Myocardial Layers Research Articles

Sarcoidal Pericardial Effusion Masquerading As Acute Myocardial Infarction

Sarcoidosis is a multisystemic granulomatous disease, with varying modes of presentation. Pericardial sarcoidosis is rare and cardiac tamponade secondary topericardial sarcoidosis is very uncommon. We present a case of a young man who presented with signs and symptoms suggestive of acute myocardial infarction who was thrombolysed but subsequently died. The cause of his death was made apparent on the post mortem examination which revealed a massive pericardial effusion and a necrotic mature mediastinal teratoma. INTRODUCTION We discuss one case of a young man with symptoms and electrocardiographic evidence of acute myocardial infarction who was thrombolysed but later died. Postmortem findings were suggestive of widespread sarcoidosis with a massive pericardial effusion and a necrotic mature mediastinal teratoma. CASE REPORT A 43-year-old obese man with type 2 diabetes mellitus was brought with a 2 hour history of central crushing chest pain and shortness of breath. On initial assessment his blood pressure was 150/90 mm Hg, equal in both arms with a pulse of 90 per minute, sinus rhythm and respiratory rate of 24/min. Cardiovascular examination was normal. An ECG performed in the ambulance showed 1-2 mm ST elevation in the inferior leads -II, III, aVF. (Figure1). He was transferred to the coronary care unit where he was thrombolysed with reteplase. Subsequent ECG's performed in the CCU showed near normalization of the ST segments. AP view of the chest radiograph showed a prominent right hilum and patchy consolidation of the left upper and lower lobes. After remaining stable and pain free for 4-5 hours, his condition deteriorated and he became hypotensive, tachypnoeic and acidotic. An ECG at this stage showed a sinus tachycardia of 120 per minute. He developed extensive haemorrhagic mottling of his back and rapidly succumbed to the cardiogenic shock despite attempt at resuscitation. Post mortem study of the gross specimen of the heart showed a 650 ml, blood stained pericardial effusion. Extensive loose pericardial adhesions were also seen. There wasminimal (20%) coronary atherosclerosis and no evidence of scarring or acute myocardial infarction. The ascending and descending aorta were unremarkable without evidence of dissection. In the upper mediastinum, a 7 cm cystic, necrotic tumour containing blood adherent to the left lung and superior pericardium was seen. Extensive hilar lymphadenopathy was also seen. On histopathological examination, non caseating granulomas and inflammation of the lungs, mediastinal lymph nodes, myocardium, epicardium (Figure 2a) and liver were seen suggestive of extensive multisystem sarcoidosis. The mediastinal mass showed an extensively necrotic and inflamed teratoma with cartilage.(Figure 2b). Figure 1 Electrocardiogram on admission showing ST segment elevation in inferior leads, II, III, aVF Sarcoidal Pericardial Effusion Masquerading As Acute Myocardial Infarction 2 of 4 Figure 2 Histopathological section showing epicardium and outer layer of myocardium. There is a well defined granuloma consistent with sarcoidosis in the epicardial fat. Section of the mediastinal tumour showing a necrotic mass. Preserved areas of the tumour show mature elements including cartilage. These features are those of mature mediastinal teratoma. (Haematoxylin and eosin x 40).

A Common Progenitor at the Heart of Development

Formation of the heart requires the coordinated functions of cardiac myocytes, smooth muscle cells, endothelial cells, and connective tissue elements. Several recent studies now reveal that these different cell types arise from a common progenitor (). These findings raise interesting questions about the lineage relationships of cardiovascular progenitor cell populations and suggest possibilities for cardiac repair in both congenital and acquired heart disease.

Tissue viability by contrast echocardiography

Residual tissue viability within the infarct area is one of the major determinants of regional functional recovery after acute myocardial infarction, playing also a protective role against LV remodelling. However, viability and functional recovery are not synonymous: functional recovery is only one of the aspects of viability. Several studies have shown how important it is to maintain perfusion independently from functional recovery. In patients with an extensive endocardial necrosis and a preserved normal perfusion in the middle and epicardial myocardium layers, even though functional recovery does not occur, remodelling processes may be attenuated. Tissue viability may be detected using several different methods. Perfusion-based techniques (i.e. PET, SPECT, MRI and MCE) are more accurate in predicting global function and LV remodelling whereas inotropic reserve-based methods (i.e. DE) are more accurate in predicting functional recovery. Several studies support the hypothesis that either LV remodelling or the possibility of myocardial dysfunction to recover are strictly dependent on the extent of microvascular damage. To date, myocardial contrast echocardiography and magnetic resonance imaging have shown to be very effective techniques for assessing microvascular perfusion. Our initial experience showed a very close correlation between these two perfusional techniques. In particular by MCE, it has been demonstrated that the persistence of residual anterograde or retrograde blood flow within the infarct zone can maintain myocardial viability for a prolonged time span. The incidence of LV remodelling is significantly lower in dysfunctioning but still perfused segments than in non-perfused ones. Therefore MCE can be used to identify viable segments that may help to prevent infarct expansion and remodelling, and thus improve patient outcomes.

Analysis of Postsystolic Myocardial Thickening Work in Selective Myocardial Layers During Progressive Myocardial Ischemia

Myocardial function is transmurally heterogeneous. Postsystolic work may functionally reflect ischemic but viable myocardium. We calculated systolic and postsystolic regional myocardial work index (RMWi) in subendocardial and subepicardial layers of myocardium supplied by a slowly occluding coronary artery. Progressive stenosis of the left anterior descending coronary artery lasting 11 +/- 5 days (end point) was induced in 10 dogs, and pressure-strain loops were obtained from subendocardial and subepicardial layers of apical and middle anterior segments by intracardiac ultrasound. At baseline, the RMWi was significantly higher (P < .05) in the subendocardial layer. At the end point, there was no significant change in the RMWi in ischemic myocardium; however, the postsystolic RMWi was higher (P < .05) in the subendocardial layer and accompanied a decrease in subendocardial myocardial blood flow, although viability was largely maintained. A significant subendocardial postsystolic RMWi at rest suggests an impending ischemic injury in coronary artery disease when segmental function is still preserved.

Non-compacted cardiomyopathy: clinical-echocardiographic study

The aim of the present study was to describe the clinical and echocardiographic findings of ventricular noncompaction in adult patients. Fifty-three patients underwent complete clinical history, electrocardiogram, Holter and transthoracic echocardiogram. Forty patients (75%) were in class I/II of the New York Heart Association, and 13 (25%) in class III/IV. Ventricular and supraventricular escape beats were found in 40% and 26.4%, respectively. Holter showed premature ventricular contractions in 32% and sustained ventricular tachycardia in 7.5%. Ventricular noncompaction was an isolated finding in 74% of cases and was associated with other congenital heart disease in 26%. Noncompacted ventricular myocardium involved only left ventricle in 62% of the patients and both ventricles in 38%. The mean ratio of noncompacted to compacted myocardial layers at the site of maximal wall thickness was 3.4 ± 0.87 mm (range 2.2–7.5). The presence of ventricular noncompaction in more than three segments was associated with a functional class greater than II and ventricular arrhythmia with demonstrable statistical significance by χ2(p < 0.003).Conclusiona) Noncompacted cardiomyopathy is a congenital pathological entity that can occur in isolated form or associated with other heart disease and often involves both ventricles. b) A ratio of noncompacted to compacted myocardium greater than 3 and involvement of three or more segments are indicators of poor prognosis. c) Since the clinical manifestations are not sufficient to establish diagnosis, echocardiography is the diagnostic tool that makes it possible to document ventricular noncompaction and establish prognostic factors.

Mechanisms of destabilization and early termination of spiral wave reentry in the ventricle by a class III antiarrhythmic agent, nifekalant

Nifekalant (NF) is a novel class III antiarrhythmic agent that is effective in preventing life-threatening ventricular tachycardia/fibrillation (VT/VF). We investigated mechanisms of destabilization and early termination of spiral-type reentrant VT by NF in a two-dimensional subepicardial myocardial layer of Langendorff-perfused rabbit hearts (n = 21) using a high-resolution optical action potential mapping system. During basic stimulation, NF (0.1 microM) caused uniform prolongation of action potential duration (APD) without affecting conduction velocity and an increase of APD restitution slope. VTs induced by direct current stimulation in the presence of NF were of shorter duration (VTs > 30 s: 2/54 NF vs. 19/93 control). During VTs in control (with visible rotors), the wave front chased its own tail with a certain distance (repolarized zone), and they seldom met each other. The average number of phase singularity (PS) points was 1.31 +/- 0.14 per 665 ms (n = 7). In the presence of NF, the wave front frequently encountered its own tail, causing a transient breakup of the spiral wave or sudden movement of the rotation center (spatial jump of PS). The average number of PS was increased to 1.63 +/- 0.22 per 665 ms (n = 7, P < 0.05) after NF. The mode of spontaneous termination of rotors in control was in most cases (9/10, 90.0%) the result of mutual annihilation of counterrotating wave fronts. With NF, rotors frequently terminated by wave front collision with the atrioventricular groove (12/19, 63.2%) or by trapping the spiral tip in a refractory zone (7/19, 36.8%). Destabilization and early termination of spiral wave reentry induced by NF are the result of a limited proportion of excitable tissue after modulation of repolarization.

Santaandvalentinepattern concentric growth of cardiac myocardium in the zebrafish

During embryogenesis, the myocardial layer of the primitive heart tube grows outward from the endocardial-lined lumen, with new cells added to generate concentric thickness to the wall. This is a key evolutionary step, demarcating vertebrates from more primitive chordates, and is essential for normal cardiac function. Zebrafish embryos with the recessive lethal mutations santa (san) and valentine (vtn) do not thicken, but do add the proper number of cells to the myocardium. Consequently, the heart chambers are huge, constituted of a monolayered myocardium lined by endocardium. This phenotype is similar to that of the heart of glass (heg) mutation, which we described previously as a novel endocardial expressed gene. By positional cloning, we here identify san as the zebrafish homolog of human CCM1, and vtn as the homolog of human CCM2. Dominant mutations of either in humans cause vascular anomalies in the brain, known as cerebral cavernous malformations. The synergistic effects of morpholino pairs indicate that san, vtn and heg are in a genetic pathway, and san and vtn contain protein motifs, NPxY and PTB domain, respectively, known to interact. This suggests that concentric growth of the myocardium, crucial for blood pressure generation, is dictated by a heg-san-vtn signaling pathway.

Diverse morphological lesions and serious arrhythmias with hemodynamic insults occur in the early myocardial contusion due to blunt impact in dogs

To investigate the morphology and hemodynamics of the early myocardial contusion, an animal model of cardiac contusion was established by impact to the precordial region at sternum at velocity of 10.0 m/s with a mechanical elastic-cord propelled impactor in 19 dogs. The electrocardiogram and both the left and right intra-ventricular pressures were recorded continuously throughout the experiment. Histological and immunohistochemical examinations of myoglobin, creatine kinase-MB and fibrinogen were conducted. At the moment of impact, abrupt over-pressures within the left and right ventricles occurred with concomitant serious arrhythmias followed by variety of cardiac conduction disorders and depressed left and right ventricular systolic pressures during the observation times. Histologically, lesions of myocardial contusions were identified at subepicardial, myocardial or subendocardial layer as interstitial hemorrhage, disruption or coagulative necrosis as well as contraction band necrosis of the muscle fibers, which might be categorized into the hemorrhagic, necrotized and mixed forms. The three forms of lesions were found to exist independently, or co-existed in a heart. However, severity of the lesions varied greatly with different parts even within a heart. Intravascular thromboses were occasionally discovered post-impact. Immunohistochemically, loss of myoglobin and creatine kinase-MB from cardiac cells, and accumulation of fibrinogen at the cell membranes were detected 5 min post-impact. The intracellular accumulation of fibrinogen increased with extension of post-impact intervals. Our results indicate that diverse morphological lesions concomitant with hemodynamic compromise and serious, even fatal arrhythmias occur in the early myocardial contusion, and intravascular thromboses are occasionally produced, suggesting that traumatic myocardial ischemic lesion may be induced due to blunt impact to the precordial region.

Prognosis of coronary flow reserve: a new therapeutic target?The opinions expressed in this article are not necessarily those of the Editors of the European Heart Journal or of the European Society of Cardiology.

Coronary circulation, as in other vascular territories, is able to maintain its constant flow even with changes in the myocardial perfusion pressure. This physiological adaptation mechanism is defined as autoregulation. The concept of coronary flow reserve (CFR) is related to the ratio between the coronary blood flow after maximum vasodilatation, and the coronary blood flow at rest.1 The highest CFR is in the subepicardial layer of the myocardium. The CFR is lower in the subendocardial layer, so in relation to a decrease in myocardial flow, the subendocardial CFR is exhausted first. It is well known that in the absence of macroscopic coronary artery disease, the decrease of the CFR can be attributed to alterations in the microvascular circulation.2 CFR can be measured by magnetic resonance imaging, positron emission tomography, coronariography, and transthoracic echocadiography. The last technique is especially useful because of its disposability, low costs, and the absence of radiation exposure. The lower limit of CFR proposed by Dimitrow et al .3 using different methods in control groups is 3.0. A reduction in CFR can be found in some diseases associated with coronary microvascular dysfunction such as hypertrophic cardiomyopathy (CFR 2.21±0.2), dilated cardiomyopathy (DCM) (CFR 1.9±0.2), and Syndrome X (CFR 2.27±0.3).4 The assessment of CFR … *Corresponding author. Tel: +34 91 3303290; Fax: +34 91 3303292. E-mail address : jlzamorano{at}vodafone.es

Fabry’s Disease Cardiomyopathy: Echocardiographic Detection of Endomyocardial Glycosphingolipid Compartmentalization

We sought to identify echocardiographic hallmarks of Fabry's disease cardiomyopathy (FC). The recognition of FC from other forms of left ventricular hypertrophy (LVH) by noninvasive imaging techniques is not yet available, and diagnosis, mostly in the absence of systemic manifestations, still relies on genetic and invasive studies. Forty consecutive patients (mean age 39 +/- 15 years, 22 men and 18 women) with an established diagnosis of Fabry's disease were submitted to echocardiographic evaluation. Control population consisted of 40 consecutive patients with hypertrophic cardiomyopathy (HCM), 40 hypertensive patients with echocardiographic evidence of LVH, and 40 age- and gender-matched healthy subjects with no LVH. All HCM patients and FC with LVH and/or cardiac symptoms underwent cardiac catheterization with left ventricular endomyocardial biopsy. Echocardiography showed in 83% of FC patients (95% of FC patients with LVH) a binary appearance of endocardial border absent in all HCM, hypertensive, and healthy subjects. The sensitivity and specificity of this echocardiographic feature in detecting Fabry patients in study population were 94% and 100%, respectively. Comparison of echocardiographic with histologic and ultrastructural findings showed the binary appearance to reflect an endomyocardial glycosphingolipids compartmentalization, consisting of thickened glycolipid-rich endocardium, free glycosphingolipid subendocardial storage, and an inner severely affected myocardial layer with a clear subendocardial-midwall layer gradient of disease severity. Echocardiographic binary appearance of left ventricular endocardial border, reflecting endomyocardial glycosphingolipids compartmentalization, represents a sensitive and specific diagnostic hallmark of Fabry's disease cardiomyopathy.

Effects of amiodarone on transmural dispersion of ventricular effective refractory periods across myocardial layers in the normal and hypertrophic canine heart

The effects of amiodarone on transmural dispersion of ventricular effective refractory periods (ERPs) in the normal and hypertrophic canine heart were investigated in vivo. By using the programmed stimulation protocol, the ERPs of epicardium (Epi), midmyocardium (Mid) and endocardium (Endo) were measured by inserting specially-designed electrodes into the three myocardial layers before and after mainlining of amiodarone. No significant ERPs-dispersion was observed in the three layers before and after mainlining of amiodarone in the normal group. In contrast, ERPs of all the three layers were prolonged in the hypertrophic heart, while the ERPs-dispersion was reduced significantly after mainlining of amiodarone. The ERPs-dispersion was significantly increased in the hypertrophic heart but not in the normal heart using "long-short" and "short-long" interval stimulation technique. It was concluded that (1) the differences in ERPs-dispersion among the three layers were significant in hypertrophic heart, and differences were not significant in normal canine heart; (2) ERPs of each three-myocardial layers were significantly prolonged after using amiodarone, but the ERPs-dispersion decreased in hypertrophic heart and (3) the programmed extrastimulus technique of "long-short" and "short-long" intervals increased the transmural ERPs-dispersion in the hypertrophic heart.

Compartmentalization of caveolin and its relating molecules in striated muscles of murine following their developmental stage

Compartmentalization of caveolin and its relating molecules in striated muscles of murine following their developmental stage We have investigated the expression level of caveolin-isoforms, Akt and calcineurin in cardiac and skeletal muscles of spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY) following four different developmental stages (10days, 4wk, 8wk, and 16-wk-old). The expression of caveolin-3 in cardiac muscle (CM) was highest in 10days old and gradually decreased from 4wk to 16-wk-old WKY rats. In contrast, the expression of caveolin-3 of SHR rats showed the opposite patterns. The expression of Akt in CM of WKY and SHR rats showed similar pattern upon aging. The expression of caveolin-3 in skeletal muscle (SM) of WKY rats was decreased with aging. In contrast, the expression of caveolin-3 in SM was highest in 4-wk-old SHR rats and became decreased upon aging. The expression of Akt in SM of WKY and SHR rats showed similar pattern to Akt expression in CM of WKY and SHR rats. Immunohistochemical analysis showed that caveolin-3 and calcineurin became co-localized in myocardial layer starting from 8-wk thru 16-wk-old SHR cardiac muscles. In situ hybridization analysis indicated that caveolin-3 mRNA was increased in CM of 16-wk-old compared to 8-wk-old SHR rats. (This work was supported in part by fund from Ministry of Agriculture and Forestry made in Program year 2005 to Research Project on the Production of Bio-organs)

In vivo and in vitro analysis of the vasculogenic potential of avian proepicardial and epicardial cells†

Coronary vessel formation is a special case in the context of embryonic vascular development. A major part of the coronary cellular precursors (endothelial, smooth muscle, and fibroblastic cells) derive from the proepicardium and the epicardium in what can be regarded as a late event of angioblastic and smooth muscle cell differentiation. Thus, coronary morphogenesis is dependent on the epithelial-mesenchymal transformation of the proepicardium and the epicardium. In this study, we present several novel observations about the process of coronary vasculogenesis in avian embryos, namely: (1) The proepicardium displays a high vasculogenic potential, both in vivo (as shown by heterotopic transplants) and in vitro, which is modulated by vascular endothelial growth factor (VEGF) and basic fibroblast growth factor signals; (2) Proepicardial and epicardial cells co-express receptors for platelet-derived growth factor-BB and VEGF; (3) Coronary angioblasts (found all through the epicardial, subepicardial, and compact myocardial layers) express the Wilms' tumor associated transcription factor and the retinoic acid-synthesizing enzyme retinaldehyde-dehydrogenase-2, two markers of the coelomic epithelium involved in coronary endothelium development. All these results contribute to the development of our knowledge on the vascular potential of proepicardial/epicardial cells, the existent interrelationships between the differentiating coronary cell lineages, and the molecular mechanisms involved in the regulation of coronary morphogenesis.

Candidate genes for the hereditary component of cardiac hypertrophy

Candidate genes for the hereditary component of cardiac hypertrophy

Diagnosis and outcome in congenital ventricular diverticulum and aneurysm

True congenital ventricular diverticulum and aneurysm in children are very uncommon. We report our experience to clarify the diagnosis and outcome of these little-known entities. Twenty-two patients with congenital ventricular outpouchings were identified in our database from 1973 to 2004. Morphologic characteristics (localization, connection to a ventricle, contractility), histologic findings, and cardiac and/or extracardiac abnormalities were analyzed in all 22 patients. Cardiovascular events and clinical courses were reviewed. Congenital ventricular diverticula (n = 16) were characterized by synchronal contractility and three myocardial layers on histologic examination. Two categories of congenital ventricular diverticulum could be identified with regard to their localization: apical and nonapical. Apical diverticula (n = 8) were always associated with midline thoracoabdominal defects and other heart malformations. Nonapical diverticula (n = 8) were always isolated defects. Congenital ventricular aneurysms (n = 6) were characterized by akinesis with paradoxical systolic motion, wide connection to the ventricle, fibrosis on histologic examination that appeared with high signal on T2 weighted magnetic resonance imaging, and absence of other heart or midline thoracoabdominal defects. The outcome was different in these two types of outpouchings: congential ventricular aneurysms were associated with adverse outcomes whereas the prognosis for congenital ventricular diverticula was good. Congenital ventricular diverticulum and aneurysm are two distinct entities, with different histologic and morphologic characteristics and outcomes. Assessment of these differential characteristics is of importance for prenatal counseling.

Release of calcitonin gene-related peptide from the isolated mouse heart: Methodological validation of a new model

Calcitonin gene-related peptide (CGRP), a potent vasodilator released from a subset of sensory Adelta- and C-fiber afferents, has been suggested to play a beneficial role in myocardial ischemia. Variations in CGRP release can possibly be correlated with diseases that involve changes in activity or degeneration of cardial afferent fibers. The aim of the present study was to evaluate a simple and easily reproducible model for measuring stimulated CGRP release from cardial afferents. For this reason freshly isolated mouse hearts were passed through incubations in series of 25 min. Solutions consisting of oxygenated synthetic interstitial fluid. Dissolved substances such as capsaicin, bradykinin and potassium chloride were used as excitatory test stimuli. For comparison, isolated mouse hearts were perfused with the same solutions through a cannula inserted into the rising aorta. The eluates were processed using an enzyme immuno-assay for measurement of CGRP concentrations. Capsaicin, bradykinin and the potassium solution caused concentration-dependent increases in CGRP release. There were no differences in CGRP release when oxygen was replaced by nitrogen in the solutions. Immersion of hearts caused significantly more CGRP release than perfusion with same solutions. The results suggest that mouse heart immersion is more effective than coronary perfusion in measuring stimulated CGRP release from cardial afferents which are widely distributed in the epicardium but rare in deeper myocardial layers. The results are discussed with respect to the potentially important vasodilatory and cardioprotective functions of CGRP released from activated epicardial afferents.

Histology of Vascular Myocardial Wall of Left Atrial Body After Pulmonary Venous Incorporation

During embryonic development, the common pulmonary vein (PV) becomes incorporated into the left atrium, giving rise to separate PV ostia. We describe the consequences of this incorporation process for the histology of the left atrium and the possible clinical implications. The histology of the left atrial (LA) wall in relation to PV incorporation was studied immunohistochemically in 16 human embryos and fetuses, 1 neonate, and 5 adults. The PV wall, surrounded by extrapericardially differentiated myocardial cells, was incorporated into the LA body. After incorporation, the composition of PVs and the smooth-walled LA body wall was histologically identical. The LA appendage, however, consisted of endocardial and myocardial layers without a vessel wall component. In 2 adults, the myocardium in the LA posterior wall was absent. At the transition of the LA body and LA appendage, a smooth-walled myocardial zone lacking the venous wall was observed. This zone was histologically identical to the sinus venarum of the right atrium. In conclusion, the LA body arises by incorporation and growth of PVs, presenting with a histologically identical structure of vessel wall covered by extrapericardially differentiated myocardium of PVs. Discontinuity of myocardium may be the substrate for arrhythmias, and absence of myocardium in some patients makes this area potentially vulnerable to damage inflicted by ablation strategies. A border zone between the LA body and LA appendage is hypothesized to be the left part of the embryonic sinus venosus.

Increased coronary flow may prolong transmural ventricular repolarisation

An increase in spatial dispersion of ventricular refractory periods reflects inhomogeneity of ventricular refractoriness and is associated with an increased risk of life-threatening ventricular arrhythmias. Spatial dispersion in ventricular refractoriness is determined by the differences in refractory periods of myocytes in epicardium, mid-myocardium and endocardium. Prolongation of ventricular repolarisation with drugs or physical means may reduce the spatial dispersion and the risk of arrhythmia. An increase in coronary flow has been shown to prolong the duration of ventricular repolarisation measured from epicardium in the intact animal heart. We hypothesised that an increase in coronary flow may also prolong ventricular repolarisation cross the three layers of ventricular myocardium through the release of nitric oxide. The simultaneously prolongation of transmural repolarisation may reduce the spatial dispersion of ventricular repolarisation and hence, the risk of life-threatening ventricular arrhythmias.

CT of Uhl’s Anomaly in an Adult

Uhl's anomaly is an extremely rare condition of unknown cause characterized by complete or partial absence of the right ventricular myocardial layer, which is replaced by nonfunctional fibroelastic tissue. The disease causes progressive right-sided heart failure, increased right-sided cardiac pressure, massive peripheral edema, and ascites. Patients usually present in infancy and rarely survive to adulthood. The disease appears to be congenital in origin. Diagnosis was previously made at autopsy, but advances in imaging now permit diagnosis by echocardiography or cross-sectional imaging (computed tomography or magnetic resonance). We present a case of a 51-year-old patient with Uhl's anomaly who underwent placement of a ventricular assist device as a bridge to cardiac transplantation, and discuss CT findings.

Side‐to‐side linking of myocardial cells in hypertrophic cardiomyopathy: Whole heart microscopic observation with tangential sections

By cross-section or longitudinal section, it is difficult to investigate longitudinal features of myocardial cells in the whole heart. Here, introducing the use of tangential sections to obtain longitudinal aspect of myocardial cells in any part of myocardium, the authors evaluated myocardium in the left ventricle in 10 normal hearts and four hearts with hypertrophic cardiomyopathy (HCM). Tangential sections were obtained by peeling the superficial layer of myocardium. After peeling the whole surface, secondary deep layer was peeled. These procedures were repeated more than five times through the wall. Intercalated discs (ICD) were observed immunohistochemically with anti-N-cadherin and antidesmoplakin. In normal hearts, myocardial cells were cut longitudinally and ran parallel in tangential sections. They linked end-to-end with simple and regular ICD with average lengths of 120-130 microm and average sarcomere numbers of 56-65. In HCM hearts, many myocardial cells were cut almost longitudinally running approximately parallel in tangential sections. Myocardial cells frequently showed side-to-side linking characterized by skewed ICD, indistinct ICD counterparts, and longitudinally arranged ICD. Two young HCM hearts had circle-shaped ICD and vacuole-like structures highlighted by immunostaining for N-cadherin, which were actually extracellular structures comparable with irregular side-to-side linking. It is considered that side-to-side linking of myocardial cells is a characteristic microscopic feature in HCM rather than myocardial disarray.