Cardiac Denervation and Cardiac Function

With respect to neural control of the heart, intrathoracic ganglia and their interconnections form the final common pathway for autonomic modulation of regional cardiac function. In this review, data are presented indicating that such ganglia that include those distributed on the heart contain afferent (sensory) and efferent (motor) neurons that intercommunicate via local circuit neurons. The intrathoracic reflexes involving these neurons function in a coordinated fashion with central neurons located in the spinal cord, brain stem, and supraspinal central neuronal regions to regulate cardiac output on a beat-to-beat basis. The focus of this review is the putative role that these various populations of intrathoracic neurons play in regulating normal cardiac function and, in particular, how their interactions can become altered following their decentralization or in the presence of altered regional cardiac function. It is proposed that a thorough understanding of the interactions that occur among the hierarchy of neurons within intrinsic cardiac and intrathoracic extracardiac ganglia is required in order to assess cardiac regulation in normal as well as diseased states.     

Primary Cardiac Angiosarcoma Accompanying Cardiac Tamponade

A de novo cardiac malignant tumor is rare and sometimes challenging to diagnose. We encountered a 67-year-old man without any medical history complaining of dyspnea on effort. On admission, his hemodynamics were deteriorated due to cardiac tamponade, which was improved by percutaneous drainage of 1,200 mL pericardial effusion, showing 11.0 g/dL of hemoglobin. We suspected primary cardiac malignancy following multidisciplinary tests, and a cardiac biopsy via sternotomy demonstrated the definitive diagnosis of primary malignant tumor (angiosarcoma) infiltrating the right atrial myocardium. We initiated weekly paclitaxel therapy. Further studies are warranted to establish the optimal diagnostic and therapeutic strategy for de novo cardiac malignancy.     

心律失常与心脏再同步化治疗无反应性的相关性

虽然基于肾素-血管紧张素-醛固酮抑制剂、β受体阻滞剂的药物治疗使心力衰竭治疗取得了很大进展,但心力衰竭患者的发病率及病死率仍居高不下.心脏再同步化治疗是近年心力衰竭非药物治疗上的重大进展.但是研究表明心脏再同步化治疗后,仍有约30%的心力衰竭患者对心脏再同步化无反应.现综述了心脏再同步化治疗无反应与心律失常之间的关系,并简要讨论对心脏再同步化治疗无反应的可能机制及预防策略.     

心脏核磁共振成像与心内电生理

透视介导的心脏内电生理术一个主要缺点为术中无法正确识别软组织及其与比邻结构关系,然而,心脏核磁共振成像介导的心内电生理术却弥补了这一缺陷.心脏核磁共振成像-心内电生理术不仅可精确地展示出心脏的三维空间形态结构,而且能直接识别心律失常病灶及观察射频消融的疗效,提高复杂心律失常手术成功率及减少并发症有重要作用.因而,心脏核磁共振成像被认为在心内电生理领域具有广泛运用前景.     

Cardiac Amyloidosis

ABSTRACT. Two male patients with primary cardiac amyloidosis are described. Patient 1 presented with typical effort angina pectoris with no ischemic electrocardiographic changes and a normal coronary angiogram. At necropsy, a severe diffuse, intravascular amyloid deposition was observed in the intramural coronary arteries. In patient 2 the presenting symptom was congestive heart failure with echocardiographic evidence of asymmetric septal hypertrophy and pericardial effusion. Technetium-99m pyrophosphate scintigraphy showed diffuse myocardial uptake, and the diagnosis of cardiac amyloidosis was confirmed in the postmortem examination. The diagnostic and therapeutic problems associated with cardiac amyloidosis are discussed in the light of these case reports.     

Cardiac efficiency

Summary Efficiency is defined as the ratio of the energy delivered by a system to the energy supplied to it. Depending on the particular question being addressed, there exist a plethora of definitions of efficiency in medical texts, thus hampering their comparison. If only the ventricular work seen by the arterial system is under investigation, pressure-volume work will serve as a useful numerator. If, on the other hand, external and internal work together, i.e. the total mechanical work, is of interest, the pressure-volume area might be employed.Total myocardial oxygen consumption (MVO₂) will be a useful denominator in the case of aerobic energy production. The MVO₂ for the unloaded contraction must be assessed if, as in other energy transfer systems, net efficiency is to be addressed. If even smaller steps in the chain of energy transfer are to be investigated MVO₂ for the arrested heart must be assessed.With an appropriate therapy, hemodynamic determinants can be varied, to improve cardiac efficiency. Nonetheless, measurement of all variables necessary for the calculation of efficiency remains a challenge, in particular in the clinical setting. Separation of the direct effects of drugs on efficiency is even more difficult, since hemodynamic conditions can hardly be controlled throughout the observation period, and changes in efficiency might be secondary to changes in hemodynamics.Whether the heart by itself employs mechanisms to improve its efficiency is still a matter of discussion: there is evidence that when oxygen supply decreases, the heart can switch from one substrate to a less costly one, or possibly can improve efficiency through better use of oxygen. Moreover, the heart seems to sense an even more decreased oxygen supply and reduce function in response. Myocardial stunning could be regarded as a protective mechanism as well, with function remaining depressed and the oxygen supply being normal or close to normal. One may conclude from the decreased efficiency that the excess oxygen consumption is used up for repair processes. The improved efficiency found in hypertrophied hearts represents another adaptive process. The underlying mechanism is unclear: a shift towards isomyosin V₃ or some undefined shift in metabolic pathway is discussed.It is also still a moot question towards which objective the efficiency of the heart is adjusted. It has been described that under physiologic conditions, the efficiency of both the left and the right ventricle ought to be maximized. The alternative finding that the heart and the arterial system are adjusted to maximize stroke work is only a serious contrast if both maxima are narrow and clearly separated from each other.     

Cardiac sarcoidosis

Cardiac sarcoidosis can have a variety of manifestations including conduction disease, congestive heart failure, valvular heart disease, pericardial effusions, tamponade, ventricular arrhythmias and sudden cardiac death. In patients with sarcoidosis, the reported incidence of cardiac involvement ranges from 20% in US autopsy studies to nearly 60% in Japan, where it accounts for the majority of deaths as a result of sarcoidosis. Despite this, the diagnosis of cardiac sarcoidosis remains difficult and no single diagnostic test has emerged that combines a high degree of sensitivity and specificity. Recent evidence suggests that gadolinium-enhanced magnetic resonance imaging can potentially offer high sensitivity and specificity for both disease presence and activity. It may also be possible to track response to treatment of cardiac sarcoidosis with cardiac magnetic resonance imaging. Corticosteroids are the mainstay of treatment for cardiac sarcoidosis as with systemic sarcoid but at present no prospective trial has shown a survival benefit. Pharmacological treatment of heart failure should follow standard heart failure guidelines, whereas anti-arrhythmic treatment is problematic. The role of implantable cardiac defibrillators in sarcoid has not been well defined, although the risk of ventricular arrhythmias and sudden cardiac death are high. Cardiac transplantation remains an option for younger patients, although overall cardiac involvement in sarcoidosis carries a relatively poor prognosis.     

Cardiac pheochromocytoma

Abstract. Cardiac pheochromocytoma is a rare tumour and may be difficult to localize. We present a 32-year-old male with a cardiac pheochromocytoma that was successfully resected. An initial unenhanced CT did not reveal the tumour. MIBG-scintigraphy indicated the location, but to get full information, a dynamic contrast-enhanced CT of the chest during adequate alpha and beta blockade was essential. ECG-gated MRI gave further information about the anatomical details.     

心脏淀粉样变性

淀粉样变性是以不可溶性的淀粉样物质沉积于器官或组织的细胞外区,导致相应的器官或组织功能障碍为特征的一组疾病。心脏是淀粉样变性常累及的器官。心脏淀粉样变性临床上通常按其病因分为原发性、家族性、老年性、继发性及透析相关性五种类型。其最常见的临床表现为限制性心肌病和顽固性心力衰竭,有时伴有传导阻滞。心肌活检可以确定诊断,近年来随着心外组织取样和显像技术的发展已大大减少了心内膜心肌活检的必要。尽管治疗上有所改进,但心脏淀粉样变性患者预后仍然较差,主要取决于原有疾病类型。     

心源性晕厥或猝死的原因分析

分析 32例在入院时或入院后至少发生 1次或 1次以上心源性晕厥或猝死患者的原因及其发作时与发作前、后的常规 12导联心电图或持续心电监视心电图。结果 :引起心源性晕厥或猝死的基本原因可分为以下几种类型 :①冠心病急性或陈旧性心肌梗死 ;②长QT(U)综合征 ;③Brugada综合征 ;④扩张型和肥厚型心肌病 ;⑤特发性巨大异常J波 ;⑥其他原因。上述各种心源性晕厥或猝死患者有各自不同的心电学特征。结论 :心源性晕厥或猝死是由不同原因、不同心电学特征所致的非单一独立的临床实体