Exam 3 AEP

normal sinus rhythm

normal rhythm that originates from the SA node with a heart rate of 60-100 BPM

what is the normal heart rate

60-100 bpm

what is the normal PR interval

0.12-0.20 sec

Normal QRS duration

0.06-0.10sec

what does the P wave represent

Atrial depolarization

what does the QRS represent

ventricular depolarization

what does the T wave represent

ventricular repolarization

what rhythm originates from the SA nide

normal sinus rhythm

normal sinus rhythm rate.

60-100 bpm.

normal sinus rhythm

regular

normal sinus rhythm p wave

present, uniform, one P for every QRS

normal sinus rhythm PR interval

0.12 - 0.20sec

normal sinus rhythm QRS

0.06 - 0.10

The PR interval is

0.12-0.20 sec

The QRS duration should be

0.06-0.10 seconds

the normal sinus rhythm originates from the

SA node

One P wave should occur before every

QRS

Rhythm analysis steps

heart rate, rhythm regularity, p waves, pr interval, qrs duration, overall interpretation

Rhythm analysis steps easy

rate, rhythm, p waves, PR, QRS, diagnosis

why is it called “sinus” rhythm

becuase the electrical impulse begins in the SA node, also called the sinus node.

ecg small box

0.04 sec

ecg large box

0.20 sec

what interval represents AV conduction

PR interval

what is an arrhythmia

any abnormality in heart rate, rhythm, or conduction

causes of arrhythmias

coronary artery disease, myocardial ischemia, electrolyte imbalances, hypoxia, certain medications, increased sympathetic stimulation, structural heart disease

what are the two main mechanisms that produce arrhythmias

abnormal impulse formation, abnormal impulse condition

causes of bradycardia

athletes, sleep, increased vagal tone, beta blockers, hypothyroidism

tachycardia causes

exercise, stress, pain, fever, anxiety

sinus arrhythmia

normal sinus rhythm but HR changes with respiration

premature atrial contraction (PAC)

an ectopic focus in the atria fires before the SA node

ECG characteristics of premature atrial contraction

early beat, abnormal p wave, narrow QRS

premature ventricular contraction (PVC)

an ectopic ventricular beat occurs before the next normal beat

ECG characteristics of premature ventricular contraction (PVC)

wide QRS, no preceding P wave, premature beat, usually followed by compensatory pause

how to recognize PVS

is there a p wave? no → is the QRS wide? yes then PVC

Atrial flutter

rapid atrial rhythm usually around 250-350 BPM

ECG apperance for atrial flutter

saw-tooth flutter waves, no distinct p waves, regular ventricular rhythm (looks like ^^^^^^^ instead of normal p waves)

atrial fibrillation (most common tested arrhythmia)

chaotic atrial electrical activity

ecg characteristics of atrial fibrillation

no p wave, irregularly irregular rhythm, variable r-r intervals

easy memory of atrial fibrillation

Everything is irregular. no organized atrial contraction

ex. (QRS~~~~~QRS~~~~~~~~~~~~QRS~~~~QRS)

Difference between flutter and fib

Flutter= saw-tooth waves, usually regular ventricular rhythm, organized atrial activity

Fib= no p waves, irregularly irregular rhythm, chaotic atrial activity

ventricular tacycardia

rapid rhythm, originates in ventricles

ecg characteristics ventricular tacycardia

HR more than 100 bpm, wide qrs, no normal p waves, regular rhythm

ventricular fibrillation

medical emergency

ecg characteristics of ventricular fibrillation

medical emergency

ECG characteristics of ventricular fibrillation

no identifiable p, QRS, or T waves just chaotic waves

ex. (~~~~~~~~~~~~~) random squiggles

asystole

no electrical activity

ECG characteristics of asytole

flat line (_________)

PVCs originate from the

ventricles

Atrial fibrillation has __ P waves

No

ventricular tachycardia usually has __ QRS complexes

wide

Atrial flutter has __ waves

saw-tooth

ventricular fibrillation has __ identifiable QRS compex

no

explain why atrial fibrillation increases stroke risk

in atrial fibrillation, the atria do not contract effectively, they quivers instead. Blood can pool in the atria, allowing clots to form. If a clot travels to the brain, it can cause a stroke

explain why PVCs have wide QRS complexes

PVCs start in the ventricles instead of following the normal conduction pathway. Because the impulses spread slowly through the ventricular muscle rather than rapidly through the purkinje fibers, the QRS complex becomes wide.

look

What is a junctional rhythm

occurs when the AV junction (av node/bundle of his region) takes over instead of the SA node

pacemaker rates

SA node= 60-100 BPM

AV junction= 40-60 BPM

Ventricles 20-40 BPM

where do junctional rhythms originate from

the av junction (av node/bundle of his region)

what is the intrinsic firing rate of the AV junction

40-60 BPM

why do junctional rhythms occur?

becuase the SA node fails to fire, fires too slowly, or the impulse is blocked, allowing the AV junction to become the pacemaker

Junctional rhythm ECG charateristics

rate: 40-60

rhythm: regular

QRS: (normal)narrow

P wave (may be): absent, inverted hidden.

why is the p wave inverted

in a junctional rhythm, the impulse starts in the AV junction and travels backwards (retrograde) through the atria. Becuase the atria are activated in the opposite direction, the P wave becomes inverted

p waves

Normal = impulse travels downward

Junctional = impulse travels backward

Backward activation = inverted P wave