Cardiovascular Pathology Flashcards
Basic features of the heart
- Normal weight 280-340 g male, 230-280 g female
- Two sides, right thinner than left
- Two stage electrical generated contraction
- Sarcomere proteins
- Contraction initiated by depolarisation and changes to calcium concentration
- Protein conformational change – contraction
- Removal of calcium (energy dependent) for relaxation to occur
What are the 2 types of cardiac myocytes?
- Atrio-ventricular conduction system – slightly faster conduction
- General cardiac myocyte
What can all cells do in the heart?
Act as a pacemaker
Normal cardiac conduction
Normal coronary circulation
Blood flow through myocardium from aortic root is diastolic
Key features of myocardial hypertrophy and heart failure
- Normal systolic ejection fraction 60-65%
- Failure to transport blood out of heart = cardiac failure
- Cardiogenic shock = severe failure
- Frank–Starling mechanism and pericardial sac limitations
What also increases as venous return increases?
Cardiac volume
What happens if you exceed stretch capability of sarcomeres?
cardiac contraction force diminishes
What is a hypertrophic response triggered by?
angiotensin 2
ET-1
insulin-like growth factor 1
TGF-β
What is left sided cardiac failure?
pulmonary congestion and then overload of right side.
What is right sided cardiac failure?
venous hypertension and congestion.Right-sided
Congenital heart disease
> results from faulty embryonic development
may complicate up to 1% of all live births.
misplaced structures or arrest of the progression of normal structure development.
What happens when there is an initial left to right shunt in congenital heart disease?
- VSD, ASD, PDA, truncus arteriosus, anonymous pulmonary venous drainage, hypoplastic left heart syndrome
What happens when there is right to left shunt in congenital heart disease?
- Tetralogy of Fallot, tricuspid atresia
What happens if there is no shunt in congenital heart disease?
- Complete transposition of great vessels
- Coarctation
- Pulmonary stenosis
- Aortic stenosis
- Coronary artery origin from pulmonary artery
- Ebstein malformation
- Endocaradial fibroelastosis
Anatomy of the pericardium
A fibro-serous fluid filled sac
Separates the heart and roots of the great vessels from other mediastinal structures
fibrous and serous
Serous divided into outer parietal and internal visceral (= epicardium)
Fist into balloon = 2 layers and pericardial reflections
Great vessels found here
What is the pericardial cavity?
potential space between outer parietal and visceral
What is a cardiac tamponade?
rapid collection of pericardial fluid – heart is restricted and impairs filling – when you have more fluid than usual in this area – blood after trauma – that means there isn’t much space in the heart to contract – aware of this space
What is pericarditis?
inflammation of pericardium
Chest pain, can cause acute cardiac tamponade due to accumulation of fluid in pericardial cavity
Pleura pericardium peritoneum – all have visceral and parietal – visceral inner parietal outer
Where is the left atrium found?
Mainly outside the pericardial space
Pericardium physiology
Mechanical function restrains the filling volume of the heart
Similar properties to rubber initially stretchy but becomes stiff at higher tension
Thus pericardial sac has a small reserve volume
Tamponade physiology
If this volume is exceeded of the pericardial sac the pressure is translated to the cardiac chambers
Small amount of volume added to space has dramatic effects on filling but so does removal of a small amount
Acute tamponade
quickly resolved by smallest volume reduction in pericardial space
Chronic pericardial effusion
Chronic accumulation allows adaptation of the parietal pericardium
This compliance reduces the effect on diastolic filling of the chambers
As a result very slowly accumulating effusions rarely cause tamponade
What is acute pericarditis?
Acute pericarditis is an inflammatory pericardial syndrome with or without effusion
How can we make a clinical diagnosis of acute pericarditis?
Clinical diagnosis made with 2 of 4 from:
Chest Pain (85-90%)
Friction rub (33%)
ECG changes (60%)
Pericardial effusion (up to 60% usually mild)
Infectious causes of acute pericarditis
Viral (common): Enteroviruses (coxsackieviruses, echoviruses), herpesviruses (EBV, CMV, HHV-6), adenoviruses, parvovirus B19 (possible overlap with aetiologic viral agents of myocarditis).
Bacterial: Mycobacterium tuberculosis (other bacteria rare).