LP #105 Dysfunction As A Fxn Of Lost Structural Or Functional Integrity Flashcards
- Checks heart fxn
- measures cardiac cycle rhythm (electrical activity)
- Predictable & repeated pattern of waves
(ECG) Electrocardiography tracings
Reading ECG tracings (P wave)
- 1st wave, small amplitude
- depolarization wave from SA node to atria
Reading ECG tracings (QRS complex)
- small dip (Q) to large peak (R) to larger dip (S)
- d/t ventricular depolarization & precedes ventricular contraction
Reading ECG tracings (T wave)
- 3rd wave, small amplitude
- ventricular repolarization
- abn rate of heart contractions
- d/t problems w/intrinsic conduction
- leads to uncoordinated myocardial contractions
- affects circulation
- may occur in healthy or diseased hearts
- may cause tachycardia or bradycardia
Cardiac arrhythmia
- Excessive rapid heart rate
- decrease blood filing heart (diastole)= decrease blood pumped out (systole)
- requires increase O2 & nutrients but needs not met d/t decrease blood filling heart in diastole
- leads to decrease coronary circulation (ischemia)
Tachycardia
- excessive flow heart rate
- causes impaired BF & ischemia to vital organs
Bradycardia
- rapid irregular contractions of the myocardium= poor blood pumping
- life threatening (defibrillation)
Fibrillation
Disruptions in AP initiation or signal conduction=
Cardiac dysfxn
- excitable focus outside a faulty SA node
- assumes control of HR
Ectopic pacemakers
- occurs w/damaged nn
- impulses are unable to move across damaged section d/t scar tissue
Heart conduction block
-medical replacement of defective intrinsic pacemakers
Artificial pacemakers
Causes of cardiac arrhythmia & conduction block
- congenital defects
- degenerative changes
- ischemia & myocardial infractions
- fluid & electrolyte imbalances
- P changes in hearts chambers open/closes vavles (depends on structural integrity)
- structural integrity is lost d/t scar tissue build up on valves & chordae tendinae
Valvular defects
Causes of valvular defects
- congenital
- ischemia
- inflammation & fibrosis
2 general types of valvular defects
- stenosis
- incompetent valves
- narrowing of opening b/w:
- atrium & ventricle, or ventricle & bv’s
- d/t fibrosis
- leads to stiff valves
- difficult for valves to open/close
- leads to restricted bl flow
Stenosis
Stenosis is often d/t
Chronic rheumatic fever (debilitating)
- narrowing of opening b/w L ventral & aorta
* leads to restricted blood ejection into aorta
Aortic valve stenosis
Aortic valve stenosis results in
- L ventricle enlargement- becomes weakened
- decrease SV & BP
- poor effusion of coronary aa
Aortic valve stenosis often d/t
- rheumatic fever (endocarditis)
- congenital heart defects
S/s aortic valve stenosis
- dyspnea
- vertigo
- angina pectorals
- narrowing of opening b/w L atrium & ventricle
* leads to resistance to BF & decrease SV
Mitral valve stenosis
Mitral valve stenosis causes
- increase P in left atrium
- leads to pulmonary congestion & increase BP d/t backup of blood in pulmonary vv
S/s mitral valve stenosis
- nocturnal dyspnea & orthopnea
- atrial tachycardia & fibrillation
- palpitations, angina pectoris, weakness & fatigue
- heart murmurs
- d/t valve distortion, valves don’t close properly & cause back flow into affected chamber
- back flow increase chamber P
- leads to dilation of heart chamber
- all heart valves are susceptible
- most often affected: aortic & mitral valves
Incompetent (regurgitant) valves
S/s aortic valve regurgitation
- dyspnea on exertion
- pulmonary edema
- angina pectoris
- orthopnea
- decrease ability for strenuous physical Activity
- blood backs up from aorta to L ventricle:
- L ventricle hypertrophies d/t increase BVol
- some blood remains in ventricle
- systemic BP difficult to maintain
- decrease blood entering aorta= decrease P in bv’
Aortic valve regurgitation
- causes back flow of blood from L ventricle into L atrium
- blood leaks into L atrium during L ventricle systole
Mitral valve regurgitation
S/s mitral valve regurgitation
- increase BVol & P in L atrium
- increase BP in pulmonary vv
- enlarged L atrium
- rapid atrial fibrillation (leads to ABN & turbulent BF)
- clots may form in L atrium
- an embolus may be pumped out of heart & cause blocked aa
Israel valve regurgitation may be asymptomatic for ___ to ___ years as ventricle is initially able to:
- 10-20 years
- maintain sufficient output
- maintain adequate BP & circulation
- present at birth, indicates
- disease
- detrimental intrauterine events
- fetal exposure to a maternal condition
Congenital heart defects
S/s associated w/ congenital heart defects
- altered heart fxn
- heart failure
- pulmonary disorders
- tissue ischemia
Sx’s include: congenital heart defect
- interrupted growth of heart structures
- displaced positioning of chambers or bv’s
- altered closure of fetal cardiac-lung shunts
