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PubMed1984

M-mode echocardiographic findings in children with idiopathic restrictive cardiomyopathy.

The M-mode echocardiographic findings in five pediatric patients, ages 4-15 years, with primary idiopathic restrictive cardiomyopathy, diagnosed by cardiac catheterization, and of 12 normal children (control group) are presented. The M-mode echocardiographic findings in patients with restrictive cardiomyopathy were (1) normal left and right ventricular end-diastolic dimension, (2) normal left ventricular posterior wall and interventricular septal thickness (three patients) or mild concentric hypertrophy (two patients), (3) normal opening and closing velocity of the mitral valve, (4) consistently enlarged left atrium (more than 40 mm) in all, and (5) right ventricular systolic time intervals compatible with pulmonary artery hypertension. The left ventricular ejection phase parameters (systolic time intervals, shortening fraction, and mean velocity of circumferential fiber shortening) were normal. Left ventricular relaxation phase parameters (diastolic function) were abnormal. The isovolumic relaxation time index was prolonged, 68 +/- 40 ms (+/- SD), in the study group as compared with 11 +/- 6 ms (+/- SD) in the control group (P less than 0.001). Percent relaxation of left ventricular posterior wall endocardium at 50% of diastole was decreased, 58 +/- 4% (+/- SD), in the study group as compared with 85 +/- 6% (+/- SD) in the control group (P less than 0.005). We conclude that M-mode echocardiography provides a relatively useful and specific noninvasive method for the diagnosis of primary restrictive cardiomyopathy in pediatric patients.

Adolescent↗
PubMed1982

Clinical appraisal of his bundle electrocardiogram taken under cardiotomy in congenital heart disease.

The specialized conduction system in the heart was electrophysiologically delineated under cardiotomy in 74 patients with congenital heart disease primarily to determine the topographic relationship of the conduction system to intracardiac structures. Histological study was also done to evaluate the electrophysiological data. Differences were found between the ordinary ventricular septal defect (VSD), inlet-type perimembranous defect, and the ordinary tetralogy of Fallot (TOF), outlet-type perimembranous defect. A superficial run of the His bundle along the lower rim summit of defect was often demonstrated electrophysiologically in large VSD of types II or III, whereas the bundle took marked leftward course in TOF. The right bundle branch (RBB) ran beneath or slightly posterior to the Lancisi equivalent structure (LES) in VSD, while it ran under or slightly anterior to LES in TOF. This papillary muscle could be a rough landmark of the RBB. The course of the RBB in TOF, however, had to be histologically confirmed, since its deep location made electrophysiological delineation difficult. All the sites with a high deflection were the areas where the conduction system was histologically demonstrated beneath the endocardium.

Adolescent↗
PubMed1985

Relationship between perfusion pressure and myocardial microcirculation in the beating empty or spontaneously fibrillating heart.

The influence of graded perfusion pressure (30, 60, and 90 mmHg) at cardiopulmonary bypass were studied on beating empty hearts (BEH) or spontaneously fibrillating hearts (SFH) in the normothermic state. The adequacy and distribution of coronary flow and the myocardial oxygen consumption (MVO2) were examined using the tracer microsphere technique in twelve mongrel dogs. In the SFH, the left ventricular (LV) endocardium (ENDO)/epicardium (EPI) flow ratio indicated significant decrease at 30 and 60 mmHg (0.83 +/- 0.05 and 0.86 +/- 0.06, p less than 0.005, respectively), but was recovered to control value at 90 mmHg (1.01 +/- 0.13). In the BEH, these low perfusion pressures did not result in an abnormal flow distribution in the LV (1.03 +/- 0.03 at 30 mmHg). The flow distribution to the right ventricle (RV) relatively increased in both the BEH and the SFH (p less than 0.001). The ENDO/EPI ratio of the RV did not decrease at 30 mmHg in both groups (1.11 +/- 0.03 in BEH and 1.16 +/- 0.08 in SFH). Coronary blood flow and MVO2 were significantly higher in the SFH than in the BEH. Coronary blood flow increased significantly with increase in the perfusion pressure, in both groups. The MVO2 was constant in the BEH, regardless of the perfusion pressure, but increased in the SFH at increasing pressure. These results show that in the SFH, subendocardial underperfusion of the LV is induced at the perfusion pressure of 30 and 60 mmHg.

Animals↗
PubMed1999

Improvement of eosinophilic heart disease after steroid therapy: successful demonstration by endomyocardial biopsied specimens.

A 62-year-old man with acute eosinophilic endomyocarditis developed congestive heart failure. The biopsy specimens revealed degranulated eosinophils and eosinophil cationic protein (ECP) in the endocardium, and in activated eosinophils and the myocardial interstitium. On electronmicroscopy, a characteristic cardiac myocytolytic change showing disruption at the intercellular junctional site was observed. After steroid treatment, clinical symptoms, systolic dysfunction and laboratory data dramatically improved. In the subsequent biopsy specimens, eosinophilic infiltration and ECP disappeared. Steroid therapy provided a beneficial effect in preventing the progression of cardiac damage. This effect was clearly documented by histochemical studies of the serial endomyocardial biopsy samples.

Biopsy↗
PubMed1997

Magnetic source imaging in the human heart: estimating cardiac electrical sources from simulated and measured magnetocardiogram data.

The estimation of pseudo primary current dipoles on a 2D-manifold in the atrial and ventricular myocardium and septum, and of the transmembrane potential on the endocardium and epicardium, from the magnetic heart field is investigated. The human thorax surrounding the heart is modelled by an inhomogeneous boundary element volume conductor model, including the outer thorax surface and the surfaces of the lungs. The influence of the blood mass is neglected. In the inverse problem Tikhonov's regularisation is applied. The regularisation parameter is determined by the L-curve method. An algorithm for iterative improvement is applied to estimate the pseudo primary current dipoles. Synthetic magnetic field and electric potential data are generated using a cellular automaton model of the entire human heart. Real world magnetic field data for a normal subject are analysed to demonstrate the practicability and effectiveness of the presented method.

Algorithms↗
PubMedDate not supplied

A computer model of human ventricular myocardium for simulation of ECG, MCG, and activation sequence including reentry rhythms.

A computer model is presented for simulation of the spread of activation and repolarization in ventricular myocardium. The program calculating the activation sequence is based on an algorithm similar to Huygen's principle of constructing wavefronts. Physiological parameters of the heart, such as areas of early activation on the endocardium, conduction velocity, anisotropy of propagation, duration of action potentials and refractory periods are taken into account. The time-course of ECG and MCG is calculated using the equations of the bidomain model. Simulation of pathologic cases of activation is performed through variation of the physiological heart parameters. The simulations presented here show good agreement of ECG and MCG with measurements in the normal case, the case of bundle branch block and abnormal repolarization. A special feature of the model is the possibility of simulating reentry rhythms following a premature stimulus in ventricular myocardium. Two kinds of reentry are simulated: reentry around an anatomical obstacle and the leading-circle model. The widespread capability for investigating not only ECG but also MCG and various kinds of pathologic activation patterns including reentry rhythms indicates that the model may be useful in studying numerous problems in cardiologic research.

Action Potentials↗
PubMed2005

Isolated right ventricular metastasis of uterine cervical carcinoma.

Isolated direct metastasis of uterine cervical carcinoma to the right ventricular endocardium is very rare. A 68-year-old woman was initially diagnosed as having stage IIIb squamous cell carcinoma of the uterine cervix, and was treated with radiation therapy. After 2 years, she developed heart failure and presented with a mass in the right ventricle. The results of further examinations were consistent with a tumor or a thrombus in the right ventricle. She underwent excision of the mass under cardiopulmonary bypass, and histopathologic examination of the resected tissue revealed metastatic squamous cell carcinoma of the uterine cervix. She was discharged 3 weeks after the operation, and underwent chemotherapy. However, she was readmitted with drug-induced interstitial pneumonia and died 5 months after the surgery. Patients with an intracardiac mass and a history of uterine cervical cancer should be suspected of having a myocardial metastasis until it is proven otherwise.

Aged↗
PubMed2005

Effect of lidocaine and amiodarone on transmural heterogeneity of ventricular repolarization in isolated rabbit hearts model of sustained global ischemia.

To study the effect of of lidocaine and amiodarone on the transmural heterogeneity of ventricular repolarization in isolated rabbit hearts model of sustained global ischemia and to explore the mechanisms underlying the antiarrhythmic activity of lidocaine and amiodarone, rabbits were randomly divided into 4 groups: control group, ischemia group, lidocaine group and amiodarone group. By the monophasic action potential (MAP) recording technique, MAPs of epicardium, mid-myocardium and endocardium were simultaneously recorded across the left ventricular free wall in rabbit hearts perfused by low-flow ischemia (2.5 mL/min) in Langendorff method to study the transmural dispersion of repolarization (TDR) and arrhythmic induced by ischemia. Our results showed that TDR of three myocardial layers in ischemia group were significantly lengthened after ischemia. TDR was increased from 17.5 +/- 3.9 ms to 31.2 +/- 4.6 ms at the time that concided with the onset of sustained ventricle arrhythmic. Amiodarone could decrease TDR, but lidocaine could increase TDR at initial ischemia, and no significant difference was found at other ischemia time points. 5 cases had ventriclar arrhythmia in ischemia group (62.5%), but no case in lidocaine group (P < 0.01) and only 1 case in amiodarone group had ventrilar arrhythmia (P < 0.01). No significant difference was found between amiodarone group and lidocaine group. It is concluded that TDR of of three myocardial layers increases significantly at ischemia and it is closely associated with development of ventricular arrhythmia, and amiodarone could decrease TDR, but lidocaine could increase TDR at initial ischemia and has no effects at other ischemia time points.

Action Potentials↗
PubMed2004

Effects of volsartan on transmural heterogeneous changes of transient outward potassium currents in hypertrophic cardiomyocytes in rabbits.

The transmural heterogeneous changes of transient outward potassium currents (Ito) in rabbit hypertrophic cardiaomyocytes and the effects of long-term prophylactic treatment with volsartan were investigated. Rabbits were divided into hypertrophy group (left ventricular hypertrophy induced by partial ligation of abdominal aorta), vol-treated group (volsartan was administrated after the ligation), and control group (sham operated). Myocytes were isolated by a two-step enzymatical method. The sub-endocardial (Endo) and sub-epicardium (Epi) tissues were separated from midmyocardium (Mid) with a razor. Whole-cell patch-clamp technique was used to record potassium currents. The results showed that membrane capacitance was larger in hypertrophic cells than those in control and vol-treated cells (P<0.01 vs control cells, n=30). The densities of Ito in hypertrophic cells were reduced by sub-epicardium (Epi) (27.8 +/- 2.9) %, midmyocardium (Mid) (41.0+/-4.7) %, and sub-endocardium (Endo) (20.3 +/- 3.4) % compared with those in control cells. The decrease of Ito density was more pronounced in Mid than in Epi and Endo (P<0.01 vs Epi or Endo). There were no significant differences in Ito densities between vol-treated group and control group in three layers separately. In conclusion, volsartan can inhibit the transmural heterogeneous changes of Ito in left ventricular hypertrophic cardiomyocytes in rabbit.

Animals↗
PubMed2002

Experimental study of the effect of autonomic nervous system on the transmural dispersion of ventricular repolarization under acute myocardial ischemia in vivo.

The effect of the autonomic nerves on the transmural dispersion of ventricular repolarization (TDR) under acute myocardial ischemia in intact canine was investigated. Using the monophasic action potential (MAP) recording technique, MAPs of the epicardium (Epi), mid-myocardium (Mid) and endocardium (Endo) were recorded simultaneously by specially designed plunge-needle electrodes at the left ventricular free wall under acute myocardial ischemia in 12 open-chest dogs. MAPD90 and TDR among three myocardial layers as well as the incidence of the early afterdepolarization (EAD) before autonomic nervous stimulation and during autonomic nervous stimulation were compared. It was found that 10 min after acute myocardial ischemia, TDR was increased from 55 +/- 8 ms to 86 +/- 15 ms during sympathetic stimulation (P < 0.01). The TDR (53 +/- 9 ms) during parasympathetic stimulation was not significantly different from that of the control (55 +/- 8 ms) (P > 0.05). The EAD was elicited in the Mid of 2 dogs (16%) 10 min after acute myocardial ischemia, but the EAD were elicited in the Mid of 7 dogs (58%) during sympathetic stimulation (P < 0.01). It was concluded that: (1) Sympathetic stimulation can increase the transmural dispersion of repolarization and induce early afterdepolarizations in the Mid under acute myocardial ischemia, which provide the opportunity for the ventricular arrhythmia developing; (2) Parasympathetic stimulation has no significant effect on the transmural dispersion of repolarization under myocardial ischemia.

Action Potentials↗
PubMed2006

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.

Amiodarone↗
PubMed2002

Experimental study of assessment on ventricular activation origin and contraction sequence by Doppler tissue imaging.

To evaluate the possibility and accuracy of Doppler tissue image (DTI) on assessment of normal and abnormal ventricular activation and contraction sequence, 9 open chest canine hearts were analyzed by acceleration mode, M-mode, and spectrum mode DTI. Our results showed that: (1) Acceleration mode DTI could show the origin of activation and conduction sequence on line; (2) M-mode DTI revealed that the activation in mid-interventricular septum was earlier than that in mid-left ventricular posterior wall at sinus activation; (3) Spectrum DTI showed the ventricular endocardium was activated earlier than the ventricular epicardium in all segments at sinus rhythm. The earliest site of activation of the normal ventricular wall was at middle interventricular septum; the latest site was at basal-posterior wall; the contraction sequence was different at the different walls; (4) During abnormal ventricular activation, mid-left ventricular posterior wall was activated earliest in accordance with the pacing sites. Abnormal ventricular activation was slower than sinus activation, and the contraction sequence varied at different sites of ventricular wall. It is concluded that DTI can be used to localize the origin of normal or abnormal myocardial activation and to assess the contraction sequence conveniently, accurately and non-invasively.

Animals↗
PubMed1996

Comparison of nifedipine and metoprolol on collateral coronary blood flow in a swine model of chronic coronary obstruction and acute ischaemia during isoflurane anaesthesia.

PURPOSE: This study compared the effects of nifedipine and metoprolol on collateral-dependent myocardial blood flow in a swine model of chronic coronary obstruction and acute ischaemia during isoflurane anaesthesia. METHODS: Collateral coronary circulation was induced in 15 three-week-old piglets by banding of the proximal left anterior descending coronary artery (LAD). After 8-10 wk, the distal LAD was ligated and the open-chest pigs were randomized to receive infusions of either saline, nifedipine (5 micrograms.kg-1.min-1) or metoprolol (10 micrograms.kg-1.min-1) for 30 min during isoflurane anaesthesia (2%). Transient ischaemia was induced by 30 sec occlusion of the left circumflex artery. Arterial blood pressures, heart rate and regional myocardial blood flow (radiolabelled microspheres technique) were measured at the end of drug infusion (baseline) and one minute after transient ischaemia. RESULTS: No differences in the blood flow to the collateral-dependent (CD) myocardium or haemodynamic variables were observed at baseline among the three groups. Following transient ischaemia, in the nifedipine but not in the metoprolol group, blood flow to the CD myocardium was reduced by 28 +/- 24% in the epicardium (P < 0.05) and 56 +/- 20% in the endocardium (P < 0.01), resulting from intercoronary and transmural steal. This was associated with a moderate increase (10%, P < 0.05) in the heart rate in the nifedipine group. CONCLUSIONS: In a swine model of chronic coronary obstruction and acute ischaemia during isoflurane anaesthesia, the collateral coronary blood flow was maintained in the presence of metoprolol, but reduced in the presence of nifedipine following transient ischaemia due to intercoronary and transmural steal.

Adrenergic beta-Antagonists↗
PubMed1999

Functional characteristics of the coronary microcirculation.

For over 50 years, it has been recognized that coronary blood flow is precisely matched to cardiac metabolism. The interactions which govern this matching remain unknown. In the current review, 3 specific aspects of coronary flow regulation will be discussed: Specialization of function in different microvascular domains, influence of cardiac region on microvascular function and the interactions of vasoactive agents in control of coronary blood flow. Each level of the coronary microcirculation is affected by different physical and chemical forces within the heart. These forces place special demands on these vessels and are in turn met by specialized vasodilator responses, including metabolic and flow-mediated vasodilation. Perfusion of the heart is also profoundly affected by the region perfused. The endocardium is affected by forces, notably cardiac contraction, in a different manner than the epicardium. Thus, the microcirculation has specialized to meet these demands. Finally, the factors determining microvascular tone appear to be coordinated such that the loss of any individual dilator, such as nitric oxide, can be compensated for by the increased contribution of another, such as adenosine. This interplay may serve to protect the heart from ischemia during the early phases of coronary vascular disease when individual dilators may be impaired.

Animals↗
PubMed1998

[Surgical treatment with infarction exclusion technique and postoperative percutaneous cardiopulmonary support for a patient with ventricular septal perforation--a case report].

A 76-year-old woman was referred to our hospital because of postinfarction ventricular septal perforation (VSP). VSP occurred twelve days after acute myocardial infarction and resulted in interventricular shunt with Qp/Qs of 4.8. Because she suffered from pulmonary edema and oligouria, she underwent emergent surgical treatment after application of the intraaortic balloon pump. The infarction involved whole of right ventricle and the infero-posterior wall of left ventricle, and the location of the perforation was infero-septum with the size of 10 x 6 mm. A bovine pericardial patch was tailored in a triangular shape of approximately 7 x 7 x 5 cm. The base of the patch was sutured to the fibrous annulus of the mitral valve and medial margin of the patch was sewn to healthy septal endocardium. And the lateral side of the patch was sutured to the posterior wall of the left ventricle. Because of difficulty in weaning of the cardiopulmonary bypass, a percutaneous cardiopulmonary support system (PCPS) was inserted via femoral artery and vein with a flow support of 2.0 L/min. After 4 days support of PCPS, improvement of right ventricular function was detected by echocardiogram and PCPS was removed. While PCPS support, low dose heparin to maintain ACT level around 150 seconds was continuously administered. Any complication including bleeding and thrombosis was not remarkable. The patient was discharged on the 53th postoperative day, and is now doing well.

Aged↗
PubMed1998

[Right ventricular myxoma in a 71-year-old female].

Right ventricular myxoma in elderly is very rare and this is the 36th case report of right ventricular myxoma in Japan. A healthy 71-year-old female with no symptoms or constitutional signs except heart murmur was hospitalized. Findings of transthoracic echocardiogram, CT scan, MRI and angiocardiogram demonstrated a mobile tumor in the right ventricular outflow tract. Transesophageal echocardiogram clearly revealed that the stalk was arising from the right ventricular free wall. Under cardiac arrest, right atriotomy was made and a gelatinous tumor (4.5 x 2 x 2 cm in size, 7.3 g in weight) was excised with 5 mm of surrounding endocardium and a few millimeters of underlying myocardium through the tricuspid valve. Histopathologically, the tumor was diagnosed as a myxoma. Her postoperative course was uneventful.

Aged↗
PubMed1999

Fate of atrial flap used in repair of total anomalous pulmonary venous connection.

Histological changes in the right atrial flap used in repair of total anomalous pulmonary venous connection were observed when the patient underwent repair of peripheral pulmonary venous stenosis after two months. The flap, 35 mm in length and 15 mm in width, was thin and soft. Microscopically, endocardium and myocardium were preserved well, with only moderate thickening of the epicardium. We can anticipate the viability of the right atrial flap, but care should be taken to keep blood supply to the flap intact.

Cardiac Surgical Procedures↗
PubMed1999

Surgical treatment of tricuspid regurgitation caused by Löffler's endocarditis.

A 25-year-old man with a history of bone-marrow-transplantation for the treatment of Löffler's endocarditis underwent surgery for massive tricuspid regurgitation with paroxysmal atrial flutter. Dense fibrosis in the right ventricular endocardium with complete obliteration of the apex was seen intraoperatively, and the right ventricular cavity was diminished. Annular dilatation of the tricuspid valve and entrapment of the posterior leaflet to the endocardial fibrosis were also seen. Annuloplication at the posterior leaflet was performed. In addition, the right atrial free wall was widely resected and the septal and inferior vena cava-tricuspid valve isthmi were cryoablated for the treatment of atrial flutter. Postoperative catheterization revealed rather high right ventricular end-diastolic pressure. However, tricuspid regurgitation disappeared with the increased cardiac output. Atrial flutter could not be induced by repetitive stimulation in the postoperative electrophysiological examination.

Adult↗