Heart II Flashcards
Most common cause of rhythm DOs is:
Ischemic injury
Sick sinus syndrome
SA node is damaged —> bradycardia
AFib
Myocytes depolarize sporadically (atrial dilation) w/ variable transmission thru AV node —> irregular irregular HR
What is a heart block?
1st, 2nd and 3rd degree heart blocks
Dysfunctional AV node
1st - prolonged PR interval
2nd - intermittent trasmission
3rd - complete failure
What hereditary pattern causes most genetic arrythimias?
AD
What are channelopathies?
What other diseases are associated? (2)
Mutations in genes that are required for normal ion channel function.
Skeletal m. DOs and DM
Abnormalities in gap junction structure or spatial relationship can cause:
Arrythmias (ischemic heart DZ, cardiomyopathies, myocyte hypertrophy, inflammation, amyloid, etc.)
Long QT syndrome causes dysfunction in what?
LOF mutations in K+ channels
GOF mutations in Na+ channels
Often seen in swimmers.
SCD is unexpected death from a cardiac cause, either….
80-90% of successfully resuscitated pts show….
Without SX, or within 1-24 hrs of SX onset.
Show no lab or ECG changes.
What is the most common precipitating cause of SCD?
80-90% are from CAD, usually >75% stenosis of one or more of the 3 main coronary aa.
Unfortunately, SCD is often the first manifestation of ischemic HD.
SCD is due to a…
SCD is due to a fatal arrhythmia most often arising from an ischemia-induced myocardial irritability.
Left-sided (systemic) Hypertensive heart DZ (HHD)
Pressure overload causes LVH —> LV wall is *concentrically thickened (>1.5 cm and >500 mg).
Diastolic dysfunction may result in LA enlargement, and can lead to AFib.
Might also lead to CHF.
Right-sided (pulmonary) Hypertensive heart DZ (HHD)
Arises in the setting of pulm. HTN.
Acute cor pulmonale may arise from a large pulmonary embolus (marked dilation of the RV w/o hypertrophy.
Most common cause of pulmonary HTN is:
Left-sided HD
What are 3 pathologic changes that occur to cardiac valves?
Damage to collagen that weakens the leaflets (ex: MVP)
Nodular calficiation (ex: calcified aortic stenosis)
Fibrotic thickening (ex: rheumatic heart DZ)
Functional regurgitation
Ex:
Incompetence of a valve stemming from an abnormality in one of its support structures, as opposed to a primary valve defect.
Ex: functional MV regurg, which is important in IHD and dilated cardiomyopathy
How is blood flow to a valve impacted when there is pathologic changes to it?
Usually, valves get nourishment via diffusion. However, if the valve becomes to thick, angiogenesis must occur and leads to an increase risk of valvular insufficiency.
Valvular HD may present with: (2)
Stenosis or insufficiency
Stenosis impedes flow in which direction?
Chronic stenosis may lead to:
Impedes forward flow. Valve does not open all the way.
Chronic stenosis may lead to pressure overload hypertrophy —> CHF.
Insufficiency allows flow in which direction?
Chronic insufficiency may lead to:
Allows flow in the reversed direction. Valves don’t close completely.
Chronic insufficiency may cause volume overload hypertrophy —> CHF.
Mitral stenosis is caused by:
Postinflammatory scarring (rheumatic heart DZ)
Mitral regurg is caused by: (3)
Abnormalities of leaflets and commissures
MVP
Drugs (fen-phen)
Aortic stenosis is caused by: (4)
Calcification of congenitally deformed valve
Postinflammatory scarring (RHD)
Abnormalities in tensor apparatus
Abnormalities of LV and/or annulus
Aortic regurg is caused by: (4)
Aortic insufficiency: dilation of ascending aorta.
Postinflammatory scarring (RHD)
Syphilitic aortitis
Marfan’s syndrome