what is an EKG?
graphic representation of the electrical currents of the heart
what is the function of a 12 lead EKG?
used to diagnose dysrhythmias, conduction abnormalities, and chamber enlargement
what is the standards of care for patients who are at high risk of dysrhythmias?
continuous EKG monitoring
what are the two types of continuous EKG monitoring?
hardwire cardiac monitoring (ED, critical care, progressive care)
telemetry (acute care, outpatient)
what is the function of hardwire cardiac monitoring?
used to continuously observe the heart for dysrhythmias and conduction disorders using 1 or 2 EKG leads
what is telemetry?
the transmission of radio waves from a battery operated transmitter to a central bank of monitors
what is the benefit of telemetry?
system is wireless
transmitter can be placed in a pouch and worn around the neck
batteries must be changed every 24 to 48 hours
what are the 2 leads that are most often selected for continuous EKG monitoring?
leads 2 and 5(1)
what does lead 2 provide?
the best visualization of atrial depolarization (represented by the p wave)
what does lead 5(1) provide?
best records ventricular depolarization and is most helpful when monitoring for certain dysrhythmias
what is ambulatory electrocardiography?
form of continuous or intermittent ECG home monitoring
what is the procedure for applying electrodes?
D�bride the skin surface of dead cells with soap and water; dry well using a wash cloth or gauze
Clip (do not shave) hair from around the electrode site, if needed.
Connect the electrodes to the lead wires prior to placing them on the chest (connecting le
what is ablation?
it is the purposeful destruction of heart muscle cells, usually in an attempt to correct or eliminate a dysrhythmia
what is artifact?
distorted, irrelevant, and extraneous electrocardiographic (ECG) waveforms
what is automaticity?
ability of the cardiac cells to initiate an electrical impulse
what is cardiac resynchronization therapy?
biventricular pacing used to correct interventricular, intraventricular, and atrioventricular conduction disturbances that occur in patients with heart failure
what is cardioversion?
electrical current given in synchrony with the patient's own QRS complex to stop a dysrhythmia
what is chronotropy?
rate of impulse formation
what is conduction?
transmission of electrical impulses from one cell to another
what is defibrillation?
electrical current given to stop a dysrhythmia, not synchronized with the patient's QRS complex
what is depolarization?
process by which cardiac muscle cells change from a more negatively charged to a more positively charged intracellular state
what is dromotropy?
conduction velocity
what is a dysrhythmia?
disorder of the formation or conduction (or both) of the electrical impulse within the heart, altering the heart rate, heart rhythm, or both and potentially causing altered blood flow
what is an elective replacement indicator?
a signal produced by a pacemaker when it is interrogated to indicate a near-depleted battery
what is an implantable cardioverter defibrillator?
a signal produced by a pacemaker when it is interrogated to indicate a near-depleted battery
what is inotropy?
force of contraction
what is p wave?
the part of an ECG that reflects conduction of an electrical impulse through the atrium
atrial depolarization
what is the PR interval?
the part of an ECG that reflects conduction of an electrical impulse from the sinoatrial node through the atrioventricular node
what is the QRS complex?
the part of an ECG that reflects conduction of an electrical impulse through the ventricles; ventricular depolarization
what is QT interval?
the part of an ECG that reflects the time from ventricular depolarization through repolarization
what is repolarization?
process by which cardiac muscle cells return to a more negatively charged intracellular condition, their resting state
what is the ST segment?
the part of an ECG that reflects the end of the QRS complex to the beginning of the T wave
what is the t wave?
the part of an ECG that reflects repolarization of the ventricle
what is the R to R interval?
the duration between the beginning of one QRS complex and the beginning of the next QRS complex; used to calculate ventricular rate and rhythm
what is the u wave?
the part of an ECG that may reflect Purkinje fiber repolarization; usually, it is not seen unless a patient's serum potassium level is low
what is the rate of the SA node?
60 to 100 bpm
what is the heart rate influenced by?
autonomic nervous system which consists of parasympathetic and sympathetic fibers
what is a lead?
an imaginary line that serves as a reference point from which the electrical activity is viewed
what are the locations of the leads for a 12 lead EKG?
right upper extremity
right lower extremity
left upper extremity
left lower extremity
V1
V2
V3
V4
V5
V6
where is V1 placed?
4th intercostal space at the right sternal border
where is V2 placed?
4th intercostal space at the left sternal border
where is V3 placed?
Midway between V2 and V4
where is V4 placed?
5th intercostal space at the left midclavicular line
where is V5 placed?
left anterior axillary line at the same horizontally plane as V4
where is V6 placed?
left midaxillary line at the same horizontal plane as V4
what is the normal p wave?
less than 0.08 seconds
what is the normal QRS complex?
less than 0.12 seconds
what is the normal PR interval?
0.12 to 0.20 seconds
how do you determine the heart rate from an electrocardiogram?
count RR interval and multiple by 10
count the number of small boxes within an RR interval and divide 1,500 by that number
what is electrocardioversion?
the delivery of a timed electrical current to terminate a dysrhythmia
the defibrillator is set to synchronize with the ECG on a cardiac monitor so that the electrical impulse discharges during ventricular depolarization (QRS complex
The synchronization pr
when is defibrillation used?
emergency situations as the treatment of choice for ventricular fibrillation and pulseless ventricular tachycardia
what is an electrophysiology study?
invasive procedure used to evaluate and treat various chronic dysrhythmias that have caused cardiac arrest or significant symptoms
what is the purpose of an electrophysiology study?
Identify the impulse formation and propagation through the cardiac electrical conduction system
Assess the function or dysfunction of the SA and AV nodal areas
Identify the location (called mapping) and mechanism of the dysrhythmogenic foci (the exact sit
what is a pacemaker?
an electronic device that provides electrical stimuli to the heart muscle
what are the two components of pacemakers?
an electronic pulse generator and pacemaker electrodes
what are the first EKG signs of an acute MI?
changes in the t wave and st segment
what is a key indicator for a myocardial infarction?
st segment elevation
abnormal Q waves
what is an unstable angina?
The patient has clinical manifestations of coronary ischemia, but ECG and cardiac biomarkers show no evidence of acute MI
what is a STEMI?
The patient has ECG evidence of acute MI with characteristic changes in two contiguous leads on a 12-lead ECG. In this type of MI, there is a significant damage to the myocardium
what is a NSTEMI?
The patient has elevated cardiac biomarkers (e.g., troponin) but no definite ECG evidence of acute MI. In this type of MI, there may be less damage to the myocardium
what is the AV node rate?
40 to 60 bpm
what is the purkinje fiber rate?
20 to 40 bpm
what are the indications for cardiac pacing?
severe bradycardia with hemodynamic instability that is not responsive to atropine
symptomatic bradycardia
high degree of heart block
sinus arrest
what are the symptoms of sinus bradycardia?
syncope
dizziness
fatigue
shortness of breath
chest pain
confusion
how does a pacemaker work?
An electronic device that provides an electrical signal to make the heart beat when it's own pacemaker fails
what are the key functions of a pacemaker?
Senses the patient's own rhythm using a sensing circuit. "Sensing"
Sends out electrical signals using an output circuit. "Capturing
what is a transvenous pacemaker?
called endocardial pacing, is a potentially life-saving intervention used primarily to correct profound bradycardia
what is a transthoracic pacemaker?
an artificial cardiac pacemaker of which the electrodes for delivering rhythmic electric stimuli to the heart are placed on the chest wall
how do you pace on a defibrillator?
Pacer Button
Choose Rate
Then increase the current till "capture" then 5-10
Use pause button to check underlying rhythm
what are the characteristics for output failure for pacemakers?
output failure occurs when apaced stimulus is not generated in a situation where expected
results in decreased or absent pacemaker function
multiple causes including oversensing, wire fracture, lead displacement, or interference
what are the characteristics of failure to capture in pacemakers?
failure to capture occurs when paced stimulus does not result in myocardial depolarization
multiple causes including electrode displacement, wire fracture, electrolyte disturbances, MI or exit block
what is an automatic implantable cardioverter defibrillator?
a device implantable inside the body, able to perform cardioversion, defibrillation, and pacing of the heart
what are the indications for an AICD?
Heart failure
VT/VF
Sudden Cardiac Death
what are the precautions for a pacemaker or AICD?
No raising elbow above shoulder for 2 months
No heavy lifting
Microwaves do not impact
Can go through security detectors
No MRI
Cell phones 6 in away (not in breast pocket)
Notify MD or dentist for any procedures
No Transcutaneous electrical nerve stimula
what are different drug therapies that can be used for acute coronary syndrome?
oxygen
aspirin
nitroglycerin
opiates
fibrinolytic therapy
heparin
additional agents: beta blockers, ADP antagonists, ACE inhibitors, HMG-Coa reductase inhibitors, glycoprotein inhibitors
what is the pathophysiology of acute coronary syndrome?
unstable plaque
plaque rupture
unstable angina
microemboli
occlusive thrombus
what are the signs and symptoms of ACS?
uncomfortable pressure, fullness, squeezing, or pain in the center of the chest lasting several minutes
chest discomfort spreading to the shoulders, neck, arm, or jaw
chest discomfort spreading to the back or shoulder blades
light headedness, dizziness, f
when should oxygen be administered for acute coronary syndrome?
dyspneic
hypoxic
obvious signs of heart failure
SpO2 less than 90%
oxygen saturation is unknown
what is the dose of aspirin for acute coronary syndrome?
a dose of 160 to 325 mg of non-enteric coated aspirin causes immediate and neartotal inhibition of thromboxane a2 production by inhibiting cox 1
what should be done if the patient has not taken aspirin and has no history of true aspirin allergy and no evidence of recent gi bleeding during an acute coronary syndrome?
give the patient to aspirin to chew
what should be done if the patient is experiencing nausea, vomiting, peptic ulcer disease, or other disorders that cause bleeding during an acute coronary syndrome?
rectal aspirin suppositories (300 mg)
what is the administration of nitroglycerin for acute coronary syndrome?
give 1 sublingual tablet every 3 to 5 minutes for a total of 3 doses
what are the precautions for nitroglycerin?
inferior wall MI and RV infarction
hypotension, bradycardia, or tachycardia
recent phosphodiesterase inhibitor use
what are the characteristics for nonsteroidal anti-inflammatory drugs during an acute coronary syndrome?
contraindicated and should be discontinued because increase risk for mortality, reinfarction, hypertension, heart failure, and myocardial rupture
what is at the center of the decision pathway in the management of ischemic chest discomfort and is the only means of identifying STEMI?
12 lead ecg
what is the goal of reperfusion for a STEMI?
give fibrinolytics within 30 minutes of arrival or perform PCI within 90 minutes of arrival
what should be included in the first 10 minutes of assessment for acute coronary syndrome?
vitals signs and oxygen saturation
establish IV access
history and physical exam
fibrinolytic checklist
obtain a blood sample for cardiac markers
obtain and review x-ray
what is the major contraindication for morphine and nitroglycerin?
hypotension
what is the mainstay treatment for a STEMI?
early reperfusion therapy with primary PCI or fibrinolytics
what are the 4 D's for acute coronary syndrome?
door
data
decision
drug
For PCi what is the door to balloon inflation time?
90 minutes
what is the most commonly used form of PCI?
coronary intervention with stent placement
what does the inappropriate dosing and monitoring of heparin therapy caused?
excess intracerebral bleeding and major hemorrhage in STEMI patients
what are the indications for initiation of IV nitroglycerin in STEMI patients?
recurrent or continuing chest discomfort unresponsive to SL or spray nitroglycerin
pulmonary edema
hypertension
what is the shock for a monophasic defibrillator?
single 360 J shock
what is the shock for a biphasic defibrillator?
initial dose of 120 to 200 J
what is the most effective way to treat ventricular fibrillation?
electrical defibrillation
what is a rhythm check?
the pause in chest compressions to check the rhythm should not exceed 10 seconds
why is epinephrine used during resuscitation?
vasoconstriction
what is transcutaneous pacing?
delivers pacing impulses to the heart through the skin by use of cutaneous electrodes
what are the indications for transcutaneous pacing?
hemodynamically unstable bradycardia
unstable clinical condition likely due to bradycardia
bradycardia with symptomatic ventricular escape rhythms
what are the contraindications for transcutaneous pacing?
severe hypothermia and is not recommended for asystole
what are the precautions for transcutaneous paicng?
conscious patients require analgesia for discomfort
do not assess the carotid pulse to confirm mechanical capture
what is the procedure for transcutaneous pacing?
place pacing electrodes on the chest according to package instructions
turn the pacer on
set the demand rate to approximately 60/minute (can be adjusted once pacing is established)
set the current milliamperes output 2 mA above the dose at which consisten
What is unsynchronized cardioversion?
the electrical shock will be delivered as soon as the operator pushes the shock button to discharge the device
what is synchronized cardioversion?
uses a sensor to deliver a shock that is synchronized with a peak of the QRS complex which may cause a delay until it is synchronized
when are synchronized cardioversion shocks recommended?
unstable SVT
unstable atrial fibrillation
unstable atrial flutter
unstable regular monomorphic tachycardia with pulses
when are unsynchronized cardioversion shocks recommended?
for a patient who is pulseless
for a patient demonstrating a clinical deterioration
when you are unsure whether monomorphic or polymorphic vt is present
what is the energy dose for a monophasic cardioversion?
deliver an initial 200 J synchronized shock
what is the energy dose for a biphasic cardioversion?
deliver an initial 120 to 200 J synchronized shock
what is the energy dose for a monophasic or biphasic waveform for cardioversion of atrial flutter or SVT?
50 to 100 J
what is the energy dose for unstable monomorphic VT?
100 J
what is the procedure for cardioversion?
sedate all conscious patients
turn of defibrillator
attach monitor leads to patient and ensure display of rhythm
press the sync control
look for markers on r wave
select the appropriate energy levels
clear team members and charge defibrillator
press the c