3 lead ecg Flashcards
what is included in the 8 methods of ecg interpretation?
- determine the rhythm-is it regular?
2.determine the rate. what is the heart rate. - assess the P waves. are they present? does every QRS have a P wave? are they all similar shapes and sizes?
- assess the PR interval duration.
- assess QRS complex. is the QRS between 0.04-0.12 seconds.
are the QRS complexes the same size and shape.
is there a QRS after every p wave. - assess the T waves. are they present, normal shape, same amplitude
- assess the duration of the QT interval. is it between 0.36-0.44 seconds?
QT is affected by the heart rate the quicker the heart the shorter QT interval. - evaluate the rest? is there a u wave present?
what is included in a normal sinus rhythm?
PR is between 120-2200ms
QRS is less than 120ms
QRS is positive in lead 1 and 2
QRS and T waves have the same direction in limb leads
all waves are negative in a VR
what is sinus bradycardia? what should it treated with?
has a heart rate of less than 60 beats per minute. absolute bradycardia is a heart rate under 40 and should be treated with atropine.
what is sinus tachycardia?
rate will be over 100bpm and will be regular. the origin of the rhythm is the sinoatrial node.
what are the causes of tachycardia?
exercise, fever, stress, pain, fear and anxiety.
what are the causes of bradycardia?
sleep, being physically fit, vomiting, hypothermia, MI, medications.
what is sinus arrhythmia?
can be a normal variant and can be commonly found. rate is usually between 60-100bpm. slows down exhalation and speeds up during inhalation. irregular rhythm
what is atrial fibrillation?
caused by chaotic firing of the pacemakers cells. this rate can be fast or slow and it is irregular. has an absent P wave, has QRS complex, has a indiscernible T wave.
what are the causes of atrial fibrillation?
cardiac surgery, long term hypotension, COPD, MI, coronary artery, hypoxia, drugs.
what is the treatment of atrial fibrillation?
cardioversion, pacemaker, catheter ablation.
what is supraventricular tachycardia?
p waves are hidden in the ST segment wave
PR interval is unmeasurable
Normal QRS complex
T wave is distorted by the p wave
QT interval is short
ST depression and t wave inversion may occur with ischaemia (a condition in which blood flow (and thus oxygen) is restricted or reduced in a part of the body. )
what is a 1st degree AV block?
caused by a prolonged block in the AV node. rate is between 60-100bpm. it is regular rhythm. p waves are present, there is a p wave for every QRS complex, PR interval is greater than 0.2 seconds
what are the causes of 1st degree av block?
hyperkalemia ( a potassium level in your blood that’s higher than normal.)
what is 2nd degree av block type 1?
the rhythm is irregular with a normal rate between 60-100 beats per minute.
p waves are normal, PR interval gets progressively prolonged. QRS complex is normal but regulary drops. t waves are normal but are missing when QRS is dropped
what are the causes of a 2nd degree av block type 1
drugs such as beta blockers, calcium channel blockers, digoxin and amiodarone
inferior MI.
myocarditis (inflammation of the heart muscle)
what are signs of 2nd degree av block type 1?
dizziness, fainting, palpitations, chest pain, shortness of breath
what is a 2nd degree av block type 2?
the rhythm is either regularly irregular or irregular. missed T waves after dropped QRS. potential prolonged pr interval, occasional QRS complex missing.
what are the causes of 2nd degree av block type 2?
diseased AV node, anterior mi, some cardiac surgery, inflammatory conditions, auto immmune.
signs of 2nd degree av block type 2
dizziness, fainting, light headed, palpations, chest pain or nausea.
what is a left bundle branch block?
if the left bundle is completely blocked the electrical potential will travel down the right bundle first and then proceeds right to the left via direct cell to cell transmission.
what are the ecg changes of a left bundle branch block
QRS duration is less than 120ms. dominant s wave in V1. absence of Q waves in lateral leads. prolonged P wave
what are the causes of a left bundle branch
mi
hypertension
myocarditis (inflammation of the heart muscle)
cardiomyopathy (heart disease making it harder to pump blood)
what are the signs of a left bundle branch?
asymptomatic
fainting.
what is a right bundle branch block?
the left ventricle works as normal and the right ventricle is not directly activated by the electrical potential going through the right bundle branch
