216 Cardiovascular Emergencies Flashcards
List the vasculature that branches off the aorta from the base of the aorta, through the ascending aorta and the aortic arch
-R coronary
-L coronary
-brachiocephalic trunk (splits into: R subclavian & R common carotid)
-L common carotid
- L subclavian
List the vasculature that branches off the aorta in the descending thoracic aorta
-bronchial
-mediastinal
-esophageal
-pericardial
-superior phrenic
-intercostal and subcostal
List the vasculature that branches off the aorta in the abdominal aorta
-inferior phrenic
-celiac (splits into: L gastric, splenic, common hepatic)
-superior mesenteric
-middle suprarenal
-renal
-gonadal (testicular or ovarian)
-inferior mesenteric
-median sacral
-lumbar
define aortic dissection
a separation of the layers of the wall of the aorta due to an intimal tear
What do the bronchial arteries supply?
bronchi, bronchioles, lung tissue
What do the pericardial arteries supply?
pericardium
What do the esophageal arteries supply?
esophagus
What do the mediastinal arteries supply?
mediastinal structures
what do the intercostal arteries supply?
vertebrae, spinal cord, back muscles, body wall, skin
What do the superior phrenic arteries supply?
vertebrae, spinal cord, back muscles, body wall, skin, diaphragm
What do the inferior phrenic arteries supply?
diaphragm, inferior portion of esophagus
What does the left gastric artery supply?
stomach, adjacent portion of esophagus
What does the splenic artery supply?
spleen, stomach, pancreas
What does the common hepatic artery supply?
Liver, stomach, gallbladder, duodenum, pancreas
What does the superior mesenteric artery supply?
pancreas, small intestine, appendix, first 2/3 of large intestine
What does the inferior mesenteric artery supply?
last 1/3 of the large intestine
What do the suprarenal arteries supply?
Adrenal glands
What do the renal arteries supply?
Kidneys
What do the gonadal arteries supply?
Testes or ovaries
What do the lumbar arteries supply?
Vertebrae, spinal cord, abdominal wall, lumbar region
What is a Stanford Type A dissection? Which De Bakey classifications fall into it?
Aortic dissection involving the ascending aorta. May progress to involve aortic arch and thoracoabdominal. De Bakey Type 1 and Type 2 fall into this category. These are always surgical emergencies
What is a Stanford Type B dissection? Which De Bakey classifications fall into it?
Aortic dissection involving the descending thoracic or thoracoabdominal aorta distal to the L subclavian artery without involvement of the ascending aorta. De Bakey Type 3a and Type 3b fall into this category. Likely can be managed medically.
define De Bakey Type 1 dissection
Involves ascending aorta, aortic arch, descending thoracic aorta and may involve the abdominal aorta
define De Bakey Type 2 dissection
Involves the ascending aorta only
define De Bakey Type 3a dissection
Involves the thoracic aorta distal to the L subclavian and proximal to the celiac artery
define De Bakey Type 3b dissection
Involves the thoracic and abdominal aorta distal to the L subclavian and distal to the celiac artery
Describe the pathophysiology of an aortic dissection
An initial tear occurs in the intima of the aorta. Blood at high pressure passes through the tear and separates the intima from thee media and/or adventitia, creating a false lumen which can spread proximally or distally and whatever arteries that branch off the aorta that are affected will often cause associated symptoms.
What is the difference between an uncomplicated and complicated Type B aortic dissection?
Considered complicated if there is evidence of poor perfusion, rapid expansion, impending or frank rupture, uncontrolled pain or refractory hypertension (refractory to 3 or more antihypertensives at max dose)
What are risk factors for aortic dissection?
HTN, atherosclerosis, prior cardiac Sx, aortic aneurysm, connective tissue disorder (Marfan’s, Loeys-Dietz syndromes), bicuspid aortic valve, prior aortic Sx.
What are the S/S of aortic dissection?
- sudden onset severe pain to the anterior chest, may radiate to neck, back, abd and may migrate.
- comparison of bilat carotid, subclavian or femoral pulses shows different strengths
- aortic valve regurg (diastolic murmur)
- signs of cardiac tamponade
- signs of ischemic stroke, spinal cord ischemia, ischemic neuropathy, hypoxic encephalopathy
- ECG: type A can cause coronary ischemia (RCA most common)
- CXR: widened mediastinum, unexplained pleural effusion
Causes of R axis deviation on ECG
- RVH
- Acute RV strain (i.e. PE)
- Lateral STEMI
- Chronic lung disease (COPD)
- HyperK
- Sodium-channel blockade (TCA OD)
- WPW
- Dextrocardia
- Ventricular ectopy
- L posterior fascicular block (diagnosis of exclusion)
- Normal pediatric ECG
Causes of L axis deviation on ECG
- LVH
- LBBB
- Inferior MI
- Ventricular pacing/ectopy
- WPW
- L anterior fascicular block (diagnosis of exclusion)
Causes of extreme axis deviation on ECG
- ventricular rhythms
- HyperK
- severe RVH
List the components of the cardiac electrical conduction system
- SA node
- AV node
- Bundle of HIS
- L and R bundle branches
- L divides into anterior, septal and posterior fascicles
- Purkinje fibres
What properties of vasculature will differentiate arteries vs veins on ultrasound?
- veins are compressible
- arteries are pulsatile
- arteries will have a thicker wall due to the musculature
Describe the cardiac action potential
-Phase 0: Rapid depolarization. Cell is brought to threshold, Na+ channels open, Na+ rapidly enters the cell and the cell becomes positively charged around +45mV. Ca2+ channels also open during depolarization but the Ca2+ moves into the cell much slower than the Na+
-Phase 1: Initial repolarization. K+ channels open and K+ moves out of the cell.
-Phase 2: Plateau. Ca2+ enters the cell and K+ leaves the cell.
-Phase 3: Repolarization. Potassium moves out of the cell and the cell returns to -90mV.
-Phase 4: Na+/K+ pump maintains resting membrane potential at -90mV
Define preload
the particular stretch of LV myocardial fibers at end-diastole, which is determined by the resting force, myocardial compliance and degree of filling from the LA.
Define afterload
The impedance during ejection. (or) The wall stress in the ventricle during contraction. Wall stress is the tension in any one myocyte during contraction.
