Sum Sum | Sum'bout it |
Heart begins to beat at___ and develops from____ | week 4, mesodermal cells |
Septa form between___ as out growth of___ | 4th and 6th weeks, endocardial surface (all septation occurs simultaneously) |
Atrioventricular Canal split into two canals by | endocardial cushions |
Primitive atrial septum process of dividing into LFT and RT chambers | sept primum grows down toward the AV cushions (space bw two= ostium primum), superior sept primum obliterates= ostium secundum, sept secundum grows along SP, space bw top and bottom portions of SS form foramen ovale, SP one way valve |
Atrial Septal Defect will show | LFT—> RT shunt (non-cyanotic), RA/RV/PA enlargement, tall P wave, wide fixed splitting, pulmonic flow murmur |
Interventricular Septum consists of | muscular septum (upward expansion of primitive ventricle), membranous septum (fusion of aorticopulmonary septum with muscular portion, grows downward from AV cushions) |
Ventricular Septal Defect will show | LFT —> RT shunt, LA/LV enlargement, small ones close by age 2, larger ones may present with late cyanosis, easy fatiguability |
Aorticopulmonary Septum | from neural crest cells, separates truncus arteriosus into aorta/pulmonary artery, spins 180 as descends and failure to do so= RT—> LFT shunting/ early cyanosis |
Persistent Truncus arteriosus | Abnormal migration of neural crest cells, failure of AP septum to form, common tact leaving both ventricles |
Transposition of great vessels | AP septum fails to spiral (LV—> pulmonary trunk, RV—> aorta [two closed circuits]), complete RT—> LFT shunt, early cyanosis |
Tetralogy of Fallot | anterior displacement of AP septum => overriding aorta, pulmonic stenosis, RV hypertrophy, VSD. overriding aorta obstructs RV outflow —> pulmonic stenosis—> increased pressure requirement—> hypertrophy. VSD= RT—> LFT shunting (early cyanosis) |
5 T’s of early cyanosis | Tetralogy of fallot, Transposition of GV, Truncus arteriosus, Total anomalous pulmonary venous return, Tricuspid atresia (failure of T valve to form) |
Infantile coarctation of aorta | Pre/Postductal based on location related to a patent ductus arteriosus, results in increased after load. Preductal= RT—>LFT shunt, cyanosis of lower body, Postductal= RT—>LFT shunt, decreased blood flow to lower half |
Adult coarctation of aorta | distal to arch, absent PDA, hypertension in upper extremities and hypotension in lower extremities, collateral circulation to lower limbs (SC,IT, SE, IE, EI) forms rib notches via IC arteries |
Congenital aortic stenosis | Aortic valve develops abnormally, bicuspids more susceptible to calcification and fibrosis |
Patent ductus arteriosus | Increased O2/ decreased prostaglandins should result in closure, if open LFT—> RT shunt bc LFT heart is higher pressure system, continuous “machine like” murmur bc blood is consistently flowing, LA/LV/PA/Aorta enlarged |
Untreated LFT—> RT shunts | Pulmonary arterial system becomes hypertrophic—> pulmonary hypertension, increased RT pressure—> RV hypertrophy—> shunt reverses—> late cyanosis (Eisenmenger syndrome) |
Allantois—>___ | Urachus (connects the fetal bladder to the yolk sac and removes nitrogenous waste from the fetal bladder)—> mediaN umbilical ligament |
Ductus arteriosus—>___ | ligamentum arteriosum |
Ductus venosus—>___ | ligamentum venosum |
Foramen ovale—>___ | Fossa ovalis |
Notochord—>___ | nucleus pulposus |
Umbilical arteries—>___ | MediaL umbilical ligamentS |
Umbilical vein—>___ | ligamentum teres hepatis (contained in falciform ligament) |
Fetal Hemoglobin | 2 alphas/ 2 gammas, lower affinity for 2,3-BPG = higher affinity for O2 (ensures transfer across placenta), physiologic anemia normal (4-8 weeks) before steady state production of adult hemoglobin |
3 shunts of fetal circulation | umbilical vein—> DUCTUS VENOSUS—> Ivc —>FORAMEN OVALE—> aorta; DO blood from Svc—> RA—>RV—> main pulmonary artery—> PATENT DUCTUS ARTERIOSUS |
Apex/ A Arch/ SVC anatomic locations | apex (PMI)= 5th IC space @MC line, Arch= sternal notch= T2, SVC enters RA @3rd rib |
Layers of heart | Endo (innermost, simp squamous), Myo (middle/ thickest, composed of myocytes), Peri (outer fibrous= tough connective tissue; inner serous= [parietal layer continuous with internal FP, visceral/epicardium= contains coronary arteries]) |
Coronary circulation: SA/AV__; RV__; AV (lil bit)/post interventricular septum__; LV/ Ant interventricular septum___; LV__ | RCA; RMA; PDA; LAD; LCxA |
At rest, membrane conductance/ permeability higher for___ | K+ (resting potential close to K equilibrium) |
Conduction velocity rates | fastest in His-Purkinje > Atrial myocytes > Ventricular myocytes > AV node |
Underlying basis for refractory period | Closure of Na channel inactivation gates |
Cardiac myocytes utilize___ Ca channels (phase 2) | L-Type |
Nodal AP utilizes___ Ca channels (phase 0) | T-type (L-type present but activated at higher MP) *pg 16 |
After contraction, intracellular Ca is moved to SR via___ and extracellular Ca is expelled via___ | SERA pump (Ca ATPase), Ca/Na pump |
S1 | M/T valve closure, M closes before T but juuuust barely so probably wont hear it |
S2 | A/P closure, A closes before P (normal splitting) |
S3 | Ventricular gallop, turbulent blood flow right after S2, seen in children, athletes and preggos . Loudest at apex |
S2 splits: | wide= delayed RV emptying, fixed= ASD, paradoxical= delayed A valve closure |
Highest resistance in CV system | Arterioles, responsible for largest drop in arterial pressure |
Largest total cross sectional and surface area of CV system | Capillaries |
Highest capacitance in CV system | Veins |
Diastolic VS Systolic affects on MAP | D pressure impacts more bc diastole is longer in healthy patient at rest |
P wave represents | atrial depolarization |
QRS complex represents | Ventricular depolarization (masks atrial repolarization) |
T wave | Ventricular repolarization |
4 rules of ECG | Depol towards (+) pole= upward deflection; Depol toward (-) pole= downward deflection; magnitude of deflection= how parallel the net electrical vector is to lead measuring it; Net electrical vector reads 0 magnitude in any lead perpendicular to it |
PR interval represents | time of electrical impulse from SA node to beginning of ventricular depol |
QT interval represents | mechanical contraction of ventricles |
Brady/Tachycardia [ECG] | normal P wave, QRS rate <60/ >100 |
1st degree AV block | PR interval > 5 small boxes, 1:1 P/QRS |
3rd degree (complete) AV block | AV dissociation, atria and ventricles beat independently of each other, atrial rate is faster than ventricular rate |
Atrial flutter | regular, rapid succession of identical back-to-back P waves given sawtooth appearance |
Atrial fibrillation | rapid, irregularly irregular/ no discernible p waves, RR distances will all be different but present QRS |
Ventricular Tachycardia | wide QRS complex at regular rhythm |
Ventricular fibrillation | completely erratic baseline |
QISSS & QIQ | [Sym] A1, A2, B1, B2, B3 & [Para] M1, M2, M3 |
Coronary arteries/ venus counterparts: Ant IV (LAD)___; Post IV___; Marginal (from RCA)___; Circumflex___ | Great cardiac vein, middle cardiac vein, small cardiac vein, Post vein (left ventricle) |
Contractility changes vs PV loop | Increase= increase SV/ EF, decrease in ESV [left wall of loop will be stretched back] |
Afterload changes vs PV loop | Increase = increase ESV, decrease SV [going to look tall and skinny] |
Preload changes vs PV loop | increase = increase in SV/ EDV [right wall of loop will be stretched forward] |
Autonomic effects on heart and blood vessels | HR and Contractility (B1-sym, M2-parasym); Vascular smooth muscle tone (A1[constriction, sym], M3[Dilation, parasym]) |
2nd degree AV block | P wave not followed by QRS w/ or w/o preceding gradual lengthening of PR interval |
Truncus arteriosus--> | aorta and pulmonary trunk |
Bulbus cordis--> Conus cordis --> | smooth parts (outflow tract) of left/right ventricles |
Endocardial cushion--> | atrial septum, membranous interventricular septum, AV (of AV canal) and semilunar valves (of outflow tract) |
Primitive atrium--> | Trabeculated part of left/right atria |
Primitive ventricle--> | Trabeculated part of left/right ventricle |
Primitive pulmonary vein (transient common PV)--> | smooth part of left atrium |
Left horn of sinus venosus--> | coronary sinus |
Right horn sinus venosus--> | smooth part of right atrium |
right common cardinal vein and right anterior cardinal vein | SVC, not from heart tube |
Vitelline veins--> | Portal system |