Newman Flashcards
What do the leads of an ECG do?
look at the electrical activity of the heart from many different angles
What leads look at the bottom of the heart (inferior)?
II, III, aVF
What leads are precordial (anterior) or located over the sternum?
V leads
Can the heart work without atrial depolarization (P wave)?
yes
What is the PR segment?
conduction from atrium to the ventricle
What are Q waves?
depolarization of intraventricular septum
What part of the ECG will tell you a lot about ischemic heart disease?
ST segment
What are the 2 major reasons for ischemia?
1) coronary arteries are not supplying enough oxygen
2) heart is demanding too much oxygen
* supply demand mismatch
What would you see on an ECG of myocardial ischemia?
ST segment depression
What are the two major determinants of myocardial oxygen demand? *on test
1) heart rate
2) systolic blood pressure
What is a STEMI?
myocardial infarction that is shown by ST elevation in either II, III, AVF (inferior) or V leads (anterior)
How do you calculate HR from the ECG?
300/ # of large boxes between QRS
What is the most common cause of stroke?
atrial fibrillation
What causes atrial fibrillaiton?
multiple “whimpy” depolarizations in the artrium that are not coming from SA node
What causes QT prolongation?
medications and metabolite abnormalities: alteration of potassium channel
What does an ECG of 3rd degree heart block look like?
P waves are independent of QRS
How do you treat someone at risk of ventricular fibrillation?
implanted cardioverter defibrillator (shock goes off when HR gets around 180-200 beats/min)
What does a “pacemaker” treat? What triggers it?
complete heart block
low heart rate (below set point) triggers this
What is the definition of CHF? What causes it?
Symptoms and signs resulting from cardiac dysfunction. Dysfunction may be caused by damage to the heart or external forces preventing the adequate forward flow of blood from the heart to the peripheral organs.
What does increased proload do to SV?
increases
What does increased afterload do to SV?
decreases (it is a form of resistance)
What are the 2 determinants of afterload?
1) size of ventricle
2) systolic BP
What is contractility?
ability of heart to contract (how well are myocytes working) that is independent of preload or afterload
What is the ejection fraction?
EF= SV/EDV
What is the major determinant of heart failure?
ejection fraction being low
How might you get the external JV to stick out?
Valsalva manuever (straining)
What are you measuring when you measure JVP?
right atrial pressure
What pathologic processes directly damage the myocardium and result in CHF?
MI infection (viruses) amyloidosis drugs (doxorubicin) cocaine, alcohol
What is the first thing you look for when you suspect heart failure?
JVP
What can cause heart failure without directly damaging myocardial cells?
valve problems
pericardial disease
High output states: anemia; hyperthyroidism
What is a normal finding when you palpate the patients chest for the PMI?
feel sustained, apical impulse right below right nipple (size of the dime) with interphalangial joints
What is a major sign of heart failure associated with palpitation?
apical impulse pushed to the left (larger)
What heart sound is diagnostic of heart failure?
S3
How do you listen for S3?
Listen at apical impulse with bell, put just enough pressure on the stethoscope to keep the air out. Press hard and ease up.
When does the a wave occur?
right before carotid pulse
What does the a wave in venous pulsation signify?
atrial contraction
What does the c wave in venous pulsation signify?
beginning of systole (he said you never see this)
What is the x descent in venous pulsation?
relaxation of atria
What is the v wave in venous pulsation?
ventricular contraction
What is the y descent in venous pulsation?
relaxation of ventricle
What are the two major humoral manifestation of the renin-angiotensin-aldosterone curve?* on test
Kidney thinks your body is dehydrated if it is getting poor perfusion, so it releases lots of rein. Which will lead to:
1) vasoconstriction of the vessels (increase afterload)
2) retention of salt and fluid, release of potassium (via aldosterone)
(can reduce CO and GFR)
What was the first drug shown to save lives in CHF? What is the second?
ACE inhibitors
Spirinolactone
What is the most potent vasoconstrictor in the body?
angiotensin II
What, other than drugs, can be used to treat CHF?
heart transplant
What is the cause of chronic, stable angina? *on exam
mismatch between myocardial oxygen supply and myocardial oxygen demand
What is characteristic of the chest pain in chronic, stable angina?
- caused by exertion (increase in systolic BP)
- always more than 5 minutes
- tightness or pressing pain that can radiate down arm
- SNS in overdrive- turn white as a ghost and get sweaty
What do you see on a treadmill test of someone with ischemia from chronic stable angina?
ST segment depression
What is the characteristic description of a patient with unstable angina?
patient waking up in the middle of the night with severe chest pain, sweaty, and pale