Robbins Flashcards
component of the conduction system that has a gatekeeper function
AV node
what pattern of hypertrophy -new sarcomeres are predominantly assembled in parallel to the long axes of cells, expanding the cross-sectional area of myocytes in ventricles and causing a concentric increase in wall thickness.
pressure-overload hypertrophy
what pattern of hypertrophy?
-is characterized by new sarcomeres being assembled in series within existing sarcomeres
volume-overload hypertrophy
best measure of hypertrophy in dilated hearts
heart weight
T/F myocyte hypertrophy is accompanied by a proportional increase in capillary numbers
False
____ is associated with volume-load hypertrophy accompanied by increases in capillary density
aerobic exercise
what physiologic mechanism?
Increased filling volumes dilate the heart, thereby increasing actin-myosin cross-bridge formation, and enhancing contractility and stroke volume.
Frank-Starling mechanism
the most common known genetic cause of CHD is
trisomy 21 (Down syndrome)
deletion of chromosome 22q11.2 casuse CHD in a syndrome called
DiGeorge syndrome
deletion of this transcription factor gene in DiGeorge syndrome causes CHD
TBX1
pathway associated with a variety of congenital heart defects
Notch pathway
gene mutation in bicuspid aortic valve
NOTCH1
gene mutations in tetralogy of Fallot (2)
JAG1 and NOTCH2
right-to-left shunts cause (5)
hypoxemia and cyanosis
paradoxical emobolism
polycythemia
clubbing
hypertrophic osteoarthropathy
Most important right-to-left shunts (5)
-tetralogy of Fallot (TOF)
-transposition of the great arteries (TGA)
-persistent truncus arteriosus
-tricuspid atresia
-total anomalous pulmonary venous connection
left-to-right shunts increase _____ blood flow
pulmonary
In left-to-right shunts, pulmonary vascular resistance eventually approaches systemic levels, and the shunt becomes a right-to-left shunt that introduces poorly oxygenated blood into the systemic circulation. This is called ______ syndrome
Eisenmenger syndrome
left-to-right shunts (3)
ASD
VSD
PDA
CHD category where there is abnormal narrowing of chambers, valves, or blood vessels
obstructive
obstructive CHDs (3)
coarctation of the aorta
aortic valvular stenosis
pulmonary valvular stenosis
the most common CHD category
left-to-right shunt
most common type of ASD
Secundum ASD
Left-to-right shunt that is usually asymptomatic until adulthood
ASD
patent foramen ovale closes permanently in ~80% by age
2
most common form of CHD
VSD
what causes irreversible obstructive pulmonary vascular disease
prolonged pulmonary arterial vasoconstriction stimulates the development of irreversible obstructive intimal lesions analogous to the arteriolar changes seen in systemic hypertension
ductus arteriosus constricts and and closes in response to (3)
-increased arterial oxygenation
-decreased pulmonary vascular resistance
-declining local levels of prostaglandin E2
the most common right-to-left shunt
TOF
four cardinal features of TOF
vsd
subpulmonic stenosis
overiding aorta
right ventricular hypertrophy
CHD that produces ventriculoarterial discordance (the ventricle outflow going to the wrong outflow vessel)
Transposition of the Great Arteries (TGA)
the aorta arises from the right ventricle, and the pulmonary artery emanates from the left ventricle (ventriculoarterial discordance). The atrium-to-ventricle connections are normal (concordant), with the right atrium joining the right ventricle and the left atrium emptying into the left ventricle.
dextro-TGA
TGA that does not lead to cyanosis
levo-TGA
2 forms of the obstructive CHD, coarctation of the aorta
infantile with PDA (preductal coarctation)
adult (postductal coarctation)
main abnormality in hypoplastic left heart syndrome
aortic stenosis or atresia
an imbalance between myocardial supply (perfusion) and cardiac demand for oxygenated blood
Ischemic heart disease (IHD)
how does tachycardia decrease oxygen functional supply to the heart
by decreasing the relative time spent in diastole, when cardiac perfusion occurs
is typically cited as the threshold for symptomatic ischemia precipitated by exercise (characteristically manifesting as exertional angina).
critical stenosis (>70%)
obstruction of ___% of the cross-sectional area of the lumen generally leads to inadequate coronary blood flow, even at rest.
90
earliest detectable feature of myocyte necrosis
disruption of the integrity of the sarcolemmal membrane
Irreversible injury of ischemic myocytes first occurs in the
subendocardial zone
An infarct usually achieves its full extent within
3-6 hours
Transmural infarctions occur when there is occlusion of an
epicardial vessel in the absence of any therapeutic intervention
In the subendocardial infarcts that occur as a result of global hypotension, myocardial damage is often ____
circumferential
time interval when dark mottling is grossly apparent after MI
12-24 hours
time interval when scarring is grossly complete after MI
> 2 mos
Owing to the characteristic electrocardiographic changes resulting from myocardial ischemia or necrosis in various distributions, a transmural infarct is sometimes referred to as an
ST-elevation myocardial infarct (STEMI)
Owing to the characteristic electrocardiographic changes resulting from myocardial ischemia or necrosis in various distributions, a subendocardial infarct is sometimes referred to as
non–ST-elevation infarct (NSTEMI)
The most common of all valvular abnormalities and is usually the consequence of age-associated “wear and tear” of either anatomically normal valves or congenitally bicuspid valves
Calcific Aortic Stenosis
The characteristic anatomic change in MVP is
ballooning (hooding) of the mitral leaflets
The key histologic change in MVP
myxomatous degeneration of spongiosa layer
Distinctive lesions in the heart in rheumatic fever
aschoff bodies
five most common tumors of the heart in descending order of frequency
myxomas
fibromas
lipomas
papillary fibroelastomas
rhabdomyomas
most common primary tumor of the adult heart
myxomas
About 90% of cardiac myxomas arise in the
atria
favored site of origin of a myxoma in the atria
fossa ovalis
usual locations of fibroelastomas
valves
the most frequent primary tumor of the pediatric heart
rhabdomyomas
Approximately one-half of cardiac rhabdomyomas are due to sporadic mutations; the other 50% of cases are associated with _____ with mutations in (2)
tuberous sclerosis, TSC1 and TSC 2
The TSC1 and TSC2 proteins (hamartin and tuberin, respectively) function in a complex that inhibits the activity of_______ a kinase that stimulates cell growth and regulates cell size.
mammalian target of rapamycin (mTOR)
Metastases can reach the heart and pericardium by
retrograde lymphatic extension from the mediastinum (mostly carcinomas), by hematogenous seeding (many tumors), by direct contiguous extension (of intrathoracic tumors), or by venous extension (tumors of the kidney or liver)
