B/1-15 PATHOLOGY OF CARDIOVASCULAR SYSTEM

Question 1

Congenital heart disease, What means that?

Answer 1

IS MEANING

abnormalities of the heart or great vessels that are present at birth. Most arise from faulty of embryogenesis during gestational weeks 3rd-8th.

• Environmental factors (rubella infection, alcohol) as well as genetics (trisomies 13, 15, 18, 21 and turner syndrome) may be in the background.

Even if operated, the repaired heart may still not be completely normal → development of endocarditis, hypertrophy, arrhythmias, polycythemia (compensation of hypoxia).

Therefore, long-standing medical care is needed.

Question 2

What are the are the 3 major groups of congenital heart diseases?

Answer 2

Congenital heart diseases can be subdivided into 3 major groups:

• malformations causing left to right shunt
  
  • Oxygenated blood goes to the hypoxic area. Initially, it is not associated with cyanosis.
• malformations causing right to left shunt
  
  • (cyanotic congenital heart diseases, “blue babies”).
• malformations causing obstruction
  
  • ​​called atresia if it is complete

Question 3

What is the result of Left to right shunts?

• Give the names of 3 left to right shunts.

Answer 3

Left-to-right shunts increase blood flow into the pulmonary circulation and are not associated with cyanosis. However, they expose the low-pressure, low-resistance pulmonary circulation to high pressures and increased volumes; these alterations lead to adaptive changes that increase lung vascular resistance to protect the pulmonary bed, resulting in right ventricular hypertrophy and—eventually rightsided— failure. With time, increased pulmonary resistance also can cause shunt reversal (right to left) and late-onset cyanosis (Eisenmenger syndrome). Once significant pulmonary hypertension develops, the structural defects of congenital heart disease are considered irreversible. This is the rationale for early intervention, in most cases surgically.

1. Atrial Septal Defects
2. Ventricular Septal Defects
3. Patent Ductus Arteriosus

Question 4

What is atrial-septal defects?

Answer 4

abnormalities in the sequence of atrial septation leads to the development of ASD’s.

3 types are recognized:

• ostium secondum: also called “foramen ovale aperta”. 90% of the cases. Occurs when the septum secundum does not enlarge sufficiently to cover the ostium secundum.
• ostium primum: 5% of the cases. Occurs due to failure of fusion of the septum primum and endocardial cushion.
• sinun venosus: 5% of the cases. Due to frameshift mutation in NKX2.5 transcription factor.

If the hole is less than 1cm → well tolerated. A bigger hole makes problems:

• The left to right shunt makes volume overload in the right side → right sided hypetrophy, pulmonary hypertrophy, Eisenmenger syndrome.
• A shunt increases the risk for paradox embolism.

Question 5

ventricular septal defect

Answer 5

Highly-located communication, which means, missing of pars membranosa. If it occurs as an isolated disease it is called “Roger disease” and it can also be a part of a complex cardiac malformation.

The other option is when there are holes in the pars muscularis.

The consequences of it are right sided hypertrophy (to compensate the shunt) and due to the high pressure and “hitting” of the endocardium → jet lesions which are also prone to superimposed infective endocarditis.

Question 6

Patent ductus arteriosus

Answer 6

Shortly after birth, the ductus arteriosus constricts due to decreased pulmonary vascular resistance, increased arterial oxygenation and decrease in the local levels of PgE2.

The ductus arteriosus does not close when:

• the resistance of the lung does not decrease, as in the case of IRDS.
• when the baby is hypoxic → no oxygen to make the closure.

leads to the development of pulmonary hypertension and Eisenmenger syndrome.

Question 7

What is the result of Righ to left shunts?

• Give the names of 2 right to left shunts.
• What are the clinical consequences?

Answer 7

Cardiac malformations associated with right-to-left shunts are distinguished by early cyanosis.

Two of the most important conditions associated with cyanotic congenital heart disease are tetralogy of Fallot and transposition of the great vessels.

Clinical consequences of severe, systemic cyanosis include clubbing of the tips of the fingers and toes (hypertrophic osteoarthropathy), polycythemia, and paradoxical embolization.

Question 8

Fallot tetralogy

Answer 8

Composed of 4 malformations:

• high position of ventricular-septal defect
• narrowing of the pulmonary trunk
• dextra-position of the aorta=”riding aorta”. The aorta is riding on the VSD.
• hypertrophy of the right ventricle (compensatory mechanism).

The most important factor is the severity of the pulmonary stenosis:

• If it is mild → the shunt is left to right. Also called “pink tetralogy” since the baby has no cyanosis.
• severe → the shunt is bidirectional (from the left and the right). In the severe cases there is right to left shunt with cyanosis.

Question 9

Transposition of the great vessels

Answer 9

The pulmonary trunk originates from the left ventricle and the aorta originates from the right ventricle. Incompatible with life unless a shunt develops

The shunts are:

• VSD
• PDA
• patent foramen ovale.

surgical intervention is required, during which a catheter is introduced into the heart by which artificial holes are made on the chambers to provide communication.

Question 10

truncus arteriosus

Answer 10

the step of septation of the aorta and the pulmonary trunk is missing → the patient has a common trunk for both vessels. This case is associated with VSD and therefore in both sided of the heart blood goes to the common trunk. Leads to right-sided hypertrophy because the right side has to reach the pressure of the left side (compensatory mechanism)

Question 11

Obstruction

Answer 11

at the level of the heart valves or within the great vessels.

Common examples are

• pulmonic valve stenosis
• aortic valve stenosis or atresia
• coarctation of the aorta (Most common)
  
  • There are two classic forms:
    
    • An “infantile” preductal form featuring hypoplasia of the aortic arch proximal to a PDA
    • An “adult” postductal form consisting of a discrete ridgelike infolding of the aorta, adjacent to the ligamentum arteriosum

Question 12

What can we expect that will happen to a patient has a cardiac malformation?

Answer 12

1. arrhythmia
2. calculate the altered hemodynamic → endocarditis
3. calculate the degree of hypertrophy and its ischemic lesions

Question 13

MI needed here? If yes, copy from topic A/5

Question 14

Sudden cardiac death

Answer 14

Defined as unexpected death from cardiac causes either without symptoms or within 1 to 24 hours of symptoms onset.

Coronary artery disease is the most common underlying cause.

younger: can be nonatherosclerotic causes:
* cardiomyopathis, myocarditis or sarcoidosis, congenital coronary arterial abnormalities, autosomal dominant long-QT syndrome.

The ultimate mechanism of SCD is most often severe arrhythmia.

Severe coronary atherosclerosis with critical (75% or more) stenosis is present in 80-90% of SCD victims.

Only 10-20% of cases of SCD are of nonatherosclerotic origin.

Question 15

Angina pectoris

• Definition
• Names of the 3 types

Answer 15

Angina pectoris is an intermittent chest pain caused by transient, reversible myocardial ischemia.

3 types:

• Typical or stable angina
• Unstable or crescendo angina
• Prinzmetal or variant angina

Stable → unstable → AMI

Question 16

Describe the typical / stable angina

Answer 16

• squeezing substernal sensation that can radiate to the left arm or to the left jaw.
• The pain is associated with increased myocardial demand in a patient with a fixed atherosclerotic narrowing (75% or more) of the coronary artheries.

The pain is relieved by nitroglycerin (peripheral vasodilator) → reduced venous blood which is delivered to the heart → reduced cardiac work. Pain is also relived by rest.

Question 17

Describe the unstable or crescendo angina

Answer 17

• Characterized by increasing frequency of pain, precipitated by progressively less exertion.
• The episodes also tend to be more intense and longer lasting than stable angina.
• Is the result of plaque disruption and superimposed partial thrombosis, distal embolization (which cause microinfarcts) of the thrombus and/or vasospasm.
• It is the harbinger of more serious, potentially irreversible ischemia (due to complete luminal occlusion by thrombus).

Question 18

Describe prinzmetal / variant angina

Answer 18

occurring during rest due to coronary artery spasm. Complete normal vessels may be affected as well. Etiology is not clear.

Question 19

Chronic ischemic heart disease

Answer 19

The patient have ischemia but the degree and speed of development is slow.

2 pathways:

1. following AMI: the remaining ventricle have to take over the work → hypertrophy → needs more oxygen and nutrients. This cannot be supplied because there is coronary disease. The result is that between the hypertrophied myocardium there are necrotic areas which are replaced by fibrosis (scar tissue, white spots)
2. without AMI: there is hypertension → left ventricular hypertrophy → higher demand. Or, the patient have 3 coronary disease but the degree of stenosis doesn’t make necrosis but just shortage of blood supply . this causes ischemia. Left sided heart failure or fibrosis developes.

Question 20

Give a general description of Rheumatic fever

Answer 20

• acute inflammation
• immunologically mediated disease
• multisystem inflammatory disease
• occurs few weeks after an episode of group A β-hemolytic streptococcus. most typically, it occurs after pharyngitis. The bacteria grows on the tonsils and never gets into the circulation. Its antigens get into the circulation → recognized by B cells → production of immunoglobulins. This causes 2 problems:
  
  • the Ig cross react with the 3 layers of the heart
  • formation of immune complexes which causes vasculitis, glomerulonephritis.