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Current
Cardiology Reviews
ISSN: 1573-403X
Current Cardiology Reviews
Volume 5, Number 1, January 2009
Contents
Patient Radiation Doses in Interventional Cardiology Procedures
Pp. 1-11
Ioannis Pantos, Georgios Patatoukas, Demosthenes
G. Katritsis and Efstathios Efstathopoulos
[Abstract] [Full
Text Article]
Thyroid Hormone-Induced Angiogenesis Pp.
12-16
Paul J. Davis, Faith B. Davis and
Shaker A. Mousa
[Abstract]
[Full
Text Article]
Evaluation of the Pulmonary Veins and Left Atrial Volume using
Multi-detector Computed Tomography in Patients Undergoing
Catheter Ablation for Atrial Fibrillation Pp.
17-21
Hiroki Ito and Khaled A. Dajani
[Abstract] [Full
Text Article]
The Right Ventricle: Biologic Insights and Response
to Disease Pp. 22-28
Lori A. Walker and Peter M. Buttrick
[Abstract] [Full
Text Article]
Management of Asymptomatic Severe Aortic Stenosis
Pp. 29-35
Robert L. Stewart and Kwan L.
Chan
[Abstract] [Full
Text Article]
Anaerobic Bacteria as a Cause of Mycotic Aneurysm of the Aorta:
Microbiology and Antimicrobial Therapy Pp.
36-39
Itzhak Brook
[Abstract] [Full
Text Article]
Cardiac Resynchronization Therapy in Children Pp.
40-44
Anjan S. Batra and Seshadri Balaji
[Abstract] [Full
Text Article]
Natriuretic Peptide Signaling via Guanylyl Cyclase
(GC)-A: An Endogenous Protective Mechanism of the Heart
Pp. 45-51
Ichiro Kishimoto, Takeshi Tokudome, Takeshi
Horio, David L Garbers, Kazuwa Nakao and Kenji Kangawa
[Abstract] [Full
Text Article]
The Evolving Roles of Nuclear Cardiology Pp.
52-55
Andrea De Lorenzo
[Abstract] [Full
Text Article]
Risk Stratification for Sudden Cardiac Death: Current Approaches
and Predictive Value Pp. 56-64
Gustavo Lopera and Anne B. Curtis
[Abstract] [Full
Text Article]
Renin Angiotensin System as a Regulator
of Cell Volume. Implications to Myocardial Ischemia Pp.
65-68
Walmor C. De Mello
[Abstract] [Full
Text Article]
Cardiovascular Disease Risk Among the
Poor and Homeless – What We Know So Far Pp.
69-77
Charlotte A. Jones, Arjuna Perera, Michelle Chow,
Ivan Ho, John Nguyen and Shahnaz Davachi
[Abstract] [Full
Text Article]
Abstracts
[Back to top]
Patient Radiation Doses in Interventional Cardiology
Procedures
Ioannis Pantos, Georgios Patatoukas, Demosthenes
G. Katritsis and Efstathios Efstathopoulos
[Full
Text Article]
Interventional cardiology procedures result in substantial
patient radiation doses due to prolonged fluoroscopy time
and radiographic exposure. The procedures that are most frequently
performed are coronary angiography, percutaneous coronary
interventions, diagnostic electrophysiology studies and radiofrequency
catheter ablation. Patient radiation dose in these procedures
can be assessed either by measurements on a series of patients
in real clinical practice or measurements using patient-equivalent
phantoms. In this article we review the derived doses at non-pediatric
patients from 72 relevant studies published during the last
22 years in international scientific literature. Published
results indicate that patient radiation doses vary widely
among the different interventional cardiology procedures but
also among equivalent studies. Discrepancies of the derived
results are patient-, procedure-, physician-, and fluoroscopic
equipment-related. Nevertheless, interventional cardiology
procedures can subject patients to considerable radiation
doses. Efforts to minimize patient exposure should always
be undertaken.
[Back to top]
Thyroid Hormone-Induced Angiogenesis
Paul J. Davis, Faith B. Davis and
Shaker A. Mousa
[Full
Text Article]
A series of reports in the past decade have ascribed
pro-angiogenic activity to several thyroid hormone analogues,
including L-thyroxine (T4),
3,5,3-triiodo-L-thyronine (T3)
and diiodothyropropionic acid (DITPA). Model systems of angiogenesis
have demonstrated that thyroid hormone-induced neovascularization
is initiated at a cell surface receptor for the hormone on
an integrin. The hormone signal is transduced within the cell
by extracellular regulated kinase 1/2 (ERK1/2) into secretion
of basic fibroblast growth factor (bFGF) and other vascular
growth factors and consequent angiogenesis. Intact animal
studies have shown that endogenous thyroid hormone supports
blood vessel density in heart and brain and that thyroid hormone
administration can induce angiogenesis in ischemic limbs.
[Back to top]
Evaluation of the Pulmonary Veins and Left Atrial
Volume using Multi-detector Computed Tomography in Patients
Undergoing Catheter Ablation for Atrial Fibrillation
Hiroki Ito and Khaled A. Dajani
[Full
Text Article]
Catheter ablation is an evolving treatment option in
patients with atrial fibrillation. Contrast enhanced electrocardiogram-gated
multi-detector computed tomography (MDCT) has rapidly evolved
over the past few years into an important tool in the diagnosis
of coronary atherosclerosis. There is increasing recognition
that MDCT is a useful tool to evaluate non-coronary structures,
such as cardiac chambers, valves, the coronary sinus and adjacent
structures including pulmonary veins. In particular, MDCT
is playing an increasingly important role in the evaluation
of the left atrium and the pulmonary veins in patients undergoing
catheter ablation for atrial fibrillation. It provides accurate
and reliable identification of the pulmonary veins and anatomical
relationship between the left atrium and esophagus although
the mobile esophagus may limit the value of MDCT to reduce
the risk of atrio-esophagus fistula. In this article, we will
review the evaluation of the left atrium and pulmonary veins
using MDCT in patients undergoing catheter ablation of atrial
fibrillation.
[Back to top]
The Right Ventricle: Biologic Insights and Response
to Disease
Lori A. Walker and Peter M. Buttrick
[Full
Text Article]
Despite ample evidence that right ventricular function
is a critical determinant of the clinical response to a spectrum
of cardiovascular diseases, there has been only a limited
analysis of the unique and distinguishing physiologic properties
of the RV under normal circumstances and in response to pathologic
insults. This review highlights some of these features and
underscores the fact that rational therapy in RV failure should
acknowledge this physiology and ought to be chamber specific.
[Back to top]
Management of Asymptomatic Severe Aortic Stenosis
Robert L. Stewart and Kwan L.
Chan
[Full
Text Article]
Patients with symptomatic severe aortic stenosis (AS)
benefit from aortic valve replacement surgery, but the management
of patients with asymptomatic severe AS is more controversial.
While cholesterol and angiotensin have been linked to AS progression,
we should await the results of ongoing randomized trials before
medical therapy to lower cholesterol or inhibit angiotensin
can be recommended to limit disease progression. Clinical
factors, echocardiographic parameters, valve morphology, exercise
stress testing results, and cardiac biomarkers may be useful
in identifying patients who will have early development of
symptoms during follow-up and require closer monitoring. The
risks associated with aortic valve replacement outweigh the
benefits in the majority of patients with asymptomatic severe
AS.
[Back to top]
Anaerobic Bacteria as a Cause of Mycotic Aneurysm
of the Aorta: Microbiology and Antimicrobial Therapy
Itzhak Brook
[Full
Text Article]
This review summarizes the microbiology, and antimicrobial
management of mycotic aneurysm of the aorta (MAA) due to anaerobic
bacteria. Anaerobic bacteria are an uncommon but important
cause of MAA. Most cases of anaerobic MAA are caused anaerobic
gram-negative bacilli (mostly B. fragilis group),
Clostridium spp. (mostly Clostridium septicum,
and Propionobacterium spp. (mostly P. acnes).
Clostridial infection is frequently associated with gastrointestinal
or hematologic malignancy. A review of all the reported cases
is presented. Treatment of MAA involving anaerobic bacteria
includes the use of antimicrobial effective against these
organisms.
[Back to top]
Cardiac Resynchronization Therapy in Children
Anjan S. Batra and Seshadri Balaji
[Full
Text Article]
Cardiac Resynchronization therapy has become an important
management tool in adults with heart failure and dilated cardiomyopathy.
The role of CRT in children with CHF is still unclear. Evidence
is slowly emerging in the pediatric cardiology literature
that CRT may have an important and useful role in certain
select populations with CHF. These include patients with complete
heart block who develop pacing-induced cardiomyopathy, certain
forms of congenital heart disease associated with systemic
ventricular failure (even if the systemic ventricle is a morphologic
RV) and in patients with idiopathic dilated cardiomyopathy.
Studies in children supporting the use of CRT include many
case reports, a few studies of CRT in post-operative patients,
and one multi-center registry reporting the use of CRT in
children. These papers will be summarized.
[Back to top]
Natriuretic Peptide Signaling via Guanylyl Cyclase
(GC)-A: An Endogenous Protective Mechanism of the Heart
Ichiro Kishimoto, Takeshi Tokudome, Takeshi
Horio, David L Garbers, Kazuwa Nakao and Kenji Kangawa
[Full
Text Article]
Atrial and brain natriuretic peptides (ANP and BNP, respectively)
are cardiac hormones, secretions of which are markedly upregulated
during cardiac failure, making their plasma levels clinically
useful diagnostic markers. ANP and BNP exert potent diuretic,
natriuretic and vasorelaxant effects, which are mediated
via their common receptor, guanylyl cyclase (GC)-A (also
called natriuretic peptide receptor (NPR)-A). Mice deficient
for GC-A are mildly hypertensive and show marked cardiac hypertrophy
and fibrosis that is disproportionately severe, given their
modestly higher blood pressure. Indeed, the cardiac hypertrophy
seen in these mice is enhanced in a blood pressure-independent
manner and is suppressed by cardiomyocyte-specific overexpression
of GC-A. These results suggest that the actions of a local
cardiac ANP/BNP-GC-A system are essential for maintenance
of normal cardiac architecture. In addition, GC-A was shown
to exert its cardioprotective effects by inhibiting angiotensin
II-induced hypertrophic signaling, and recent evidence suggests
that regulator of G protein signaling (RGS) subtype 4 is involved
in the GC-A-mediated inhibition of Gαq-coupled
hypertrophic signal transduction. Furthermore, several different
groups have reported that functional mutations in the promoter
region of the human GC-A gene are associated with essential
hypertension and ventricular hypertrophy. These findings suggest
that endogenous GC-A protects the heart from pathological
hypertrophic stimuli, and that humans who express only low
levels of GC-A are genetically predisposed to cardiac remodeling
and hypertension.
[Back to top]
The Evolving Roles of Nuclear Cardiology
Andrea De Lorenzo
[Full
Text Article]
The use of cardiac imaging modalities has grown steadily,
and cardiac nuclear studies constitute a large part of this
number. Nuclear Cardiology is often mistakenly considered
a synonym of myocardial perfusion imaging (MPI), but has broader
applications, including metabolic imaging, innervation imaging,
among other technologies. MPI has been a powerful diagnostic
and prognostic tool in the assessment of patients for known
or suspected CAD for decades, and is now increasingly used
for the evaluation of the anti-ischemic effects of various
therapies, according to changes in left ventricular perfusion
defect size defined by sequential MPI. Neuronal dysfunction
identified with iodine-123-metaiodobenzylguanidine may give
information on prognosis in different disease conditions,
such as after myocardial infarction, in diabetes and dilated
cardiomyopathy. Molecular imaging may identify the predominant
cellular population in the atherosclerotic plaque and help
predict the likelihood of clinical events. Therefore, although
its usefulness is well established, Nuclear Cardiology remains
a moving science, whose roles keep in pace with evolving clinical
needs and expectations.
[Back to top]
Risk Stratification for Sudden Cardiac Death: Current
Approaches and Predictive Value
Gustavo Lopera and Anne B. Curtis
[Full
Text Article]
Sudden cardiac death (SCD) is a serious public health
problem; the annual incidence of out-of-hospital cardiac arrest
in North America is approximately 166,200. Identifying patients
at risk is a difficult proposition. At the present time, left
ventricular ejection fraction (LVEF) remains the single most
important marker for risk stratification. According to current
guidelines, most patients with LVEF <35%
could benefit from prophylactic ICD implantation, particularly
in the setting of symptomatic heart failure. Current risk
stratification strategies fail to identify patients at risk
of SCD in larger population groups encompassing a greater
number of potential SCD victims. However, the best approach
to identifying patients and the value of various risk stratification
tools is not entirely clear. The goal of this review is to
discuss the problem of SCD and the value of the different
risk stratification markers and their potential clinical use
either alone or in combination with other risk stratification
markers.
[Back to top]
Renin Angiotensin System as a Regulator of Cell Volume.
Implications to Myocardial Ischemia
Walmor C. De Mello
[Full
Text Article]
It is known that long lasting changes in cell volume
are incompatible with cellular functions. In the present review,
I discussed the role of cell volume on gene expression and
protein synthesis as well as the importance of the renin angiotensin
system on the regulation of cell volume in the failing heart.
Moreover, the relationship between mechanical stretch, cell
volume and the renin angiotensin system as well some translational
studies are also described and their relevance to the prevention
or reduction of cardiac damage during myocardial ischemia
is emphasized.
[Back to top]
Cardiovascular Disease Risk Among the Poor and Homeless
– What We Know So Far
Charlotte A. Jones, Arjuna Perera, Michelle Chow,
Ivan Ho, John Nguyen and Shahnaz Davachi
[Full
Text Article]
Homelessness [and poverty] is rapidly escalating across
North America and is associated with dire implications for
public health and our health care systems. Both are compelling
states of existence affecting all ages, ethnicities and both
genders. Homelessness frequently evolves through a complex
interaction of factors that are both internal and external
to the individual themselves. Once homeless, equitable access
to both preventative and remedial health care is lacking and
is associated with a higher than average burden of cardiovascular
disease [CVD] risk factors, morbidity and mortality and is
accompanied by disproportionately high health care costs.
The emergence of limited, small scale programs aimed at addressing
the unique health and social needs of the homeless is encouraging.
However, there has been inadequate commitment at the National,
State or Provincial and local levels to implement policies
and dedicate funding and resources to the expansion of such
“individual level” interventions into comprehensive
programs that deliver sustainable, integrated prevention and
services, especially with regard to CVD. The long-term solutions
that address the links between homelessness and CVD lie in
preventing homelessness and reversing the trends in our health
care system that create disparities for lower socioeconomic
status [SES] and homeless individuals.
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