Cardiology 2 Flashcards
What creates a bouncing pulse?
aortic regurgitation, anaemia, sepsis cause large stroke volume typically causing a bouncing pulse with a high amplitude and wide pulse pressure
what may cause a slow rising pulse?
aortic stenosis
what is the JVP determined by?
determined by right atrial pressure
what does tricuspid regurgitation do to the JVP wave form?
giant V waves
Where does the right atrium receive blood from?
the superior and inferior vena cavae
where does the left atrium receive blood from?
the four pulmonary veins
what are the atrium and ventricles separated by?
the annulus fibrosus - this forms a skeleton for the AV valves and electrically insulates the atria from the ventricles
what is the cardiac silhouette formed by on CXR
the left is formed by the aortic arch, pulmonary trunk, the left atrial appendage and the LBV
The right the silhouette is formed by the RA and the superior and inferior venae cave and the lower right border is formed by the RV
where to the left and right coronary arteries arise from?
the left and right sinuses of the aortic root distal to the aortic valve
What does the left coronary artery divide into ?
left anterior descending (which runs in the inter ventricular groove
left circumflex artery which runs posteriorly in the atrioventricular groove
Which part of the heart does the LAD supply?
supply to the anterior part of the septum and the anterior, lateral and apical walls of the LV.
What part of the heart does the circumflex supply?
the posterior and inferior segments of the LV
where does the RCA run and what does it supply?
runs in the right atrioventricular groove
gives branches that supply the RA, RV and inferoposterior aspects of the LV
Where does the posterior descending artery run and what does it supply?
it runs in the posterior interventricular groove and supplies the inferior part of the of the interventricular septum
This vessel is a branch of the RCA in 90% of people
in the remainder of people it is supplied by the circumflex
which coronary artery supplies the SA and AV node?
the RCA supplies the SA node in 60% of individuals and the AV node in 90% of individuals.
Proximal occlusion of the RCA can result in sinus bradycardia and AV nodal block
Where is the SA node located?
it is situated at the junction of the superior vena cava and the right atrium
Function of SA node?
specialised arterial cells that depolarise at a rate influenced by the autonomic nervous system and by circulating catecholamines.
During normal sinus rhythm, this depolarisation waves propagates through the atria via sheets of atrial myocytes.
How is depolarisation conduction from atrial to ventricles?
through the AV node
the annulus fibrosus forms a conduction barrier between the atria and the ventricles, preventing transmission of conduction except through the AV node.
where is the AV node located and what is its function ?
The AV node is a midline structure extending from the right side of the inter arterial septum , penetrating the annulus fibrosus anteriorly. It conducts relatively slowly, producing necessary time delay between atrial and ventricular contraction.
what is the His-purkinje system composed of ?
the bundle of His extending from the AV node in the inter ventricular septum, the right and left bundle branches passing along the ventricular septum and into the respective ventricles
The anterior and posterior fascicles of the left bundle branch
The smaller Purkinje fibrest that ramify through the ventricular myocardium
The tissues of the His-Purkinje system conduct very rapidly and allow near-simultaneous depolarisation of the entire ventricular myocardium
Nerve supply of the heart
The heart is innervated by both sympathetic and parasympathetic fibres.
Adrenergic nerves from the cervical sympathetic chain supply muscle fibres in the atria and ventricle and the eletrical conducting system
Parasympathetic pre-ganglionic fibres and sensory fibres reach the heart through the vagus nerve.
Cholinergic nerves supply the AV and SA nodes via muscarnic (M2) receptors
What does activation of beta 1 adrenoreceptors in the heart result in ?
Activation of beta 1 adreoceptors in the heart results in positive inotropic and chronotropic effects