ECG Cheat Sheet
The typical EKG waveform
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Sinoatrial (SA) node in __________ ______________ generates a rhythmical
depolarization (firing frequency)
Modified by stimulation from nerves from the brain
o Sympathetic - increases firing frequency (_____________) in response to:
 Exercise
 Anxiety, stress
 ________________, certain medications, adrenaline
o Para-sympathetic - slows the firing frequency (_____________________)
 Breathing (sinus arrhythmia) - rate decreases following prolonged
expiration
 ________________ - reflex tachycardia occurs to correct transient
drop in blood pressure
 Certain medications
Depolarization causes right atrium to contract (P-wave, _________ms)
Stimulates Atrio-ventricular (AV) node, which fires in turn
Passes down right and left bundles in septum (Q-wave, _______________ms)
Depolarizes right and left ventricles, which now contract (________, 240-350ms)
Signal voltage 1 to 10 mV, frequency 0.67 to 40-Hz
ECG Leads
These are what detect the electrical signal of the heart
6 leads are called ________________ Leads and are placed as follows:
The additional 6 leads are called __________________ Leads and are placed in different
areas according to what is going on with the heart. They make be placed on the arms and
legs, or chest.
Disorders of the Heart
 Ischemic Heart Disease (IHD)
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_______________ of coronary arteries supplying the myocardium (heart muscle)
Caused by smoking, high fat diet, _____________ (high blood pressure), diabetes
EKG shows ________ depression
Can be treated by angioplasty, coronary artery bypass graft (CABG)
 Angina
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Spasm of sclerotic coronary artery
Causes chest pain reversed by nitroglycerine (nitro spray under tongue)
Unstable (recurring) angina indicates impending ____________________
 Myocardial Infarction (MI, heart attack)
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_____________________________ of coronary artery
Causes chest pain which is ______ reversed by nitro
Diagnose by EKG (ST _________________, T-wave inversion)
Complications: arrhythmia, cardiac failure
Treatment: morphine, aspirin, monitor for complications, thrombolysis
 ________________________________
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Irregular heart rhythm, e.g. atrial fibrillation (AF), heart block, ventricular
fibrillation (VF), supraventricular tachycardia (SVT)
Treatment
o digoxin for AF
o atropine, pacemaker for bradycardias
o VF (may cause sudden death) - treat quickly with electroshock
(defibrillator) and chest compressions
 Cardiac Failure (heart failure)
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Reduced cardiac output (pump failure) due to weakened ____________________
May be acute (complicating myocardial infarction) or chronic (chronic IHD)
Kidneys retain sodium and water - results in pulmonary ________ (fluid in lungs)
Treated with diuretics
Normal ECG
Heart Blockage – long ___________ interval
Severe Heart Blockage – two _____ Waves per QRS Complex
________________________ – flat line
Bradycardia -- Normal P, QRS, T, rate < _________________
Hypercalcemia -- Short/absent _______ segment
Hyperkalemia -- _____________-shaped Twave
Idioventricular Rhythm (IVR) -- No ____________, bizarre QRS, rate 20-40
Premature Atrial Contraction (PAC) -- ______________ Pwave, irregular P-P interval
Premature Ventricular Contraction (VAC) – Wide ____________, unrelated to Pwave
Tachycardia -- Normal P, QRS, T, rate > _________________
Ventricular Fibrillation (VFIB) -- _______________ waves
Ventricular Tachycardia (VTAC) -- Bizarre, wide QRS, no __________, rate > 100
To help you study these:
http://www.gwc.maricopa.edu/class/bio202/cyberheart/ekgqzr0.htm
For a really cool website of heart sounds: http://www.med.ucla.edu/wilkes/inex.htm