Cardio Path Flashcards
Blubus Cordis
-Superior portion of the primitive heart tube, desdends and moves anterolaterally, forms a major part of RV
Primative Ventricle
-Forms the majority of left ventrile and moves laterally in the chest
Primative Atria
-Is located on the inferior aspect of the heart tube and moves posterior and superioly (looping around) to form atria
Sinus Venosus
- Bilateral structures at the base of the primitive heart tube the get pulled along with atrium
- Form portion of atria and coronary sinus.
Truncus Arteriosus
- Forms from the superior aspect of the primative heart tube and comes off bulbus chorus/primative Vent
- Neural Crest and endochardial cushion tissue are crucial to proper spinning and septation
- Transposition of GV: DM
- Tetrology of Fallot: DiGeorge
- Persistant Truncus: Di George
Interventricular Septation
- Muscular portion comes from the bottom
- Membranous portion forms from joining with the AP septation and neural crest
- Endochardial Cushion Tissue grows to form the atrial/ventricular sepations
Endochardial Cushion Tissue
- Forms the atrial/ventricular sepations
- Problems commonly with trisomy 21
Membranous Septal Defects
- Much more common than muscular
- Result in left to right shunt along pressure gradient. Leads to hypertrophy of Right Ventricle and eventual reversal of shunt
- Eisenmeingers Syndrome
Atrial Septation
- Begins with the formation of a membranous septum primum that grows from the superior aspect to join with the endochardial cushion tissue at the AV border
- Foramen secundum forms when there are partial disintigration of the septum primum.
- Development of rigid Septum secundum on the right ventricle side of septum primum, grows from superior and inferior
- Septum primum is now flappy and acts like a one way valve allowing for flow during fetal development. Foramen Ovale
- At birht, increased LA pressure closes spetums and they fuse. Failure is patent foramen Ovale
Down Syndrome
- Associated with defects in endocardial cushion tissue
- Membranous VSD
- ASD with osteum primum
1st aortic Arch
-Maxillary artery gives rise to middle meningeal that exits through foramen spinosum and can lead to epidural hematomas
2nd aortic arch
-Stapedial artery
3rd aortic arch
- Common carotid and internal carotid
- Pouch 3 is 9th CN, which innervates carotid baroreflex
4th aortic arch
- Arch of aorta
- Pouch 4 is CN 10 which innervates the baroreflex
Aortic arch 6
-Pulmonary artery and ductus arteriosus
Eryhtropoesis in fetal life
- 3-10 weeks is in yolk sac
- 6 weeks to birth is in liver
- Some is made in spleen around the time of birth
- Bone marrow, especially sternum, skull, etc take over
Fetal hemoglobin
-Has decreased affinity for 2,3 BPG which leads to stronger bonding with oxygen, allowing it to be picked up at umbilical vein
Fetal Circulation
- Umbilical Vein to ductus venosus to IVC to RA through foramen ovale to aorta to umbilical arteries
- Blood can also be sent from RA to RV through pulmonary artery and then through ductus arteriosus
Ductus Venosus
- Umbilical vein to IVC
- Bypasses portal circulation
- Become ligamentum teres heptis
Ductus arteriosus
- Pulmonary artery to arch of aorta
- Becomes ligamentum arteriosum
Ligamentum Arteriosum
- Anchors aorta to pulmonary veins and can be a site of traumatic rupture
- The recurrent laryngeal nerve (Phonation arch 6) goes around the ligamentum arteriosum
Foramen ovale
- Septum primum acts as floppy protion and secundum as strong portion of one way valve.
- Permits flow from RA to LA bypassing pulmonary and RV
Changes at Birth
Inflation of lungs leads to decreased pulmonary pressure and increased LAP this closes foramen ovale.
- Increased Oxygen leads to decrese in prostaglandins and a closure of the ductus arteriosus
- If want to keep open give PGE1/2
- If want to close foramen ovale give indomethacin
Umbilical Arteries remnant
-Medial umbilical ligaments
Median umbilical ligament
- Urachus, derivative of allantois
- Normally functions to connect the yolk sac and the bladder
Urachal cyst
Extraperitoneal mass that may cause pain and inflammation
-May lead to bladder adenomcarcinoma
Coronary Arteries
-Fill during diastole, occlusion causing ischemia and coagulative necrosis
RCA
- Supplies Right atrium and ventricle
- Supplies SA and AV in nearly all individuals
- 85% are right dominant, meaning RCA gives rise to posterior descending branch that supplies the posterior 1/3 of the interventricular septum
LCA
- Supplies posterior half of left ventricle and atrium.
- Can rarely supply AV node
- Left dominant circulation means gives rise to posterior descending and posterior 1/3 of interventricular septum.
LAD
- Supplies anterior surface of left heart and is most commonly occluded artery
- Supplies anterior 2/3 of interventricular septum
Coronary Sinus
- Drains all blood from heart except for anterior veins which drain directly into the heart
- Embryologic origin is sinus venosus (also SVC)
Anterior heart (facing sternum)
-RV and RA
Base of heart, posterior
- Left atrium
- In close opposition to esophagus and recurrent laryngeal nerve.
- Atrial enlargment from CHF/DCM leads to dysphagia and hoarsness
- TEE can be used to visualize LA and other vascular structures
Diaphragmatic surface of heart
-Both ventricle, mainly left ventricle
Stroke Volume
-Effected by contractility, preload, and afterload
Contractility Increase
- Increased Intracellular Ca
- Caetacholamines (increase intracellular Ca)
- Digoxin (inhibit Na/K pump leading to increased Na intracellularly and decreased Na leaving through Na/Ca channel)
- Increased Preload (sarcomere stretch) Starling Law
Contractiliy Decrease
- Decreased intracellular Ca
- Beta 1 blockers
- Acidosis
- Hypokia
- Ca Channel blockers (non DHP)
P=QR
Pressure = Flow* resistance Flow = delta P / Resistane
Preload
- increased preload will increase cardiac output
- Caetacholamines, increased filling time, increase blood volume (increase venous return)
- Decrease preload will decrease oxygen requirements
- Nitroglycerin used in angina
Afterload
- Pressure needed to pump against
- Vasodilators will decrease this and decrease oxygen demands
Resistance
- Mainly inverse function of radius to the 4th power
- Can also be effected by viscosity (Multiple Myeloma hyperprotein, Polycythemia, Spherocytosis
Heart Failure/DCM
Increasd preload with decreased ejection fraction
S1
Caused by mitral and tricuspid closure
- End diastole
- Occurs after the isovolumetric filling phase of ventricles
S2
- Aortic and pulmonic closing
- End systole
- Occurs after ejection phase
S3
- Early Diastolic Murmur
- Caused by elevated filling volumes
- Increased atrial pressure necessary to fill increased volume
- CHF, DCM, Mitral Regurg
- Normal in pregnant and kids
S4
- Late diastolic murmur
- From increased pressure/stiff ventricular walls that oppose atrial kick and cause murmur
- LVH most commonly
JVP Wave form
- initial a wave from atrial contraction followed by brief descent to c wave
- C wave is ventricular contraction against closed tricuspid
- X descent is relaxation of atria
- V wave is filling of atria passively
- Y descent is opening of tricuspid valve and RV filling/RA emptying
Elevated JVP
-Pericardial effusion, pHTN, CHF
Absent Pulsation elevated JVP
-Superior vena cava syndrome
Large A wave
- Elevated RA pressures
- RV failure/thickening, tricuspid steonosis
Absent A wave
-Atrial fibrillation
Paradoxical JVP, Kussmauls
- During inspiration there is an increase in JVP (normally would expect less because of reduced intrathoracic pressures)
- Seen with Pericardial effusion, cardiac tamponade
Normal Splitting of S2
- Normally during inspiration there is an increase in venous return to the RV because of decreased intrathoracic pressures. This leads to a longer time for volume to be expelled and a delay in the pulmonic portion of S2
- Normal!
Wide splitting
- Splitting still increases during inspiration, but the splitting is wider than would be expected because of exageratedly long RV emptying
- Pulmonic stenosis, RBBB
Fixed Splitting
- There is no relative change in ventricular pressures with the intrathoracic changes of breating.
- ASD and VSD allow for blood to flow between chambers regargless of pressure.
- ASD, VSD
Paradoxical Splitting
- There is a longer time for LV emptying meaning the aortic portion of S2 will come before the pulmonic on normal breathing and the two will converge on inspiration (longer pulmonic component)
- Aortic Stenosis, LBBB
Inspiration Effects on on heart sounds
Increase Right heart sounds
Expiration
Increase Left Heart Sounds
Handgrip
-Increases systemic resistance and increases regurgitations and decreases stenosis/S4
Valsalva
- Increase in intrathoracic pressure
- Decreases all murmurs except increases MVP, LVH
Mitral Regurgitation
- Holosystolic blowing murmur begining at apex and radiating to axilla
- Increased with elevated systemic resistance, decreased with valsalva (increased intra thoracic)
- Endocarditis, Rheumatic Fever, MVP, DCM
Tricuspid regurg
-Holosystolic heard best at tricuspid area a radiating to the right sternal border
Aortic Stenosis
- Crescendo decrescendo systolic murmur that may have a click, heard best at apex and radiating to the carotids
- Patient will have weak and delayed pulses and may have syncope, angina, DOE
- Dystophic senile clacification, time course is increased with bicuspid aortic valve (turners)
VSD
- Harsh holosystolic murmur heard best at left sternal border
- Most commonly a membranous defect and is associated with endochardial cushion defects and Down’s Syndrome
- Worsened with handgrip and increased systemic resistance
MVP
- Most common murmur, often hear a mid systolic click with late systolic crescendo murmur. Heard at apex.
- Click is from tightening of chorda
- Marfans, myxametous degeneration, ehlers danlos, ruptured papillary
Aoritc Regurg
- High pitched, mid and late diastolic blowing murmur.
- Widened pulse pressure and may have headbobbing
- Syphilis, dilated aortic root (Marfans) endocarditis, rheumatic fever
- Worsened with handgrip and increased systemic resistance
Mitral Stenosis
- Diastolic blowing murmur with opening snap
- Rheumatic Fever
- May lead to LA dilation and compression of esophagus and laryngeal nerve leading to impaired phonation and dysphagia
Patent Ductus
- Contunous machine like murmur heard best at infraclavicular level
- Prematurity or congential rubella
- Close with indomethacin and keep open with PGE
Ventricular Action Potential
- Phase 0: Na inward current upstroke
- Phase 1: Na inactiavtion and begining of K opening
- Phase 2: L-Type Ca opening and plateau phase
- Phase 3: L-Type Ca close and K open causing repolarization
- Phase 4: High K conductance and resting potential
Nodal Action Potential
- Phase 0: T-Type and L-Type Ca channels opening leading to deoplarization
- Phase 1 and 2 absent Na V-gated channels and no Plateau
- Phase 3: T-Type and L-Type Ca channels closing and K opening allowing influx
- Phase 4: HCN channels allow Na inward current to reach T-Type and L-Type Threshold
HCN Channels
- Located most explicitely on nodal cells
- Hyperpolarization and cyclic nucleotide gated channels
- Cause a ramp potential
- Increased by cAMP in response to B1 Gs activation
- Slope will be decreasd by adenosine and Ach which bind M2 Gi receptor leading to decreased cAMP
- Adensoine binds A1 receptor leading to decreased cAMP and increased K efflux
Ca Channels
- T Type are enriched on nodal cells and almost gone in ventricular cells. Mediate lower potential (early opening) rapid increase, but close rapidly
- L-Type stay open longer and are responsible for plateau phase
Muscle Contraction
- Driven by Ca induced Ca release from sarcoplasmic reticulum
- Influx through DHP (L-Type) ca channels opens ryr on SR
Na/Ca exchanger
- Increases Ca efflux and Na influx driven gradient
- Decreased in digitalis leading to increased inotropy
Ionotropy
- Strength of contraction, mediated by Ca levels
- Increased with SANS