Current Cardiology Reviews - Volume 9, Issue 3, 2013

Peripartum cardiomyopathy (PCM) is a relatively rare disease with potentially devasting consequences requiring prompt identification and correct treatment. Overall prognosis is good in majority of the cases, although some patients may progress to irreversible heart failure. Early diagnosis is important and effective treatment reduces mortality rates and increases the chance of complete recovery of ventricular systolic function. The aetiology and pathogenesis seems to be multifactorial and poorly understood, with the available literature rather conflicting. In recent years, there has been increased interest in the role played by genetic predisposition in the development of PCM. It probably develops as a result of a complex interaction of pregnancy-associated factors and genetic factors and recently there have been many observations pointing out the central role played by a genetic predisposition. The direct and indirect observations on genetic susceptibility may offer new insights into the pathogenesis of PCM. However, larger studies are needed before advising routine genetic testing in these patients.

Late gadolinium enhancement is a useful tool for scar detection, based on differences in the volume of distribution of gadolinium, an extracellular agent. The presence of fibrosis in the myocardium amenable to be detected with late gadolinium enhancement MRI is found not only in ischemic cardiomyopathy, in which it offers information regarding viability and prognosis, but also in a wide variety of non-ischemic cardiomyopathies. In the following review we will discuss the methodological aspects of gadolinium-based imaging, as well as its applications and anticipated future developments.

Takotsubo cardiomyopathy (TCM), otherwise cardiomyopathy,apical ballooning syndrome or broken heart syndrome is a reversible cardiomyopathy, predominantly occurs in post-menopausal women and commonly due to emotional or physical stress. Typically, patients present with chest pain and ST elevation or T wave inversion on their electrocardiogram mimicking acute coronary syndrome, but with normal or non-flow limiting coronary artery disease. Acute dyspnoea, hypotension and even cardiogenic shock may be the presenting feature of this condition. The wall motion abnormalities typically involve akinesia of the apex of the left ventricle with hyperkinesia of the base of the heart. Atypical forms of TCM have also recently been described. An urgent left ventriculogram or echocardiogram is the key investigation to identify this syndrome. Characteristically, there is only a limited release of cardiac enzymes disproportionate to the extent of regional wall motion abnormality. Transient right ventricular dysfunction may occur and is associated with more complications, longer hospitalisation and worse left ventricular systolic dysfunction. Recently, cardiac MRI has been increasingly used to diagnose this condition and to differentiate from acute coronary syndrome in those who have abnormal coronary arteries. Treatment is often supportive, however beta-blocker and angiotensin-converting enzyme inhibitor or angiotensin II receptor blocking agent are being used in routine clinical practice. The syndrome is usually spontaneously reversible and cardiovascular function returns to normal after a few weeks. This review article will elaborate on the pathophysiology, clinical features including the variant forms, latest diagnostic tools, management and prognosis of this condition.

The ventricular gradient (VG) as a concept was conceived in the 1930s and its calculation yielded information that was not otherwise obtainable. The VG was not utilized by clinicians at large because it was not easy to understand and its computation time-consuming. The contemporary spatial QRS-T angle is based on the concept of the VG and defined as its mathematical and physiological integral. Its current major clinical use is to assess the cardiac primary repolarization abnormalities in 3-dimensional spatial vectorial plans which are normally untraced in the presence of secondary electrophysiological activity in a 2-dimensional routine electrocardiogram (ECG). Currently the calculation of the spatial QRS-T angle can be easily computed on the basis of a classical ECG and contributes to localization of arrhythmogenic areas in the heart by assessing overall and local heterogeneity of the myocardial ventricular action potention duration. Recent population-based studies suggest that the spatial QRS-T angle is a dominant ECG predictor of future cardiovascular events and death and it is superior to more conventional ECG parameters. Its assessment warrants consideration for intensified primary and secondary cardiovascular prevention efforts and should be included in everyday clinical practice. This review addresses the nature and diagnostic potential of the spatial QRS-T angle. The main focus is its role in ECG assessment of dispersion of repolarization, a key factor in arrythmogeneity.

Aortic coarctation represents a distinct anatomic obstruction as blood moves from the ascending to the descending aorta and can present in a range of ages from infancy to adulthood. While it is often an isolated and discrete narrowing, it can also be seen in the more extreme scenario of severe arch hypoplasia as seen in the hypoplastic left heart syndrome or in conjunction with numerous other congenital heart defects. Since the first description of an anatomic surgical repair over sixty years ago, an evolution of both surgical and transcatheter therapies has occurred allowing clinicians to manage and treat this disease with excellent results and low morbidity and mortality. This review focuses on the current state of both transcatheter and surgical therapies, paying special attention to recent data on long-term follow-up of both approaches. Further, current thoughts will be explored about future therapeutic options that attempt to improve upon historical long-term outcomes.

Cardiovascular disease (CVD), including ischemia reperfusion (IR) injury, remains a major cause of morbidity and mortality in industrialized nations. Ongoing research is aimed at uncovering therapeutic interventions against IR injury. Regular exercise participation is recognized as an important lifestyle intervention in the prevention and treatment of CVD and IR injury. More recent understanding reveals that moderate intensity aerobic exercise is also an important experimental model for understanding the cellular mechanisms of cardioprotection against IR injury. An important discovery in this regard was the observation that one-to-several days of exercise will attenuate IR injury. This phenomenon has been observed in young and old hearts of both sexes. Due to the short time course of exercise induced protection, IR injury prevention must be mediated by acute biochemical alterations within the myocardium. Research over the last decade reveals that redundant mechanisms account for exercise induced cardioprotection against IR. While much is now known about exercise preconditioning against IR injury, many questions remain. Perhaps most pressing, is what mechanisms mediate cardioprotection in aged hearts and what sex-dependent differences exist. Given that that exercise preconditioning is a polygenic effect, it is likely that multiple mediators of exercise induced cardioprotection have yet to be uncovered. Also unknown, is whether post translational modifications due to exercise are responsible for IR injury prevention. This review will provide an overview the major mechanisms of IR injury and exercise preconditioning. The discussion highlights many promising avenues for further research and describes how exercise preconditioning may continue to be an important scientific paradigm in the translation of cardioprotection research to the clinic.

The stretch of cardiac muscle increases developed force in two phases. The first phase, which occurs rapidly, constitutes the well-known Frank-Starling mechanism and it is generally attributed to enhanced myofilament responsiveness to Ca2+. The second phase or slow force response (SFR) occurs gradually and is due to an increase in the calcium transient amplitude as a result of a stretch-triggered autocrine/paracrine mechanism. We previously showed that Ca2+ entry through reverse Na/Ca2+ exchange underlies the SFR, as the final step of an autocrine/paracrine cascade involving release of angiotensin II/endothelin, and a Na+/H+ exchanger (NHE-1) activation-mediated rise in Na+. In the present review we mainly focus on our three latest contributions to the understanding of this signalling pathway triggered by myocardial stretch: 1) The finding that an increased production of reactive oxygen species (ROS) from mitochondrial origin is critical in the activation of the NHE-1 and therefore in the genesis of the SFR; 2) the demonstration of a key role played by the transactivation of the epidermal growth factor receptor; and 3) the involvement of mineralocorticoid receptors (MR) activation in the stretch-triggered cascade leading to the SFR. Among these novel contributions, the critical role played by the MR is perhaps the most important one. This finding may conceivably provide a mechanistic explanation to the recently discovered strikingly beneficial effects of MR antagonism in humans with cardiac hypertrophy and failure.

There have been significant advancements in the ability of echocardiography to provide both morphological and functional information in children with congenitally malformed hearts. This progress has come through the development of improved technology such as matrix array probes and software which allows for the off line analysis of images to a high standard. This article focuses on these developments and discusses some newer concepts in advanced echocardiography such is multi-planar reformatting [MPR] and tissue motion annular displacement [TMAD]. Our aim is to discuss important aspects related to the quality and reproducibility of data, to review the most recent published data regarding advanced echocardiography in the malformed heart and to guide the reader to appropriate text for overcoming the technical challenges of using these methods. Many of the technical aspects of image acquisition and post processing have been discussed in recent reviews by the authors and we would urge readers to study these texts to gain a greater understanding [1]. The quality of the two dimensional image is paramount in both strain analysis and three dimensional echocardiography. An awareness of how to improve image quality is vital to acquiring accurate and usable data. Three dimensional echocardiography (3DE) is an attempt to visualise the dynamic morphology of the heart. Although published media is the basis for theoretical knowledge of how to practically acquire images, electronic media [eg.www.3dechocardiography.com] is the only way of visualising the advantages of this technology in real time. It is important to be aware of the limitations of this technology and that much of the data gleaned from using these methods is at a research stage and not yet in regular clinical practice.

Biobanks play a crucial role in "-Omics" research providing well-annotated samples to study major diseases, their pathways and mechanisms. Accordingly, there are major efforts worldwide to professionalize biobanks in order to provide high quality preservation and storage of biological samples with potentially greater scientific impact. Biobanks are an important resource to elucidate relevant disease mechanisms as well as to improve the diagnosis, prognosis, and treatment of both pediatric and adult cardiovascular disease. High-quality biological sample collections housed in specialized bio-repositories are needed to discover new genetic factors and molecular mechanisms of congenital heart disease and inherited cardiomyopathies in order to prevent the potential risk of having a fatal cardiac condition as well as to facilitate rational drug design around molecular diseases (personalized medicine). Biological samples are also required to improve the understanding the environmental mechanisms of heart disease (environmental cardiology). The goal of this paper is to focus on preanalytical issues (informed consent, sample type, time of collection, temperature and processing procedure) related to collection of biological samples for research purposes. In addition, the paper provides an overview of the efforts made recently by our Institute in designing and implementing a high-security liquid nitrogen storage system (-196°C). We described the implementations of reliable preservation technologies and appropriate quality control (the right temperature, the right environment, fully traceable with all possible back-up systems) in order to ensure maximum security for personnel as well as the quality and suitability of the stored samples.

Percutaneous coronary angioplasty is increasingly employed in the treatment of patients with complex coronary artery disease. Different steerable guide wires used to open occluded vessel and facilitate balloon and stent deployment. However, the guide-wire itself is not without hazard: it may perforate or dissect the vessel, but fracture or entrapment is uncommon. Its management depends on the clinical situation of the patient, as well as the position and length of the remnant. In this review we discuss the angioplasty guide-wire fracture and entrapment risk factors, potential risks and management.