial motion and the presence of “shadows” and other image quality problems. In addition, motion vector decomposition and dynamic tracking of the ventricular region of interest are used to extract information regarding the myocardial segmental motion. The proposed method was validated using simulation images and 50 clinical cases (25 patients and 25 healthy volunteers) for myocardial motion analysis.ResultsThe results demonstrated that the proposed method could track the motion information of myocardial segments well and reduce the estimation errors of optical flow caused due to the use of low-quality echocardiogram images.ConclusionsThe proposed method improves the accuracy of motion estimation for the cardiac ventricular wall.

Pulsed field ablation as a precise approach for cardiac arrhythmia treatment via cardiac microenvironment remodeling

PFA uses short-duration, high-voltage electrical pulses to induce transient or irreversible electroporation on cell membranes, causing cell death. Selective inhibition of chaotic electrical signals in morbid cardiomyocytes significantly aids the treatment of atrial fibrillation, ventricular tachycardia, and other heart arrhythmias. Recent preclinical and clinical studies have only investigated physical changes, such as lesion size and myocardial scar. Compared to radiofrequency ablation and cryoballoon ablation, PFA causes less postoperative myocardial cell fibrosis and inflammatory reaction and does not result in myocardial necrosis or tissue scar formation. However, the regulatory mechanism of cellular stress following PFA treatment remains unknown. This study aimed to analyze the transcriptome of the mouse ventricle after PFA treatment. The animals were subjected to a 225-V electric pulse with a 1.5-mm gap between the positive and negative electrodes. Hearts were harvested at 3, 6, 12, 24 h, and 2, 5 days for myocardial zymogram testing. PFA-treated ventricular regions were selected for single-nucleus sequencing. We discovered that PFA remodeled the cardiac microenvironment as a whole. Further, we discussed the possible stress response and wound-healing mechanism in non-targeted cells. In conclusion, PFA allowed effective and selective ventricular myocardium ablation with controllable inflammation.

Neurobiological factors of aggressive behavior in patients with multi-infarction dementia

Introduction. In the modern literature, the problem of the influence of multifocal brain damage in vascular dementia on the development of aggressive behavior in patients is only partially covered.The purpose of this work is to study the influence of neurobiological factors (number, localization of lesions) on the development of aggressive behavior in multi-infarct dementia.Materials and methods. The study involved 98 subjects diagnosed in multi-infarct dementia (F 01.1), established according to the ICD-10 criteria (1992), in which 52 were men (53.1 %) and 46 women (46.9 %), aged 60 to 90 years, the average age was 74.5 [67; 81] years. Patients are divided into a main group – with aggressive behavior (n = 49), and a control group − without aggressive behavior (n = 49). The study used clinical-anamnestic, clinical-psychopathological, psychometric and neuroimaging methods.Results. The study showed that patients with aggressive behavior compared to patients without aggressive behavior have a greater number of lesions (p < 0.0001). The localization of which is statistically significantly more often determined in the left frontal lobe, subcortical nuclei on the left and in the left ventricular region (p = 0.0002, 0.0212, 0.0036), and patients without aggressive behavior often do not have frontal lobe lesions.Discussion. Patients who show aggression in general, or in isolation physical, verbal aggression, or irritability, have a statistically significantly greater number of lesions than patients without these symptoms (p < 0,0001). Each additional lesion increases the likelihood of developing aggression and its severity. In patients with irritability, lesions localized in the left frontal lobe and left ventricle.Conclusion The study suggests that the number of lesions from four or more, as well as their predominant localization in the left hemisphere of the brain, leads to the development of various types of aggressive behavior.

Clinico-epidemiological Profile of Primary Brain Tumours in North-Eastern Region of India:A Retrospective Single Institution Study

Background: Brain tumours are mixed group of neoplasms originating from the intracranial tissues. The two basic types of brain tumours are primary and metastatic tumours. Very little is known about the epidemiology of primary brain tumours in the North-Eastern region of India. We carried out a 5-year retrospective study on the epidemiology of the primary brain tumour treated in our hospital.Aim: To study the clinico-epidemiological patterns of brain tumour in a tertiary care center in North-Eastern region of India. Materials and Methods: A retrospective epidemiological approach has been used. The records of patients registered in our hospital from 2017-2022 diagnosed as primary brain tumours have been selected. Data regarding age,sex,site of the tumour, histology, geographical distribution and treatment delivered have been collected. Results: Out of a total of 100 patients studied, males (68%) outnumbered females (32%) with a male:female ratio of 2.1:1. Frequency of brain tumours was found to be higher in the age group 31-40 years i.e. 23% compared to age groups 21-30 years and 41-50 years which were 18% and 15% respectively. Mean age was 38.23 years with ages ranging from 4 to 73 years. The most common presenting symptom was headache (53%), followed by vomiting (28%).The most common anatomical site was found to be cerebrum (81%), followed by ventricular and periventricular regions (6%). Supratentorial tumours (91%) were predominant over infratentorial tumours (9%). Histologically, the most common variety was found to be Glioblastoma Multiforme(30%) followed by Grade II Astrocytoma (15%) and GradeIII Astrocytoma (15%). Patients were mostly seen to be belonging to Lower Assam region (46%) . Among all the patients in the study, surgery was done for 90% of patients while 10% did not undergo surgery. 61% of the patients took radiotherapy and chemotherapy, 22% took radiotherapy alone, 7% defaulted treatment(drop outs) and 10% didn’t turn up for treatment. All patients received a radiation dose of 54-60 Gy. A total of 41 patients took adjuvant chemotherapy with Temozolomide. Conclusion: Glioblastoma Multiforme and Astrocytoma are the most common brain tumours in our study. Multimodality management including surgery, radiotherapy and chemotherapy is the cornerstone in the management of brain tumours.

Toward Right Ventricle Segmentation in Cardiac MRIs via Feature Multiplexing and Multiscale Weighted Convolution.

Cardiovascular diseases are the leading cause of mortality, and accurate segmentation of ventricular regions in cardiac magnetic resonance images (MRIs) is crucial for diagnosing and treating these diseases. However, fully automated and accurate right ventricle (RV) segmentation remains challenging due to the irregular cavities with ambiguous boundaries and mutably crescentic structures with relatively small targets of the RV regions in MRIs. In this article, a triple-path segmentation model, called FMMsWC, is proposed by introducing two novel image feature encoding modules, i.e., the feature multiplexing (FM) and multiscale weighted convolution (MsWC) modules, for the RV segmentation in MRIs. Considerable validation and comparative experiments were conducted on two benchmark datasets, i.e., the MICCAI2017 Automated Cardiac Diagnosis Challenge (ACDC), and the Multi-Centre, Multi-Vendor & Multi-Disease Cardiac Image Segmentation Challenge (M&MS) datasets. The FMMsWC outperforms state-of-the-art approaches, and its performance can approach that of the manual segmentation results by clinical experts, facilitating accurate cardiac index measurement for the rapid assessment of cardiac function and aiding diagnosis and treatment of cardiovascular diseases, which has great potential for clinical applications.

Ablation of left ventricle summit PVCs using guidewire and 2F octapolar microcatheter mapping

Abstract Funding Acknowledgements Type of funding sources: None. Background Ventricular arrhythmias originating in the left ventricular summit region are especially difficult to map and ablate. The development of microcatheters allows access to the septal coronary venous system, which facilitates its mapping. Purpose To describe the strategy for mapping and ablation of ventricular LV-Summit extrasystoles in the first 6 cases at our center, performed using a 2F octapolar microcatheter, as well as the results obtained. Methods 6 cases of left ventricular summit PVCs were recruited between January 2019 and October 2022. TTE and/or MRI were performed as well as initial Holter, evidencing a high density of PVCs. The studies were carried out with intracardiac echo and anatomical reconstruction with a navigator. The coronary sinus was cannulated with a 6F guide catheter for venography. Mapping of the septal coronary venous system was performed with a 4F vertebral catheter and angioplasty guidewire, connecting the guidewire to the polygraph where good precocity (up to -30 ms) was obtained with a QS pattern in the monopolar lead during PVCs. An octapolar catheter was advanced, obtaining maximum precocity and appreciating fragmented late potentials and local abnormal ventricular activities (LAVA) during sinus rhythm with greater precocity during extrasystole and achieving a topostimulation of 95% concordance with PVCs. Radiofrequency applications were made with an irrigated contact catheter in the areas facing the octapolar catheter until acute suppression of PVC was achieved and its absence was verified after infusion of isoprenaline. Results The mean age of the sample was 60 years, 3 of them women, with a mean LVEF of 51% and a daily average of PVCs of 17.28%. Three of the patients had previously studied cardiomyopathies. After ablation, antiarrhythmics were stopped in 80% of cases and beta-blockers in 40%. The percentage of PVCs was significantly reduced (mean after the procedure 4.4%, p = 0.04) with a single recurrence at follow-up. No complications were recorded. Conclusions The microcatheter-guided ablation of the septal coronary venous system is a safe and effective procedure for the removal of left ventricular summit PVCs.

PO-04-072 THERMOCHROMIC HEART PHANTOM TO MODEL RADIOFREQUENCY ABLATION

We have previously developed a conductive hydrogel for use as an intermediate between heart tissue and catheter tips in cardiac ablation, providing a more uniform and precisely shaped lesion with the goal of minimizing the occurrence of steam pops and repeat procedures in arrythmia patients. Characterization of the gel has involved the repeated use of porcine hearts for an approximation of ablation behavior in human models. As this gel will require testing and iterative development to characterize its performance in ablation, a more conservative, safe, and affordable model of the heart is paramount. The heart phantom is to mimic the visible formation of lesions in ventricular myocardial tissue upon contact with a catheter that imparts radiofrequency (RF) energy. To predict lesion formation as mediated with the hydrogel, we seek to produce a heart model with similar thermally conductive properties as myocardial tissue. Various gel materials were prepared and evaluated for similarity to physiological myocardium, visual appeal, and ease of use for multiple trials, among other factors. Each gel was mixed with a thermochromic pigment (transition temperature of 60 C) and placed in a water bath of normal saline at 37 C for at least ten minutes for temperature equilibration. Preliminary tests were conducted with bare catheters alone instead of with hydrogel. An RF generator was set to 30 then 50 Watts, then Thermocool SF non-irrigated catheters were lightly applied to the gel surface in the saline bath for thirty seconds (Fig 1C). Lesions (white) are formed as shown in the figure for tests with silicone and black pigment, the most successful material combination thus far (Fig 1A and 1B). Compared to lesions formed in prior ex vivo experiments with ventricular myocardial tissue, the width and depth of the lesions formed in the gel model varied up to 22% and 76% from the ex vivo values, respectively. A thermochromic phantom heart for lesion characterization is feasible. Further development of this model seeks to better mimic myocardial tissue by selecting or synthesizing a material that matches the heart's experimental thermal conductivity and designing the phantom to contain similar anatomical compartments as in the left ventricular region. Once the phantom material displays lesions approximately equal in size to those formed in heart tissue, it may be used as a substitute for further characterization of the conductive hydrogel.

Reduced inferior wall longitudinal strain is associated with malignant arrhythmias in non-ischemic heart failure.

Reduced systolic myocardial function in the inferior region of the left ventricle has been suggested to be associated with malignant arrhythmias. We tested this hypothesis in patients with non-ischemic heart failure. Patients with non-ischemic heart failure (left ventricular ejection fraction [LVEF]<35%) were evaluated by 2D-speckle-tracking echocardiography. The regional longitudinal strain was calculated for each of the six left ventricular walls. The reduced regional function was defined as strain below the median. The outcome was a composite of sudden cardiac death, admission with sustained ventricular arrhythmia, resuscitated cardiac arrest, and appropriate therapy from a primary prophylactic implantable cardioverter defibrillator. Time-to-first-event analysis was performed using a Cox model. From two centers, 401 patients were included (median age: 63 years, 72% male) with a median LVEF of 25% (interquartile range [IQR] 20;30), and a median inferior wall strain of -9.0% (-12.5; -5.4). During a median follow-up of 4.0 years, 52 outcomes occurred. After multivariate adjustment for clinical and electrocardiographic parameters, inferior wall strain was independently associated with the outcome (HR 2.50 [1.35; 4.62], p=.003). No independent association was found between the composite outcome and reduced strain in any of the other left ventricular walls, Global Longitudinal Strain (HR 1.66 [0.93; 2.98], p=.09), or LVEF (HR 1.33 [0.75; 2.33], p=.33). Below median strain in the left ventricular inferior region was independently associated with a 2.5-fold increase in the risk of malignant arrhythmias and sudden cardiac death in patients with non-ischemic heart failure.

Ablation of ventricular arrhythmias in cardiogenetic diseases.

Sudden cardiac death is a leading cause of mortality, claiming millions of lives every year. Recent advances in cardiac arrhythmia mapping have demonstrated that the ventricular epicardial region has a critical arrhythmogenic role in some inherited cardiogenetic diseases. Historically, electroanatomic abnormalities have been identified in the ventricular epicardium of patients with arrhythmogenic right ventricular cardiomyopathy. More recently, epicardial pathological substrates have been identified also in electrical disease (Brugada syndrome, early repolarization syndrome) and currently in long QT syndrome. In light of these findings, the epicardial area has emerged as an important determinant in sudden cardiac death-related cardiomyopathies.

Bi-DCNet: Bilateral Network with Dilated Convolutions for Left Ventricle Segmentation.

Left ventricular segmentation is a vital and necessary procedure for assessing cardiac systolic and diastolic function, while echocardiography is an indispensable diagnostic technique that enables cardiac functionality assessment. However, manually labeling the left ventricular region on echocardiography images is time consuming and leads to observer bias. Recent research has demonstrated that deep learning has the capability to employ the segmentation process automatically. However, on the downside, it still ignores the contribution of all semantic information through the segmentation process. This study proposes a deep neural network architecture based on BiSeNet, named Bi-DCNet. This model comprises a spatial path and a context path, with the former responsible for spatial feature (low-level) acquisition and the latter responsible for contextual semantic feature (high-level) exploitation. Moreover, it incorporates feature extraction through the integration of dilated convolutions to achieve a larger receptive field to capture multi-scale information. The EchoNet-Dynamic dataset was utilized to assess the proposed model, and this is the first bilateral-structured network implemented on this large clinical video dataset for accomplishing the segmentation of the left ventricle. As demonstrated by the experimental outcomes, our method obtained 0.9228 and 0.8576 in DSC and IoU, respectively, proving the structure's effectiveness.

Left ventricular deformation: similarities and dissimilarities in elite sport activity- and acromegaly-related abnormalities.

Acromegaly is a chronic endocrine disorder, which produces a significant amount of human growth hormone and consequently insulin-like growth factor in adulthood due to a tumor in the pituitary gland. If left untreated, it can have a significant effect on the cardiovascular system. It is also known that elite sport activity is also associated with physiologic cardiac transformation, the so-called athletes' heart, in which volumetric and functional adaptation of the heart cavities can be observed. In accordance with the above facts, the question may rightly arise as to what differences can be observed in left ventricular morphology and function in acromegaly, and what similarities and dissimilarities do the obtained results show compared to the values of healthy non-athlete adults compared to the values of the left ventricle of young elite athletes. The present study comprised 21 elite athletes playing high dynamic sports (mean age: 31.2 ± 6.4 years, 13 males) and 18 acromegaly patients (mean age: 47.9 ± 8.9 years, 9 males). Their results were compared to those of 22 negative controls (mean age: 47.7 ± 10.6 years, 13 males). Left ventricle is dilated, but its function is preserved in both elite athletes and patients with acromegaly. While increased longitudinal and circumferential left ventricular strains could be seen in elite athletes primarily due to the more pronounced contractility of left ventricular apical segments, increased radial left ventricular strain was detected in acromegaly due to increased function of the left ventricular basal region. Left ventricular rotational mechanics show different patterns as well: while basal left ventricular rotation is decreased in elite athletes, apical left ventricular rotation showed a reduction leading to the significant deterioration of left ventricular twist in acromegaly. Both elite athletes playing high dynamic sports and acromegaly patients have dilated left ventricle, more pronounced regional left ventricular contractility and left ventricular rotational abnormalities with differences in nature and extent of these alterations as compared to those of non-sporting healthy subjects. Orv Hetil. 2023; 164(8): 308-316.

Computational Modeling of Thermodynamical Pulsatile Flow with Uncertain Pressure in Hydrocephalus

The watery cerebrospinal fluid that flows in the subarachnoid space (SAS) surrounds the entire central nervous system via symmetrical thermo-solute flow. The significance of this study was to present a flexible simulation based on theoretical vivo inputs onto a mathematical framework to describe the interaction of cerebrospinal fluid circulation restricted to a pathological disorder. The pathophysiology disorder hydrocephalus is caused by an enormous excess of asymmetric fluid flow in the ventricular region. This fluid imposition increases the void space of its boundary wall (Pia mater). As a result, the dumping effect affects an inertial force in brain tissues. A mathematical model was developed to impose the thermal dynamics of hydrocephalus, in which solute transport constitutes the excess watery CSF fluid caused by hydrocephalus, in order to demonstrate perspective changes in ventricular spaces. This paper investigated brain porous spaces in order to strengthen the acceleration and thermal requirements in the CNS mechanism. To characterize neurological activities, a unique mathematical model that includes hydrodynamics and nutrient transport diffusivity was used. We present the analytical results based on physical experiments that use the novel Laplace method to determine the nutrients transported through permeable pia (brain) parenchyma with suitable pulsatile boundary conditions. This causes high CSF pressure and brain damage due to heat flux over the SAS boundary wall. As a result of the increased Schmidt number, the analysis of the hydrocephalus problem revealed an increase in permeability and drop in solute transport. A high-velocity profile caused a rise in thermal buoyancy (Grashof number). When the CSF velocity reached an extreme level, it indicated a higher Womersley number. Additionally, the present study compared a number of clinical studies for CSF amplitude and pressure. We validated the results by providing a decent justification with the clinical studies by appropriate field references.

Cardiac MRI Segmentation Using Efficient ResNeXT-50-Based IEI Level Set and Anisotropic Sigmoid Diffusion Algorithms

Endocardial and epicardial border identification has been of extensive interest in cardiac Magnetic Resonance Images (MRIs). It is a difficult job to segment the epicardium and endocardium accurately and automatically from cardiac MRI owing to the cardiac tissues’ complexity even though the prevailing Deep Learning (DL) methodologies had attained significant success in medical imaging segmentation. Hence, by employing effectual ResNeXT-50-centric Inverse Edge Indicator Level Set (IEILS) and anisotropic sigmoid diffusion algorithms, this system has proposed cardiac MRI segmentation. The work has endured some function for an effectual partition of epicardium and endocardium. Initially, by employing the Truncated Kernel Function (TK)-Trilateral Filter, the noise removal function is executed on the input cardiac MRI. Next, by wielding the ResNeXT-50 IEILS, the Left and Right Ventricular (LV/RV) regions are segmented. The epicardium and endocardium are segmented by the ASD algorithm once the LV/RV is separated from the Left Ventricle (LV) region. Here, the openly accessible Sunnybrook and the Right Ventricle (RV) datasets are wielded. Then, the prevailing state-of-art algorithms are analogized to the outcomes achieved by the proposed framework. Regarding accuracy, sensitivity, and specificity, the proposed methodology executed the cardiac MRI segmentation process precisely along with the other surpassed state-of-the-art methodologies.

Fully automated cardiac MRI segmentation using dilated residual network.

Cardiac ventricle segmentation from cine magnetic resonance imaging (CMRI) is a recognized modality for the noninvasive assessment of cardiovascular pathologies. Deep learning based algorithms achieved state-of-the-art result performance from CMRI cardiac ventricle segmentation. However, most approaches received less attention at the bottom layer of UNet, where main features are lost due to pixel degradation. To increase performance, it is important to handle the bottleneck layer of UNet properly. Considering this problem, we enhanced the performance of main features at the bottom layer of network. We developed a fully automatic pipeline for segmenting the right ventricle (RV), myocardium (MYO), and left ventricle (LV) by incorporating short-axis CMRI sequence images. We propose a dilated residual network (DRN) to capture the features at full resolution in the bottleneck of UNet. Thus, it significantly increases spatial and temporal information and maintains the localization accuracy. A data-augmentation technique is employed to avoid overfitting and class imbalance problems. Finally, output from each expanding path is added pixel-wise to improve the training response. We used and evaluated our proposed method on automatic cardiac diagnosis challenge (ACDC). The test set consists of 50 patient records. The overall dice similarity coefficient (DSC) we achieved for our model is 0.924 ± 0.03, 0.907 ± 0.01, and 0.949 ± 0.05 for RV, MYO, and LV, respectively. Similarly, we obtained hausdorff distance (HD) scores of 10.09 ± 0.01, 7.25 ± 0.05, and 6.86 ± 0.02 mm for RV, MYO, and LV, respectively. The results show superior performance and outperformed state-of-the-art methods in terms of accuracy and reached expert-level segmentation. Consequently, the overall DSC and HD result improved by 1.0% and 1.5%, respectively. We designed a dilated residual UNet (DRN) for cardiac ventricle segmentation using short-axis CMRI. Our method has the advantage of restoring and capturing spatial and temporal information by expanding the receptive field without degrading the image main features in the bottleneck of UNet. Our method is highly accurate and quick, taking 0.28 s on average to process 2D MR images. Also, the network was designed to work on predictions of individual MR images to segment the ventricular region, for which our model outperforms many state-of-the-art methods.

Cardiac Troponin I-Interacting Kinase Affects Cardiomyocyte S-Phase Activity but Not Cardiomyocyte Proliferation.

Identifying genetic variants that affect the level of cell cycle reentry and establishing the degree of cell cycle progression in those variants could help guide development of therapeutic interventions aimed at effecting cardiac regeneration. We observed that C57Bl6/NCR (B6N) mice have a marked increase in cardiomyocyte S-phase activity after permanent coronary artery ligation compared with infarcted DBA/2J (D2J) mice. Cardiomyocyte cell cycle activity after infarction was monitored in D2J, (D2J×B6N)-F1, and (D2J×B6N)-F1×D2J backcross mice by means of bromodeoxyuridine or 5-ethynyl-2'-deoxyuridine incorporation using a nuclear-localized transgenic reporter to identify cardiomyocyte nuclei. Genome-wide quantitative trait locus analysis, fine scale genetic mapping, whole exome sequencing, and RNA sequencing analyses of the backcross mice were performed to identify the gene responsible for the elevated cardiomyocyte S-phase phenotype. (D2J×B6N)-F1 mice exhibited a 14-fold increase in cardiomyocyte S-phase activity in ventricular regions remote from infarct scar compared with D2J mice (0.798±0.09% versus 0.056±0.004%; P<0.001). Quantitative trait locus analysis of (D2J×B6N)-F1×D2J backcross mice revealed that the gene responsible for differential S-phase activity was located on the distal arm of chromosome 3 (logarithm of the odds score=6.38; P<0.001). Additional genetic and molecular analyses identified 3 potential candidates. Of these, Tnni3k (troponin I-interacting kinase) is expressed in B6N hearts but not in D2J hearts. Transgenic expression of TNNI3K in a D2J genetic background results in elevated cardiomyocyte S-phase activity after injury. Cardiomyocyte S-phase activity in both Tnni3k-expressing and Tnni3k-nonexpressing mice results in the formation of polyploid nuclei. These data indicate that Tnni3k expression increases the level of cardiomyocyte S-phase activity after injury.

Shark Fin Electrocardiogram in the Intensive Care Unit.

Shark Fin Electrocardiogram in the Intensive Care Unit.

New echocardiographic approaches to differentiate cardiac amyloidosis and Fabry disease: the right heart and mitral valve thickness

Abstract Background Infiltrative cardiomyopathies such as cardiac amyloidosis (CA) and Fabry disease (FD) are associated with high cardiovascular morbidity and mortality. Diagnosis is often challenging as CA and FD may present similar cardiac phenotypes on standard echocardiographic imaging, especially in early stages of disease. Purpose Our study focuses on right ventricular (RV) two-dimensional speckle tracking imaging and mitral valve thickness as diagnostic strategies to discriminate CA from FD. Here, we report preliminary data of our study registry of CA and FD patients. Methods We retrospectively screened patients with diagnosed CA or with genetically confirmed FD from our study registry. Global and free wall RV strain and mitral leaflet thickening in both groups were analysed using 2D speckle tracking echocardiography and linear measurements from a parastenal long axis view, respectively (Vivid E9 or E95, GE Vingmed, Horton, Norway, M5S 1.5–4.5MHz transducer). The diagnostic accuracy for discriminating CA and FD in both groups was evaluated using receiver operating characteristic (ROC) curve analysis. Results A total of 33 FD and 27 CA patients, including 17 patients with wild-type transthyretin-related (ATTR) CA, 8 patients with hereditary ATTR CA, one patient with light chain CA, and one patient with AA CA, were included. RV function was significantly reduced in CA compared to FD patients as measured by global longitudinal RV strain (−13.6±5.1 in CA vs. −18.4±3.9 in FD, p&amp;lt;0.001) and free wall longitudinal RV strain (−17.5±5.7 in CA vs. −21.3±4.4 in FD, p=0.005). Significantly lower longitudinal RV strain was observed in the basal to mid ventricular region in CA compared to FD patients, while RV apical strain was not significantly different between the two groups. RV global longitudinal strain had the highest diagnostic accuracy of strain analyses (area under the curve [AUC] 0.79, 95% confidence interval [CI] 0.66–0.93) to discriminate CA from FD. Additional measurement of the mitral valve in mid diastole in the parasternal long axis view revealed a significantly thickened leaflet in CA patients (4.6±1.2 mm in CA vs. 2.9±1.0 mm in FD, p&amp;lt;0.001) corresponding to an AUC of 0.84 (95% CI 0.72–0.96) in ROC analysis. Conclusion Global longitudinal RV strain was significantly reduced in CA patients while the mitral valve leaflets were significantly thickened compared to FD patients. Therefore, both parameters may be useful to discriminate CA from FD in the echocardiographic workup of patients with unclear left ventricular wall thickening. Funding Acknowledgement Type of funding sources: Other. Main funding source(s): Alnylam Pharmaceuticals (Cambridge, MA, USA)

Relative Apical Sparing of Longitudinal Strain in Cardiac Amyloidosis: An Intervendor Software Variability Assessment

The relative sparing of regional longitudinal strain (LS) in the apex compared to the mid and basal left ventricular (LV) regions is a valuable clue in the echocardiographic detection of cardiac amyloidosis (CA).1 Phelan et al.2 found that a relative apical strain ratio (RASR) threshold of 2, defined as the mean apical LS being twice the mean strain in the remainder of the heart using EchoPAC postprocessing software (General Electric Medical Systems), was highly sensitive and specific for the diagnosis of CA.