|
Current Cardiology Reviews
ISSN: 1573-403X
Current Cardiology Reviews
Volume 3, Number 1, February 2007
Contents
Risk Factors for Development of Heart Failure
Pp. 1-9
Jennifer Listerman, Robert L. Huang, Carrie Geisberg and
Javed Butler
[Abstract] [Full
Text Article]
Cardiac Adiposity and Cardiovascular Risk: Potential
Role of Epicardial Adipose Tissue Pp. 11-14
Gianluca Iacobellis, Navneet Singh and Arya M. Sharma
[Abstract] [Full
Text Article]
Immunoglobulin Therapy, Myocardial Diseases and Atherosclerosis:
Recent Experimental and Clinical Studies Pp. 15-21
Chiharu Kishimoto
[Abstract] [Full
Text Article]
Prognosis and Treatment of Ventricular Arrhythmias
Following Myocardial Infarction Pp. 23-33
Douglas W. Laidlaw, Munther K. Homoud, Jonathan Weinstock,
N.A. Mark Estes III and Mark S. Link
[Abstract] [Full
Text Article]
Nitric Oxide in the Dorsal Medulla Modulates Excitatory
Somatosympathetic Reflexes Pp. 35-42
Sheng-Xing Ma
[Abstract] [Full
Text Article]
Role of Vasa Vasorum in Arterial Disease: A Re-emerging
Factor Pp. 43-55
Erik L. Ritman and Amir Lerman
[Abstract] [Full
Text Article]
The ACE2-Ang-(1-7)-Mas Axis and Cardioprotection
Pp. 57-64
Robson A.S. Santos, Sérgio V.B. Pinheiro and Anderson
J. Ferreira
[Abstract] [Full
Text Article]
Effect of Aging On Angiogenesis and Arteriogenesis
Pp. 65-74
Hsiao T. Yang
[Abstract] [Full
Text Article]
Remote Control of Pulmonary Blood Flow Pp.
75-80
Antonio F. Corno
[Abstract] [Full
Text Article]
Tissue Doppler Imaging: Beautiful Noise Pp.
81-90
Brent D. Wilson and Sheldon E. Litwin
[Abstract] [Full
Text Article]
Cardiac Surgery and Inflammation: The Inflammatory
Response and Strategies to Reduce the Systemic Inflammatory
Response Syndrome Pp. 91-98
Ian J. Hunt and Jon R.S. Day
[Abstract] [Full
Text Article]
Abstracts
[Back to top]
Risk Factors for Development of Heart Failure
Jennifer Listerman, Robert L. Huang, Carrie Geisberg and
Javed Butler
[Full
Text Article]
Heart failure carries significant morbidity and mortality
burden, with median survival from onset of symptoms been reported
as low as 1.7 years among men and 3.2 years among women. It
is the only major cardiovascular disease which is increasing
in incidence and prevalence. There are several reasons for
this including general aging of the population, improved outcomes
from acute cardiovascular disease, and worsening risk factor
profile in United States including increasing obesity and
diabetes trends. Heart failure is also widely prevalent, with
a reported prevalence of about 5 million people in the United
States. A wide variety of demographic characteristics, life
style factors, comorbidites, pharmacologic exposures, biochemical
markers, echocardiographic parameters, and genetic markers
have been linked to heart failure risk. Several risk factors
such as increasing age, male gender, and prior MI are well
established with respect to new onset heart failure chances
whereas others risk factors such as many of the genetic markers
are more recently discovered and need to undergo further evaluation
to assess their association. This review article outlines
the current state of the literature on risk factors for developing
heart failure.
[Back to top]
Cardiac Adiposity and Cardiovascular Risk: Potential
Role of Epicardial Adipose Tissue
Gianluca Iacobellis, Navneet Singh and Arya M. Sharma
[Full
Text Article]
Emerging evidence suggests that cardiac adiposity may play
an important role in the development of an unfavorable cardiovascular
risk profile. The concept of adiposity of the heart, as new
cardiovascular risk factor and marker, is rapidly emerging.
Recent papers suggest that epicardial fat, an index of cardiac
visceral adiposity could locally modulate the morphology and
function of the heart. The close anatomical relationship between
epicardial adipose tissue and the adjacent myocardium should
readily allow local paracrine interactions between these tissues.
Epicardial fat may play a functional and mechanical role in
left ventricular hypertrophy, atrial dilatation or diastolic
dysfunction. Echocardiography has been recently proposed for
the direct assessment of epicardial adipose tissue. Echocardiographic
assessment of epicardial fat may be a helpful tool not only
for diagnostic purposes, as marker of visceral adiposity and
inflammation, but also for therapeutic interventions with
weight reduction drugs or pharmaceuticals targeted to adipose
tissue. Nevertheless the subject is in its infancy and further
studies are needed. In fact it is difficult to determine whether
epicardial fat has a direct pathogenic role in the development
of cardiac changes. It also remains to be determined whether
this location of fat is physiologically or pathologically
important and whether it can be used to replace abdominal
obesity, or its surrogate marker, waist circumference, as
a cardiovascular risk factor.
In this article, epicardial adipose tissue’s structure,
function, method of assessment and reliability as a marker
of visceral and cardiac adiposity is briefly reviewed.
[Back to top]
Immunoglobulin Therapy, Myocardial Diseases and Atherosclerosis:
Recent Experimental and Clinical Studies
Chiharu Kishimoto
[Full
Text Article]
Immunoglobulin therapy has been used for the treatment of
primary and secondary antibody deficiency for more than 25
years. It is a safe preparation with no long-term side effect.
Although the mode of action remains unknown, the drug is thought
to have potent immunomodulating and anti-inflammatory actions.
Recently we have found that immunoglobulin treatment is beneficial
upon myocardial diseases and atherosclerosis. In basic aspects,
immunoglobulin therapy for experimental myocarditis has been
found to be effective not only by the Fab portion for anti-pathogen
effects but by the Fc portion for antiinflammatory effects.
Also, the drug was useful for the treatment of experimental
atherosclerosis in apolipoprotein E-deficient mice. In clinical
aspects, the effect of immunoglobulin administration for fulminant
myocarditis and acute dilated cardiomyopathy was investigated.
Immunoglobulin administration was very useful for the treatment
of such patients. That is, although the study population was
small, the drug showed the potential beneficial effects against
active myocardial damage with myocardial dysfunction, and
the left ventricular ejection fraction of the patients was
recovered by the treatment. Accordingly, immunoglobulin treatment
for patients with heart failure and atherosclerosis appears
to be novel and effective treatment strategies.
[Back to top]
Prognosis and Treatment of Ventricular Arrhythmias
Following Myocardial Infarction
Douglas W. Laidlaw, Munther K. Homoud, Jonathan Weinstock,
N.A. Mark Estes III and Mark S. Link
[Full
Text Article]
Ventricular arrhythmias are common in the setting of acute
myocardial infarction (AMI). In today’s era of reperfusion
therapy, anti-arrhythmic medications, and Implantable Cardioverter
Defibrillators (ICDs), an understanding of these arrhythmias
and the prognosis of patients with these arrhythmias is essential
in determining the proper treatment strategy. In general,
ventricular arrhythmias occurring in the first 48 hours (early)
following admission for AMI do not predict an increased risk
of arrhythmias in follow-up. While early sustained ventricular
tachycardia and ventricular fibrillation predict increased
in-hospital mortality, the medium and long-term mortality
is comparable to control populations in most studies. In contrast,
ventricular arrhythmias occurring after 48 hours (late) generally
predict an increased risk of arrhythmias and sudden cardiac
death. This review focuses on the different ventricular arrhythmias
which occur in both the early and late stages following myocardial
infarction. Special attention is made to the incidence and
prognosis of these arrhythmias, and how this relates to current
treatment recommendations.
[Back to top]
Nitric Oxide in the Dorsal Medulla Modulates Excitatory
Somatosympathetic Reflexes
Sheng-Xing Ma
[Full
Text Article]
Activation of afferent cutaneous or mixed nerves, such as
the sural or the sciatic, results in changes in sympathetic
activity and arterial blood pressure by excitatory somatosympathetic
reflexes (SSR). The underlying causes and modulation of SSR
functions in the dorsal medulla are poorly understood. This
review focuses our recent findings incorporated with the publications
from other investigators implicating that: 1) The gracile
nucleus is an integration center for somatic and visceral
information flowing into the thalamus, and sensory stimulation
of the hindlimb somatic afferent modifies neuronal activities
in the nucleus tractus solitarius (NTS); 2) nitric oxide (NO)
in the NTS produces decreases in arterial blood pressure and
heart rate, but the effects are independent to baroreflexes;
3) L-arginine-derived NO synthesis in the gracile nucleus
inhibits the excitatory cardiovascular responses to stimulus-evoked
SSR; and 4) Neuronal NO synthase (nNOS) expression is increased
in the dorsal medulla, the gracile nucleus and the NTS by
electrical stimulation of the sural nerve. These results suggest
that stimulation of somato-sensory afferents induces nNOS
expression in the dorsal medulla, and L-arginine-derived NO
synthesis in the nuclei produces an inhibitory regulation
of excitatory SSR, which plays a role in the feedback autonomic
control of the circulation.
[Back to top]
Role of Vasa Vasorum in Arterial Disease: A Re-emerging
Factor
Erik L. Ritman and Amir Lerman
[Full
Text Article]
Vasa vasorum are microscopic vessels that perfuse the walls
of macroscopic arteries and veins. Numerous observations over
the years underpin the speculation that vasa vasorum play
a significant role in arterial disease. For instance, atheromatous
plaques tend to form in arteries that normally have vasa vasorum,
when there is damage to the outer adventitia or when vasa
vasorum are ligated. Although, atheromatous plaques do form
in small arteries that do not initially have vasa vasorum
– they do so only when the plasma concentrations of
lipids are exceptionally high, such as occurs in LDL-/-
apoE-/- double knockout mice.
Recent developments in micro-CT imaging provide 3D images
of intact segments of arteries and therefore can now provide
heretofore inaccessible information. Examples are the perfusion
territory size and location of individual vasa vasorum “trees”
as well as an index of the spatial distribution of solute
diffusion into, and washout from, the arterial wall. In addition,
several types of genetically modified “knockout”
mice that have recently been developed have a propensity for
developing atheromatous plaques and vasa vasorum and thereby
serve as powerful tools to further examine the bio-molecular
and genetic aspects of atheroma development and the response
to interventions.
[Back to top]
The ACE2-Ang-(1-7)-Mas Axis and Cardioprotection
Robson A.S. Santos, Sérgio V.B. Pinheiro and Anderson
J. Ferreira
[Full
Text Article]
It is well known that the renin-angiotensin system (RAS) is
a crucial regulator of the cardiovascular system playing an
important role in the control of blood pressure and cardiac
function. The relevance of the RAS in cardiovascular diseases
is illustrated by the efficiency of RAS blockade to improve
survival and cardiac function in patients with heart failure.
Emerging evidence suggest that, at least, part of the benefits
observed with the use of angiotensin-converting enzyme inhibitors
(ACEi) and AT1 receptor blockers (ARBs) could be
attributed to the increased Ang-(1-7) levels observed during
administration of these agents. Moreover, several experimental
studies in animal models of cardiomyopathies have demonstrated
that Ang-(1-7) can exert its effects through direct effects
produced by ligation to its recent identified G-protein coupled
receptor Mas or indirectly through ACE or AT1 receptors-related
mechanisms. The identification of the novels components of
the RAS, ACE2 and Ang-(1-7) receptor Mas, provided essential
elements for considering the existence of a vasodilator arm
of the RAS, represented by the ACE2-Ang-(1-7)-Mas axis. This
review briefly highlights the Ang-(1-7) effects in the heart,
paying special attention to emerging data suggesting its cardioprotective
actions in several cardiomyopathies with focus on the possible
role of the ACE2-Ang-(1-7)-Mas axis. In addition, we will
discuss the relationship between Ang-(1-7), SRA blockers,
and the kallikrein-kinin system.
[Back to top]
Effect of Aging On Angiogenesis and Arteriogenesis
Hsiao T. Yang
[Full
Text Article]
Aging is one of the important risk factors for cardiovascular
disease. Cardiovascular structure and function are continually
under the remodeling process as we age. Two forms of vascular
remodeling are associated with physiological and pathological
processes: (1) angiogenesis, a process of developing new capillaries
from pre-existing capillaries, and (2) arteriogenesis, a process
of forming functional collateral conduit arteries from the
existing small arteries or arterioles in the matured individual.
Current research suggests that aging may attenuate the both
angiogenesis and arteriogenesis by producing less angiogenic
stimulating cytokines, or by increasing expression of anti-angiogenic
factors. Yet, aged individuals remain responsive to physical
(e.g. exercise training) and/or biochemical stimuli (e.g.
exogenous angiogenic growth factors) to improve the angiogenic
and arteriogenic capacity. At present our knowledge of the
biological mechanisms of aging and angiogenesis/arteriogenesis
interactions is limited. NO-donors, single (FGF-2, VEGF, PDGFs)
or combined angiogenic growth factors (VEGF, Ang-1) demonstrated
efficacy in promoting collateral function in the ischemic
tissues of aged animals. Future studies should aim at the
basis of aging-impaired angiogenic capacity at molecular level,
and search for more effective strategies for therapeutic angiogenesis
to treat ischemic cardiovascular diseases.
[Back to top]
Remote Control of Pulmonary Blood Flow
Antonio F. Corno
[Full
Text Article]
Pulmonary artery banding is a suitable approach for complex
heart defects suitable to later bi-ventricular repair, functionally
uni-ventricular hearts, and left ventricular retraining.
Despite the existence of a very large spectrum of congenital
heart defects and clinical situations with potential indication
for pulmonary artery banding, the availability of only the
conventional surgical technique is still limiting the application
of this approach.
A solution to the clinical need for an adjustable pulmonary
artery banding has been found with a telemetrically controlled
adjustable pulmonary artery banding, FloWatch® (EndoArt,
Lausanne, Switzerland). This new implantable, wireless, battery
free, device (FloWatch®), demonstrated the feasibility
of repeated progressive occlusions and re-openings of the
device at the wanted percentage of occlusion through a remote
control, with long-term experimental evaluation in animals,
followed by successful introduction in clinical practice in
different institutions.
The availability of a reliable adjustable pulmonary artery
banding, avoiding any re-operation and the need for pulmonary
artery reconstruction at the moment of de-banding, has substantially
modified the clinical management of infants with congenital
heart defects with increased pulmonary artery blood flow and
pressures. New therapeutic strategies can now be considered
to expand the applicability of this device.
[Back to top]
Tissue Doppler Imaging: Beautiful Noise
Brent D. Wilson and Sheldon E. Litwin
[Full
Text Article]
Once regarded as “noise”, the Doppler shift recorded
from moving myocardium provides a great deal of information
about cardiac function and forms the basis of tissue Doppler
imaging (TDI). TDI is rapidly becoming a routine part of echocardiographic
evaluation of the heart. Given the large amplitude signal
obtained with TDI, recordings of myocardial velocities are
technically easy to acquire and they provide reproducible,
quantitative measurements even when 2-dimensional images are
suboptimal. Although TDI has broad potential utility in cardiac
functional assessment, its most rigorously validated applications
include: 1) estimation of left ventricular filling pressures;
2) assessment of systolic and diastolic function; 3) quantification
of ventricular dyssynchrony and evaluation for cardiac resynchronization
therapy; and 4) detection of myocardial ischemia or segmental
contractile dysfunction. Here we highlight some of the fascinating
discoveries that led to the development of TDI and discuss
its clinical application in each of these areas. Because TDI
is such a powerful means of noninvasively assessing cardiac
physiology and pathophysiology, its application in clinical
practice will undoubtedly continue to increase as it is becomes
more widely understood.
[Back to top]
Cardiac Surgery and Inflammation: The Inflammatory
Response and Strategies to Reduce the Systemic Inflammatory
Response Syndrome
Ian J. Hunt and Jon R.S. Day
[Full
Text Article]
Despite advances in the techniques of ‘off-pump’
Cardiac surgery, the vast majority of cardiac operations still
involve using cardiopulmonary bypass (CPB) along with some
form of myocardial protection. The extracorporeal circuits
used in the modern bypass-machine have developed considerably
in the last few decades. However contact activation of blood
leading to a systemic inflammatory response is to some degree
inevitable. Although often remaining sub-clinical and resolving
promptly at the end of CPB, in its most extreme form this
inflammatory response may be associated with the development
of the systemic inflammatory response syndrome (SIRS) that
can often lead to major organ dysfunction syndrome (MODs)
and death. Here we review the pathophysiology behind the development
of this “whole body” inflammatory response and
consider the mechanical and pharmacological methods that are
currently used to minimise it.
|
