Cardiac Flashcards
Acute Myocardial Infarction
A heart attack:
occurs when sudden narrowing or complete inclusion of coronary arteries causes myocardial tissue necrosis.
Responsibilities of the cardio vascular system
This system delivers oxygenated blood and nutrients to every cell in the body, also delivers chemical messengers(hormones) within the body and transports the waste products of metabolism from the cells to sites of recycling or disposal.
The coronary sinus
A large vein on the posterior side of the heart that collects blood from the great cardiac vein and several coronary veins and then drains the blood in to the right atrium.
Cardiac cells four important properties that help a heart funtion efficiently
automaticity, excitability, conductivity, contractility.
The six parts of the cardiac conduction system.
The SA node, the AV node, the bundle of His, and the purkinje fibers.
Stimulation of the sympathetic nerves.
Strengthends the force of contraction and increases the heart rate.
Stimulation of the parasympathetic nerve fibers
Slows the rate of discharge of the SA node, slows the conduction through the AV node, weakends the strength of atrial contraction, and can cause a small reduction in the force of ventricular contraction.
How can the primary survey/primary assessment change in a cardiac patient.
If the patient is unresponsive and suspected of being in cardiac arrest then the order will change from ABCDE to CABDE.
What are Acute coronary syndromes
Acute coronary syndromes are a series of cardiac conditions that are caused by an abrupt reduction the blood flow through a coronary artery. The three major ACSs are unstable angina, non-ST segment elevation myocardial infarction(NSTEMI), and ST segment elevation myocardial infarction(STEMI).
Syncope cause
brief loss of conciousness cause by a temporary, sudden decrease in blood flow to the brain.
Pulmonary edema is accompanied by what type of cough
Productive cough containing pink, frothy sputum.
What is Paroxysmal nocturnal dyspnea`and what cardiac conditions can cause it.
PND is a sudden onset of difficulty breathing in which the patient suddenly awakens from sleep. PND is often associated with left ventricular failure. It is often accompanied by coughing, wheezing, and sweating.
Why is it important to know the time that cardiac symptoms started.
Reperfusion therapy(therapies and medications to open blocked coronary arteris) may or may not be used depending on how long the tissue has been infarcted. Time will also help diagnose the type of cardiac problem present.
Commonly perscribed Antiarrhythmics
digoxin(Lanoxin), procainamide(Procan, Pronestyl), amiodorone(Cordarone), verapamil(Calan, Isoptin, Verelan)
Commonly perscribed anticoagulants
enoxaparin(Lovenox), clopidogrel(Plavix), warfarin(Coumadin)
Angiotension-converting enzyme inhibitors commonly perscribed
captopril(Capoten), enalapril(Vasotec), lisinopril(Prinivil, Zestril)
Beta-blockers commonly perscribed
atenolol(Tenormin), metoprolol(Lopressor), propranolol(Inderal)
Lipid lowering agents commonly perscribed
gemfibrozil(Lopid) atorvastatin(Lipitor), fluvastatin(Lescol), lovastatin(Mevacor), pravastatin(Pravachol), rosuvastatin calcium(Crestor), simvastatin(Zocor)
diuretics commonly perscribed
furosemide(Lasix)
vasodilators commonly perscribed
nitroglycerin(Nitrostat) or isosorbide(Isordil)
What is cool diaphoretic skin caused by
Cool diaphoretic skin is a sympathetic response. The body shunts blood to the vital organs via peripheral vasoconstriction to maintain perfusion of the vital organs. this leads to less blood in the skin causing less heat and sweating.
Venous pressure is increased in what cardiac situations
Venous pressure increases with a significant increase in blood volume, when the right ventricle fails, or increased pressure in the pericardial sac hinders venous return to the heart.
Venous pressure is decreased in what cardiac situations.
Venous pressure decreases when blood volume is decreased significantly or if ejection of blood occurs from the left ventricle
What lung sounds may be present in patients with left ventricle failure
Wheezes or crackles
Strong pulsations in the epigastric area may be a sign of what cardiac condition
abdominal aortic aneurysm
Bilateral pitting edema may be a sign of what cardiac condition
Right ventricular failure
Pitting edema to one side of the body may be a sign of what cardiovascular condition
A blockage of a major vein.
Reduced cardiac output will do what to the pulse
The patients pulse will become weak and thready.
What are the three types of electrical therapy
Defibrillation, synchronized cardioversion, or transcutaneous pacing.
How do u measure a pulse deficit and what does it indicate
Place a stethoscope over the hearts apex which is located between the fifth and sixth ribs on the left side of the chest. Listen to the stethoscope while palpating the peripheral pulse. The difference between the pulses indicates an abnormal heart rhythm.
A difference of more that 10mmhg between inspirationiand expiration blood pressure is called.
pulsus paradoxus
Pulsus Alternans is
A beat to beat difference in the strength of a pulse caused by severe ventricular failure. Decreased number of myocardial cells contracting.
Elevated blood pressure may cause
AMI, Stroke, aortic dissection
How to determine pulse pressure and normal pulse pressure
Pulse pressure is the difference between diastolic and systolic blood pressures. Normal pulse pressure is 30 to 40 mm hg
What is a murmur
an abnormal whooshing sound that is associated with turbulent blood flow through heart valves. This turbulent blood flow can occur from increased blood flow accross normal valve, an irregular or constricted valve, blood flow into an enlarged heart chamber, or backwards blood flow.
A resting(polarized) cardiac cell normally has a net internal charge of…?
-90 mV relative to the outside of the cell.
Steps and order of ions entering and leaving a cell during depolarization and re-polarization of a cardiac cell.
The cell receives an electrical stimulus, sodium ions rush in making the cell charge more positive, calcium ions also enter more slowly(these help maintain the depolarized state), the cell is depolarized and if all the cells are acting together then mechanical contraction occurs, sodium and calcium channels close halting depolarization and beginning re-polarization, potassium channels open allowing rapid escape of potassium ions, net negative charge is restored in the cell, proper ion distribution of cells is restored as sodium and calcium are pumped out and potassium is pumped back in.
Cardiac action potential phase 0
Starts when the cardiac muscle receives an impulse, depolarization, qrs, sodium(+) in, calcium(+) in
cardiac action potential phase 1
repolarization, sodium channels close, chloride(-) in, potassium(+) out,
Cardiac action potential phase 2
plateau phase, repolarization sodium(+) and calcium(+) in, while potassium(+) out. contraction ends when the outward flow of potassium exceeds the inward flow of sodium and calcium. ST
Cardiac action potential phase 3
Final repolarization phase. calcium channels close and calcium is transported out of the cell. Potasium(+) out. by the end of phase 3 the cell is back to normal potential. T
Cardiac action potential phase 4
resting phase. Potential of -90mV
Refractory period
The period in which the cell is depolarized or in the process of repolarizing.
The two phases of the refractory period.
Absolute refractory period. (cells unable to respond to any electrical stimulus)
Relative refractory period(middle of phase 3 to the beginning of phase 4) the cell has been partially repolarized and may depolarize in response to an electrical stimulus.
Which cell in the heart can act as the cardiac pacemaker
any cell can potentially act as the cardiac pace maker. The usual pacemaker in a healthy person is SA node.
Intrinsic rate of the SA node
60 - 100
Intrinsic rate of the AV node
40 - 60
Location of the SA node
Junction of the superior vena cava and the right atrium.
Location of the AV node.
floor of the right atrium behind the tricuspid valve.
The amount of blood that fills the ventricles via gravity vs atrial contraction.
70 to 80% comes from gravity.
20 to 30% comes from atrial contraction.
Intrinsic rate of the purkinje network
20 - 40
What are accessory conduction pathways.
extra heart muscle tissue that connects the atria and the ventricles that creates an alternative electrical pathway that can bypass the AV node.
also called accessory pathway or bypass tract.
Delta wave
slurring of the upstroke on the first part of the qrs complex that occurs in wolf parkinson white syndrome.
Bundle of Kent
accessory conduction pathway located between the left atrium and ventricle or right atrium and ventricle. creates a delta wave on the ECG
Ways the Vegas nerve can be stimulated causing a decreased heartrate
increasing pressure on the carotid sinus, straining or forced exhalation against a closed glottis, distention of a hollow organ such as the bladder or stomach.
The chemical messenger released at the SA node by the vegas nerve that signals the SA node and AV node to slow.
Acetylcholine(ACh)
Where are Baroreceptors located
internal carotid arteries and the aortic arch.
What is it that Chemo receptors measure in the blood
They measure the concentration of hydrogen ions(pH), oxygen, and carbon dioxide.
Lead I direction
right arm to left arm
Lead II direction
right arm to left leg
Lead III direction
left arm to left leg
aVR direction
right arm to combination of left arm and leg
aVL direction
left arm to combination of right arm and leg
aVF direction
up and down
Contiguous leads definition
leads that view similar areas of the myocardium.
On a right sided ECG, how will the leads be placed and labeled.
v1 and v2 remain in the same position. v3 through v6 will be mirrored across the midline. All leads will be labeled with an R after the lead name. (VxR)
What can a right sided ECG be used for
to detect a right ventricular AMI.
What lead is most important in looking for a right ventricluar AMI
V4R. Most likely the only one recorded
What is a posterior ECG used for
to determine the posterior electrical activity of the heart.
How are the leads placed and labeled in a posterior ECG
place three of the precordial leads on the left posterior thorax. V7 is between V6 and V8 in the fifth ICS. V8 is midscapular in the fifth ICS. V9 is just to the left of the spine in the fifth ICS
One small box of ECG graph equals how much time.
0.04 second. 40 milliseconds.
One large box of ECG graph equals how much time.
5 small boxes. 0.20 seconds. 200 milliseconds.
P wave normal shape and size
Smooth, round, upright less than 0.11 seconds and less than 2.5 mm tall
PR interval and its normal length.
Start of the P wave to the start of the QRS complex. 3 to 5 small boxes
QRS normal size
narrow with normal duration of 0.11 seconds or less.
Q wave normal size
no more than 0.04 second and less than 1/3 the overall height(or depth) of the QRS.
R wave is.
the first upward deflection in the QRS
S wave is
The downward deflection after the R wave.
R prime wave is
the second upward deflection at the end of the QRS.
J point is
Where the QRS ends and the ST segment begins.
T wave size and shape
upright, flat or inverted wave following the QRS. Should be asymmetric, less than half the overall height of the QRS, orientated in the same overall direction.q
Changes in the T wave during hyperkalemia
Tall pointed T waves
Changes in the T wave during a CNS event such as intracranial hemorrhage or massive stroke
inverted T waves
Changes in T wave during myocardial ischemia, injury, and infarction
T wave becomes very large, peaked or tented, symmetric, broad.
U wave is what and what is its normal size.
A wave sometimes seen after the T wave. Same direction as the T wave. Less than 2mm
A U wave taller than 2mm is a sign of
hypokalemia, cardiomyopathy, some other conditions.
QT interval is measured from what to what
the start of the Q to the end of the T
TP segment is measured from what to what
end of T to start of P
R-R interval is measured from what to what
the period between the sme to points on two QRS.
Order to interpret rhythm
- Identify waves
- Measure the PRI
- Measure QRS
- Determine rhythm regularity
- Measure heart rate.
If a patient in sinus bradycarida is unresponsive to atropine or is unstable, what intervention should be considered and why.
Transcutaneous pacing should be considered to maintain the patient at an adequate level of perfusion until the hospital is reached to prevent arrest.
What are some complications that can arise from prolonged sinus tachycardia
Further ischemia during and AMI. Cardiac output may be significantly reduced when the heart rate exceeds 150 beats/min because the ventricles will have inadequate time to fill completely between contractions.
Sinus dysrhythmia, its cause, and measurements.
SA node is still the pacemaker. The heart rate fluctuates with respirations(difference greater than 0.12 between the longest and shortest cycles.) The P wave is still upright and precedes the QRS. PRI normal, QRS normal.
Sinus Arrest is, measurements, etc.
The SA node fails to initiate impulse and the subsequent complexes do not appear. The heart then resumes its normal funtion. everything is normal except for a missed beat.
Sick Sinus Syndrome is.
encompasses a variety of rhythms characterized by a poorly functioning SA node.
A premature atrial complex that does not travel down into the ventricles is called a what.
nonconducted PAC
What size should the QRS be to indicate that the rhythm originates above the ventricles?
0.11 seconds or less. (a little less than 3 small boxes{0.04secs})
What is adenosine used for? What should be attempted before administering adenosine?
Adenosine is used for Supraventricular tachycardia. Vagal maneuvers will usually stop superventricular tachycardias, they should be attempted before administering adenosine.
What is a delta wave? Pre-excitation
A slurring of the upstroke of the first part of the QRS complex which widens the QRS. This indicates an early departure from the PR segment as a result of conduction through the accessory pathway(budle of Kent) and subsequent early depolarization of ventricular tissue.
In a cardiac rhythm originating in the AV node, how will the P wave appear if the signal travels up into the atria before being released to the ventricles? same time? late?
There will be an inverted P wave before the QRS complex. Inverted and inside the QRS(hidden). Inverted and after the QRS.
What will the length of the QRS be in a rhythm originating in the AV node(juntional rhythm)
The QRS will be 0.11 or less(normal)
What is the definition of an extopic complex
A complex originating in a location other than the SA node.
What is a compensatory pause?
A pause in the cardiac rhythm that follows a PVC or something similar that allows the heart to resume the normal rhythm. Determine by measuring the R-R interval.
multiple PVC’s that appear in a rhythm and appear the same are considered…? appear different…?
Unifocal and multifocal.
Unifocal PVC’s originate from the same location. Multifocal PVC’s originate from different locations.
How many PVC’s in sequential order are required for them to be considered a run of VTac?
3 or more.
What are two sequential PVCs called
A couplet. Also called “salvos” or “bursts”
If a PVC alternates with a normal rhyth then it is called…?
Bigeminy
If a PVC occurs every 3rd beat then it is called.
Trigeminy
What is the way that PVC’s can cause V fib
If the R wave of the PVC occurs during the T wave of the previous complex. Also called R on T.
What is cor pulmonale>
Cor pulmonale is failure of the right ventricle due to pulmonary disease.
What are the causes of cardiac dysrhythmias?
Acid - base disturbance ANS imbalance Central nervous system damage Certain poisons Cor pulmonale Distention of cardiac chambers drug effects electrolyte disturbances, especially those involving potassium, calcium, or magnesium Endorcrine disorders Hypothermia hypoxemia
Definition of an Idioventricular Rhythm
The term idoventricular means “only the ventricles” or “produced by the ventricles.” An idoventricular rhythmn (IVR) then is one that occurs when the SA and AV nodes fail and responsibility for pacing the heart shifts to the ventricles.
Electrical therapy type used for tachycardic rhythms
Syncronized cardioversion
Electrical therapy type used for bradycardic rhythms
pacing
Electrical therapy used for V Fib
Defibrillation
What are the causes of pulseless electrical activity?
PEA may occur in cardiogenic or hypovolemic shock, cardiac tamponade, massive pulmonary embolism, electrolyte imbalance
What should be done immediately following any drug administration to a peripheral IV line during a cardiac arrest?
Follow the administration with a 20 mL IV flush and raise the extremity for 1 to 2 minutes.
What concentration and amount of epinephrine is used during a cardiac arrest?
1mg of 1mg/mL(1:10,000)
How often should compressions be paused to administer ventilations in a cardiac arrest patient with an advanced airway placed?
Never. With an advanced airway(ET tube) placed, the patient should be ventilated continuously with continuous compression’s simultaneously.
What are the 5 H’s (causes of cardiac arrest)?
Hypovolemia Hypoxemia Hypothermia Hyper/hypokalemia Hydrogen ions(acidosis)
What are the 5 T’s(causes of cardiac arrest)?
Tension Pneumothorax Tamponade, Cardiac Toxins Thrombosis, pulmonary Thromosis, coronary
If ROSC is obtained during a cardiac arrest, what care should be prioritized and begun immediately
Oxygenation and ventilation. Assess breath sounds. Most patients require ventilatory assistance after ROSC. Titrate SpO2 to 94% or higher and avoid hyperventilation. Obtain 12 lead to determine if an ST segment elevation is present.
After a cardiac arrest, if the patient is hypotensive and there is a long transport time, what should be done for the patient.
Administer a fluid bolus of 1 to 2 L of normal saline or lactated ringers and consider a vasopressor infusion.
What will the PRI be in a first degree heart block
The PR interval will be greater than 0.20 sec(200milliseconds)
What is the difference between a 2nd degree AV block type 1 vs type 2?
A type 1 2nd degree heart block has a PRI that gradually increases and then a QRS complex is dropped. A type 2, 2nd degree block has a regular PRI with an occasional dropped QRS
What is undersensing and how is it identified?
Undersensing is a malfunction of an implanted pacemaker in which the pacemaker competes with the patients own intrinsic rhythm. It is indicated on an ECG when pacer spikers are visible within the p wave, qrs complex, or t wave.
Why is a undersensing dangerous to a patient.
The patients artificial pacemaker may fire during a refractory period causing VT or VF
How is a right bundle branch block identified on an ECG?
QRS greater than 0.12 sec
rsR’ (bunny ears) pattern in leads V1-V3
Slurred S waves in leads I, aVL, V5, V6
How is a left bundle branch block identified on an ECG?
A QRS greater than 0.12 secs
Absence of Q wave in leads I, V5, and V6
Monomorphic R wave in I V5, V6
What is Acetylsalicylic Acid? What is it used for
Aspirin(NSAID), used for chest pain suggestive of acute coronary syndrome.
What is the adult Acetylsalicylic Acid dosage and administration for adult and pediatric patients?
Adult: 160mg - 325mg PO. Chewing is preferred
Not recommended for pediatric patients.
What are the effects of Acetylsalicylic Acid?
prevents clots, reduces fever, reduces pain.
When would you not administer Acetylsalicylic Acid?
hypersensitivity(NSAIDs), active ulcer disease, asthma.
What is the principle symptom of Coronary Artery Disease?
angina pectoris(“choking in the chest”)
What causes angina pectoris?
insufficient oxygen supply to the myocardium to meet demand. Cardiac muscle becomes ischemic and switching to anaerobic metabolism. Anaerobic metabolism leads to the buildup of lactic acid and carbon dioxide.
Which is more severe, angina pectoris at rest or during physical activity?
At rest. The ischemia is not severe enough to reduce oxygen supply below the demand threshold when the patient is resting indicates that the blockage is not as severe in patients who only experience angina pectoris upon physical exertion.
What is stable angina
stable angina is episodic chest discomfort caused by myocardial ischemia that usually follows a recurrent pattern. Pain is experienced after certain, predictable amount of exertion, with predictable location, intensity, and duration.
What medications are patients with stable angina usually perscribed?
Nitro, ASA.
What might be observed on an ECG of a patient with stable angina?
ST segment depression or inverted T waves. Usually resolved after rest or Nitro is taken.(when supplied oxygen begins to meet oxygen demand.
What is unstable angina?
A more serious angina pectoris. Characterized by changes in frequency, severity, and duration of pain and other symptoms. Often occurs unpredictably. The patient may report that the anginal attacks have become more frequent and severe. The attacks may more may not be relieved by rest or medications. Warning of impending MI.
What is an Acute Myocardial Infarction.
AMI, heart attack. Occurs when a portioni of the cardiac muscle is deprived of coronary blood flow long enough for portions of the muscle to die(undergo necrosis).
What are the ECG findings present in a patient suffering from an Acute Myocardial Infarction?
ST-segment elevation.
For the purposes of treatment of a patient with chest pain outside the medical facility, what should be assumed until proven otherwise?
The patient is suffering from an Acute Myocardial Infarction.
What is Starlings Law?
Increased Venous return to the heart stretches the ventricles somewhat, resulting in increased cardiac contractility. If a muscle is stretched slightly before it is stimulated to contract, it will contract with greater force. If the heart is stretched, the muscle contracts more forcefully.
How does a vagal maneuver reduce tachycardia?
Vagal maneuvers stimulate the baroreceptors causing the brain to trigger the vagal nerve, releasing Acetylcholine into the heart.
Where are the baroreceptors located
Interior carotid arteries and the aortic arch.
What are leads that view the same general area called?
Contiguous leads
What leads are included in a 15 lead ECG
The normal 12 plus V4R, V7, V8
What are all possible Treatments for symptomatic bradycardia
Atropine, Transcutaneous pacing, dopamine, epinephrine.
What rhythms can result from an ectopic atrial pacemaker.
Premature atrial complexes, supraventricular tachycardia, AV reentry tachycardia, atrial fibrillation, atrial flutter, wandering atrial pacemaker, multifocal atrial tachycardia.
What types of cardiac rhythms can originate in the AV node.
premature junctional complexes, junctional escape rhythms, accelerated junctional rhythms, junctional tachycardia.
What treatments are used for beta blocker overdoses.
Glucagon(increased chronotropic and inotropic effects without directly activating beta 1 receptors) high doses needed.
Atropine(0.5mg IV/IO every 3 to 5 minutes as needed. 3mg total max)
Calcium chloride( 500 to 1000mg IV push{5 to 10ml of 10% solution})
Transcutaneous pacing.
Adenosine mechanism of action
Slows AV conduction
Amiodarone mechanism of action
Blocks sodium, potassium, and calcium channels; prolongs the action potential and repolarization; decreases AV conduction and sinoatrial (SA) node funtion.
Atropine mechanism of action
Inhibits the action of acetylcholine at the postganglionic parasympathetic neuroeffector sites. Increases heart rate in symptomatic bradydysrhythmias.
Calcium chloride mechanism of action
Increases cardiac contractile state(positive inotropic effect). may enhance ventricular automaticity.
Diltiazem mechanism of action
Inhibits calcium influx, dialates main coronary and systemic arteries. substantial inhibitory effects on the cardiac conduction system. principally on AV node with some effects on the SA node.
Dopamine mechanism of action
Immediate metabolic precursor to norepinephrine. Produces positive ino, chrono effects. constricts systemic vasculature, increasing BP and preload, increases myocardial contractility and stroke volume.
Lidocaine mechanism of action
Decreases automaticity by slowing the rate of spontaneous phase 4 depolarization
Norepinephrine mechanism of action
Potent alpha agonist resulting in intense peripheral vaso constriction, some beta effects.
Procainamine mechanism of action
Suppresses phase 4 depolarization in normal ventricular muscle and purkinje fibers, reducing ectopic pacemakers automaticity. suppresses intraventricular conduction.
Sodium Bicarbonate mechanism of action
Buffers metabolic acidosis and lactic acid buildup. reacts with hydrogen ions to form water and carbon dioxide.
Furosemide mechanism of action
Blocks absorption of sodium and chloride in the loop of henle, causing increased urine output.
Labetalol mechanism of action
BP reduction without reflex tachycardia. total peripheral resistance reduced without significant alteration in cardiac output.
Metoprolol mechanism of action
Decreases heart rate, conduction velocity, myocardial contractility, cardiac output. Used to control ventricular response in SVT(PSVT, AF, Atrial Flutter) considered second line agent after adenosine, diltiazem, or digitalis derivative.
Propranolol mechanism of action
Non selective beta adrenervic blocker.
What is Atherosclerosis
Narrowing of blood vessels due to fatty deposits
What are the modifiable risk factors associated with CHD
Diabetes Excessive alcohol use High blood cholesterol and triglyceride levels high blood pressure obesity physical inactivity smoking stres unhealthy diet
What are the modifiable risk factors associated with CHD
Age
family history
sex
race or ethnicity
What is an anginal equivalent definition
A sign of myocardial ischemia other than chest pain or discomfort.
What are the anginal equivalents?
Abdominal pain Altered mental status Dizziness Dyspnea Dysrhythmia Epigastric pain Fatigue Generalized weakness Indigestion Isolated arm of jaw pain Light headedness Palpitations Restlessness Syncope or near syncope Unexplained nausea or vomiting.
How would you determine if nitro medication has gone stale when a patient takes it before your arrival for chest pain with no relief.
The medication will have the other usual effects, such has a burning sensation under the tongue, transient throbbing headache.
Why is it important to reduce the pain in a patient with chest pain.
If a patient is suffering from chest pain then it is possible that the patient is suffering from myocardial ischemia. The pain will raise the patients anxiety levels which will in turn increase the patients sympathetic nervous system response which will increase the heart rate and myocardial oxygen demand. Increased oxygen demand in the ishemic cells will cause them to become infarcted faster.
What does a large p wave indicate?(taller)
right atrium hypertrophy
What does an elongated p wave indicate? (longer)
left atrium hypertrophy
What causes right atrium hypertrophy?
Chronic pulmonary disorders
What causes left atrium hypertrophy?
Valvular heart disease, particularly in patients with mitral or aortic valve stenosis, hypertensive heart disease, cardiomyopathy, and CAD. Can also occur in athletic individuals.
