19 CEN: cardiac Flashcards
19 items on exam
What is cardiac output?
Cardiac output (L/min) = heart rate (HR) X stroke volume (SV)
HR is bpm. SV is the volume w/ each beat
What is the primary compensatory mechanism for low CO in pediatric patients?
tachycardia
-because they cannot increase SV
NOTE: hypotension is a late sign, bradycardia is an ominous sign in pediatrics
How is SV influenced?
preload, afterload, and contractility
How is preload evaluated?
CVP
What decreases preload and how is it increased?
hypovolemia (fluid loss, diuretics, or vasodilators)
-increased with volume (fluids, blood) and vasoconstictors:
alpha-adrenoceptor agonists.
vasopressin
epinephrine.
norepinephrine.
phenylephrine
dopamine.
dobutamine
How is afterload evaluated?
SVR.
-It is the resistance to ventricular emptying
How is afterload decreased and how it is treated?
↓ in distributive shock (neurogenic, septic, anaphylactic) and with vasodilation
-tx: vasopressors like Norepi
In a state of shock, how does the body respond?
-SNS stimulation causes catecholamines epi and Norepi to release which ↑HR
-adrenal glands release catecholamines as well which ↑BG through glycogenolysis
*Glycogenolysis occurs primarily in the liver and is stimulated by the hormones glucagon and epinephrine (adrenaline)
What increases afterload and how is it treated?
↑ by HTN, Aortic stenosis, and through other shock compenstation
-tx: vasodilators like NTG
What happens to HR in neurogenic shock and why?
the PSNS ↓HR because the SNS response is blocked
What does a narrowed pulse pressure indicate?
Early shock
What does a widened pulse pressure indicate?
↑ICP
What is cushing’s triad?
The 3 signs of ↑ICP
-widened PP or ↑SBP
-bradycardia
-irregular breathing pattern
How do chronotropes affect the heart? Examples.
HR at the SA node
Diltiazem or Cardizem (negative) reduces HR and BP.
Diltiazem is a calcium channel blocker. It works by affecting the movement of calcium into the cells of the heart and blood vessels. This relaxes the blood vessels, lowers blood pressure, and increases the supply of blood and oxygen to the heart while reducing its workload.
How do inotropes affect the heart? Examples.
Contractility
Dopamine (positive)
Dobutamine (positive)
How do dromotropes affect the heart? Examples.
Automaticity (electrical impulse) at the AV node
-Epinephrine (positive)
-Beta blocker (negative)
What does Beta Blockers mask signs of?
Shock and hypoglycemia
What organs do Beta-1 medications affect? Examples.
Heart only
The cardio-selective beta-1-blockers include atenolol, betaxolol, bisoprolol, esmolol, acebutolol, metoprolol, and nebivolol.
**nonselective carvedilol affects the lungs and not given to asthma and COPD patients
Angiotensin Converting Enzymes Inhibitors:
What are ACE-I given for? Examples.
↓BP by blocking converstion of angiotensin 1 to 2
Lisinopril, Benazepril (Lotensin), Enalapril (Vasotec)
What are adverse effects of ACE-I medications?
-dry non-productive cough (leads to noncompliance), ARB prescribed instead
-angioedema
Angiotensin Receptor Blockers:
What are ARBs given for? Examples.
↓BP by inhibiting angiotensin 2 receptors
Irbesartan (Avapro).
Losartan (Cozaar).
Telmisartan (Micardis).
Valsartan (Diovan).
What are indications for CCBs (calcium channel blockers)? Examples.
Diltiazem (Cardizem) controls ventricular rate in A-fib and HTN
Amlodapine (Norvasc) for HTN and chest pain
Nifedipine (Adalat CC) for HTN and prophylaxis angina
What effects does NTG have on the body?
Vasodilation
-↓ preload and afterload
-↓ BP
-↓ O2 consumption
With what drugs is NTG contraindicated? Examples.
Do not give if Phosphodiesterase inhibitors taken within the past 24Hrs.
-Viagra (Sildenafil), Cialis (tadalafil), Levitra (vardenafil)
What effects does Nitroprusside have on the body?
This is a potent preload and afterload reducer
-often used in HTN crisis** [180/120 millimeters of mercury (mm Hg) or greater => MEDICAL EMERGENCY. It can lead to a heart attack, stroke or other life-threatening health problems.]
3 primary Vasopressors and 1 that augments?
Primary: Epi, Norepinephrine (Levophed) and Phenylephrine
Secondary: Vasopressin
Stable vs Unstable Angina?
BOTH have negative troponin
Stable: CP with exertion, short duration, relieved with rest or NTG
Unstable: CP with little exertion, longer duration, unrelieved
What is NSTEMI and how is it dx?
(+) troponin with no STE
What does a STEMI indicate?
(+) troponin with STE (meaning there is arterial obstruction w/ thrombosis
What is variant angina (Prinzmetal’s)? What are the causes?
Coronary vasospasms that cause cyclical pain at rest d/t ischemia
-causes: stress, Raynaud’s, and migraines.
STE resolves and pain relieved when vasospasm resolves
**BB may exacerbate vasospasm due to unopposed alpha stimulation
S/S of Acute coronary syndrome? How might women and diabetics present differently?
chest tightness, jaw pain, neck pain, left arm pain, epigastric (indigestion-like) pain, scapular discomfort; N/V; signs of shock; dysrhythmias; diaphoresis; dizziness
-women c/o ↑ fatigue, scapular and RUQ pain
-diabetics more likely to have silent MI
When does troponin elevate and peak?
Elevation in 3-12hrs, peaks at 10-24hrs.
When should you get posterior V7-V9 ECG?
When there is ST depression in V1 & V2, ECG may show STE in V7-V9 for Posterior infarct
Which leads indicate an inferior infarct?
II, III, aVF; Inferior is RCA
-you want to get a R-sided ECG to look at V4R
Which leads indicate an anterior infarct?
V1-V4 Anterior = LAD
It is anterior septal if V1-V2
Which leads indicate lateral infarct?
If I, aVL, V5-V6; LAD/circumflex
High lateral STEMI: High lateral STEMI can present as ST-elevation involving lead I and aVL. Subtle ST elevation in V5, V6 and reciprocal changes in lead III and avF may be present. This is usually caused by occlusion of the first diagonal branch of LAD
Ischemia vs Injury vs Infarction
-A zone of ischemia typically produces ST segment depression and/or inverted or tall T waves.
-A zone of injury produces ST segment elevation (STEMI) , T wave may invert
-A zone of infarction produces a large Q wave in the QRS complex. If old, Q is deep and wide.
What vessel is occluded and what type of infarct is the “widow maker”? S/S?
LAD- left anterior descending
S/S: CRUSHING CHEST PAIN, ventricular dysrhythmias, tachycardia, FEELING OF IMPENDING DOOM, BBB, SOB, crackles in lungs and S3 from LV failure (cardiogenic shock),
**second degree type 2 (Mobitz 2) is an OMINOUS SIGN.
*a new onset heart murmur = VSD –> EMERGENCY
What vessel is occluded with INFERIOR infarct? S/S?
most commonly RIGHT CORONARY ARTERY– supplies SA and AV nodes
S/S: Epigastric pain, bradycardias resulting in hypotension, second degree heart block type 1, N/V, risk of mitral regurg and papillary muscle rupture (new onset heart murmur)
If an inferior infarct is suspected, what other diagnostic test should be done?
a RIGHT-SIDED ECG to look at V4R
-30 to 50% of inferior MIs are RIGHT VENTRICLE
What S/S are associated with a RV infarction? Treatment?
S/S: JVD, hypotension, shock, STE at V4R
Tx: infuse NS bolus and dobutamine for contractility
-caution with preload-reducing agents like NTG and morphine
What is the PCI goal for STEMI tx?
<90min door to balloon
When is fibrinolytic therapy given instead of PCI?
If PCI unavailable in 90-120 min
**expect reperfusion dysrhythmias like accelerationed IVR or VT (good sign of reperfusion!)
What are other interventions for STEMI tx?
-O2 at 4L NC if SpO2 <94% or respiratory distress
-NTG SL (q5 x3 tab max)
-ASA 162-325 chewable to prevent platelet aggregation
-BB for HTN STEMI
-ACE-I or ARB to reduce infarct size and improve venticular remodeling
-Antiplatelets: aspirin, plavix, effient, brilinta
-Anticoagulants: heparin, lovenox, coumadin, eliquis, xarelto, pradaxa