Thoracic Cardiology Flashcards
Divisions of mediastinum and relationships to heart
Superior and inferior mediastinum separated by sternal angle
Inferior mediastinum separated into 3 divisions:
Anterior- anterior to heart
Middle- is the heart
Posterior- posterior to heart
Right/left side of heart receive blood from
Right: superior/inferior vena cava- pumps blood to lungs for oxygenation
Left: receives from lungs and pumps to entire body
System circulation pathway
From left atrium, past bicuspid valve into left ventricle, out of heart past aortic valve into aorta, through the arterial system, through the capillaries, through the venous system and back into heart through sup/inf vena cava
Pulmonary circulation pathway
From superior/inferior vena cava, into right atrium past the tricuspid valve, into the right ventricle, out of the heart past the pulmonary valve into the pulmonary trunk, through the right/left lungs and back into the heart through the pulmonary veins
Cardiac layers
Epicardium: outermost layer made of visceral serous pericardium
Myocardium: thick muscular layer made of spiraling, overlapping layers of cardiac muscle
Endocardium: thin internal endothelial and subendothelial layer lining the inside of the chambers of the heart and valves
Fibrous skeleton of the heart: dense collagenous fibers
Myocardial infarction
Lack of blood flow to a specific area of the myocardium, usually the result of a blockage in a coronary artery
Coronary atherosclerosis, or a buildup of lipids on the internal walls of the coronary arteries decreases the size of the lumen of that vessel, increasing the likelihood of an embolus, or plug blocking off a vessel entirely
Angina pectoris
Pain that originates in the heart and produces a strangling pain of the chest
Angina pectoris literally means strangling pain of the chest
The pain is usually the result of narrow or obstructed coronary arteries that produces ischemia of the myochardium
Fibrous skeleton of the heart functions
Produces attachment points for the myocardium and valves of the cuspid valves
Supports and strengthens atrioventricular and semilunar orifices
Provides and electrically insulated barrier b/w the atria and ventricles
External surfaces of the heart and their relationship to heart structures
Sternocostal- right ventricle
Diaphragmatic- right and left ventricles
Pulmonary- paired: right atrium and left ventricle, occupying the cardiac impression on both lungs
Borders of heart and their relationships to structures
Right: right atrium
Inferior: right ventricle
Left: left ventricle
Superior: right/left atria and the exit point for the aorta and pulmonary trunk
Right atrioventricular groove
B/w right atrium and right ventricle
Transmits the right coronary artery
Left AV groove
B/w the left atrium and left ventricle
Houses the coronary sinus
Anterior interventricular groove
B/w right and left ventricles on anterior aspect of heart
Transmits the anterior interventricular artery and great cardiac vein
Posterior interventricular groove
B/w right and left ventricles on posterior surface of heart
Transmits the posterior interventricular artery and the middle cardiac vein
Sulcus terminalis
External vertical groove corresponding to the internal crista terminalis
Ligamentum arteriosum
Embryological remnant of the ductus arteriosus, which shunted blood from the pulmonary trunk to the aorta to bypass the nonfunctional lungs
Communication b/w the pulmonary trunk and the arch of the aorta
Ligamentum arteriosum location and relationship to nerves
Travels from superior pulmonary trunk to inferior border of the aortic arch
The left recurrent laryngeal nerve loops around the aortic arch and ligamentum arteriosum then ascends to the larynx
Right atrium structures
Sinus venarum - located posteriorly, where the venae cavae and coronary sinus empty
Pectinate muscle- anterior, contains right auricle
Crista terminalis- internal ridge separating smooth and rough regions
Interatrial septum- wall b/w two atria, contains fossa ovalis (remnant of the foramen ovalis)
Opening for the coronary sinus
Atrial septal defects
Typically involves an incomplete closure of the foramen ovale
It is estimated that 15-20% of adults have a small patency of their foramen ovale which is considered clinically insignificant
Larger openings in the interatrial septum can be clinically significant as they allow mixture of oxygen rich and oxygen depleted blood
Right atrioventricular orifice
Passage from right atrium to right ventricle, variably occluded by the tricuspid valve
Tricuspid valve
Anterior, posterior and septal cusps
Chordae tendinae- attach free edges of the three cusps to the corresponding papillary muscles
Anterior papillary muscle: joined to anterior cusp of tricuspid valve
Posterior papillary muscle: joined to posterior cusp of tricuspid valve
Septal papillary muscle: joined to septal cusp of tricuspid valve
Trabecula carnae
Rough muscular region
Contains septomarginal trabeculum: moderator band, from the interventricular septum to the base of the anterior papillary muscle
-transmits the right bundle branch of the AV bundle to the anterior papillary muscle
Conus arteriosus
Leads into the pulmonary trunk
Pulmonary valve
Semilunar valve possessing right, left and anterior cusps, separates right ventricle from pulmonary trunk
Pulmonary sinuses- space b/w the wall of the pulmonary trunk and the cusps of the pulmonary valve
Cardiac catheterization
Insertion of a catheter into the femoral vein which is then passed up to the inferior vena cava allowing radiographic visualization of the right atrium, right ventricle, pulmonary trunk and pulmonary arteries
Left atrium
Contains:
Left auricle (contains pectinate muscle)
Openings for the 4 pulmonary veins
Interatrial septum
Left AV orifice
Passage from left atrium to left ventricle, variably occluded by the bicuspid valve
Bicuspid valve
AKA mitral valve, separates left atrium from left ventricle
Anterior, posterior cusps
Separates left ventricle from left atrium
Chordae tendinae- attaches cusps to ventricular surfaces
Anterior papillary muscle: joined to anterior cusp of bicuspid valve
Posterior papillary muscle: joined to posterior cusp of bicuspid valve
Left ventricle contains:
Bicuspid valve
Trabecula carnae- rough muscular region
Aortic vestibule- leads into ascending aorta
Interventricular septum: myocardial wall separating the two ventricles, houses the AV bundle, right and left bundle branches and subendocardial branches
- described as having a fibrous part that belongs to the fibrous skeleton of the heart and much larger muscular part
Aortic valve
Ventricular septal defects
Due to the embryologically divergent tissues that make up the interventricular septum that structure is particularly susceptible to defects. All defects are clinically relevant as they allow the mixture of oxygen rich and oxygen depleted blood
Aortic valve
Semilunar valve possessing right, left and posterior (non coronary) cusps
Separates L ventricle from the ascending aorta, occupies the aortic orifice
Aortic sinuses- space b/w the wall of the ascending aorta and cusps of the aortic valve, the right and left aortic sinuses house the openings for the right and left coronary arteries
Conducting system of the heart
Consists of cardiac muscle cells, specialized conducting fibers and two bundles of nodal tissue responsible for coordinating the cardiac cycle
-SA/AV nodes and bundles
SA node
Located in myocardium, where the superior vena cava meets the right atrium
Small bundle of specialized cardiac muscle fibers that initiate and regulate impulses that propagates through the atrial walls, producing diastole
“pacemaker” of the heart
AV node
Small bundle of specialized cardiac muscle fibers located in the interatrial septum near the opening for the coronary sinus, responds to the impulse from the SA node that distributed through the wall of the atrium and distributes that signal through the ventricles
AV bundle
Crosses the electrically insulated barrier provided by the fibrous skeleton of the heart and distributes the impulse from the AV node into a right/left AV bundle which then distributes as subendocardial branches
Subendocardial branches
Distribute the AV nodal impulse from the R/L AV bundle branches first to the interventricular septum, then to the papillary muscles, and finally to the rest of the ventricular wall; also called purkinje fibers
Artificial cardiac pacemaker
Produces a regular electrical impulse that is carried to the ventricles via electrodes which are inserted through a large vein to the superior vena cava, into the right atrium past the tricuspid valve into the endocardium of the trabecula carnae of the right ventricle
Atrial fibrillation
Irregular twitching of the atrial cardiac muscle fibers to which the ventricles respond at irregular intervals
Circulation usually remains satisfactory
Ventricular fibrillation
Rapid irregular twitching of the ventricles rendering the heart unable to pump blood.
An electric shock administered by electrodes can cease all cardiac movement (defibrillation), in the hopes that the heart may begin beating regularly after a period of time
Cardiac referred pain
Ischemia stimulates visceral pain sensory fibers in the heart of the autonomic nervous system
These visceral sensory fibers often share a spinal ganglion with the somatic sensory fibers of areas such as the upper limb and superior lateral chest wall
Anginal pain is typically referred to the area innervated by the left medial brachial cutaneous nerve, the left substernal area, left pectoral area and medial aspect of the left upper limb are often involved in this variety of referred pain
Pericardium
Serous
-parietal: adhered to the fibrous pericardium
-visceral: adhered to the heart, makes up epicardium
Fibrous
Oblique pericardial sinus- wide recess posterior to base of heart
Transverse pericardial sinus- transverse passage traversing the origins of the great vessels
Surgical significance of the transverse pericardial sinus
This space allows cardiac surgeons to access the area posterior to the aorta and pulmonary trunk to clamp or insert the tubes of a bypass machine into these large vessels
Pericarditis
Inflammation of the pericardium, which can make the pericardium rough and produce friction
This friction called a pericardial friction rub can be observed with a stethoscope
If left untreated the pericardium can calcify
Pericardial effusion
Inflammation of the pericardium can result in the accumulation of fluid or pus in the pericardial sac which can compress the heart
Heart compression is known as cardiac tamponade
Pericadiocentesis
Drainage of blood, fluid or pus from the pericardial sac
This is usually done to relieve cardiac tamponade
