Spatial orientation of the ventricular muscle band: physiologic contribution and surgical implications

Acute Right Ventricular Dysfunction in Intensive Care Unit

The role of the left ventricle in ICU patients with circulatory shock has long been considered. However, acute right ventricle (RV) dysfunction causes and aggravates many common critical diseases (acute respiratory distress syndrome, pulmonary embolism, acute myocardial infarction, and postoperative cardiac surgery). Several supportive therapies, including mechanical ventilation and fluid management, can make RV dysfunction worse, potentially exacerbating shock. We briefly review the epidemiology, pathophysiology, diagnosis, and recommendations to guide management of acute RV dysfunction in ICU patients. Our aim is to clarify the complex effects of mechanical ventilation, fluid therapy, vasoactive drug infusions, and other therapies to resuscitate the critical patient optimally.

Design and Comparison of Large Vessel Stents: Balloon Expandable and Self-Expanding Peripheral Arterial Stents

Endovascular stenting has evolved over the last 50 years since its inception into the framework of management of vascular atherosclerotic disease. Stent design has evolved as lesion complexity has increased. Nevertheless, certain first principles regarding stent design have been recapitulated time and again with every iteration of endovascular stents. This article reviews principles of endovascular stent design and compares and contrasts key aspects of balloon expandable and self-expanding stents.

Effects of cellular electromechanical coupling on functional heterogeneity in a one-dimensional tissue model of the myocardium

Based on the experimental evidence, we developed a one-dimensional (1D) model of heterogeneous myocardial tissue consisting of in-series connected cardiomyocytes from distant transmural regions using mathematical models of subendocardial and subepicardial cells. The regional deformation patterns produced by our 1D model are consistent with the transmural regional strain patterns obtained experimentally in the normal heart in vivo. The modelling results suggest that the mechanical load may essentially affect the transmural gradients in the electrical and mechanical properties of interacting myocytes within a tissue, thereby regulating global myocardial output.

Electrocardiographic appearance of aortic stenosis before and after aortic valve replacement

BACKGROUND

So far, the specific appearance of QRS complex, ST-segment, and T wave was observed in aortic stenosis (AS). S-wave dynamic change in leads V₁ -V₃ was not reported in AS.

METHODS

In a single-center, prospective study, we included a total number of 1.175 patients who underwent surgical aortic valve replacement (AVR). We conducted 3-year gathering of patients with symptomatic and asymptomatic severe AS, and separated them by hemodynamic stability into groups A and B, through EFLV (of more or less than 50%), AVA (of more or less than 0.9 cm² ), PG (between 55 and 75 mm Hg or over 75 mm Hg), and end-diastolic LV dimension (of more or less than 56 mm). We evaluated the impact of S-wave magnitude in right precordial leads before and after AVR in all patients. We followed S-wave changes in electrocardiogram altogether with hemodynamic measurements derived from echocardiography.

RESULTS

Analysis of echocardiographic parameters, measured in patients before surgery, did not show statistical significance between asymptomatic and symptomatic group. The statistical significance was observed in the change in S-wave magnitude in the right precordial leads in both subsets of patients before AVR. We found statistically significant predictive value of S-wave magnitude in leads V₂ -V₃ for dependent variables PG and end-diastolic LV dimension.

CONCLUSIONS

S-wave changes in right precordial leads can predict increase in PG and critical narrowing of AVA, suggestive of timely referral for AVR.

Strain Imaging Echocardiography: What Imaging Cardiologists Should Know

Despite recent advances in clinical imaging, echocardiography remains as the most accessi-ble and reliable noninvasive. Since knowledge of left ventricular systolic function remains so critically important in determining prognosis; every effort should be made to prevent subjective estimations. The advent of strain imaging echocardiography now offers a readily available and portable imaging tool that not only offers an objective characterization of myocardial dynamics; but also allows for early detection of subclinical left ventricular dysfunction. This review outlines the basic concepts of strain imaging to better understand the mechanism of myocardial function as well their applicability in the least common cardiac diagnosis among current clinical practice.

Posterior ventricular restoration treatment for heart failure: a review, past, present and future aspects

Congestive heart failure (CHF) is one of the major causes of death and occurs in more than 15,000,000 patients worldwide. The incidence is expected to increase in parallel with the aging population. Most current therapies for CHF are medications, and biventricular pacing implantation as appropriated by cardiologists, or surgical interventions. The heart transplantation for indicated patients is still gold standard surgery although the 10-year survival rate is approximately 60% based on the worldwide data. However, the cardiac transplantation remains epidemiologically insignificant because of donor pool limitations. New strategies for treating CHF are needed. In addition to conventional cardiac surgery, surgical ventricular restoration was reported as a promising surgical therapy in 1990s. After the first report of partial left ventriculectomy in which posterior wall was widely resected for dilated heart, many controversial clinical and animal research studies have been reported. In this review, the principles of posterior cardiac restoration therapy will be discussed. An overview of posterior cardiac restoration, structure, and torsion are presented. By understanding the structure of cardiac muscle, shape, and torsion of left ventricle for surgical restoration, the procedure can be performed based on appropriate indication and this knowledge can be used to optimize and improve its efficacy. The use of mechanical support devices has recently become commonplace in many centers, and the use of implantable ventricular assist devices as destination therapy will increase. Surgeons will be able to select several options of the treatment for CHF by understanding the advantages and disadvantages of those surgical treatments.

Left ventricular rotational mechanics in infants with hypoxic ischemic encephalopathy and preterm infants at 36 weeks postmenstrual age: A comparison with healthy term controls

BACKGROUND AND AIMS

There is a paucity of data on left ventricle (LV) rotational physiology in neonates. We aimed to assess rotational mechanics in infants with hypoxic ischemic encephalopathy (HIE) and premature infants (<32 weeks) at 36 weeks postmenstrual age (PMA) (preterm group) and compare them with healthy term controls (term controls). We also compared the parameters in preterm infants with and without chronic lung disease (CLD).

METHODS

Echocardiography was performed within 48 hours of birth or at 36 weeks PMA. LV basal and apical rotation, twist (and torsion=twist/LV length), twist rate (LVTR), and untwist rate (LVUTR) were measured. One-way ANOVA was used to compare values.

RESULTS

There was no difference in gestation (40.0 [39.1-40.3] vs 39.9 [39.0-40.9], P>.05) or birthweight (3.7 [3.4-4.1] vs 3.5 [3.2-3.9], P>.05) between the HIE group (n=16) and term controls (n=30). The preterm group (n=35) had a gestation and weight of 36.0 [34.6-36.3] weeks and 2.3 [2.0-2.4] kg. The HIE group had lower twist, torsion, LVTR, and LVUTR than the other two groups. The preterm group had a more negative (clockwise) basal rotation while the term group had a more positive (counterclockwise) apical rotation. Preterm infants with CLD had higher apical rotation, twist, and torsion when compared to infants without CLD.

CONCLUSION

Infants with HIE have reduced rotational mechanics. Preterm infants at 36 weeks PMA have comparable measurements of twist to term infants. This is achieved by predominant basal rather than apical rotation. Infants with CLD have increased apical rotation.

Quantitative evaluation of longitudinal strain in layer-specific myocardium during normal pregnancy in China

Background

The myocardial wall of the left ventricle is a complex, multilayered structure and is not homogenous. The aim of this study was to determine longitudinal strain (LS) in the three myocardial layers in normal pregnant women according to gestation proceedings.

Methods

The advanced two-dimensional speckle tracking echocardiography (2D STE) was performed on 62 women during each pregnancy trimester and 6 to 9 weeks after delivery, while 30 age-matched, healthy, nonpregnant women served as controls. LS on endocardial, mid-myocardial and epicardial layers at 18 cardiac segments were measured.

Results

As gestation proceeded, all of layer-specific LS and global LS progressively decreased, which subsequently recovered postpartum (P < 0.05), and the LS gradient between inner and outer myocardium became greater, which reached its maximum in the late pregnancy. Peak systolic LS was the highest at endocardium and the lowest at epicardium, while the highest at the apical level and the lowest at the base (P < 0.05). In the early pregnancy and postpartum, LS at basal level was homogenous, meanwhile layer-specific LS showed significant differences at mid-ventricular and apical level throughout the progress of normal pregnancy (P < 0.05).

Conclusions

Using 2D STE, three-layer assessment of LS can be performed in pregnant women and shall give us new insights into the quantitative analysis of global and regional LV function during pregnancy. Future studies on the detection of pregnancy related heart disease would require these parameters as reference values for each time point of a normal pregnancy.

Prospective validation of right ventricular role in primary graft dysfunction after lung transplantation

Primary graft dysfunction is a significant cause of lung transplant morbidity and mortality, but its underlying mechanisms are not completely understood. The aims of the present study were: 1) to confirm that right ventricular function is a risk factor for severe primary graft dysfunction; and 2) to propose a clinical model for predicting the development of severe primary graft dysfunction.A prospective cohort study was performed over 14 months. The primary outcome was development of primary graft dysfunction grade 3. An echocardiogram was performed immediately before transplantation, measuring conventional and speckle-tracking parameters. Pulmonary artery catheter data were also measured. A classification and regression tree was made to identify prognostic models for the development of severe graft dysfunction.70 lung transplant recipients were included. Patients who developed severe primary graft dysfunction had better right ventricular function, as estimated by cardiac index (3.5±0.8 versus 2.6±0.7 L·min^-1·m^-2, p<0.01) and basal longitudinal strain (-25.7±7.3% versus -19.5±6.6%, p<0.01). Regression tree analysis provided an algorithm based on the combined use of three variables (basal longitudinal strain, pulmonary fibrosis disease and ischaemia time), allowing accurate preoperative discrimination of three distinct subgroups with low (11-20%), intermediate (54%) and high (75%) risk of severe primary graft dysfunction (area under the receiver operating characteristic curve 0.81).Better right ventricular function is a risk factor for the development of severe primary graft dysfunction. Preoperative estimation of right ventricular function could allow early identification of recipients at increased risk, who would benefit the most from careful perioperative management in order to limit pulmonary overflow.

Diastolic Filling Reserve Preservation Using a Semispherical Dacron Patch for Repair of Anteroapical Left Ventricular Aneurysm

In postinfarction left ventricular aneurysm, abnormal geometry and desynchronized wall motion may cause a highly inefficient pump function. The traditional endoventricular patch plasty according to the Dor technique might result in a truncated and restrictive left ventricular cavity in small adults. We report a modified technique of left ventricular anteroapical aneurysm repair by using a semispherical reshaping patch to restore the left ventricular geometry.

Left Ventricular Systolic Function Changes in Primary Hypertension Patients Detected by the Strain of Different Myocardium Layers

This study investigated left ventricular (LV) systolic dysfunction associated with differential strain among myocardial layers in primary hypertension (PH) patients with or without LV hypertrophy (LVH), and normal patients.In 63 PH and 42 healthy patients, two-dimensional speckle tracking echocardiography was used to measure the peak systolic longitudinal and circumferential strain of the myocardial subendocardial, middle and subepicardial layers, and the peak systolic radial strain. To assess LV systolic function, the apical long axis, 4- and 2-chamber views, and parasternal short axis at the basal, middle, and apical levels were acquired by cardiovascular ultrasound (Vivid E9, GE Healthcare, USA).Overall, the pattern in peak systolic longitudinal strain among myocardial layers was subendocardial > middle > subepicardial. In the peak systolic circumferential strain, this was middle > subepicardial > subendocardial. The peak systolic longitudinal strain was normal > NLVH > LVH. Among the groups, the peak systolic circumferential strain at the basal parasternal short-axis level was statistically similar, but at the middle and the apical parasternal short-axis levels were NLVH > normal > LVH. In normal and NLVH patients, the peak radial strain was middle > apical > basal, and in LVH patients was apical > middle > basal. The peak averages of the longitudinal and subendocardial circumferential strains differed significantly when LVH compared with NLVH and normal patients.The systolic function of PH patients was damaged in comparison with normal individuals, which could be detected conveniently and accurately using two-dimensional speckle tracking echocardiography.

RV diastolic dysfunction: time to re-evaluate its importance in heart failure

Right ventricular (RV) diastolic dysfunction was first reported as an indicator for the assessment of ventricular dysfunction in heart failure a little over two decades ago. However, the underlying mechanisms and precise role of RV diastolic dysfunction in heart failure remain poorly described. Complexities in the structure and function of the RV make the detailed assessment of the contractile performance challenging when compared to its left ventricular (LV) counterpart. LV dysfunction is known to directly affect patient outcome in heart failure. As such, the focus has therefore been on LV function. Nevertheless, a strategy for the diagnosis and assessment of RV diastolic dysfunction has not been established. Here, we review the different causal mechanisms underlying RV diastolic dysfunction, summarising the current assessment techniques used in a clinical environment. Finally, we explore the role of load-independent indices of RV contractility, derived from the conductance technique, to fully interrogate the RV and expand our knowledge and understanding of RV diastolic dysfunction. Accurate assessment of RV contractility may yield further important prognostic information that will benefit patients with diastolic heart failure.

The cardiac torsion as a sensitive index of heart pathology: A model study

The torsional behaviour of the heart (i.e. the mutual rotation of the cardiac base and apex) was proved to be sensitive to alterations of some cardiovascular parameters, i.e. preload, afterload and contractility. Moreover, pathologies which affect the fibers architecture and cardiac geometry were proved to alter the cardiac torsion pattern. For these reasons, cardiac torsion represents a sensitive index of ventricular performance. The aim of this work is to provide further insight into physiological and pathological alterations of the cardiac torsion by means of computational analyses, combining a structural model of the two ventricles with simple lumped parameter models of both the systemic and the pulmonary circulations. Starting from diagnostic images, a 3D anatomy based geometry of the two ventricles was reconstructed. The myocytes orientation in the ventricles was assigned according to literature data and the myocardium was modelled as an anisotropic hyperelastic material. Both the active and the passive phases of the cardiac cycle were modelled, and different clinical conditions were simulated. The results in terms of alterations of the cardiac torsion in the presence of pathologies are in agreement with experimental literature data. The use of a computational approach allowed the investigation of the stresses and strains in the ventricular wall as well as of the global hemodynamic parameters in the presence of the considered pathologies. Furthermore, the model outcomes highlight how for specific pathological conditions, an altered torsional pattern of the ventricles can be present, encouraging the use of the ventricular torsion in the clinical practice.

Haemodynamics and Flow Modification Stents for Peripheral Arterial Disease: A Review

Endovascular stents are widely used for the treatment of peripheral arterial disease (PAD). However, the development of in-stent restenosis and downstream PAD progression remain a challenge. Stent revascularisation of PAD causes arterial trauma and introduces abnormal haemodynamics, which initiate complicated biological processes detrimental to the arterial wall. The interaction between stent struts and arterial cells in contact, and the blood flow field created in a stented region, are highly affected by stent design. Spiral flow is known as a normal physiologic characteristic of arterial circulation and is believed to prevent the development of flow disturbances. This secondary flow motion is lost in atheromatous disease and its re-introduction after endovascular treatment of PAD has been suggested as a method to induce stabilised and coherent haemodynamics. Stent designs able to generate spiral flow may support endothelial function and therefore increase patency rates. This review is focused on secondary flow phenomena in arteries and the development of flow modification stent technologies for the treatment of PAD.

Multimodality Evaluation of the Right Ventricle: An Updated Review

The assessment of the volumes, function, and mechanics of the right ventricle (RV) is very challenging because of the anatomical complexity of the RV. Because RV structure, function, and deformation are very important predictors of cardiovascular morbidity and mortality in patients with heart failure, pulmonary hypertension, congenital heart disease, or arrhythmogenic RV cardiomyopathy, it is of great importance to use an appropriate imaging modality that will provide all necessary information. In everyday clinical practice, 2-dimensional echocardiography (2DE) represents a method of first choice in RV evaluation. However, cardiac magnetic resonance (CMR) remained the gold standard for RV assessment. The development of new imaging tools, such as 3-dimensional echocardiography (3DE), provided reliable data, comparable with CMR, and opened a completely new era in RV imaging. So far, 3DE has shown good results in determination of RV volumes and systolic function, and there are indications that it will also provide valuable data about 3-dimensional RV mechanics, similar to CMR. Two-dimensional echocardiography-derived strain is currently widely used for the assessment of RV deformation, which has been proven to be a more significant predictor of functional capacity and survival than CMR-derived RV ejection fraction. The purpose of this review is to summarize currently available data about RV structure, function, and mechanics obtained by different imaging modalities, primarily 2DE and 3DE, and their comparison with CMR and cardiac computed tomography.

Measurement of ventricular three-dimensional torsion

BACKGROUND

In this study, three-dimensional torsion angle of myocardium was extracted by two-dimensional images of the left ventricle at three levels of base, mid, and apex of interventricular septum wall.

METHODS

Two-dimensional echocardiography images of long- and short-axis views of healthy men were synchronized using an electrocardiogram of each individual and processed. Interventricular septum wall motion at three levels of base, mid, and apex were measured using a motion-detection algorithm throughout three cardiac cycles. Considering position vectors in long and short-axis views, the three-dimensional torsion angle is extracted throughout the cardiac cycle.

RESULTS

The average and standard deviation of Φ(M) during three cardiac cycles for interventricular septal wall in healthy individuals in this study are estimated as 16.3 ± 3.0° at base level, 22.8 ± 5.0° at mid level, and 14.6 ± 5.8° at apex level of septum wall, respectively.

CONCLUSIONS

This angle suggested for examination of regional and global biomechanical behavior of myocardium in different pathologic conditions.

Left ventricular subclinical dysfunction associated with myocardial deformation changes in obstructive sleep apnea patients estimated by real-time 3D speckle-tracking echocardiography

BACKGROUND

Previous studies have demonstrated that patients with obstructive sleep apnea (OSA) may develop left ventricular (LV) diastolic dysfunction. We aimed to study whether OSA patients have LV regional systolic dysfunction with myocardial deformation changes, despite a normal LV ejection fraction, using real-time 3D speckle-tracking echocardiography (Rt3D-STE).

METHODS

Seventy-eight patients with OSA and no comorbidities were studied. They were divided into the following three groups according to the apnea-hypopnea index (AHI): 5~15/h as group I (mild OSA, 26 cases), 15~30/h as group II (moderate OSA, 29 cases), and ≥30/h as group III (severe OSA, 23 cases). Thirty gender-age-matched normal subjects were included as controls. The parameters of LV diastolic function were acquired with traditional echocardiography. The LV myocardial deformation parameters were obtained, including the longitudinal (LS), circumferential (CS), radial (RS), and area (AS) strains, with Rt3D-STE.

RESULTS

LV global systolic function was normal in all patients, but diastolic function was impaired in groups II and III (E/E' was 9.6 ± 2.8 and 10.4 ± 2.5, respectively, p < 0.0001). The global LS and AS were significantly reduced in groups II and III compared with the controls and group I (LS 15.9 ± 1.4 % and 14.8 ± 1.5 % vs 18.2 ± 1.7 % and 17.8 ± 1.5 %; AS 27.4 ± 1.8 % and 24.9 ± 2.3 % vs 33.4 ± 2.2 % and 32.7 ± 2.9 %, respectively, p < 0.0001), but the global CS and RS were significantly reduced only in group III (17.3 ± 1.4 % and 43.1 ± 6.5 % vs 19.6 ± 1.6 % and 55.4 ± 4.0 %, respectively, <0.0001). The severity of OSA was significantly associated with the LV global AS value (r = -0.80, p < 0.0001), LS (r = -0.64, p < 0.0001), CS (r = -0.51, p < 0.0001), and RS (r = -0.62, p < 0.0001).

CONCLUSIONS

Patients with moderate and severe OSA tended to have both LV diastolic dysfunction and abnormalities in regional systolic function with myocardial deformation changes, in spite of the normal LV ejection fraction. Myocardial strains of the LV were negatively correlated with the AHI. Rt-3DST had important clinical significance in the early evaluation of cardiac dysfunction in OSA patients.

Two-Dimensional Strain Imaging: Basic principles and Technical Consideration

Tissue Doppler Imaging (TDI) and TDI-derived strain provide considerably accurate information in the non-invasive assessment of local myocardial functions. Given its high temporal and spatial resolution, TDI allows assessment of local myocardial functions in each phase of cardiac cycle. However, the most important limitation of this method is its angle dependence. New techniques to measure myocardial deformation, such as speckle tracking echocardiography, overcome the angle-dependence limitation of TDI-derived strain. Moreover, these techniques provide more unique information about myocardial fiber orientation. This review examines the architectural structure and function of the myocardium and includes technical revisions of this information that will provide a basis for STE.

Hemodialysis-associated cardiomyopathy: a newly defined disease entity

Cardiovascular disease is the most common cause of the greatly elevated rates of mortality characteristic of patients undergoing maintenance hemodialysis. This article is an attempt to describe the complex and evolving features of cardiac disease routinely encountered in HD patients. Furthermore, by trying to appreciate the pathophysiological drivers, and the crucial interaction with the HD treatment itself, this article seeks to define cardiac disease in this setting (HD-associated cardiomyopathy) as a unique and complex entity. By understanding the phenotype and basis of HD-associated cardiomyopathy, we can develop an evolved understanding of the dominant processes involved in its development and offer up dialysis-based interventions specifically designed to mitigate the cumulative ischemic insults consequent to conventional HD treatment. This article explores the justification of this approach and recent evidence of its efficacy.

Kinetics of left ventricular rotation during exercise and its relation to exercise tolerance in atrial fibrillation: assessment by two-dimensional speckle tracking echocardiography

BACKGROUND

Left ventricular (LV) rotation plays an important role in cardiac function both at rest and during exercise in sinus rhythm. The kinetics of rotation during exercise and the relation between exercise tolerance and rotation-related parameters in patients with atrial fibrillation (AF) are unknown.

METHODS

Twenty-nine patients (age 62 ± 13 years, 6 females) with AF and preserved LV ejection fraction (LVEF) were studied using two-dimensional speckle tracking echocardiography at rest and during exercise with a supine bicycle ergometer (20 W, 10 min). We measured the systolic rotation (Rot) and the peak rotation rate in systole and early diastole (eRotR) at the apical and basal levels of the LV. All patients underwent cardiopulmonary exercise testing to obtain their percent achieved of the predicted peak oxygen consumption (% peak VO2) value.

RESULTS

During exercise, apical Rot-related indices were significantly increased only in the preserved % peak VO2 group. In contrast, E/e' was significantly elevated only in the reduced % peak VO2 group. Multivariable stepwise regression analysis showed that apical ΔRot was independently associated with % peak VO2 (β = 0.72; p < 0.01). Apical ΔeRotR, which could not be selected as an independent predictor of % peak VO2, had a good linear correlation with apical ΔRot (r = 0.81, p < 0.01).

CONCLUSIONS

The augmentation of apical rotation in response to exercise may coincide with an increase of the apical derotation rate, and apical rotation reserve may reflect exercise tolerance in patients with AF and preserved LVEF.

Ventricular structure-function relations in health and disease: part II. Clinical considerations

Normal cardiac function of the left and right ventricles, together with the septum, is related to form/function interactions within the helical ventricular myocardial band. This knowledge is a prerequisite to understanding form/function interactions in diseases and for planning new treatments. Topics discussed include congestive heart failure in dilated hearts of ischaemic, valvar or nonischaemic origin as well as diastolic dysfunction. Similar thinking underlies novel treatments for dyssynchrony in pacing, together with focusing upon varying global left or right ventricular anatomy to correct mitral and tricuspid insufficiency caused by tethering of the leaflets. The septum is the lion of the right ventricle and insight is provided into offsetting septal damage during cardiac surgery, rebuilding its anatomical structure in post-tetralogy pulmonary insufficiency, as well as rectifying its dysfunction by decompression in patients with a left ventricular assist device.

Targeting survival pathways to create infarct-spanning bridges of human embryonic stem cell-derived cardiomyocytes

OBJECTIVE

Generating myocyte grafts that bridge across infarcts could maximize their functional impact and best utilize small numbers of stem cells. To date, however, graft survival within acute infarcts has not been feasible. To enhance intrainfarct graft viability, human embryonic stem cell-derived cardiomyocytes (hESC-CMs) were pretreated before implantation with cobalt protoporphyrin (CoPP), a pharmacologic inducer of cytoprotective heme oxygenase-1.

METHODS

After preculturing with CoPP (vs phosphate-buffered saline), hESC-CMs were injected intramyocardially into acutely infarcted rat hearts, using directed injections to span the infarct. A further group received CoPP-pretreated hESC-CMs plus 4 weekly doses of systemic CoPP to prolong exposure to cytoprotectants. Two control groups with infarcts received vehicle-only intramyocardial injections or weekly systemic CoPP without cell therapy. Postinfarct ventricular function was gauged by echocardiography and graft size quantified at 8 weeks by histomorphometry.

RESULTS

CoPP-preconditioned hESC-CMs formed stable grafts deep within infarcted myocardium, while grafts without CoPP exposure survived mainly at the infarct periphery. Fractional shortening was improved at 4 and 8 weeks in all hearts receiving cell therapies (P < .01 vs vehicle-only injections). CoPP treatment of both graft hESC-CMs and recipient animals resulted in the largest grafts, highest fractional shortening, preserved wall thickness, and reduced infarct dimensions.

CONCLUSIONS

Cellular therapy delivered acutely after infarction significantly improved postinfarct ventricular function at 1 and 2 months. CoPP pretreatment of cells resulted in stable hESC-CM grafts within infarcted myocardium. This design enables construction of directionally oriented, infarct-spanning bands of new cardiomyocytes that might further improve functional restoration as engrafted myocytes proliferate and mature.

Estimating the Myocardium's Angle of Three-Dimensional Trajectory, Using the Tracking of Sequential Two-Dimensional Echocardiography Images

BACKGROUND

In this study, the angle of the myocardium's trajectory in three dimensions (ф) was estimated by simultaneous use of long-axis and short-axis views of left ventricle septum two-dimensional images. Then correlation of three-dimensional trajectory's angle with the rotation angle from the long (χ) and short (θ) axis views was estimated and compared at the three levels of base, mid and apex of the interventricular septum wall.

METHODS

Two-dimensional echocardiography images of long- and short-axis views of 19 healthy men were recorded and analyzed. Using an electrocardiogram of each individual, the images of the two views were synchronized. The interventricular septum wall motion at the three levels of base, mid and apex were estimated, using a block matching algorithm throughout three cardiac cycles. Considering the defined system of coordinates and the position vectors in long and short-axis views, the 3-dimensional angle of the trajectory was calculated.

RESULTS

Maxima of the ф, θ, and χ angles were extracted at 16.33 ± 3.01, 10.61 ± 3.38, and 15.11 ± 3.30 degrees at base level, 22.77 ± 4.95, 7.78 ± 2.96, and 16.72 ± 2.66 degrees at mid level and 14.60 ± 5.81, 10.37 ± 5.48, and 8.79 ± 3.32 degrees at apex level, respectively, of the septum wall, respectively. This study shows significant correlation between the angle of 3-dimensional trajectory (ф) with the angle in short axis view (θ) of the septum wall at the apex level; and also with the angle in long axis view (χ) of the septum wall at base and mid levels.

CONCLUSION

Due to the motion of the wall of the left ventricle in three dimensions, and the non-isotropic structure of myofibers, the angle of 3-dimensional trajectory was estimated using the speckle tracking method of 2-dimentional echocardiography images.

Left-ventricular aneurysms: from disease to repair

Myocardial infarction may be complicated by the formation of a left-ventricular aneurysm that distorts the normal elliptical geometry of the ventricle to produce a dilated spherical ventricle with limited contractile and filling capacities. One of the consequences is congestive heart failure, which may be refractory to medical therapy and require surgical treatment. Surgical methods to restore the volume and shape of the left ventricle have evolved over the years. Nevertheless, although surgery for left-ventricular aneurysms has been performed for almost 50 years, the most appropriate approach is still controversial. This review gives an overview of the postinfarction left-ventricular aneurysm, tackling issues from the disease itself to surgical and other techniques of ventricular remodeling.

Assessment of the rotation motion at the papillary muscle short-axis plane with normal subjects by two-dimensional speckle tracking imaging: a basic clinical study

Background

The aim of this study was to observe the rotation patterns at the papillary muscle plane in the Left Ventricle(LV) with normal subjects using two-dimensional speckle tracking imaging(2D-STI).

Methods

We acquired standard of the basal, the papillary muscle and the apical short-axis images of the LV in 64 subjects to estimate the LV rotation motion by 2D-STI. The rotational degrees at the papillary muscle short-axis plane were measured at 15 different time points in the analysis of two heart cycles.

Results

There were counterclockwise rotation, clockwise rotation, and counterclockwise to clockwise rotation at the papillary muscle plane in the LV with normal subjects, respectively. The ROC analysis of the rotational degrees was performed at the papillary muscle short-axis plane at the peak LV torsion for predicting whether the turnaround point of twist to untwist motion pattern was located at the papillary muscle level. Sensitivity and specificity were 97% and 67%, respectively, with a cut-off value of 0.34°, and an area under the ROC curve of 0.8. At the peak LV torsion, there was no correlation between the rotational degrees at the papillary muscle short-axis plane and the LVEF in the normal subjects(r = 0.000, p = 0.998).

Conclusions

In the study, we conclude that there were three rotation patterns at the papillary muscle short-axis levels, and the transition from basal clockwise rotation to apical counterclockwise rotation is located at the papillary muscle level.

Abnormal left ventricular rotation and twist in adult patients with corrected tetralogy of Fallot

AIMS

Left ventricular (LV) dysfunction is a major determinant of late adverse clinical outcome in adult patients with tetralogy of Fallot (ToF). Therefore, early detection is important. Speckle-tracking echocardiography (STE) has emerged as a quantitative technique to assess LV function. The aim of this study was to evaluate LV rotation and twist with STE in adult ToF patients and their association with right ventricular (RV) and LV dimensions and function, exercise capacity, and NT-proBNP level.

METHODS

Eighty-two ToF patients and 56 healthy controls matched for age and gender underwent echocardiography, electrocardiography, cardiac magnetic resonance imaging (CMR), bicycle ergometry, and NT-proBNP measurement. For STE, short-axis parasternal views were obtained at the LV base and apex. We analysed LV apical and basal rotation curves and calculated LV twist.

RESULTS

Of the 82 ToF patients (55% male, age 33 ± 10 years, 98% NYHA I), 58 (71%) had normal twist, but lower than the controls [12.5 (IQR: 6.6) vs. 16.9 (IQR: 8.2) degrees, P = 0.002] mainly due to decreased apical rotation. Twenty-one (26%) patients had abnormal apical rotation which was associated with larger LV dimensions and decreased systolic biventricular function. Multivariable regression analyses showed positive relations of LV twist with biventricular systolic function measured with echocardiography as well as CMR.

CONCLUSION

The majority of adults with corrected ToF show a reduced LV twist. Strikingly, one-quarter of these patients have an abnormal apical rotation which is associated with decreased systolic LV and RV function. These findings suggest that abnormal apical rotation is a new objective diagnostic criterion for detection of ventricular dysfunction.

Computational modeling of electromechanical propagation in the helical ventricular anatomy of the heart

The classical interpretation of myocardial activation assumes that the myocardium is homogeneous and that the electrical propagation is radial. However, anatomical studies have described a layered anatomical structure resulting from a continuous anatomical helical disposition of the myocardial fibers. To further investigate the sequence of electromechanical propagation based on the helical architecture of the heart, a simplified computational model was designed. This model was then used to test four activation patterns, which were generated by propagating the action potential along the myocardial band from different activation sites.

Helical structure of the cardiac ventricular anatomy assessed by diffusion tensor magnetic resonance imaging with multiresolution tractography

INTRODUCTION AND OBJECTIVES

Deeper understanding of the myocardial structure linking the morphology and function of the heart would unravel crucial knowledge for medical and surgical clinical procedures and studies. Several conceptual models of myocardial fiber organization have been proposed but the lack of an automatic and objective methodology prevented an agreement. We sought to deepen this knowledge through advanced computer graphical representations of the myocardial fiber architecture by diffusion tensor magnetic resonance imaging.

METHODS

We performed automatic tractography reconstruction of unsegmented diffusion tensor magnetic resonance imaging datasets of canine heart from the public database of the Johns Hopkins University. Full-scale tractographies have been built with 200 seeds and are composed by streamlines computed on the vector field of primary eigenvectors at the diffusion tensor volumes. We also introduced a novel multiscale visualization technique in order to obtain a simplified tractography. This methodology retains the main geometric features of the fiber tracts, making it easier to decipher the main properties of the architectural organization of the heart.

RESULTS

Output analysis of our tractographic representations showed exact correlation with low-level details of myocardial architecture, but also with the more abstract conceptualization of a continuous helical ventricular myocardial fiber array.

CONCLUSIONS

Objective analysis of myocardial architecture by an automated method, including the entire myocardium and using several 3-dimensional levels of complexity, reveals a continuous helical myocardial fiber arrangement of both right and left ventricles, supporting the anatomical model of the helical ventricular myocardial band described by F. Torrent-Guasp.

Transposition of great arteries: new insights into the pathogenesis

Transposition of great arteries (TGA) is one of the most common and severe congenital heart diseases (CHD). It is also one of the most mysterious CHD because it has no precedent in phylogenetic and ontogenetic development, it does not represent an alternative physiological model of blood circulation and its etiology and morphogenesis are still largely unknown. However, recent epidemiologic, experimental, and genetic data suggest new insights into the pathogenesis. TGA is very rarely associated with the most frequent genetic syndromes, such as Turner, Noonan, Williams or Marfan syndromes, and in Down syndrome, it is virtually absent. The only genetic syndrome with a strong relation with TGA is Heterotaxy. In lateralization defects TGA is frequently associated with asplenia syndrome. Moreover, TGA is rather frequent in cases of isolated dextrocardia with situs solitus, showing link with defect of visceral situs. Nowadays, the most reliable method to induce TGA consists in treating pregnant mice with retinoic acid or with retinoic acid inhibitors. Following such treatment not only cases of TGA with d-ventricular loop have been registered, but also some cases of congenitally corrected transposition of great arteries (CCTGA). In another experiment, the embryos of mice treated with retinoic acid in day 6.5 presented Heterotaxy, suggesting a relationship among these morphologically different CHD. In humans, some families, beside TGA cases, present first-degree relatives with CCTGA. This data suggest that monogenic inheritance with a variable phenotypic expression could explain the familial aggregation of TGA and CCTGA. In some of these families we previously found multiple mutations in laterality genes including Nodal and ZIC3, confirming a pathogenetic relation between TGA and Heterotaxy. These overall data suggest to include TGA in the pathogenetic group of laterality defects instead of conotruncal abnormalities due to ectomesenchymal tissue migration.

Minimally invasive cell-seeded biomaterial systems for injectable/epicardial implantation in ischemic heart disease

Myocardial infarction (MI) is characterized by heart-wall thinning, myocyte slippage, and ventricular dilation. The injury to the heart-wall muscle after MI is permanent, as after an abundant cell loss the myocardial tissue lacks the intrinsic capability to regenerate. New therapeutics are required for functional improvement and regeneration of the infarcted myocardium, to overcome harmful diagnosis of patients with heart failure, and to overcome the shortage of heart donors. In the past few years, myocardial tissue engineering has emerged as a new and ambitious approach for treating MI. Several left ventricular assist devices and epicardial patches have been developed for MI. These devices and acellular/cellular cardiac patches are employed surgically and sutured to the epicardial surface of the heart, limiting the region of therapeutic benefit. An injectable system offers the potential benefit of minimally invasive release into the myocardium either to restore the injured extracellular matrix or to act as a scaffold for cell delivery. Furthermore, intramyocardial injection of biomaterials and cells has opened new opportunities to explore and also to augment the potentials of this technique to ease morbidity and mortality rates owing to heart failure. This review summarizes the growing body of literature in the field of myocardial tissue engineering, where biomaterial injection, with or without simultaneous cellular delivery, has been pursued to enhance functional and structural outcomes following MI. Additionally, this review also provides a complete outlook on the tissue-engineering therapies presently being used for myocardial regeneration, as well as some perceptivity into the possible issues that may hinder its progress in the future.