Hemodynamic Disorders III Flashcards
The most common cause of right heart failure is:
Increase in afterload due to left heart failure. Left heart failure causes increased pressure in pulmponary veins, capillary beds and then pulmonary arteries, which increases the afterload faced by the right heart.
Isolated Right heart failure is usually caused by what>
Pulmonary vascular or parenchymal disease.
Cor pulmonale
heart disease caused by lung disease
Causes of chronic cor pulmonale
pulmonary emphysema, recurrent pulmonary thromboembolism, interstitial lung disease, and ARDS
Clinical manifestations of Right heart failure
Lower leg Edema (though this is nowhere near specific for right heart failure), Right upper quadrant pain if blood backed up from the right heart stretches out the liver capsule. Hepatomegally, JVD, ascites, decresased appetite.
Asystole
total lack of cardiac pumping.
Slow death from heart failure is associated with what?
Increasing dyspnea
Sudden cardiac death is more common in what sex>
Males
80% of sudden cardiac deaths are associated with what?
Coronary artery disease
Second most common cause of cardia death?
hypertensive heart disease.
What is automaticity?
a cell’s ability to depolarize itself to a threshold generating a spontaneous action potential
How can myocytes acquire automaticity pathologically
Injured myocytes have leaky membranes and lose part of their concentration gradients of ions. This results in a less than normal membrane potential. When that membrane potential is less negative than -60 spontaneous depolarization can occur.
afterdepolarizations in stage 2 or 3 are referred to as early
true
Afterdepolarizations in ohase 4 are
delayed
afterdeploarization during the long phase 2 can be attributed to
increased calcium inflow which is due to defected calcium channels
afterdepolarization during phase 3
abnormal sodium inflow
What does the PR interval tell you
The length of time it takes a signal to propagate from the SA node through the AV node
Normal PR interval
.12-.20 seconds
First degree heart block
PR interval longer than .20 secs
QRS interval time
usually less than .1 secs
wide complex
thats how you refer to a wide QRS. Its bad
QT interval
ventricular repolarization
QTc
QT interval corrected for heart rate
Prolonged QT
BAD…most common cause is myocardial ischemia….can also be from blood electrolyte abnormalities
how to differentiate sinus tacchycardia from taccharrythmia
sinus tacchycardia will not go over a rate of 220-the pts age
sinus tacchycardia is not associated with heart disease
true
atrial fibrillation on an EKG
regular rhythm, rate is high or normal, no P waves
Most common tachyarrhythmia
A Fib
Second most common
atrial flutter
Ventricular tachyarrhthmias are the dangerous ones
truth
Two major ventricular tacchyarhthmias
ventricular tachycardia and ventricular fibrilation
ventricular tachycardia QRS
wide QRS (over 120 ms or .12 secs) If all the QRS complexes look alike, its monomorphic. If the QRS vary in morphology, its polymorphic
Ventricular fibrillation is immediately what
lifethreatening
Totally disordered rapid stimulation of ventricles
Ventricular fibrilation
A prolonged QT over how many milliseconds is dangerous
440
acute cor pulmonale is characterized by what?
dilatation of the right heart chambers
Chronic cor pulmonale
hypertrophy of the right heart….eventually if the workload comes to exceed the capability of the hypertrophied right ventricle it begins to dilate. You get dilation superimposed on hypertrophy
What is pulmonary emphysema
permanant destructin of airspaces with the elimination of the capillaries in the alveolar walls that have been destroyed. THis is problematic for the heart because you are still pumping the same amount of blood through a decreased vascular bed. Causes increased afterload for the right heart. Can lead to occlusion of the pulmonary arteries.
What type of cardiac environment predisposes to re-entry
Small pathces of myocardial ischemia or scarring. Re erntry occurs when signals are re-directed around areas of injury and encounter myocytes that are finished with their repolarization and no longer refractory. this abnormally conducted impulse can reenter the normal conduction pathway adding an extra impulse and causing a tacchyarrhythmia.
If you see a cardiac conduction block in a young african american, what is it most likely?
Cardiac sarcoidosis
Explain the conduction pathway after the AV node
AV node-> bundle of His -> Left and Right branches of the bundle of His -> Left bundle branch divides into anterior and posterior, right keeps going (now you have threeconducting fiber bundles
How many leads are electrocardiograms
12
How do you differentiate sinus tachycardia from an arrhythmia
Sinus tacchycardia will not go over a rate of 220 minus the patients age.
Many supaventricular tacchyarrhythmias are innocent
truth
What is a channelopathy?
hereditary diseases of sodium, potassium, or calcium channels
Torsades de pointes is a channelopathy and features what?
closely spaced QRW complexes twisting around the baseline of the electrocardiogram
What is the most common type of congenital long QT syndrome?
Type 1. It is caused by mutations in the gene for a subunit of the Iks potassium channel. DOesnt allow potassium to flow out like it should and thus presents problems with depolarization
Brugada syndrome
young adult asian males. mutation in gene for cardiac sodium channels. Reduce action potential durations. Inverted T wave in leads V1-3 with ventricular fib
