Cardiac System Flashcards
6 principal mech of cardiovasc pathology
1 Failure to pump (systolic or diastolic) 2 obstruction to flow 3 regurgitant flow 4 shunted flow 5 conduction disorder 6 rupture of heart or vessel
Inadequate myocardial contractile function from IHD or HTN
Systolic dysfunction HF
Inability of the heart to relax and fill (massive LVH, myocardial fibrosis, amyloid deposition, constrictive pericarditis)
Diastolic dysfunction HF
40-60%
Common in women, elderly, diabetics
CHF pathophy
Dec pumping efficiency Inc EDV Inc EDP Inc Venous pressure Inadequate CO (forward failure) with Congestion of venous circ (backward failure)
Heart failure compensations (3)
Frank starling mechanism
Neurohormonal activation
Myocardial structural change
Heart failure is said to be compensated if
Dilated ventricle is able to maintain cardiac output
Inc wall tension and O2 req heart unable to propel sufficient blood to meet needs of the body
Decompensated
Neurohormonal system
NE
RAAS
Pressure overload state anatomic change (HTN valvular stenosis)
Parallel addition of sarcomeres - concentric hypertrophy
Inc wall thickness without inc in chamber size
Volume overload (valvular regurg or shunt)
Sarcomeres in series
Muscle fiber length inc
Dilation of ventricles
Best measure of hypertrophy in volume overloaded heart
Heart weight
Independent risk factor for sudden cardiac death
Cardiac hypertrophy
Severe pulmonary hypertension resulting in right sided pathology
Cor pulmonare
Isolated RSHF also occur in pulmonic or tricuspid valve disease, CHF, left to right shunt
Passive liver congestion in histology
Nutmeg liver
LSHF causes central hypoxia in liver
Centrilobular necrosis
Sinusoidal congestion
Severe RSHF cardiac cirrhosis
Hallmark of R sided HF
Ankle and pretibial edema
Chronic dilation of left atrium may lead to
Afib and stagnat blood formation in appendage leading to thrombi and emboli
MI, Systemic HTN, mitral or aortic valve disease, myocardial disease
systemic hypoperf cause renal and cerebal dysfunction
LVHF
LHF, Pulmo HTN, pulmonary valve stenosis
RSHF
Most common CHD
VSD
ASD
Pulmonary stenosis
CHD arises from faulty embryogenesis during
week 3-8
Genetic defect in ASD VSD
GATA4
Genetic defect in TOF
ZFPM2 or NKX2.5
Hemodynamic consequences in CHD
1 right to left shunt
2 left to right shunt
3 obstruction to flow
Most common type of CHD
Left to right shunt
Once pulmo HTN develops, structural defects of CHD are
irreversible
Reversal of flow shunting of unox blood back to systemic circulation
Eisenmenger Syndrome
Abnormal fixed opening in septum that allows unrestricted bf bet atrial chambers
ASD
90% ostium secundum
R atrial and ven dilation
R ventricular hypertrophy
Dilation of pulmonary artery
Inc volume overload
ASD
5% of defects at lowest part of atrial septum
assoc with mitral and tricuspid valve abn
Close relationship with endocardial cushion
Ostium primum ASD
5% located high in atrial septum with anomalous drainage of pulmonary veins into R atrium and SVC
Sinus venosus ASD
Most common defect detected in adult
ASD
Site of 90% of VSDs
Basal membranous
Close spont in childhood
20-30% occur in isolation most with other malf
High pres left to right shunt producing harsh machinery like murmur
Lifesaving if with aortic or pulmonic atresia
PDA
Early cyanosis Right to Left shunt Clubbing of fingers (hypertrophic osteoarthropathy) Polycythemia Paradox embolization
Right to left shunt
Most common cause of cyanotic CHD
TOF
4 Cardinal features of TOF
VSD
SubPulmonic stenosis (R ventricular outflow ob)
Overriding of the VSD by aorta
RVH
Cardinal features of TOF arise from
Anterosuperior displacement of infundibular septum -> abnormal septation
Major site of egress of blood flow from both ventricles
Overriding aorta
Severity of TOF depends on
pulmonary outflow obstruction
R to L shunt
Dec pulmonary blood flow
Inc aortic volume
TOF