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Ventricular Wall (ventricular + wall)
Kinds of Ventricular Wall Terms modified by Ventricular Wall Selected AbstractsLeft Ventricular Non Compaction in ChildrenCONGENITAL HEART DISEASE, Issue 5 2010Sara H. Weisz MD ABSTRACT Left ventricular non compaction (LVNC) is a myocardial disease characterized by a hypertrabeculated myocardium. The hypertrabeculations in the left ventricular wall define deep recesses communicating with the left ventricular chamber where blood penetrates with increased risk of blood clots in the meshwork of the prominent trabeculations. The left ventricular apex and the free wall are particularly affected. During in utero ventriculogenesis, myocardial blood supply is initially linked to the presence of sinusoids, in which blood penetrates and diffuses nutriments and oxygen to myocardial cells. Progressively, with the development of the heart and the increase of cells demand of blood, coronary arteries system develops. This step is associated with myocardial modification that leads to compaction of hypertrabeculated myocardial net. Probably, the premature interruption of this process leads to ventricular noncompaction. Many studies have been conducted in adults with hypertrabeculated myocardium. To date, data regarding childhood LVNC are sparse. The aim of this review is to summarize the clinical and preclinical knowledge about LVNC in children. [source] Unusual Cause of Heart Failure in a 65-Year-Old WomanECHOCARDIOGRAPHY, Issue 10 2008Mirela Tomescu M.D., Ph.D. Left ventricular (LV) free wall rupture is a potentially lethal mechanical complication after myocardial infarction (MI). Pericardial adhesions or slow extracardiac leak and pericardial inflammation may result in a contained cardiac rupture. LV pseudoaneurysm is a relatively uncommon clinical entity. It may occur after MI, but also as a complication of infective endocarditis, cardiac surgery, or trauma. Patients developing LV pseudoaneurysm after MI may present angina pectoris or signs of congestive heart failure (HF) but often are asymptomatic. Surgery is the treatment of choice for LV pseudoaneurysms diagnosed in the first months after MI. The management of chronic LV pseudoaneurysms is still subject of debate. This report highlights a 65-year-old patient newly hospitalized for acute decompensated HF who was diagnosed with a large chronic LV pseudoaneurysm and severe mitral regurgitation. The patient underwent successful resection of the pseudoaneurysm and patch repair of the ruptured ventricular wall. [source] Real-Time Three-Dimensional Echocardiography in Diagnosis of Right Ventricular Pseudoaneurysm after Pacemaker ImplantationECHOCARDIOGRAPHY, Issue 3 2006Xuedong Shen M.D. Right ventricular rupture is a critical cardiac complication associated with cardiac tamponade and death. Occasionally, the site of rupture may be contained by the parietal pericardium and thrombus, thus forming a pseudoaneurysm. Cases of traumatic pseudoaneurysm of the right ventricle have been reported. However, right ventricular pseudoaneurysm following pacemaker implantation has not been previously reported. This case demonstrates two right ventricular pseudoaneurysms following perforation of the right ventricular wall using real-time three-dimensional echocardiography (3DE) after pacemaker implantation although only one definite pseudoaneurysm was diagnosed by routine two-dimensional echocardiography (2DE). We also found that color Doppler 3DE enhanced visualization of the connections between the right ventricle and the pseudoaneurysm. Color Doppler 3DE allowed us to peel away the myocardial tissue and rotate the image to study the jets from different angles. In summary, real-time 3DE and color Doppler 3DE provided excellent visualization of the right ventricular pseudoaneurysm, flow between the ventricle and the pseudoaneurysm, and additional information to that obtained by 2DE. [source] Restitution Properties and Occurrence of Ventricular Arrhythmia in LQT2 Type of Long QT SyndromeJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 9 2002SOU YAMAUCHI M.D. Mechanisms of Ventricular Arrhythmia in LQT2 Heart.Introduction: The aim of this study was to clarify the ventricular tachyarrhythmia mechanism induced by the IKr -blocking agent E4031, simulating the LQT2 form. Electrophysiologic properties were examined in 13 canines before and after administration of E4031. Method and Results: Thirty-six needle electrodes were inserted into the anterior left ventricular wall. From each needle, local unipolar electrograms were obtained from four intramural sites. Activation time (AT) and activation-recovery interval (ARI) were measured. To evaluate the susceptibility to ventricular arrhythmia, intramural ARI dispersions and the restitution relationship between ARI and diastolic interval were calculated. After E4031 administration, ARI prolonged uniformly in each myocardial layer. However, ARI dispersion was not augmented compared with control. The slope of the ARI restitution curve after E4031 was significantly steeper than control. A steep slope may result from augmented ARI alternans. In 11 of the 13 canines, ventricular tachyarrhythmia was induced by programmed stimulation after E4031, whereas no arrhythmia was induced by the same protocol in control. Conclusion: Steepness of electrical restitution may play a major role in arrhythmogenicity in LQT2 hearts. [source] Laplacian Electrograms and the Interpretation of Complex Ventricular Activation Patterns During Ventricular FibrillationJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 10 2000PH.D., RUBEN CORONEL M.D. Laplacian Electrograms and Ventricular Fihrillation. Introduction. During ventricular fibrillation (VF) interpretation of a local electrogram and determination of the local activation moment are hampered by remote activity or intervening repolarization waves. Successful defibrillation depends on critical timing of the shock relative to local activation. We tested the applicabillity of Laplacian electrograms for detection of the moment of local activation during VF. Methods and Results. From isolated perfased porcine infact heart, 247 local unipolar electrograms were recorded simultaneously (13 × 19 matrix, interelectrode distance 0.3 mm) from the left ventricular wall during sinus rhythm, following pacing or during VF, Activation maps were constructed based on local unipolar electrograms, and Laplacian electrograms were calculated from local electrograms ane its eight neighbors. The Laplacian electrogram displayed a sharp R/S complex with local activation iodicted by the moment of zero crossing without interference from remote activity or repolarization waves. Its amplitude increased with decreasing interelectrode distance, Following epicardial stimulation, Laplacian amplitude was significantly larger than during complexes with different morphology. Collision of wavefronts was associated with entirely positive Laplacian waveforms; "focal" appearancce of acitivity was associated with an entirely negative waveform. Activation block in the activation maps was correlated with the appearance of substanined episodes of negativity or positivity in the Laplacian electrogram (depending on the location of the recording site relative to the line of block). Conclusion. Laplacian electrograms allow detection of the moment of local activation without interference from remote activity or repolarization, especially during complex arrhythmias. The technique applied toe automatic sensing devices, such its the internal defibrillator, may optimize defibrtilation success. (J Cardiovasc Electrophysiol, Vol. 11, pp. 1119-1128, October 2000) [source] Early homing of adult mesenchymal stem cells in normal and infarcted isolated beating heartsJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 2 2008Claudia Penna Abstract Little is known on the early homing features of transplanted mesenchymal stem cells (MSCs). We used the isolated rat heart model to study the homing of MSCs injected in the ventricular wall of a beating heart. In this model all types of cells and matrix elements with their interactions are represented, while external interferences by endothelial/neutrophil interaction and neurohormonal factors are excluded. We studied the morphology and marker expression of MSCs implanted in normal hearts and in the border-zone of infarcted myocardium. Early morphological adaptation of MSC homing differs between normal and infarcted hearts over the first 6 hrs after transplantation. In normal hearts, MSCs migrate very early through the interstitial milieu and begin to show morphological changes. Yet, in infarcted hearts MSCs remain in the site of injection forming clusters of round-shaped cells in the border-zone of the infarcted area. Both in normal and infarcted hearts, immuno-histochemistry and confocal imaging showed that, besides the proliferative marker proliferating cell nuclear agent (PCNA), some transplanted cells early express myoblastic maker GATA-4, and some of them show a VWF immunopositivity. Moreover, a few hours after injection connexin-43 is well evident between cardiomy-ocytes and injected cells. This study indicates for the first time that the isolated beating heart is a good model to study early features of MSC homing without external interferences. The results show (i) that MSCs start to change marker expression few hours after injection into a beating heart and (ii) that infarcted myocardium influences transplanted MSC morphology and mobility within the heart. [source] Catheter-Based Transendocardial Myocardial Gene TransferJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 1 2002CHRISTER SYLVÉNM.D. Ph.D. Background and Aim: Local modulation of myocardial function by gene transfer or cell depositions constitutes a potential method of cardiac treatment. This study tested the morphology of myocardial plasmid gene transfer by catheter-based transendocardial injection (NOGA). Methods: Left ventricular morphology and electrical and mechanical characteristics were mapped in three dimensions. In two pigs, 0.10 mL oftoluidine blue was injected at ten sites. In seven pigs, seven to ten injections of 0.10 mL saline containing 0.10 mg pCMV-LacZ expressing the enzyme ,-galactosidase and 0.10 mg phVEGF-A165 were given. The pigs were sacrificed after 3 days and gene expression was determined. Results: Macroscopically on the endocardial surface, all identified spots were located in the target area. However, along the transmyocardial axis, injections with color and plasmid were located randomly throughout the left ventricular wall from the endocardium to the epicardium. In each detected spot, gene expression of ,-galactosidase was observed in an approximate myocardial volume of 5 × 5 × 5 mm. Microscopically, the transfected cells were located typically at the tip of the injection scar. As a rule, 10 to 20 transfected cells were located at the end of the injection scar. In sections where expression of both transcripts was observed, 42% of the cells expressed both ,-galactosidase and vascular endothelial growth factors (VEGF), 32% only ,-galactosidase, and 26% only VEGF. Conclusions: Myocardial gene transfer following magnetic guidance can be located precisely on the left ventricular inner surface. Within the myocardium, gene expression is local around the distal tip of the injection scar and is located randomly at every level of depth of the left ventricular wall. [source] Three-dimensional diffusion tensor microscopy of fixed mouse heartsMAGNETIC RESONANCE IN MEDICINE, Issue 3 2004Yi Jiang Abstract The relative utility of 3D, microscopic resolution assessments of fixed mouse myocardial structure via diffusion tensor imaging is demonstrated in this study. Isotropic 100-,m resolution fiber orientation mapping within 5.5° accuracy was achieved in 9.1 hr scan time. Preliminary characterization of the diffusion tensor primary eigenvector reveals a smooth and largely linear angular rotation across the left ventricular wall. Moreover, a higher level of structural hierarchy is evident from the organized secondary and tertiary eigenvector fields. These findings are consistent with the known myocardial fiber and laminar structures reported in the literature and suggest an essential role of diffusion tensor microscopy in developing quantitative atlases for studying the structure,function relationships of mouse hearts. Magn Reson Med 52:453,460, 2004. © 2004 Wiley-Liss, Inc. [source] In vivo study of microcirculation in canine myocardium using the IVIM method,MAGNETIC RESONANCE IN MEDICINE, Issue 3 2003Virginie Callot Abstract The intravoxel incoherent motion (IVIM) method was implemented in closed-chest dogs to obtain measurements on microcirculation in the left ventricular wall in vivo. Specifically, it enabled us to measure the mean microflow velocity (400 ± 40 ,m/s) and the vascular volume fraction (VVF) (11.1% ± 2.2%), and observe the directional preference of capillary orientation. The apparent diffusion coefficients (ADCs) of water along and perpendicular to myofibers were also measured. With vasodilatation by adenosine infusion, a 25% increase in the VVF and a 7% increase in the mean microflow velocity were observed, while no change in the ADC was detected. A 28.5% decrease of the ADC was observed postmortem. Magn Reson Med 50:531,540, 2003. Published 2003 Wiley-Liss, Inc. [source] Nondestructive optical determination of fiber organization in intact myocardial wallMICROSCOPY RESEARCH AND TECHNIQUE, Issue 7 2008Rebecca M. Smith Abstract Mapping the myocardial fiber organization is important for assessing the electrical and mechanical properties of normal and diseased hearts. Current methods to determine the fiber organization have several limitations: histological sectioning mechanically distorts the tissue and is labor-intensive, while diffusion tensor imaging has low spatial resolution and requires expensive MRI scanners. Here, we utilized optical clearing, a fluorescent dye, and confocal microscopy to create three-dimensional reconstructions of the myocardial fiber organization of guinea pig and mouse hearts. We have optimized the staining and clearing procedure to allow for the nondestructive imaging of whole hearts with a thickness up to 3.5 mm. Myocardial fibers could clearly be identified at all depths in all preparations. We determined the change of fiber orientation across strips of guinea pig left ventricular wall. Our study confirms the qualitative result that there is a steady counterclockwise fiber rotation across the ventricular wall. Quantitatively, we found a total fiber rotation of 105.7 ± 14.9° (mean ± standard error of the mean); this value lies within the range reported by previous studies. These results show that optical clearing, in combination with a fluorescent dye and confocal microscopy, is a practical and accurate method for determining myocardial fiber organization. Microsc. Res. Tech., 2008. © 2008 Wiley-Liss, Inc. [source] Microvasculature of the human cerebral white matter: Arteries of the deep white matterNEUROPATHOLOGY, Issue 2 2003Hiroko Nonaka The vascular architecture of the human cerebral deep white matter was studied using soft X-ray and diaphanized specimens, achieved by intra-arterial injection of barium and vascular stain respectively, and also by electron microscopic examination of the corrosion cast of arteries in normal adult brains. The deep white matter arteries passed through the cerebral cortex with a few branches to the cortex and ran straight through the white matter. The arteries concentrated ventriculopetally to the white matter around the lateral ventricle. Anastomoses were noted around the ventricular wall at the terminals of the deep white matter arteries. No centrifugal branches irrigating the periventricular white matter from the lenticulo-striate arteries were observed in the present study. The presence of anastomoses among the terminal branches of deep white matter arteries protects against ischemic change or infarction in this area from an occlusion of a single deep white matter artery. This may lead to development of terminal zone infarction from ischemia or vascular diseases, affecting multiple deep white matter arteries. The subcortical and deep white matter arteries had thick adventitial sheaths and large adventitial spaces in the white matter but not in the cortex. The presence or absence of the adventitial space is regarded as another characteristic difference between the arteries in the white matter and cortex. This difference may influence pathological changes in vascular lesions in these respective areas. [source] Three-dimensional architecture of the left ventricular myocardiumTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 6 2006Paul P. Lunkenheimer Abstract Concepts for ventricular function tend to assume that the majority of the myocardial cells are aligned with their long axes parallel to the epicardial ventricular surface. We aimed to validate the existence of aggregates of myocardial cells orientated with their long axis intruding obliquely between the ventricular epicardial and endocardial surfaces and to quantitate their amount and angulation. To compensate for the changing angle of the long axis of the myocytes relative to the equatorial plane of the ventricles with varying depths within the ventricular walls, the so-called helical angle, we used pairs of cylindrical knives of different diameters to punch semicircular slices from the left ventricular wall of pigs, the slices extending from the epicardium to the endocardium. The slices were pinned flat, fixed in formaldehyde, embedded in paraffin, sectioned, stained with azan or hematoxilin and eosin, and analyzed by a new semiautomatic procedure. We made use of new techniques in informatics to determine the number and angulation of the aggregates of myocardial cells cut in their long axis. The alignment of the myocytes cut longitudinally varied markedly between the epicardium and the endocardium. Populations of myocytes, arranged in strands, diverge by varying angles from the epicardial surface. When paired knives of decreasing diameter were used to cut the slices, the inclination of the diagonal created by the arrays increases, while the lengths of the array of cells cut axially decreases. The visualization of the size, shape, and alignment of the myocytic arrays at any side of the ventricular wall is determined by the radius of the knives used, the range of helical angles subtended by the alignment of the myocytes throughout the thickness of the wall, and their angulation relative to the epicardial surface. Far from the majority of the ventricular myocytes being aligned at angles more or less tangential to the epicardial lining, we found that three-fifths of the myocardial cells had their long axes diverging at angles between 7.5 and 37.5° from an alignment parallel to the epicardium. This arrangement, with the individual myocytes supported by connective tissue, might control the cyclic rearrangement of the myocardial fibers. This could serve as an important control of both ventricular mural thickening and intracavitary shape. Anat Rec Part A 288A:565,578, 2006. © 2006 Wiley-Liss, Inc. [source] Nature, significance, and mechanisms of electrical heterogeneities in ventricleTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 2 2004Steven Poelzing Abstract Previously, dispersion of repolarization (DOR) has been extensively linked to the development of arrhythmias and sudden cardiac death. The electrical heterogeneities that cause DOR between transmural myocyte layers have been reported in a wide variety of animals and humans. The underlying causes of transmural electrical heterogeneities are in part due to heterogeneous functional expression of proteins responsible for ion handling. Recently, we found that electrophysiologic heterogeneities between subepicardial and midmyocardial cells can form a substrate for reentrant ventricular arrhythmias. However, cell-to-cell coupling through gap junctions is expected to attenuate transmural heterogeneities between cell types spanning the ventricular wall. In this article we review a hypothesis that regional uncoupling resulting from expression patterns of gap junctions across the ventricular wall underlies DOR, and DOR can be amplified under disease conditions which remodel gap junctions. We find the principle gap junction protein, connexin43 (Cx43), is selectively reduced in the subepicardium (by 24%) compared to deeper layers of normal canine left ventricle. Additionally, the greatest DOR occurs within the subepicardial-midmyocardial interface, precisely where Cx43 expression is reduced. The present data suggests that ion channel and gap junction heterogeneities act in conjunction to form and maintain transmural DOR. Importantly, both ion channel and gap junction remodeling occurs during many disease states such as heart failure. Importantly, in the absence of ion channel remodeling, pharmacological uncoupling increases transmural DOR, particularly within the epicardial-midmyocardial interface, to values observed in heart failure. Therefore, these data suggest that heterogeneous Cx43 expression produces functionally significant electrophysiologic heterogeneities across the ventricular wall and may be a mechanism for promoting DOR which underlie arrhythmias in heart failure. © 2004 Wiley-Liss, Inc. [source] Patterns of laminins and integrins in the embryonic ventricular zone of the CNSTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 6 2007Justin D. Lathia Abstract The extracellular matrix (ECM) provides both a physical framework and a microenvironment that supplies instructive signals from the earliest stages of multicellular development. As a first step toward understanding the role of the ECM in regulating the behavior of neural stem cells (NSCs), here we show the localization of laminins, a heterotrimeric family of ECM molecules expressed in many different stem cell microenvironments, and their corresponding receptors in the embryonic murine ventricular zone (VZ) within which the NSCs undergo symmetrical and asymmetrical divisions required for cortical development. In addition to the presence of laminins containing both the ,2 and ,4 chains, we find distinct patterns of ECM receptor expression in the VZ and in the overlying cortex. Neural stem cells derived from the VZ express high levels of the integrin laminin receptor ,6,1. At developmental stages at which NSCs undergo asymmetrical divisions, integrin ,1 was unevenly distributed in some mitotic pairs at the ventricular wall. These results suggest a significant role in the regulation of NSC fate for laminin/integrin signaling within the microenvironment of the VZ and provide a framework for future molecular and cellular analyses of the role of the ECM in neural development. J. Comp. Neurol. 505:630,643, 2007. © 2007 Wiley-Liss, Inc. [source] Optimization of Repolarization during Biventricular Pacing: A New Target in Patients with Biventricular Devices?ANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 1 2010Cengizhan Türko, lu M.D. Background: Evaluation of repolarization during sequentional biventricular pacing. Methods: Patients with biventricular devices, and left ventricular leads placed to the basal part of lateral left ventricular wall were enrolled. QRS, QTc, JTc, and corrected Tpeak-Tend intervals were compared during sequentional biventricular, left ventricular, and right ventricular pacing. Results: Five patients with nonischemic and five with ischemic cardiomyopathy due to anterior myocardial infarction were enrolled. No correlation was observed between values of repolarization among patients. The optimal values of repolarization were significantly different from values of echocardiographically guided hemodynamic optimization. Two patients with biventricular pacing-induced ventricular fibrillation were successfully treated by reprogramming of V-V delay according to interventricular delay resulting in shorter Tpeak-Tend interval, although delayed effect of amiodarone in one of these patients cannot be ruled out. Conclusions: Patients with biventricular devices may be prone to development of ventricular arrhythmias depending on programmed V-V interval. We suggest that optimization of repolarization may be performed in patients with biventricular pacemakers in the absence of backup ICD and those with frequent episodes of ventricular tachyarrhythmias, although this finding deserves further study. Ann Noninvasive Electrocardiol 2010;15(1):36,42 [source] Ionic Mechanisms and Vectorial Model of Early Repolarization Pattern in the Surface Electrocardiogram of the AthleteANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 3 2008Eduardo C. Barbosa M.D. Background: The electrocardiogram (ECG) of the athlete displays particular characteristics as a consequence of both electrophysiological and autonomic remodeling of the heart that follows continued physical training. However, doubts persist on how these changes directly interact during ventricular activation and repolarization ultimately affecting surface ECG waveforms in athletes. Objective: This article considers an in deep rationale for the electrocardiographic pattern known as early repolarization based on both electrophysiological mechanisms at cellular level and the vectorial theory of the cardiac activation. Methods: The mechanism by which the autonomic remodeling influences the cardiac electrical activation is reviewed and an insight model of the ventricular repolarization based on ionic models and the vectorial theory of the cardiac activation is proposed. Results: Considering the underlying processes related to ventricular electrical remodeling, we propose that, in athletes' heart: 1) vagal modulation increases regional electrophysiological differences in action potential phases 1 and 2 amplitudes, thus enhancing a voltage gradient between epicardial and endocardial fibers; 2) this gradient affects depolarization and repolarization timing sequences; 3) repolarization wave front starts earlier on ventricular wall and partially overcomes the end of depolarization causing an upward displacement of the J-point, ST segment elevation, and inscription of magnified T-waves amplitudes leading to characteristic surface ECG waveform patterns. Conclusions: In athletes, the association between epicardial to endocardial electrophysiological differences and early repolarization ECG pattern can be demonstrated by the vectorial theory of the ventricular activation and repolarization. [source] Disseminated haemangiosarcoma in an Eastern barred bandicoot (Perameles gunnii)AUSTRALIAN VETERINARY JOURNAL, Issue 9 2000KB BODLEY A captive adult male Eastern barred bandicoot (Perameles gunnii) presented with three palpable subcutaneous masses in November 1998. A diagnosis of haemangiosarcoma was made based on histological examination of one excised mass. Euthanasia of the animal was performed 11 days postsurgery and a proliferative lesion in the paralumbar musculature and similar, smaller proliferative lesions surrounding the right popliteal lymph node and in the ventricular wall of the heart were found. Metastatic lesions were found in the liver and lung. The histological features of the neoplastic tissues supported the diagnosis of a poorly differentiated, disseminated haemangiosarcoma. This is the first reported case of haemangiosarcoma in the Eastern barred bandicoot. [source] Teratogenic effects of bis-diamine on the developing myocardiumBIRTH DEFECTS RESEARCH, Issue 3 2004Nobuhiko Okamoto Abstract BACKGROUND Bis-diamine induces conotruncal anomalies and disproportional ventricular development in rat embryos when administered to the mother. To evaluate the mechanisms of disproportional ventricular development in the anomalous heart, we analyzed the morphology of the embryonic heart and investigated cardiomyocytic DNA synthesis and apoptosis. METHODS A single dose of 200 mg of bis-diamine was administered to pregnant rats Wistar on day 9.5 of pregnancy. The embryos were removed on each embryonic day from 10.5 to 18.5. Expression of cardiotrophin-1 and hepatocyte growth factor was investigated on the sections, and cardiotrophin-1, hepatocyte growth factor and myocyte enhancer factor 2 mRNA expression was examined by reverse transcriptase,polymerase chain reaction. Myocardial DNA synthesis was investigated using 5-bromo-2,-deoxyuridine and the labeling index was calculated for each heart. Apoptosis was also analyzed using TUNEL reaction and electrophoresis of DNA fragmentation. RESULTS The embryos treated with bis-diamine had conotruncal anomalies associated with thin left ventricular wall in the later stage. The labeling index on embryonic day 15.5 and 16.5 was significantly lower than those in the controls. Hepatocyte growth factor and cardiotrophin-1 mRNA expression was upregulated on embryonic day 12.5 and 15.5 in bis-diamine,treated hearts. Fewer apoptotic cells were detected in the hearts of bis-diamine,treated embryos than in control hearts from embryonic day 14.5 to 16.5. CONCLUSIONS The ventricular disproportion in the bis-diamine,treated heart may be caused by the early myocardial differentiation delay and poor proliferation and reduced apoptosis associated with anomalous circulatory condition in the later stage. Birth Defects Research (Part A), 2004. © 2004 Wiley-Liss, Inc. [source] Nicorandil Improves Myocardial High-Energy Phosphates In Postinfarction Porcine HeartsCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 8 2002Yo Murakami SUMMARY 1.,Nicorandil is a potent vasodilator combining the effects of a nitrate with an ATP-sensitive potassium channel (KATP) opener. Because the postinfarct remodelled heart has increased vulnerability to subendocardial hypoperfusion, it is possible that the vasodilator effects of nicorandil could cause transmural redistribution of blood flow away from the subendocardium. Alternatively, the KATP channel opening effects of nicorandil could exert a beneficial effect on mitochondrial respiration. Consequently, the present study was performed to examine the effect of nicorandil on energy metabolism in the postinfarct heart. 2.,Studies were performed in swine in which myocardial infarction produced by proximal left circumflex coronary artery ligation had resulted in left ventricular remodeling. [31P] nuclear magnetic resonance spectroscopy (MRS) was used to examine the myocardial energy supply/demand relationship across the left ventricular wall while the transmural distribution of blood flow was examined with radioactive microspheres. Data were obtained during baseline conditions and during infusion of nicorandil (100 ,g, i.v., followed an infusion of 25 ,g/kg per min). 3.,Nicorandil caused coronary vasodilation with a preferential increase in subepicardial flow; however, subendocardial flow also increased significantly. Nicorandil had no significant effect on the rate,pressure product or myocardial oxygen consumption. The ratio of phosphocreatine (PCr)/ATP determined with MRS was abnormally depressed in remodelled hearts (2.01 ± 0.11, 1.85 ± 0.10 and 1.59 ± 0.11 for subepicardium, midwall and subendocardium, respectively) compared with normal (2.22 ± 0.11, 2.01 ± 0.15 and 1.80 ± 0.09, respectively). Nicorandil had no effect on the high-energy phosphate content of normal hearts. However, nicorandil increased the PCr/ATP ratio in the subendocardium of remodelled hearts from 1.59 ± 0.11 to 1.87 ± 0.10 (P < 0.05). 4.,Although nicorandil caused modest redistribution of blood flow away from the subendocardium of the postinfarct left ventricle, this was associated with an increase of the PCr/ATP ratio towards normal. These results suggest that nicorandil exerts a beneficial effect on energy metabolism in the subendocardium of the postinfarct remodelled left ventricle. [source] "Sensing alternans" in a patient with a newly implanted pacemakerCLINICAL CARDIOLOGY, Issue 3 2006Amgad N. Makaryus M.D. Abstract This report describes the case of an 80-year-old man with a history of coronary artery disease who presented with acute pericarditis secondary to pacemaker lead perforation of the ventricular wall 2 days after undergoing dual lead pacemaker implantation. The electrocardiogram revealed sinus rhythm with an intra-atrial conduction delay and intermittent failure of atrial sensing as evidenced by alternating atrial spikes in every other P wave. The noted pericardial effusion and the likely shifting of the atrial lead with each alternate beat caused the "sensing alternans" that was seen on the admission electrocardiogram. [source] Teratogenic effect of bis-diamine on embryonic rat heartCONGENITAL ANOMALIES, Issue 3 2000Masao Nakagawa ABSTRACT, Bis-diamine induces conotruncal anomalies including persistent truncus arteriosus, tetralogy of Fallot, interruption of the aortic arch, and ventricular septal defect in rat embryos when administered to the mother. Bis-diamine also induces extracardiac malformations including thymic hypoplasia, facial dysmorphism, forelimb anomalies and diaphragmatic hernia. However, the teratogenic mechanisms of this chemical in early developing rat hearts have not been fully established. Chimeric studies in chick and quail embryos demonstrated that the cranial neural crest cells reached the cardiac outflow tract, contributing to aorticopulmonary and truncal septation. Since an ablation of the cranial neural crest also produced the conotruncal anomalies, bis-diamine is proposed to disturb the normal migration of cardiac neural crest cells to the heart. Based on our data concerning cardiac anomalies induced by bis-diamine, we reviewed how the cardiac malformations were morphologically established in early developing rat hearts. Our data showed that 1) cardiovascular anomalies induced by bis-diamine are time- and species or strain- dependent. 2) bis-diamine reduces the number of neural crest cells migrating to participate in the conotruncal septation, 3) bis-diamine induces anomalous coronary arteries, thin ventricular walls and epicardial defects, and 4) some embryos cultured in the medium containing bis-diamine had extra-cardiac abnormalities including abnormal location of the otic placodes and delay in mid brain closure. Conclusively, bis-diamine does not appear to merely affect the cardiac development, but rather disturbs normal development of all the organs contributed to by neural crest cells. [source] Relationship Between Regional Shortening and Asynchronous Electrical Activation in a Three-Dimensional Model of Ventricular ElectromechanicsJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 2003TARAS P. USYK Ph.D. Introduction: Asynchronous electrical activation can cause abnormalities in perfusion and pump function. An electromechanical model was used to investigate the mechanical effects of altered cardiac activation sequence. Methods and Results: We used an anatomically detailed three-dimensional computational model of the canine ventricular walls to investigate the relationship between regional electrical activation and the timing of fiber shortening during normal and ventricular paced beats. By including a simplified Purkinje fiber network and anisotropic impulse conduction in the model, computed electrical activation sequences were consistent with experimentally observed patterns. Asynchronous time courses of regional strains during beats stimulated from the left or right ventricular epicardium showed good agreement with published experimental measurements in dogs using magnetic resonance imaging tagging methods. When electrical depolarization in the model was coupled to the onset of local contractile tension development by a constant time delay of 8 msec, the mean delay from depolarization to the onset of systolic fiber shortening was 14 msec. However, the delay between the onset of fiber tension and initial shortening varied significantly; it was as late as 60 msec in some regions but was also as early as ,50 msec (i.e., 42 msec before depolarization) in other regions, particularly the interventricular septum during free-wall pacing. Conclusion: The large variation in delay times was attributable to several factors including local anatomic variations, the location of the site relative to the activation wavefront, and regional end-diastolic strain. Therefore, we conclude that these factors, which are intrinsic to three-dimensional ventricular function, make the regional sequence of fiber shortening an unreliable surrogate for regional depolarization or electromechanical activation in the intact ventricles. (J Cardiovasc Electrophysiol, Vol. 14, pp. S196-S202, October 2003, Suppl.) [source] Cardiac amyloidosis: MR imaging findings and T1 quantification, comparison with control subjectsJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 6 2007Gabriele A. Krombach MD Abstract In cardiac amyloidosis an interstitial deposition of amyloid fibrils causes concentric thickening of the atrial and ventricular walls. We describe the results of tissue characterization of the myocardium by T1 quantification and MRI findings in a patient with cardiac amyloidosis. The T1 time of the myocardium was elevated compared to that in individuals without amyloidosis. The T1 time of the myocardium was 1387 ± 63 msec (mean value obtained from four measurements ± standard deviation [SD]) in the patient with cardiac amyloidosis, while the reference value obtained from the myocardium of 10 individuals without known myocardial disease was 1083 ± 33 msec (mean value ± SD). In combination with other MR findings suggestive of amyloidosis, such as homogeneous thickening of the ventricular and atrial walls, thickening of the valve leaflets, restrictive filling pattern, and reduction of systolic function, T1 quantification may increase diagnostic confidence. J. Magn. Reson. Imaging 2007;25:1283,1287. © 2007 Wiley-Liss, Inc. [source] Expression of brain natriuretic peptide in the rat heart studies during heart growth and in relation to sympathectomyMICROSCOPY RESEARCH AND TECHNIQUE, Issue 1 2004Magnus Hansson Abstract Brain natriuretic peptide (BNP) might be of importance during heart development and is described to be increasingly expressed in congestive heart failure and to affect the progress of this condition. However, details in the normal expression of BNP are still unclear in various parts of the adult and growing heart, including the conduction system. In this study, we investigated the expression of BNP in relation to that of atrial natriuretic peptide (ANP) in the growing as well as in the adult rat heart. The effects of chemical sympathectomy in adult rats were also examined. Contrary to previous BNP immunohistochemical studies, the BNP antiserum was preabsorbed with an excess of ANP before staining to abolish the crossreactivity with ANP. There was a pronounced BNP immunoreaction in the auricles, the trabeculated ventricular walls, and the peripheral parts of the conduction system at 0,1 days postnatally. The degree of immunoreaction gradually decreased with increasing age. A similar developmental pattern was seen concerning ANP expression, but the magnitude of the latter clearly exceeded that for BNP. Immunoreaction for BNP was never detected in the atrioventricular (AV) node and AV bundle at any stage. In contrast to the situation for ANP previously observed, no obvious changes in BNP immunoreaction patterns were observed in response to sympathectomy. This is the first study to thoroughly demonstrate the expression of BNP in the various regions of the rat heart during growth and in the normal and sympathectomized adult stage. The observations are related to possible functions of natriuretic peptides in the growing and adult heart. Microsc. Res. Tech. 64:30,42, 2004. © 2004 Wiley-Liss, Inc. [source] Three-dimensional architecture of the left ventricular myocardiumTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 6 2006Paul P. Lunkenheimer Abstract Concepts for ventricular function tend to assume that the majority of the myocardial cells are aligned with their long axes parallel to the epicardial ventricular surface. We aimed to validate the existence of aggregates of myocardial cells orientated with their long axis intruding obliquely between the ventricular epicardial and endocardial surfaces and to quantitate their amount and angulation. To compensate for the changing angle of the long axis of the myocytes relative to the equatorial plane of the ventricles with varying depths within the ventricular walls, the so-called helical angle, we used pairs of cylindrical knives of different diameters to punch semicircular slices from the left ventricular wall of pigs, the slices extending from the epicardium to the endocardium. The slices were pinned flat, fixed in formaldehyde, embedded in paraffin, sectioned, stained with azan or hematoxilin and eosin, and analyzed by a new semiautomatic procedure. We made use of new techniques in informatics to determine the number and angulation of the aggregates of myocardial cells cut in their long axis. The alignment of the myocytes cut longitudinally varied markedly between the epicardium and the endocardium. Populations of myocytes, arranged in strands, diverge by varying angles from the epicardial surface. When paired knives of decreasing diameter were used to cut the slices, the inclination of the diagonal created by the arrays increases, while the lengths of the array of cells cut axially decreases. The visualization of the size, shape, and alignment of the myocytic arrays at any side of the ventricular wall is determined by the radius of the knives used, the range of helical angles subtended by the alignment of the myocytes throughout the thickness of the wall, and their angulation relative to the epicardial surface. Far from the majority of the ventricular myocytes being aligned at angles more or less tangential to the epicardial lining, we found that three-fifths of the myocardial cells had their long axes diverging at angles between 7.5 and 37.5° from an alignment parallel to the epicardium. This arrangement, with the individual myocytes supported by connective tissue, might control the cyclic rearrangement of the myocardial fibers. This could serve as an important control of both ventricular mural thickening and intracavitary shape. Anat Rec Part A 288A:565,578, 2006. © 2006 Wiley-Liss, Inc. [source] | |||||||||||||||||||||||||