12. Heart Flashcards
What are the three layers of the cardiac valves?
Fibrosa: dense collagen, mechanical integrity
Spongiosa: loose connective tissue
Ventricularis or atrialis: inflow surface, rich in elastin, provides leaflet recoil
List (there are 20+) changes to the 5 components of the heart associated with aging.
Robbins table 12.1
Chambers:
increased left atrial cavity size
decreased left ventricular cavity size
sigmoid-shaped ventricular septum
Valves: aortic valve calcific deposits mitral valve annular calcific deposits fibrous thickening of leaflets buckling of mitral leaflets toward the left atrium Lambl excresences
Epicardial coronary arteries: tortuosity diminished compliance calcific deposits atherosclerotic plaque
Myocardium: decreased mass increased subepicardial fat brown atrophy lipofuscin deposition basophilic degeneration amyloid deposits
Aorta:
dilated ascending aorta with rightward shift
elongated (tortuous) thoracic aorta
sinotubular junction calcific deposits
elastic fragmentation and collagen accumulation
atherosclerotic plaque
What is the difference between pressure-overload and volume-overload hypertrophy?
Pressure overload hypertrophy: New sarcomeres arranged in PARALLEL - expands cross-sectional area of myocytes in ventricles and causes CONCENTRIC increase in wall THICKNESS. examples: HTN, calcific aortic stenosis.
Volume overload hypertrophy: eg. due to valvular regurgitation. New sarcomeres arranged in SERIES within existing sarcomeres, leading primarily to dilatation.
List 4 causes of Left-sided heart failure.
- Ischemic heart disease
- Hypertension
- Aortic and mitral valvular disease
- primary myocardial disease
(obesity, diabetes, bilateral renal artery stenosis, myocardial fibrosis, infiltrative disorders like amyloidosis, exaggerated normal stiffening of heart due to age - can also be causes of diastolic failure - left ventricle cannot relax or expand normally, causes backup of pressure into lungs, leading to pulmonary edema).
list morphologic changes seen in the LUNGS due to left-sided heart failure.
Perivascular and interstitial EDEMA
Progressive edematous WIDENING of the alveolar septa
Accumulation of edema fluid in the alveoli
Hemosiderin-laden macrophages (heart-failure cells)
Pleural effusion
What is the most common cause of right-sided heart failure?
Left sided heart failure!
Isolated right-sided heart failure is infrequent, and usually with patients with lung disorder = cor pulmonale.
List causes of cor pulmonale.
Parenchymal lung diseases
primary pulmonary hypertension
recurrent pulmonary embolism
pulmonary vasoconstriction (obstructive sleep apnea, altitude sickness)
What is the characteristic liver finding in right-sided heart failure?
“nutmeg” liver: grossly, congested red-brown pericentral zones, with relatively normal-colored tan periportal regions (NORMAL PERIPORTAL, CONGESTED CENTRAL VEINS)
congestive hepatomegaly due to congestion of hepatic and portal vessels secondary to right sided heart failure. passive congestion is greatest around the CENTRAL VEINS.
Name a serum marker for heart failure.
Brain natriuretic peptide. Released by cardiac myocytes in response to increased wall stress.
Clinically, also measure CHF with echocardiography.
List syndromes associated with congenital heart disease, and the associated gene that is mutated (Robbins table 12.3)
Alagille syndrome - pulmonary artery stenosis or tetralogy of Fallot (JAG1 or NOTCH2)
Char syndrome - PDA (TFAP2B)
CHARGE syndrome (CHD7) - ASD, VSD, PDA, or hypoplastic right heart. [CHARGE: coloboma, Heart abnormality, Atresia of nasal choanae
DiGeorge syndrome - deletion 22q11.2 (TBX1 gene, one of about 30 genes in this segment) - ASD, VSD, outflow tract obstruction. –> defects in fourth branchial arch, 3rd and 4th pharyngeal pouches, involved in formation of THYMUS, PARATHYROID, HEART. [CATCH22: Cardiac abnormalies; Truncus arteriosus, Tetralogy of Fallot; Abnormal facies; Thymic hypoplasia/T-cell abnormalities; Cleft palate; Hypoparathyroidism/hypocalcemia.)]
Holt-Oram syndrome - (TBX5) ASD, VSD or conduction defect.
Noonan syndrome - pulmonary valve stenosis, VSD, or hypertrophic cardiomyopathy (PTPN11, KRAS, SOS1)
ALSO: Down syndrome, T21, most common known genetic cause of congenital heart disease.
Trisomies 13, 18, monosomy X/Turner.
List 3 transcription factors that produce sporadic congenital heart disease.
NKX2.5
GATA4
TBX5
These three genes all bind together and co-regulate the expression of target genes required for proper cardiac development.
List four causes of left-right shunting in the heart.
ASD
VSD
PDA
Patent foramen ovale
List 5 causes of right-left (cyanotic) shunting in the heart.
Tetralogy of Fallot
Total anomalous pulmonary circulation
Transposition of the great arteries (TGA)
Persistent truncus arteriosus
Tricuspid atresia (total absence of tricuspid leads to hypoplastic or absent right ventricle, with uni-left ventricle, causing mixing of blood and sending relatively hypo-oxygenated blood into systemic circulation).
(the 5 T’s - tetralogy, total, transposition, truncus, tricuspid)
What are the abnormalities seen in Tetralogy of Fallot?
FOUR abnormalities:
Over-riding aorta
Pulmonary artery stenosis (obstruction of right ventricle outflow tract)
VSD
Right ventricular hypertrophy
ASDs are classified according to their location. List the 3 types of ASD.
Secundum ASD: 90% - deficient septum secundum (near the centre of the septum)
Primum anomalies: are located adjacent to the AV valves and typically associated with some kind of valve anomaly.
Sinus venosus defects: located near the entrance of the SVC; can be associated with anomalous pulmonary venous return to the right atrium.
