Heart Flashcards
Depends through the mediastinum lateral to fibrous pericardium
Phrenic nerve
Pericardiophrenic artery
Recess between the great arteries & pulmonary veins
Transverse sinus
Recess of pericardial cavity
Ends in a cul-de-sac surrounded by pulmonary veins
Oblique sinus
Fluid compresses the heart because the fibrous pericardium is inelastic
Paradoxical pulse (inspiratory lowering of systolic BP by >10mmHg)
SVC compression –> facial & neck veins engorgement
Cardiac tamponade
Beck’s triad
Hypotension (that doesn’t respond to rehydration)
High venous pressure
Distant heart sounds
Pericardiocentesis
STERNAL APPROACH
ICS 5 or 6 left side near sternum
Penetrates the ff:
- skin
- superficial fascia
- Pectoralis major
- external intercostal muscle
- internal intercostals muscle
- transverse thoracic muscle
- fibrous pericardium
Structures at risk:
- internal thoracic artery
- coronary arteries
- pleura
Pericardiocentesis
SUBXIPHOID APPROACH
Left infrasternal angle, angled superiorly & posteriorly
Penetrates the ff:
- skin
- superficial fascia
- anterior rectus sheath
- rectus abdominis
- transverse abdominis muscle
- fibrous pericardium
- parietal layer of serous pericardium
Structures at risk:
- diaphragm
- liver
Surfaces of the heart
Posterior surface (base): LA
Apex: LV at ICS5, MCL
Sterna surface: RV
Diaphragmatic surface: LV
Borders of the heart
R border: RA, SVC
L border: Aortic arch, pulmonary trunk, LA, LV
Inferior border: RV
Superior border: SVC, aorta, pulmonary trunk
Frequency of coronary occlusion in descending order
Anterior interventricular artery (L anterior descending artery)
R coronary artery
Circumflex artery
R coronary artery
Branches:
- SA nodal artery
- R marginal artery
- AV nodal artery
- Terminal branches
- Posterior interventricular artery
- Septal branches
Structures supplied:
- RA
- RV
- SA node
- AV node
- Interventricular septum
L coronary artery
Circumflex artery
- anterior marginal artery
- obtuse marginal artery
- arterial branches
- post marginal artery
Anterior interventricular artery
- anterior diagonal artery
- septal branches
Structures supplied:
- LA
- LV
- Interventricular septum
Venous drainage
GREAT CARDIA VEIN
- follows anterior interventricular artery
- drains into coronary sinus
MIDDLE CARDIAC VEIN
- follows posterior interventricular artery
- drains into coronary sinus
SMALL CARDIAC VEIN
- follows right marginal artery
- drains into coronary sinus
ANTERIOR CARDIAC VEIN
- found on anterior aspect of RV
- drains into directly to RA
SMALLEST CARDIAC VEIN
- begin within the wall of the heart
- directly to the nearest heart chamber
Heart valves & Auscultation sites
PULMONARY VALVE (semilunar)
- 3 cusps (R,L, & posterior)
- L ICS 2, parasternal
AORTIC VALVE (semilunar)
- 3 cusps (R,L & posterior)
- R ICS 2, parasternal
MITRAL (left AV valve)
- 2 cusps (anterior & posterior) tethered to papillary muscle by chordate tendinae
- cardiac apex, L ICS 5, MCL
TRICUSPID (right AV valve)
- 3 cusps (anterior, posterior & septal) tethered to papillary muscle by chorda tendinae
- ICS 5, over the sternum
Conduction system
SA node
AV node
Bundle of His
Left & right bundle
Purkinje fibers
Pacemaker, just beneath the pericardium, at the junction of SVC & RA
SA node
Just beneath the endocardium
On the R side of interarterial septum
Near the ostium of coronary sinus
AV node
Travels in subendocardial layer
On the R side of Interventricular septum
Bundle of His
Left bundle further divides into thin anterior & thick posterior division
Left & right bundle
As terminal branches
Purkinje fibers
Abnormal migration of neural crest cells –> skewed aorticopulmosegment –> R to L shunt –> cyanosis
4 components:
- pulmonary stenosis
- RVH
- overriding aorta
- VSD
Tetralogy of Fallot (TOF)
Incomplete fusion of R and L bulbar ridge and AV cushions –> L to R shunt initially –> if uncorrected, ⬆️ pulmonary blood flow –> pulmonary hypertension –> R to L shunt (Eisenmenger complex)
Membranous VSD
Ductus arteriosus (DA)
Fails to close (connection between L pulmonary artery & aortic arch) –> L to R shunt
DA normally closes within few hours after birth to form the Ligamentum arteriosum
Premature infants
Maternal rubella during pregnancy
Maintains patency: PG E1, asphyxia
Promotes closure:
- PG inhibitors (indomethacin)
- ACH
- histamine
- catecholamines
Patent ductus arteriosus (PDA)
MC cause: atherosclerosis
Precipitated by exertion, relieved by rest, <30mins
Ischemic heart disease
Angina pectoris
