Path 12: Heart go brrrrrrrrr Flashcards
Layers of tri-layer architecture of cardiac valves
Endothelium
Fibrosa
Ventricularis/Atrialis Layer
Cardiac myocytes rely on ________ for energy
oxidative phosphorylation
Diastole comprises ____ [fraction] of the cardiac cycle
2/3
With tachycardia, the relative duration of ____ decreases
diastole
Frank-Starling mechanism
1) Increased filling volumes dilate the heart
2) Actin-myosin crossbridge formation increases
3) Contractility increases
Normal EF
45-65%
Causes of hypertrophy
Pressure overload
Volume overload
Trophic signals (aka ß activation)
Hypertrophic myocyte cellular characteristics
1) increased protein synthesis
2) Increased mitochindira
3) Multiple/enlarge nuclei
4) DNA ploidy
Patterns of hypertrophy
Pressure overload: sarcomeres are PARALLEL to long axes of cells. Wall thickness increases
Volume overload: sarcomeres assembled in series with existing ones. Heart weight increases, but wall thickness does not. Dilation of ventricle
Why does hypertrophy make heart vulnerable to ischemia
1) Increased oxygen demand
2) Hypetrophic growth not accompanied by capillary growth
3) Fibrous tissue resists diastolic filling
Genes expressed in hypertrophic myocytes
FOS
JUN
MYC
EGR1
Most common left HF causes
1) Ischemia
2) HTN
3) Aortic/mitral dx
4) Primary myocardial dx
Pulmonary changes from pulmonary edema
1) Perivascular and interstitial edema
2) Progressive widening of alveolar septa
3) Accumulation of fluid in alveolar spaces
Histologic changes pointing to previous episodes of pulmonary edema
Hemosiderin laden macrophages
AKA Heart Failure Cells
Mechanism of hemosiderin laden macrophages
Extravasated red cells phagocytosed and accumulated iron is hemosiderin
CHF auscultation findings
1) Fine rales in bases (inspiratory)
2) S3 (volume overload)
3) S4 (increased myocardial stiffness
Mitral regurgitation in HF caused by
Dilation of heart outwardly displaces papillary muscle
Most common cause of right HF
Left HF
Isolated right HF caused by
Usually pulmonary pathologies
Marker used to quantitatively assess CHF progression
BNP
Cardiac cell embryologic origin
Mesoderm
First wave of cardiac folding in embryo produces
Left ventricle
Second wave of cardiac folding in embryo produces
Right ventricle, outflow tract, atria
Most common genetic cause of congenital heart dx
Down syndrome