Spongy Myocardium Research Articles

Rare case of super-response to Cardiac Resynchronization Therapy in Macedonian patient with Dilated Left Ventricular Non-Compaction Cardiomyopathy

Background: Left ventricular non-compaction (LVNC) is rare cardiomyopathy with increased and prominent endomyocardial trabeculations also known as spongy myocardium. It is often found in association with a dilated cardiomyopathy (DCM) and has high incidence of Heart failure (HF). Cardiac resynchronization therapy (CRT) is currently recommended by the available guidelines for selected patients with Heart failure with reduced ejection fraction (HFrEF). Aim: Our case report aims to highlight the therapeutic benefits and superresponse to CRT in a patient with Left ventricular non-compaction cardiomyopathy and HFrEF. Case report: 55-year-old Macedonian male patient with HFrEF, Left bundle branch block (LBBB) remained symptomatic (NYHA III) despite optimal medical treatment (OMT). Echocardiography and CMR findings were in addition to dilated and left ventricular non-compaction cardiomyopathy. Cardiac resynchronization therapy was indicated and 18 months after implantation of CRT-P device we have achieved complete and utter reversibility of systolic myocardial function (EF from 23% to 53%), left ventricular internal diameter was reduced from 90mm to 64mm, left ventricular end systolic volume (LVESV) was reduced from 319ml to 98ml and patient quality of life significantly improved. Conclusion: Cardiac resynchronization therapy is a safe and valuable method of treatment for patients with HFrEF due to dilated left ventricular non-compaction cardiomyopathy.

Increased reliance on coronary perfusion for cardiorespiratory performance in seawater-acclimated rainbow trout.

Salmonid ventricles are composed of spongy and compact myocardium, the latter being perfused via a coronary circulation. Rainbow trout (Oncorhynchus mykiss) acclimated to sea water have higher proportions of compact myocardium and display stroke volume-mediated elevations in resting cardiac output relative to freshwater-acclimated trout, probably to meet the higher metabolic needs of osmoregulatory functions. Here, we tested the hypothesis that cardiorespiratory performance of rainbow trout in sea water is more dependent on coronary perfusion by assessing the effects of coronary ligation on cardiorespiratory function in resting and exhaustively exercised trout acclimated to fresh water or sea water. While ligation only had minor effects on resting cardiorespiratory function across salinities, cardiac function after chasing to exhaustion was impaired, presumably as a consequence of atrioventricular block. Ligation reduced maximum O2 consumption rate by 33% and 17% in fish acclimated to sea water and fresh water, respectively, which caused corresponding 41% and 17% reductions in aerobic scope. This was partly explained by different effects on cardiac performance, as maximum stroke volume was only significantly impaired by ligation in sea water, resulting in 38% lower maximum cardiac output in seawater compared with 28% in fresh water. The more pronounced effect on respiratory performance in sea water was presumably also explained by lower blood O2 carrying capacity, with ligated seawater-acclimated trout having 16% and 17% lower haemoglobin concentration and haematocrit, respectively, relative to ligated freshwater trout. In conclusion, we show that the coronary circulation allows seawater-acclimated trout to maintain aerobic scope at a level comparable to that in fresh water.

Evaluating cardiac oxygen limitation as a mechanism for female-biased mortality in coho salmon (Oncorhynchus kisutch)

Female-biased mortality has been consistently reported in Pacific salmon during their adult upriver migration. We collected coho salmon ( Oncorhynchus kisutch (Walbaum, 1792)) upon arrival at their spawning grounds to test whether females are more prone to cardiac oxygen limitations following exercise stress. We used a surgical approach to periodically sample arterial and venous blood over 48 h following recovery from a chase protocol to induce maximum metabolic rate. We found no significant differences in arterial or venous partial pressures of O2 between males and females. Female salmon had significantly elevated plasma cortisol levels but there were no effects of sex on either plasma lactate or K+. Our data show that female coho salmon do not suffer oxygen limitations to the spongy myocardium after a single exercise event at moderate temperatures (14 °C)—at least not when arriving to their spawning grounds. This study found no clear support for a cardiac oxygen limitation underlying elevated female mortality in Pacific salmon. Neither, however, does our study design nor specific findings allow us to rule out cardiac limitations in these fish. Future work should address whether potential oxygen limitations to the spongy myocardium at high temperatures or oxygen limitations to the compact myocardium via coronary blood flow contribute to female-biased mortality earlier on the migratory route.

Spatial uniformity of action potentials indicates base-to-apex depolarization and repolarization of rainbow trout (Oncorhynchus mykiss) ventricle.

The spatial pattern of electrical activation is crucial for a full understanding of fish heart function. However, it remains unclear whether there is regional variation in action potential (AP) morphologies and underlying ion currents. Because the direction of depolarization and spatial differences in the durations of ventricular APs set limits to potential patterns of ventricular repolarization, we determined AP morphologies, underlying ion currents and ion channel expression in four different ventricular regions (spongy myocardium; and apex, base and middle of the compact myocardium), and correlated them with in vivo electrocardiograms (ECGs) in rainbow trout (Oncorhynchus mykiss). ECGs recorded from three leads indicated that the depolarization and repolarization of APs propagate from base to apex, and the main depolarization axis of the ventricle is between +90 and +120deg. AP shape was uniform across the whole ventricle, and little regional differences were found in the density of repolarizing K+ currents or depolarizing Ca2+ and Na+ currents and the underlying transcripts of ion channels, providing compelling evidence for the suggested excitation pattern. The spatial uniformity of AP durations and base-to-apex propagation of activation with a relatively slow velocity of propagation indicates no special ventricular conduction pathway in the trout ventricle such as the His-Purkinje system of mammalian hearts. The sequence of repolarization is solely determined by activation time without being affected by regional differences in AP duration.

Effects of constitutively active IKKβ on cardiac development

NF-κB is a major transcription factor regulating cell survival, organ development and inflammation, but its role in cardiac development has been inadequately explored. To examine this function, we generated mice in which IKKβ, an essential kinase for NF-κB activation, was constitutively activated in embryonic cardiomyocytes. For this purpose, we used smooth muscle-22α (SM22α)-Cre mice, which are frequently used for gene recombination in embryonic cardiomyocytes. Embryonic hearts of SM22αCre-CA (constitutively active) IKKβflox/flox mice revealed remarkably thin, spongy and hypoplastic myocardium. In exploring the mechanism, we found that the expression of bone morphogenetic protein 10 (BMP10) and T-box transcription factor 20 (Tbx20), major regulators of cardiac development, was significantly downregulated and upregulated, respectively, in the SM22αCre-CAIKKβflox/flox mice. We also generated NK2 homeobox 5 (Nkx2.5) Cre-CAIKKβflox/wt mice since Nkx2.5 is also expressed in embryonic cardiomyocytes and confirmed that the changes in these genes were also observed. These results implicated that the activation of NF-κB affects cardiac development.

Trout recover from heart attack damage

Most fish's hearts have to scavenge whatever oxygen is left in the poorly oxygenated blood returning from the body, absorbing what remains of the life-giving gas through the spongy myocardium. But not super athletic salmonids. Their hearts benefit from a well-oxygenated blood supply to the outer layer of the ventricle, the chamber that pumps the blood through the gills and body. However, this arrangement leaves their hearts vulnerable if the blood supply to the ventricle is disrupted by heart disease, and wild and farmed members of the family are particularly prone to the problem. ‘In fact, coronary arteriosclerosis has been described as a “fact of life” in salmonids’, says Lucas Zena from University of São Paulo, Brazil. Zena, along with Erik Sandblom and colleagues from The University of Gothenburg, Sweden, and the Swedish University of Agricultural Sciences, were curious to find out whether trout hearts could recover from an interruption to the heart's blood supply and, if so, how?Operating on several fit young trout to restrict the blood flow to the ventricle and simulate short (3 day) and longer (33–62 day) episodes of heart disease, the team then tested how the disruption affected the performance of the heart, how the heart reacted over time and whether it was able to recover at all. Recording the fish's heart rate shortly after losing the blood supply, Zena found that the resting rate had increased from ∼37 beats min–1 to ∼49 beats min–1. However, maximum heart rate when exercising was unaffected, despite the lack of blood to the ventricle; they could exercise as hard as healthy fish, but they had less capacity to ramp up their heart rate on demand. But, when the team measured the resting heart rate after fish had experienced 2 months of simulated heart disease, they found it had returned to the more leisurely pace of the healthy fish. And, when the team tested the heart rate variability – the variation in time between consecutive heartbeats – they found it was much lower in newly operated fish than in those with a good blood supply. However, the fish that had experienced an interruption to the blood flow to the heart for a month or more had overcome the problem; their heart rate variability was essentially the same as that of healthy fish of the same age.The team then looked at the state of the fish's hearts 3 days after the interruption of the blood supply and realised that they were experiencing the same damage as human heart attack victims: losing muscle tissue and showing signs of inflammation. But, after 2 months the fish had developed a scar – a fibrous layer composed of collagen – running throughout the outer layer of heart muscle, dividing the most external region of the heart from the internal layer. ‘It is possible that the mid-myocardial fibrous layer demarks a region of the compact myocardium that continued to receive oxygen from the luminal venous blood’, says Zena.So, young trout are able to recover from an interruption of the oxygen supply to the heart, and Sandblom and colleagues are keen to find out how well the fish's cardiac adaptability protects the fish from stressful situations.

Coronary Arteries: Normal Anatomy With Historical Notes and Embryology of Main Stems.

Anatomy of subepicardial coronary arteries became a topic of investigation at autopsy in Florence (Italy) by Banchi in the early twentieth century, with the discovery of dominant and balanced patterns. Thereafter, in the 60's of the same century Baroldi in Milan did post-mortem injection with spectacular three-dimensional casts. Later Sones at the Cleveland Clinic introduced selective coronary arteriography for in vivo visualization of coronary arteries. In the present chapter we show these patterns, as well as normal variants of origin and course with questionable risk of ischemia, like myocardial bridge as well as origin of the left circumflex coronary artery from the right sinus with retroaortic course. As far as embryology, the coronary arteries and veins are epicardial in origin and finally connect the former with the aorta, and the latter with the sinus venosus. At the time of spongy myocardium, intramural blood supply derives directly by the ventricular cavities, whereas later, at the time of myocardial compaction, vascularization originates from the subepicardial network. The connection of the subepicardial plexus with the aorta occurs with prongs of the peritruncal ring, which penetrate the facing aortic sinuses. Septation of truncus arteriosus is not responsible for the final position of the coronary orifices. Infact in transposition of the great arteries coronary ostia are regularly located within facing sinuses of the anterior aorta.

Low-level embryonic crude oil exposure disrupts ventricular ballooning and subsequent trabeculation in Pacific herring

There is a growing awareness that transient, sublethal embryonic exposure to crude oils cause subtle but important forms of delayed toxicity in fish. While the precise mechanisms for this loss of individual fitness are not well understood, they involve the disruption of early cardiogenesis and a subsequent pathological remodeling of the heart much later in juveniles. This developmental cardiotoxicity is attributable, in turn, to the inhibitory actions of crude oil-derived mixtures of polycyclic aromatic compounds (PACs) on specific ion channels and other proteins that collectively drive the rhythmic contractions of heart muscle cells via excitation-contraction coupling. Here we exposed Pacific herring (Clupea pallasi) embryos to oiled gravel effluent yielding ΣPAC concentrations as low as ~ 1 μg/L (64 ng/g in tissues). Upon hatching in clean seawater, and following the depuration of tissue PACs (as evidenced by basal levels of cyp1a gene expression), the ventricles of larval herring hearts showed a concentration-dependent reduction in posterior growth (ballooning). This was followed weeks later in feeding larvae by abnormal trabeculation, or formation of the finger-like projections of interior spongy myocardium, and months later with hypertrophy (overgrowth) of the spongy myocardium in early juveniles. Given that heart muscle cell differentiation and migration are driven by Ca2+-dependent intracellular signaling, the observed disruption of ventricular morphogenesis was likely a secondary (downstream) consequence of reduced calcium cycling and contractility in embryonic cardiomyocytes. We propose defective trabeculation as a promising phenotypic anchor for novel morphometric indicators of latent cardiac injury in oil-exposed herring, including an abnormal persistence of cardiac jelly in the ventricle wall and cardiomyocyte hyperproliferation. At a corresponding molecular level, quantitative expression assays in the present study also support biomarker roles for genes known to be involved in muscle contractility (atp2a2, myl7, myh7), cardiomyocyte precursor fate (nkx2.5) and ventricular trabeculation (nrg2, and hbegfa). Overall, our findings reinforce both proximal and indirect roles for dysregulated intracellular calcium cycling in the canonical fish early life stage crude oil toxicity syndrome. More work on Ca2+-mediated cellular dynamics and transcription in developing cardiomyocytes is needed. Nevertheless, the highly specific actions of ΣPAC mixtures on the heart at low, parts-per-billion tissue concentrations directly contravene classical assumptions of baseline (i.e., non-specific) crude oil toxicity.

“A Logical Reasoning of Spongy Myocardium”- A Case of LV Non Compaction Cardiomyopathy

Left ventricular noncompaction cardiomyopathy (LVNC) or spongy myocardium is a rare congenital disorder prominently distinguished by deep abnormal trabeculations and intertrabecular recesses which communicate with the ventricular cavity that can be detected on Transthoracic Echocardiography (TTE) or cardiac MRI (CMR) studies. LVNC can occur in isolation or coexists with other cardiac and/or systemic anomalies and the common clinical complications are heart failure, arrhythmias, and cardio embolism. The American Heart Association classified it as a primary genetic cardiomyopathy. We described the case of a 28years old young adult who presented with heart failure for the first time. Transthoracic echocardiography showed a trabeculated, sponge-like appearance of the ventricular apical and inferolateral segments. Following evaluation with CMR imaging revealed non compaction of the left ventricle. Here we discussed the diagnosis of this case and reviewed the medical literature that concerned to LVNC.

Effects of hypoxic acclimation on contractile properties of the spongy and compact ventricular myocardium of steelhead trout (Oncorhynchus mykiss).

The trout ventricle has an outer compact layer supplied with well-oxygenated arterial blood from the coronary circulation, and an inner spongy myocardium supplied with oxygen poor venous blood. It was hypothesized that: (1) the spongy myocardium of steelhead trout (Oncorhynchus mykiss), given its routine exposure to low partial pressures of oxygen (PO2), would be better able to maintain contractile performance (work) when exposed to acute hypoxia (100 to 10% air saturation) relative to the compact myocardium, and would show little benefit from hypoxic acclimation; and (2) the compact myocardium from hypoxia-acclimated (40% air saturation) fish would be better able to maintain work during acute exposure to hypoxia relative to normoxia-acclimated individuals. Consistent with our expectations, when PO2 was acutely lowered, net work from the compact myocardium of normoxia-acclimated fish declined more (by ~ 73%) than the spongy myocardium (~ 50%), and more than the compact myocardium of hypoxia-acclimated fish (~ 55%), and hypoxic acclimation did not benefit the spongy myocardium in the face of reduced PO2. Further, while hypoxic acclimation resulted in a 25% (but not significant) decrease in net work of the spongy myocardium, the performance of the compact myocardium almost doubled. This research suggests that, in contrast to the spongy myocardium, performance of the compact myocardium is improved by hypoxic acclimation; and supports previous research suggesting that the decreased contractile performance of the myocardium upon exposure to lowered PO2 may be adaptive and mediated by mechanisms within the muscle itself.

Skeletal muscle and cardiac transcriptomics of a regionally endothermic fish, the Pacific bluefin tuna, Thunnus orientalis

BackgroundThe Pacific bluefin tuna (Thunnus orientalis) is a regionally endothermic fish that maintains temperatures in their swimming musculature, eyes, brain and viscera above that of the ambient water. Within their skeletal muscle, a thermal gradient exists, with deep muscles, close to the backbone, operating at elevated temperatures compared to superficial muscles near the skin. Their heart, by contrast, operates at ambient temperature, which in bluefin tunas can range widely. Cardiac function in tunas reduces in cold waters, yet the heart must continue to supply blood for metabolically demanding endothermic tissues. Physiological studies indicate Pacific bluefin tuna have an elevated cardiac capacity and increased cold-tolerance compared to warm-water tuna species, primarily enabled by increased capacity for sarcoplasmic reticulum calcium cycling within the cardiac muscles.ResultsHere, we compare tissue-specific gene-expression profiles of different cardiac and skeletal muscle tissues in Pacific bluefin tuna. There was little difference in the overall expression of calcium-cycling and cardiac contraction pathways between atrium and ventricle. However, expression of a key sarcoplasmic reticulum calcium-cycling gene, SERCA2b, which plays a key role maintaining intracellular calcium stores, was higher in atrium than ventricle. Expression of genes involved in aerobic metabolism and cardiac contraction were higher in the ventricle than atrium. The two morphologically distinct tissues that derive the ventricle, spongy and compact myocardium, had near-identical levels of gene expression. More genes had higher expression in the cool, superficial muscle than in the warm, deep muscle in both the aerobic red muscle (slow-twitch) and anaerobic white muscle (fast-twitch), suggesting thermal compensation.ConclusionsWe find evidence of widespread transcriptomic differences between the Pacific tuna ventricle and atrium, with potentially higher rates of calcium cycling in the atrium associated with the higher expression of SERCA2b compared to the ventricle. We find no evidence that genes associated with thermogenesis are upregulated in the deep, warm muscle compared to superficial, cool muscle. Heat generation may be enabled by by the high aerobic capacity of bluefin tuna red muscle.

Development of the ventricular myocardial trabeculae in Scyliorhinus canicula (Chondrichthyes): evolutionary implications

The development of the ventricular myocardial trabeculae occurs in three steps: emergence, trabeculation and remodeling. The whole process has been described in vertebrates with two different myocardial structural types, spongy (zebrafish) and compact (chicken and mouse). In this context, two alternative mechanisms of myocardial trabeculae emergence have been identified: (1) in chicken and mouse, the endocardial cells invade the two-layered myocardium; (2) in zebrafish, cardiomyocytes from the monolayered myocardium invaginate towards the endocardium. Currently, the process has not been studied in detail in vertebrates having a mixed type of ventricular myocardium, with an inner trabecular and an outer compact layer, which is presumptively the most primitive morphology in gnathostomes. We studied the formation of the mixed ventricular myocardium in the lesser spotted dogfish (Scyliorhinus canicula, Elasmobranchii), using light, scanning and transmission electron microscopy. Our results show that early formation of the mixed ventricular myocardium, specifically the emergence and the trabeculation steps, is driven by an endocardial invasion of the myocardium. The mechanism of trabeculation of the mixed ventricular myocardium in chondrichthyans is the one that best reproduces how this developmental process has been established from the beginning of the gnathostome radiation. The process has been apparently preserved throughout the entire group of sarcopterygians, including birds and mammals. In contrast, teleosts, at least those possessing a mostly spongy ventricular myocardium, seem to have introduced notable changes in their myocardial trabeculae development.

Canine infantile left ventricular noncompaction

BackgroundLeft ventricular noncompaction (LVNC) is a rare form of cardiomyopathy currently described in humans and cats. It consists of a spongy myocardium characterized by prominent trabeculation and deep recesses involving more than 50% of the ventricular thickness. We describe the clinical and pathological features of LVNC combined with tricuspid valve dysplasia, double-orifice tricuspid valve and severe pulmonary stenosis in a puppy. In addition, we briefly review the LVNC causes, pathogenesis, forms and current diagnostic criteria.Case presentationA seven-week-old intact German Shorthaired Pointer-cross male was presented with a poor body condition, exercise intolerance and dyspnea. Clinical exam identified a bilateral systolic murmur (grade IV/VI over the right heart base and grade III/VI over the left heart base). Echocardiography identified tricuspid valve dysplasia, mild mitral regurgitation, and severe pulmonic stenosis with a trans-valvar systolic pressure gradient of 106 mmHg. Left ventricular noncompaction was diagnosed by necropsy and further confirmed histopathologically by the presence of two distinct myocardial layers: an inner noncompacted zone covering more than 50% of ventricular thickness containing prominent trabeculation and deep recesses, and an outer zone of compact myocardium.ConclusionsThis is the first case describing LVNC in a canine patient, supporting the introduction of this form of heart disease as a differential diagnosis for cardiomyopathies in juvenile and adult dogs.

Isolated Non-Compaction of Right Ventricular Myocardium, A Rare Congenital Anomaly and Role of Echocardiogram: A Case Report

The ventricular non-compaction or spongy myocardium is a rare congenital cardiomyopathy which is caused by defective morphogenesis of myocardium during embryonic life. It is characterised by excessive, coarse trabeculations within ventricular myocardium beyond papillary muscle insertion which communicates freely with the ventricular cavity. This carries high risk for development of serious arrhythmia, thromboembolic stroke, pump failure etc. Isolated LV involvement is the most common presentation (68%) and biventricular involvement is the next most common presentation (22-38%). Isolated non-compaction of RV myocardium is a rare anomaly. We are hereby presenting such a case.

Prenatal ultrasound diagnosis of fetal isolated right ventricular noncompaction with pulmonary artery sling: A rare case report

Noncompaction of the ventricular myocardium (NVM), also known as spongy myocardium, is a rare type of cardiomyopathy that has a serious impact on fetuses, children, and adults. NVM mainly affects the left ventricle, as isolated right ventricular noncompaction (IRVNC) is rare. Pulmonary artery sling (PAS) is a rare condition in which the left pulmonary artery anomalously originates from a normal positioned right pulmonary artery, and only a few studies have reported PAS in fetuses. Fetal IRVNC complicated with PAS has not been reported yet. Here, we report a case of IRVNC complicated with PAS that was diagnosed prenatally at 30weeks gestation and confirmed by postpartum anatomy and pathology.

Left ventricular non‐compaction – diagnostic challenges (RCD code: III‐5A.1.o)

Left ventricular non‐compaction (LVNC), or “spongy myocardium”, is a rare cardiac morphological condition detected in 0.05–0.26% of all adults undergoing transthoracic echocardiography, with an increasing prevalence in the recent years. Our clinical case of a 54‐year‐old asymptomatic female illustrates the importance of additional cardiovascular imaging technologies in the diagnostic work‐up of the patient. The patient was referred to a cardiologist due to a left bundle branch block found on routine electrocardiogram examination. Transthoracic echocardiography did not reveal any specific changes, although a single photon emission computed tomography scan revealed a fixed myocardial perfusion defect. This defect was regarded as non‐typical for inducible myocardial ischaemia and indicative of a non‐specific cardiomyopathy. Further investigation using cardiac magnetic resonance imaging confirmed the phenotype of LVNC. JRCD 2018; 3 (8): 271–274

A Case Report of Isolated Left Ventricular Non-Compaction Presenting with Congestive Heart Failure and Intramural Thrombus

Isolated left ventricular non-compaction is recently described as a rare form of cardiomyopathy that is associated with a heart failure, life threatening cardiac arrhythmia and thromboembolic complications. The diagnosis is based on echocardiography demonstration of spongy myocardium. Here we report a case of 74 years old female patient diagnosed as an isolated left ventricular non-compaction with congestive heart failure, intramural thrombus and hypertension. There is no specific treatment for LVNC; therapeutic measures are directed towards the patient’s symptom (heart failure, arrhythmia and thrombotic events) and consideration of an implantable cardioverter defibrillator and cardiac transplantation.

Myocardial trabeculation in embryos of Scyliorhinus canicula (Elasmobranchii, Chondrichthyans)

Currently, three types of ventricular myoarchitecture are recognized in vertebrates, namely compact, spongy (trabeculated) and mixed myocardium. Mixed myocardium, which has been recently proposed as the primitive condition in gnathostomes, is composed of two myocardial layers: an inner trabeculated and an outer compact one. The trabeculation process has been studied in teleosts, showing exclusively spongy myocardium, and mammals and birds, characterized by a compact myocardial ventricular wall. In zebrafish, mouse and chicken embryos, the trabeculae develop as luminal myocardial ridges protruding into the lumen. In mammals and birds, further compactation of trabeculae leads to the formation of a compact layer. The potential mechanisms that may contribute to the formation of the ridges are under discussion and include myocardial proliferation, endocardial invagination, and bending of the entire myocardial layer. However, no description of the development of the mixed myocardium is available.To shed some light on this issue, we have studied the heart development of an elasmobranch species with mixed myocardium, the lesser spotted dogfish (Scyliorhinus canicula; Chondrichthyes), by means of histological and immunohistochemical techniques for light microscopy, semithin sections, scanning electron microscopy and transmission electron microscopy.At the beginning of developmental stage 27 the ventricle has a single layer of cardiomyocytes lined by endocardium. At stage 28, the cardiomyocytes proliferate and stratified in several cell layers. Small spaces can be seen in between cardiomyocytes of the inner layers and the endocardium locally invaginates. At stage 29, bigger spaces lined by endocardial cells are connected with the ventricular lumen. Then, two layers, outer and inner, are recognized in the ventricular wall. The outer layer is the presumptive compact myocardium and the inner one is the presumptive trabeculated myocardium. At stage 30, the trabeculae become more complex, showing a bunch‐like branching pattern. At stage 33, the inner trabeculated layer is similar to that of the adult heart, while the outer layer starts to become thicker to form the definitive compact layer.Our results suggest that in the dogfish the intertrabecular spaces develop by connections between early intramyocardial spaces and the lumen of the ventricle through invaginations of the endocardial line. Chondrichthyans are the earliest diverged lineage of gnathostomes and, consequently, they have the most primitive cardiac design. Although chicken, mouse, and recently zebrafish have been considered powerful vertebrate models to study heart development, we propose that the trabeculation process in the dogfish is representative of the early steps of the ventricular morphogenesis in vertebrates.Support or Funding InformationThis study was supported by CGL2014‐52356‐P and FPU15/03209This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

РЕДКОЕ СОЧЕТАНИЕ НЕКОМПАКТНОГО МИОКАРДА И КОРОНАРНОЙ ДИЛАТАЦИИ С НЕЙРОФИБРОМАТОЗОМ 1 ТИПА

The article describes the observation of a child with a very rare combination of noncompact left ventricular myocardium
 and coronary dilatation in type 1 neurofibromatosis (NF 1). The first of these complications, undifferentiated cardio-
 myopathy, also known as noncompact myocardium, is not described in combination with NF 1 in available literature,
 although cases of hypertrophic cardiomyopathy in patients with NF 1 have been previously reported. Dilatation of the
 coronary arteries also refers to infrequent manifestations of vascular pathology against the background of neurofibro-
 matosis, and the combination of all three signs (NF 1, noncompact myocardium and coronary dilatation) has not yet
 been reported by other authors. When examining the patient, we found the characteristic signs of NF 1 (foci of “coffee”
 pigmentation on the skin, multiple nevuses, fibroids of the forearm, cognitive disorders), electrocardiogram features of
 left ventricular hypertrophy, negative T-tooth and ST-segment displacement 1 mm below the isoline in Leads V4-6, in
 echocardiography - pronounced trabecularity, thinning of the compact myocardium layer and a “spongy myocardium”
 in the region of the left ventricle apex, dilatation of the coronary arteries.
 With magnetic resonance imaging, signs of noncompact myocardium of the left ventricle were found, with selective
 coronary angiography - slowing of the coronary blood flow. The patient receives the permanent treatment for heart
 failure and aspirin, his condition remains stable for 4 years of follow-up

ЭХОКАРДИОГРАФИЧЕСКАЯ ДИАГНОСТИКА НЕКОМПАКТНОГО МИОКАРДА ЛЕВОГО ЖЕЛУДОЧКА

The clinical cases of rare, genetically heterogeneous cardiomyopathy are described - the left ventricular noncompaction (LVNC) cardiomyopathy for four children (three boys and one girl) in age from two months to 6 years. Description of echocardiography signs is presented in accordance with modern diagnostic criteria. Noncompaction of the left ventricle is recognized in three patients, of the left and right ventricle - in one. In three patients out of four, LVNC was a separate disease, and yet in one it was associated with neurofibromatosis type 1, in combination with dilatation of coronary arteries and pericardial effusion. Three of four patients were admitted with congestive heart failure (CHF) of New York Heart Association (NYHA) functional class 3-4 (FC), and one - with CHF 2 FC. The echocardiograms are brought with description of characteristic features of LVNC (hypertrabecularity, spongy myocardium on the apex of the left ventricle, typical correlation of incompact and compact layer from 2.0 to 2.6). All four patients received treatment for CHF (diuretics, beta-blockers, captopril, in one case - digoxin); two out of four got antithrombotic therapy (aspirin, warfarin). Results of follow-up observation of the patients are described with the estimation of echocardiography signs, including dilatation of coronary arteries. Left ventricular ejection fraction - both by Simpson and Teicholz - increased in two patients, with therapy of chronic heart failure at a follow-up visits over > 5 years simultaneously with the decline of severity of CHF. Another two patients have been examined from 2 months to 5 years and have had CHF 3 FC; their left ventricular ejection fraction increased too, but cardiomegaly and right ventricular heart failure preserved.