EKGs are useful to evaluate all of the following, except?
Pumping ability of the heart
What clinical findings are most significant of the need for an EKG?
B. Orthopnea & Chest pain
For an adult, what is the normal intrinsic rate of the hearts primary pacemaker?
What does the P wave on the EKG recording represent?
What does the QRS complex on the EKG recording represent?
Ventricular depolarization & Atrial repolarization
What does the T wave on the EKG recording represent?
Which of the following is within the normal range for a PR interval?
What is the upper limit of a normal QRS complex?
< 0.10 seconds
The complexes are equally spaced w/ three large boxes between each complex. What is the heart rate?
(5 small boxes X 3 large boxes= 15)
A prolonged RP interval is indicative of which of the following?
An early, widened QRS complex with an inverted T wave and no associated P wave is consistent with which of the following?
What EKG finding is suggestive of an acute MI?
Elevated ST segments
What EKG finding is suggestive of cor pulmonale?
Which of the following statements is true regarding Sinus tachycardia?
It may be caused by fever, fear, or pain
For a pt experiencing severe CP and other acute cardiac symptoms, the immediate role of the RT is to do which of the following?
Notify the nurse & Dr and be ready to assist the cardiac arrest team
What are the two types of Cardiac cells?
What is the purpose of the myocardial cells?
These are the working cells they contain contractile filaments to help contract the heart
What is the purpose of the pacemaker cells?
They are specialized cells of the electrical conduction system and they are responsible for spontaneous generation/conduction of electrical impulses.
What are the 4 properties of the cardiac cells?
What is the purpose of excitability?
Muscles cells can respond to outside stimilus
What is the purpose of automaticity?
pacemaker cells spontaneously initiate an electrical impulse w/out being stimulated from another source
What is the purpose of conductivity?
Cardiac cells can receive an electrical stimulus and conduct it to adjacent cardiac cells
What is the purpose of Contractility?
muscle contraction in response to electrical stimulus
EKG paper small boxes
EKG paper large bozes
0.20 seconds (made up of 5 small squares)
What is happening in the cardiac cells when the heart is firing?
It is exchanging CA+ and NA+ in and out of the cells
- Atrium firing
- onset of P wave to onset of QRS complex
- 0.12-0.20 seconds long
- Ventricles firing (depolarization)
- Follows each P wave
- spread of electrical impulse through the ventricles
- 0.04-0.12 seconds
- begins w/ the end of the QRS complex
- ends w/ onset of the T wave
- on the same line as the PR interval
- represents ventricular repolarization
- beginning of T wave is the point where the slope of the ST segment appears to become steeper
- ends when it returns to baseline
what does a Depressed ST segment represent?
Myocardial ischemia (lack of blood flow)
what does an elevated ST segment represent?
myocardial injury (pericarditis)
What are two ways to calculate heart rate?
- 1500/#of small boxes
- 10 x # of R complexes in a 6 sec strip
What are SA node arrhythmias?
Bradycardia and tachycardia
What are Atrial tissue arrhythmias?
Flutter and Fibrillation
What are AV node arrhythmias?
Blocks and junctional
What are ventricular tissue arrhythmias?
Tachycardia and fibrillation
what can Tachy-arrhythmias affect?
- coronary artery blood flow occurs during diastole
- shorter diastolic time= decreased coronary artery perfusion time
- increased workload of heart, increased myocardial O2 demand
- CAD (decreased blood flow)
What are some causes of sinus tachycardia?
- Increased CNS response: Fever, pain, anxiety, anemia, meds
- Compensatory: hypovolemia
What are some interventions for sinus tachycardia?
- Goal: decrease HR to normal
- Aspirin, Beta blockers, ACE inhibitors, CA+ channel blockers
What can Brady-arrhythmias affect?
- decreased myocardial O2 demand
- prolonging of diastole
- coronary perfusion pressure may decrease if HR is too slow to provide adequate CO and BP
- May lead to MI if BP isn't adequate
What are some causes of sinus bradycardia?
- PNS dominant: Excessive vagal (Valsalva) stimulation to heart
- Decreased SA node discharge=decreased HR, and conduction
What are some interventions to sinus bradycardia?
- volume replacement
- pacemaker placement
what are some causes of atrial flutter?
- AV node selectively blocks # of impulses that reach ventricles
- Rheumatic Heart disease, CHF, AV valve disease, post cardiac surgery
what are some Interventions for atrial flutter?
- Amiodarone, Cardizem, verapalim
What are some causes of A-Fib?
- aging, MI, HR, MS, Cardiomyopathy
- can lead to formation of multiple thrombi in cardiac champers (Stroke, DVT, atrial thrombi)
What are some interventions for A-Fib?
- if initial A-Fib is < 48 hrs: decrease ventricular response and convert to NSR
- if > 48 hrs: anticoagulant therapy
- Beta blockers, CA+ channel blockers, antiarrhythmics, cardioversion
What are some symptoms of A-Fib?
- SOB, Fatigue, weakness, distended neck veins, anxiety, syncope, palpitations, chest discomfort, irregular pulse
What are some things that can cause PVCs?
- Aging, MI, HF, caffeine, decreased K+
- can be a warning sign of new onset VT, VF, R on T phenomenon
What are some interventions for PVCs?
- O2, antiarrhythmics (lidocaine)
- MONA (morphine, O2, Nitro, Aspirin)
What are some things that can cause V-TACH?
- Acute MI, CAD, K+ imbalance
- decreased QT interval, cardiac surgery
- digoxin toxicity
What are some interventions for V-Tach?
Sustained: O2, EKG, antiarrhythmics (amiodarone), cardioversion
Unstable: Emergency cardioversion, O2, antiarrhythmics
Pulseless: Defibrillation (Epinephrine/Defibrillator)
With pulse: Adenosin and Defibrillator
What are some causes of V-FIB?
- Acute MI, decreased K+, decreased Mg
- (ventricles quiver, consume lots of O2, No CO, no perfusion)
What are some interventions for V-FIB?
- amiodarone, lidocaine, Magnesium sulfate (for hypomagnesemia or Torsades de pointes)
What are some causes of Asystole?
- no electrical impulses, no depolarization, No CO, no VS, no impulses reach ventricles if SA node fires
- Cardiac arrest, unresponsive
What is Cardioversion?
- Timed (shocks on R wave) electrical current.
- syncronizes w/ EKG so it discharges during V depolarization
What is defibrillation?
- trx of choice for pulseless VT and V-Fib
- electrical current is not timed
- current discharges immediately when charged
What are heart blocks?
delay in the conduction of the impulse through the AV node
What is a 1st degree AVB?
- PR interval >0.20 seconds
- All impulses reach ventricles
What is a 2nd degree type 1
- each impulse takes longer to conduct until one is blocked and a QRS is dropped followed by a pause
What is a 2nd degree type 2
- Impulses are dropped at a regular interval causing dropped QRS compleses
What is a 3rd degree AVB?
- none of the atrial impulses reach the ventricles
- atria and ventricles are divorced
- results in inadequate CO
- requires a pacemaker