2022 Flashcards
Histologyc changes in mitral valve disease
progressive expansion
of extracellular matrix with glycosaminoglycans and proteoglycans,
valvular interstitial cell alteration and attenuation or
loss of the collagen-laden fibrosa layer that results in mitral valve
incompetence
What is the endothelial glycocalyx?
Are lines the luminal surface of endothelial cells, maintaining vascular health
Quantification of eGlx breakdown products
chondroitin sulfate, hyaluronan, and syndecan-1
Clinical aplications of quantification of eGlx breakdown products
in humans: chronic kidney disease
Conclusions: Prospective clinical trial evaluating
spironolactone in Doberman pinschers
with congestive heart failure due to
dilated cardiomyopathy
While median time to cardiac death in the spironolactone group was not statistically significantly different than that in the placebo group, adding spironolactone to conventional therapy resulted in reduced occurrence of AF
Prevalence of DCM in Doberman pinscher
58% in Europe. and it is the leading cause of death in this
breed.
Prognosis of DCM after 1 episode of cangestive heart failure in Doberman
survival time after the onset of congestive
heart failure continues to be poor and on average
less than one year in the breed
Aldosterone in cariac patiens
Aldosterone, a mineralocorticoid
hormone RAAS end product, has negative longterm
effects through activation of its mineralocorticoid
receptor in renal and non-renal tissues,
including sodium and water retention,
vascular endothelial dysfunction, baroreceptor
dysfunction, potentiation of the effects of angiotensin
II and the sympathetic nervous system, and
negative remodeling effects including myocardial
and vascular fibrosis, and myocardial necrosis and
apoptosis
Aldosterone in human
Direct relationships between
heart failure (HF) mortality and circulating aldosterone
levels and markers of myocardial fibrosis in
humans and presence of myocardial fibrosis
in dogs have been demonstrated.
Why ACEIs are only partially effective in blunting RAAS
aldosterone escape or breakthrough
due to a number of factors including
alternate angiotensin conversion pathways, alternate
stimuli for aldosterone release, and lack of
blockade of mineralocorticoid receptors ,
which may account for their lack of efficacy in
some canine CHF studies
Spirinolactone effects
Spironolactone is a competitive antagonist for
aldosterone’s mineralocorticoid receptor, thereby
directly inhibiting aldosterone’s renal effects and
non-renal effects, resulting in natriuresis, diuresis,
potassium retention, and decreased tissue fibrosis.
Spirinolactone in Dobermans with DCM
Lest risck of develop AF
Histopathologic evaluations of hearts from
Doberman pinschers with DCM
have demonstrated
remodeling characterized by the presence of diffuse
cardiomyocyte degeneration and loss,
expansion of the interstitium with collagen and
macrophages, and focal necrosis
Ideal spirinolactone dose
Guyonnet et al.
[39] used an in vivo model of hyperaldosteronism
in normal dogs to determine that a once daily dose
of 1.8 mg/kg was predicted to effectively inhibit
the actions of excess aldosterone and restore urinary
sodium to potassium ratio to normal, whereas and Esposito et al. [35] demonstrated significant
reduction in interstitial fibrosis and cytokine
expression in a pacing-induced HF model in dogs
using spironolactone 2.4 mg/kg once daily. Schuller
et al. were unable to demonstrate any survival
or clinical benefit of low dose spironolactone
(median 0.52 mg/kg once daily) in dogs with CHF
due to MMVD or DCM [29].
the estimated mean dose to inhibit the actions of
aldosterone by 50% (ED50) was 1.08 mg/kg. Bernay
et al. [28] demonstrated a significant 69% reduction
in risk of cardiac related death in dogs with
MMVD and CHF receiving an average spironolactone
dose of 2.33 0.34 mg/kg once daily
Function of the Spirinolactona preventing AF
The potential protective
effect of spironolactone may be explained
by its anti-fibrotic and anti-remodeling effects
Conclusions: Prospective evaluation of the combined value of physical examination and biomarker variables in screening for preclinical dilated cardiomyopathy in Doberman Pinschers
Both NTproBNP and cTnI had good utility as sole tests to discriminate
PC-DCM-Echo DP from all others. Models differentiating No-DCM/MMVD DP from all
other DP were improved by using PE and NTproBNP together
Pulmonary transit time (PT)
is the time for a
sample of blood to pass through the pulmonary
circulation. It depends on pulmonary blood volume
(PBV) and cardiac output (CO) according to the
formula PTT ¼ PBV/C
Epicardial pacemaker implantation indications
Epicardial pacing is a viable option
for smaller animals, animals with pre-existing infections, animals at risk for thrombotic
complications, or animals undergoing another thoracic or abdominal surgery.
Endocardial versus epicardial PM
Endocardial pacing is currently favored over epicardial
pacing because implantation does not
require opening of the thoracic cavity and thus is less
invasive compared with epicardial pacing. However,
endocardial pacing puts the lead in contact with
blood and intracardiac structures, leading to a
myriad of complications, including intracardiac
thrombosis, right ventricular outflow tract
obstruction, tricuspid stenosis, cranial or caudal vena caval fibrosis, cardiac
perforation, chylothorax, and embolic
pulmonary hypertension (personal observation).
Percentual of complications in PM
decreasingto13e33% in
the 2000s
Major complications in PM implantation
Reports since 2015 suggest major
complication rates of approximately 15% for dogs
with both HG-AVB and SSS , while the most
recent large-scale multi-institutional retrospective
study of 595 dogs with various bradyarrhythmias found a major complication rate of 21.8%.e Higher
complication rates have been reported in dogs with
pre-existing structural heart disease , postoperative
infections , previously used pulse
generators , inexperienced operators, and
procedures performed after normal business hours
[11]. In comparison, large-scale retrospective studies
in humans report major complication rates of
2.3-11.2%
Median time from
pacemaker implantation to major complication
was 38 days (range 1e983 days); most major
complications (19/25, 76%) occurred within 6
months of PAP implantation. 1 day for lead dislodgment
(n 7), 76 days for lead thrombus (n 5), 58 days
for lead infection (n 4), 194 days for generator
infection (n 3), 94 days for pacing failure (n 3),
84 days for lead perforation (n 2), and 18 days
for generator migration (n 1).
Major complications in PM
13/25 (52%)
eventually resulted in death of the affected dog Fatal complications were lead or generator infection
(n 4), lead thrombus leading to pulmonary
thromboembolism (n 4) or cranial vena cava
syndrome (n 1), pacing failure (n 2), Twiddler’s
syndrome with lead dislodgment (n 1), and
lead perforation of the right ventricle (n 1)
factors found to have an independent association
with all-cause mortality
higher patient age, higher body weight, and activation of
temporary pacing during the procedure.
Conclusions: Surgical safety checklist during pacemaker implantation
This study found that use of an SSC was associated
with decreased major complications and increased
compliance with antibiotic protocols during transvenous
PAP implantation in a veterinary teaching
hospital. Results of this study support the use of an
SSC in veterinary cardiology procedures.
The most frequently underlying
lesion leading to 3AVB in dogs
non-specific fibrosis or fibrofatty
replacement of the atrioventricular (AV) conduction
system. Although less frequently reported, 3AVB can
also arise in dogs with inflammatory lesions
affecting the AV conduction system associated
with myocarditis.
