Cardiovascular # 1 Flashcards
Aortopulmonary Window
- Small space between the aortic arch and the pulmonary trunk
- Contains ligament arteriosum and recurrent laryngeal nerve
- Also refers to a fistula between the aorta and pulmonary trunk (may occur on its own or with other heart defects0
Mediastinal Tumors Effects
- Pulmonary artery and cardiac compression
- ↑ ICP, HA, AMS
- Airway obstruction and loss of lung volumes
- Most common = 4 T’s (Thyoma, teratoma, Thyroid carcinoma, and terrible lipoma)
Superior Vena Cava Syndrome (SVCS)
The Superior Vena Cava is a major blood vessel that brings blood from the head, neck, upper chest, and arms to the heart. SVCS happens when the SVC becomes partially blocked my a mass, usually mediastinal tumors.
Causes of Cardiophrenic Angle Mass
- Common (Pericardial fat and pericardial cyst)
- Less Common - (Morgagni herniation, lymphadenopathy, malignant neoplasm
Symptoms of Cardiophrenic Angle Mass
- Mild dyspnea upon exertion
- Intermittent cough
- Lobular opacity in left cardiophrenic angle
- Diminished breath sounds in the left infra scapular region with occasional crepitus
- No prior cardiac hx
Pericardium
- Membrane that surrounds, protects and holds the heart in place
- 2 layers: fibrous and serous pericardium (together are know as parietal pericardium)
- Allows heart to beat without friction
- Allows heart room to expand
- Filled with fluid ~ 5 to 30mL
Fibrous Pericardium
- Prevents overstretching
- Anchors the heart
- Provides protection
Serous Pericardium (Parietal Layer)
- Forms a double layer (parietal and visceral)
- Thin and delicate
3 layers of the heart was from outside to inside?
Epicardium (aka serous pericardium visceral layer), myocardium, endocardium
3 attachments of the Pericardium
- Central tendon of diaphragm
- Sternopericardial ligaments
- Verteobropercardial ligaments
Pericardium Arterial blood supply
- Branches of internal thoracic arteries
- Bronchial, esophageal, and superior phrenic arteries
Venous drainage of Pericardium
- Azygos system
- Percadirophrenic veins
What is Cardiac Tamponade?
- Tamponade is when the pericardium fills with blood or serosanguinous fluid
- This compresses the heart and ↓ CO
Acute Tamponade vs. Chronic Tamponade
- Acute (Rapid volume increase)
- Chronic (Pericardium stretches over time to compensate)
Effect of Cardiac tamponade on the heart during inspiration and expiration
- Expiration allows more blood than during inspiration but still less than normal
- Inspiration further compresses the heart which makes less blood enter ventricle and further decreases CO
2 Interwoven layers of Myocardium
- Interdigiting deep and superficial (spinospiral)
- Superficial bulbospiral
Effect of Myocardium fiber orientation?
- LV chamber shortening along heart’s longitudinal axis
- Torsional twisting motion during contraction ↑ LV EJ fraction
Result of Heart Failure patients losing the “Twisting” motion due to spiral myocardium muscle fibers
↓ EF
Biomechanics of heart muscle contraction
- At rest, tropomyosin covers troponin binding sites
- Ca2+ released fro SR binds to troponin causing tropomyosin to move
- Actin binding sites exposed
- Myosin head binds and flexes
- Filaments slide past each other
Troponin I
Troponin C
Troponin T
Troponin I - Inhibits actin/myosin interaction
Troponin C - Binds Ca2+ and exposes binding sites
Troponin T - Ties or anchors the other troponin molecules and influences Ca2+ sensitivity
Effects of inhaled anesthetics on cardiac myocites
Inhibit Ca2+ influx into cardiac myocites which results in depression of contractility
4 Biomarkers of an MI
- Troponin I
- Troponin T
- Myocardial fraction of CK
- Myoglobin
Right Atrium receives deoxygenated blood from which 3 veins
- Superior Vena Cava
- Inferior Vena Cava
- Coronary Sinus
Left Atrium receives oxygenated blood from ____?
The 4 pulmonary veins:
1) Right superior PV
2) Right inferior PV
3) Left Superior PV
4) Left inferior PV
Auricles
Pouch like structures on the surface of each atria that increases capacity
Right Ventricle pumps blood_______?
- Pumps blood out to Pulmonary Trunk which divides into R and L pulmonary arteries
- Pumps blood a short distance, against less resistance, and against lower pressure
Left Ventricle pumps blood ______?
- Pumps blood out to aorta
- Pumps blood a Longer distance, against more resistance, and requires higher pressure
- Thickest chamber (works to maintain same rate of blood flow as right side
Valves of the Right Atrium
- Eustachian Valve (a rudimentary valve that protect the entrance of the IVC into the RA)
- Thebesian Valve - (valve that protects the entrance from CS into the RA)
Right Atrium wall thickness
2mm
Fossa Ovalis
A depression in the wall of the right atrium, that used to be the hole (foramen ovale) that connected RA and LA during fetal development
Right Ventricle Wall thickness
4 to 5mm
Conus Arteriosus
Conical pouch in the superior left side of the right ventricle from which the pulmonary artery arises
Right Ventricle characteristics
- SV ~ same as LV each cycle
- Contains Conus Arteriosus
- Decompensates easily with ↑ in afterload
- Easily accommodates ↑ in preload compared to LV
- Produce < 20% stroke work compared to LV
- Thin RV wall with more compliance
Left atrium Wall Thickness
3mm
Atrial Kick
- Left Atria receives 20 to 30% increase in LVEDV which increases CO
- Compromised PTs rely on Atrial Kick to achieve adequate CO
- Normal PTs do not
Left Ventricle Wall Thickness
8 to 15mm
Why is the LV so thick
- Necessary to overcome SVR, afterload and maintain SV
2 Large Papillary Muscles of the LV
- Anterior papillary muscle from ant. LV wall
- Posteriror papillary muscle from post. aspect of inferior wall
4 Areas for stethoscope placement
- Aortic area (2nd -3rd right interspace)
- Pulmonic area (2nd to 3rd left interspace)
- Tricuspid area (left lower sternal area)
- Mitral area (apex)
2 Atrioventricular Valves
- Prevent back flow into the atria
- Pressure in atria opens valve
- Pressure in ventricles closes valve
- Tricuspid valve (btw RA and RV)
- Bicuspid (mitral) Valve (btw LA and LV)
2 Semilunar Valves
- Prevent back flow into ventricles
- Pressure in ventricles opens valve
- Pressure outside ventricles closes valve
- Pulmonary Semilunar Valve (btw RV and Pulmonary trunk)
- Aortic Semilunar Valve (btw LV and aorta)
3 Valve Disorders
- Stenosis (narrowing that restricts blood flow)
- Insufficiency or Incompetency (failure of valve to close completely)
- Prolapse (when AV valve cusp is pushed up into atrium)
How is stenosis of the valve repaired?
- Balloon valvuloplasty
- Surgical repair
- Valve replacement
AV valves are anchored inside the heart by ___?
- Chordae Tendonae (cords btw valve cusps and papillary muscle)
- Papillary Muscles (cone-shaped bundles of papillary muscle)
Function of Chordae Tendonae and Papillary Muscles
Prevents mitral valve prolapse
Triscuspid Valve
- Normal area = 7cm²
- Thinner and more translucent than mitral valve
- 3 leaflets (ant., post., and septal)
- Symptoms assoc’d. w/stenosis when area < 1.5cm²
Mitral (Bicuspid) Valve
- Normal valve area 4-6cm²
- Symptoms appear when area decreased by half or more
- 2 leaflets (ant. - oval shape, post. - crescent shape)
Mitral Apparatus
The functional unit of the 4 anatomies that aid in unidirectional flow throw the mitral valve. 4 anatomies include: leaflets, chordae tendonae, papillary muscles, and mitral annulus.
Changes in anatomy from Mitral valve replacement
- Chordal attachments severed
- Reduced EF
Pulmonic valve leaflet names
Based on anatomic locations
- right
- left
- anterior
Aortic valve leaflet names
Based on Coronary artery osmium
- right coronary
- left coronary
- non coronary
Aortic Valve
- Aortic cusps thicker than pulmonary secondary to LV ejection pressures
- Normal valve area = 2.5-3.5cm²
- Area reduction by 1/3-1/2 results in symptoms
Aortic Valve Stenosis can produce _____?
- ↓ CO
- ↑ PVR
- Ventricular hypertrophy
Why aren’t Semilunar Valves anchored like AV valves?
because they are subjected to lower back pressures (20 – 80 mmHg) in the aorta and pulmonary trunk vs. 120 mmHg pressure in the ventricles.
Fossa Ovalis
- Remnant of the foramen ovale
- Opening through the atrial septum
Ligamentum Arteriosum
- Remnant of the ductus arteriosus
- Temporary blood vessel that shunts blood from pulmonary to aorta
Tribeculae Carnae
- “Meaty Ridges”
- Bundles of cardiac muscle within chambers
- Similar to papillary muscles but not attached to valves
Fibrous Skeleton of the Heart
- Dense connective tissue
- Forms ring structure of the valves
- Prevents overstretching of valves
- Electrically insulates Atria from Ventricles
What are the 4 interconnected annuli structures of the heart that forms the fibrous skeleton?
- Fibrous ring of pulmonary valve
- Fibrous ring of aortic valve
- Right atrioventricular ring
- Left atrioventricular ring
Tendon of Conus
Connects the fibrous ring of the pulmonary valve with the fibrous ring of the aortic valve
Left Fibrous Trigone
Connects fibrous ring of aortic valve with left atrioventricular ring
Right Fibrous Trigone
Connects left atrioventricular ring with right atrioventricular ring
Trace blood flow from Vena Cava and Coronary Sinus all the way to the Left Atrium (Pulmonary Circulation)
Coronary Sinus and Vena Cava»_space;> Right Atrium»_space;> Tricuspid Valve»_space;> Right Ventricle»_space;> Pulmonary Semilunar Valve»_space;> Pulmonary Trunk»_space;> Pulmonary Arteries/Arterioles»_space;> Pulmonary capillaries (where gas is exchanged)»_space;> Pulmonary Venules/Veins»_space;> Left Atrium
Trace blood flow from Left Atrium all the way back to the Right Atrium (Systemic Circulation)
Left Atrium»_space;> Bicuspid Valve»_space;> Left Ventricle»_space;>Aortic Semilunar Valve»_space;> Aorta»_space;> Systemic Arteries/Arterioles»_space;> Systemic Capillaries (gas exchange occurs)»_space;> Systemic Venules/Veins»_space;> Vena Cava»_space;> Right Atrium
Right Sided CHF vs. Left Sided CHF
- Right (Peripheral edema)
- Left (Pulmonary edema)
Sinus of Valsalva and Coronary Artery Ostia
Sinus of Valsalva is the enlargement of the area above the aortic valve that functions to permit aortic valve opening during systole without the occlusion of coronary artery ostia.
Theorized by Leonardo DiVinci?
Flow vortices behind the leaflets of aortic valve in the sinus of Valsalva allowed valves to open without occluding the coronary artery Ostia
Function of the Coronary Circulation?
- Deliver oxygen and nutrients to myocardium
- Remove CO2 and waste
Coronary Circulation Flow of Blood
Aorta»_space;> Coronary arteries»_space;> coronary capillaries»_space;> coronary veins»_space;> coronary sinus»_space;> Right atrium
Coronary Circulation Scheme of Distribution
- Ascending Aorta»_space;> R and L Coronary Artery
- R Coronary Artery»_space;> Posterior Interventricular Branch and Marginal Branch
- Posterior Interventricular Branch»_space;>Both Ventricles
- Marginal Branch»_space;> Right Ventricle
- L Coronary Artery»_space;> Anterior Interventricular Branch and Circumflex Branch
- Anterior Interventricular Branch»_space;> Both Ventricles
- Circumflex Branch»_space;> Left Ventricle and Left Atrium
Collateral Arteries
- Are connections, or anastomoses, between the branches of the coronary circulation
- Protects the heart from ischemia
- Formed by arteriogenesis or angiogenesis
- Distribution of capillaries is uniform throughout atria & ventricles, except in AV node & interventricular septum = more vulnerable to ischemia
Coronary Veins
- Brings deoxygenated blood from myocardium
- Drains via the coronary sinus into right atrium
Flow of blood through coronary veins
Aorta»_space;> Coronary arteries»_space;> coronary capillaries»_space;> coronary veins»_space;> coronary sinus»_space;> Right atrium
3 Major Coronary Veins that deliver blood to the Coronary Sinus
- Great Cardiac Vein (within the anterior interventricular sulcus)
- Middle Cardiac Vein (within the posterior interventricular sulcus)
- Small Cardiac Vein (within the coronary sulcus – posterior right side)
Causes of Myocardial Ischemia
- Blood clot
- Atherosclerosis
- Other rare causes
3 Types of Angina Pectoris
- Exertional (pain with activity, relieved with rest)
- Variant (pain at rest)
- Unstable (prolonged pain at rest)
Methods of Myocardial Reperfusion
- Thrombolytic agents (“clot busters” )
- Balloon angioplasty
- Coronary artery bypass grafts
Myocardial Infarcation
- “Heart Attack”
- Loss of living heart muscle as a result of prolonged or severe ischemia
- Tissue dies and is replaced by scar tissue
Coronary Angioplasty
Balloon catheter is inserted into an artery of an arm or leg and guided into a coronary artery
CABG
- Coronary Artery Bypass Grafting
- Grafted blood vessel between aorta and unblocked portion of coronary artery
What happens during the 5 Phases of and Action Potential of a Cardiac Cell
- Phase 0: Fast Na+ channels open and Rapid Na+ influx
- Phase 1: K+ moves out to ECF and returns TMP to 0mV
- Phase 2: L-type Ca2+ channels open and Ca2+ moves to the ICF to balance K+ efflux (plateau), also ryanodine receptors release Ca2+ from SR.
- Phase 3: Ca2+ channels close, but K+ channels remain open and return TMP to -90mV
- Phase 4: Na+ and Ca2+ channels closed. K+ open to keep TMP stable at -90mV
Refractory Period
Refractory period allows ventricles to empty before next contraction
4 Types of Refractory Periods
- ARP (absolute) = does not allow any depolarizations.
- ERP (effective) = may allow non-propagated depolarizations.
- RRP (relative) = allows stronger than normal stimulus to trigger depolarization.
- Supranormal = hyperexcitable period – even weak stimulus can cause an action potential
Action Potential of Cardiac Nodal Cells
- Nodal cells exhibit only Phases 4, 0 & 3
- Rapid depolarization is absent
- Plateau does not occur
Pressure Requirements for each Ventricle
- Left Ventricular pressure needs to surpass 80 mmHg in Aorta for valve to open
- Right Ventricular pressure needs to surpass 20 mmHg in Pulmonary Trunk for valve to open
Volume Changes
Atrial systole contributes a final 25 ml to the already 105 ml in the resting/filling ventricle, for a total EDV of 130 ml
Ejection Fraction
- Left Ventricle ejects about 70 ml (of the 130 ml) into the Aorta
- EF = SV/EDVx100
Cardiac Output
HR x SV
What happens when ventricular pressure drops below atrial pressure
- AV valves open and passive ventricular filling begins again.
- At the end of the relaxation period, the ventricles are about three-quarters full (~ 105 ml)
3 Factors that regulate Stroke Volume
- Preload
- Contractility
- Afterload
Preload
- The greater the stretch, the greater the contraction (ex: a rubberband)
- Frank-Starling Law (Preload is proportional to EDV)
Afterload
- The pressure that must be overcome before SL valves open
- 80 mmHg pressure in Aorta
- 20 mmHg pressure in Pulmonary Trunk
Efferent Sympathetic Nerve Fibers
- Originate in Thoracic S.C.
- Branch into Super, Middle & Inferior Cardiac Nerves
- Join at Cardiac Plexus (neural jct. @ root of Aorta)
- Release Norepinephrine
- Increase HR & strength of contraction.
Efferent Parasympathetic Nerve Fibers
- Originate in M.O.
- Travel via C.N. X to join Cardiac Plexus
- Release ACh
- Decrease HR & strength of contraction.
Epinephrine Effects
- β1 in conduction system (excitatory) = HR & contraction
- β2 in coronary vessels (inhibitory) = coronary vasodilation
- β3 throughout heart, opposes effects of β1 & β2 = prevents overstimulation by sympathetic nervous system
Norepinephrine Effect
- α1 in systemic & coronary arteries (excitatory) = vasoconstriction
- α2a on sympathetic ganglia & nerve terminals (inhibitory) = vasodilation
Automaticity
- Property of generating spontaneous depolarization to threshold
- Automatic cells: All heart cells capable of spontaneous depolarization
Rhythmicity
- Regular generation of an action potential by the heart’s conduction system
- SA node depolarizes spontaneously 60-100 times per minute
- AV node 40-60
- Ventricles 20-40
Interpret the following elements of an ECG:
- Pwave
- PR Interval
- QRS Complex
- ST Interval
- QT Interval
- TWave
- Pwave: Atrial depolarization
- PR Interval: Time from onset of atrial depolarization to the onset of ventricular depolarization
- QRS Complex: Sum of all ventricular depolarizations
- ST Interval: Ventricular myocardium depolarized
- QT Interval: Electrical systole of the ventricles
- Twave: Ventricular repolarization
How large can the Pericardium increase before the patient experience any symptoms?
10x
Basic Wave Abnormalities:
1) P wave enlarged
2) Q wave enlarged
3) R wave enlarged
4) T wave flatter
5) T wave elevated
1) P wave enlarged - Enlarged Atrium
2) Q wave enlarged - MI
3) R wave enlarged - Enlarged Ventricles
4) T wave flatter - Insufficient O2
5) T wave elevated - Hyperkalemia
Basic Segment Abnormalities:
1) PQ Lengthened
2) ST Elevated
3) ST Depressed
4) QT Lengthened
1) PQ Lengthened - SA node pathology or Detour around scar tissue from previous MI, CAD, or rheumatic fever
2) ST Elevated - Acute MI
3) ST Depressed - Insufficient O2
4) QT Lengthened - Myocardial damage, ischemia, conduction abnormalities
