ECG

ECG

a graph presentation of heart's electrical current used to identify and diagnose arrhythmias and signs of ischemia

axis

the imaginary line between two ECG leads

cardiac axis

the direction of movement of the heart's electrical current

isoelectric line

the base line on an ECG graph

12

standard number of leads on an ECG

חיבורי גפיים

4 electrodes connected to the limbs that show the electrical current from 6 directions

חיבורי חזה

6 electrodes connected to the chest that show the electrical current from 6 directions

ischemia

the 6 leads on the chest are used to diagnose ____

arrythmias

the 4 leads on the limbs are used to diagnose _____

chest and pelvis

when doing continuous monitoring of heart rate it is better to put the three leads on the ___________ instead of on the arms and leg

1mm by 1mm

size of the small ECG boxes

5

how many small boxes make one large one

1 second

5 large boxes show how much time on an ECG?

30

how many large boxes show 6 seconds of time

300/RR

equation used to check for a regular, סדיר, heart rate on an ECG

RR

the distance between one R wave to the next R wave on an ECG

amount of R waves in 6 seconds x 10

equation used to calculate an irregular, לא סדיר, heart rate on an ECG

P wave

shows atrial depolarization on the ECG

SA node

electrical currents are supposed to originate from the _____ and if they do than all the P waves should be identical

ectopic

if the P waves have an _____ origin, than there will be differences in the P waves from different leads

PR segment

shows the passage of the electrical current to the AV node where it will undergo a small pause

PR interval

shows atrial depolarization, the pause in the AV node, and the transfer of the signal to the purkinje fibers

from the P wave to the end of the PR segment

where does the PR interval stop and finish

0.12-0.2 seconds

normal amount of time for the PR interval

QRS complex

shows ventricular depolarization. Its shape will change based on which ECG lead it is showing

Q wave

this wave must be negative, it is very small and shows septum depolarization

myocardium

a large Q wave can hint to damage to the ______

R wave

this wave must be positive but can be different sizes depending on which lead is being displayed

S wave

this wave must be negative and it comes after the R wave. It is not always visible on every lead

0.04-0.1 seconds

regular span of time for the QRS complex

ST segment

it is supposed to be on the isoelectric line. and it shows early repolarization of the ventricles

factors that ST segment length depends on

heart rate, medications, electrolyte imbalances

T wave

represents ventricular repolarization. It is positive, rounded and a bit assymetrical

U wave

represents slow repolarization of the purkinje fibers

electrolyte imbalance

the U wave is generally caused by _____

QT interval

represents depolarization and repolarization of the ventricles. it is affected by age, sex, heart rate, and medications

8 steps of reading an ECG

identify heart rate, check beat regularity, check P wave, check PR interval, Check QRS complex, check ST segment, check T wave

60-100 bpm

normal heart rate

atrial beat regularity

you can check for this by measuring the PP, distance between two P waves

ventricular beat regularity

you can check for this by measuring the RR, distance between two R waves

regular irregular heart beat

when the heart beat is irregular but there is a pattern to the irregularity

is there a P wave? are they regular? are they before every QRS? are the all identical?

what to ask and check for when looking at the P wave of an ECG

is the PR interval greater than 0.2 seconds or less than 0.12 seconds? is it equidistant throughout the strip?

what to ask and check for when looking at the PR interval of an ECG

is the complex wider than 0.1 seconds? are the complexes identical throughout the strip?

what to ask and check for when looking at the QRS complex on the ECG

atria

if the QRS complex is narrow that means the electrical current originated in the ______

ventricles

if the QRS complex is wide that means the electrical current originated in the ______

raised ST segment

this can signify a myocardial infarction, pericarditis, or hyperkalemia

myocardial infarction

אוטם בשריר הלב

low ST segment

this can signify hypokalemia, cardiac ischemia, hypertrophy

half or less than half of the RR

correct length of the QT interval

normal sinus rhythm

NSR

60-100 bpm, regular rhythm, regular P waves, PR interval, and QRS complex

what is considered a NSR

sinus arrythmia

a type of NSR that is caused by changes in intrathoracic pressure during respiration

irregular rhythm, higher HR during inspiration and lower HR during expiration

what changes from NSR does a sinus arrthymia have

פעימות מוקדמות

when a pacemaker cell that isn't in the SA node sends an electrical current before the next current from the SA node

atrial, junctional, ventricular

premature signals can originate from which 3 types of origins?

premature atrial complex

narrow QRS (תקין), P wave hidden behind the T wave, slight pause after it until return to normal sinus rhythm

causes of PAC

stress, anxiety, tiredness, inflammation, addiction to caffeine or alcohol, medications, cardiac ischemia

palpitations

patients suffering from PAC will complain that they have _____

premature junctional complex

narrow QRS, no P wave or retrograde P wave,

retrograde P wave

a P wave that shows up at a later point on the ECG instead of before the QRS complex

דפיקות לב

palpitations

causes of PJC

PAC, bradycardia

palpitations

chief complaint of a PJC patient

premature ventricular complex

wide QRS, no P wave, upside down T wave

bigeminy

when every 2nd wave is PVC wave

trigeminy

when every 3rd wave is a PVC wave

quadrigeminy

when every 4th wave is a PVC wave

couplets

when the PVC waves occur in pairs

causes of PVC

cardiac ischemia, heart failure, COPD, anemia, hypoxia, hypokalemia, hypomagnesaemia, causes of PAC

treat the cause, beta blockers if it lasts more than 24 hours

treatment of a PVC

dangers of PVC

can cause an R wave to occur during a T wave, v-fib

it means the ventricles are pumping when they should be resting

why is it dangerous when an R wave occurs during a T wave

sinus tachycardia

caused by overstimulation of the SNS or a decrease in PSNS stimulation

100-160

heart rate level in sinus tachycardia

causes of ST

strenuous exercise, overactivity of the thyroid gland, medications, alcohol, dehydration, hypovolemic shock

signs of ST

will start out asymptomatic but can develop into weakness, headaches etc.

sinus tachycardia

100-160 bpm, regular rhythm, identical P waves throughout the strip and one before every QRS, shortened PR interval, normal QRS

Supraventricular tachycardia

overworking of the atria

SVT

100-280 bpm, no P wave, occurs in young and healthy people

circle of reentry

main cause of an SVT

circle of reentry

when the fast path of the AV node is an a refractory period so no electrical current can pass through it. the current from the slow path will loop back into the fast path instead of continuing down into the Bundle of Hiss

signs of SVT

palpitations, tiredness, weakness, pressure on the chest, shortness of breath

SVT

100-280 bpm, regular rhythm, no P wave, no PR interval, normal QRS

adenosine and the Valsalva maneuver

treatments of SVT

valsalva maneuver

ask the patient to squeeze their butt cheeks together as if there were trying to defecate. This causes pressure on the vagus nerve causing slowing of the AV node

adenosine

drug that stops the AV node for a few seconds so that the heart rhythm can reset and start again from the SA node

atrial fibrillation

many ectopic currents that try to pass through the atria at a rate of 300-600 bpm

a-fib

irregular heart rhythm, no clear P wave, no atrial compliance, no atrial kick, irregular ventricular beat

atrial kick

the blood that flows actively from the atria to the ventricles when they contract

signs of a-fib

tiredness, weakness, low blood pressure, palpitations

paroxysmal, persistent, long standing persistent, permanent, nonvalvular

the 5 different types of atrial fibrillation

paroxysmal a-fib

a singular occurence of a-fib that happens but then reverses back to NSR in 7 days

persistent a-fib

a-fib that lasts longer than 7 days

long lasting persistent a-fib

a-fib that lasts longer than 12 months

permanent a-fib

a-fib that the doctors decided to not intervene and switch the patient back into NSR

nonvalvular a-fib

a-fib that started after a valvular issue or after surgery to fix a valve

a-fib

300-600 bpm in the atria, 120-200 bpm in the ventricles, irregular irregular heart rhythm, no P wave, F wave, no PR interval, normal QRS

treatment of a-fib

Na channel blockers, beta blockers, amiodarone, electrical cardioversion

electrical cardioversion

synchronized electrical shock during the R wave in order to restart a NSR in patients with a new a-fib