N3276 - Cardiac Dysrhythmias and ECG Interpretation | Telemetry

horizontal axis

time (seconds); small box: 0.04 seconds, large box: 0.20 seconds

vertical axis

voltage (millivolt); small box: 0.1 millivolt; large box: 0.20 millivolt

P wave

atrial depolarization

normal P wave measurement

<0.12 seconds; round, upright, symmetrical

PR interval

time for impulse to travel from SA node through AV node; measured from the beginning of the P wave to beginning of QRS complex

normal PR intervaal

0.12 to 0.20 seconds

QRS complex

ventricular depolarization

normal QRS measurement

0.04 to 0.10 seconds; nice, neat, narrow; measured to J-point

U wave

thought to represent repolarization of Purkinje fibers; may or may not be present

ST segment

early ventricular repolarization; ventricles have fully contracted; elevation or depression may indicate injury or ischemia

ST segment elevation

J point is above isoelectric line; represents injury

ST segment depression

J point is below isoelectric line; represents ischemia

T wave

ventricular repolarization; relative refractory period

QT interval

total time for ventricular depolarization and repolarization; lethal if prolonged

normal QT measurement

0.35 to 0.45 seconds

six second method

count the number of QRS complexes in a 6 second strip and multiply by 10

normal sinus rhythm

rate: 60-100 bpm

rhythm: regular

P waves: upright, consistent

PR interval: 0.12-0.20 seconds

QRS duration: <0.10 seconds

sinus bradycardia

rate: <60 bpm

rhythm: regular

P waves: upright, consistent

PR interval: 0.12-0.20 seconds

QRS duration: <0.10 seconds

management of sinus bradycardia

asymptomatic - observe

symptomatic - atropine, dopamine, epinephrine; pacing

sinus tachycardia

rate: >100 bpm

rhythm: regular

P waves: upright, consistent

PR interval: 0.12-0.20 seconds

QRS duration: <0.10 seconds

management of sinus tachycardia

check the patient, treat the underlying cause

atrial flutter

rate: atrial - 220-325 bpm ; ventricular - 75-150 bpm

rhythm: regular

P waves: flutter, sawtooth pattern (should outnumber the QRS complexes)

PR interval: not measureable

QRS duration: <0.10 seconds

management of atrial flutter

cardioversion if unstable, anticoagulants, beta blockers

atrial fibrillation

rate: atrial - 300-400 bpm, ventricular: rapid, variable

rhythm: irregular

P waves: not identifiable

PR interval: not measurable

QRS duration: <0.10 seconds

management of atrial fibrillation

check the patient, treat the underlying cause; main goal: rate and rhythm control

rate control - beta blockers, calcium-channel blockers, digoxin

rhythm control - synchronized cardioversion, pharmacologic cardioversion - amiodarone

supraventricular tachycardia

rate: >150 bpm

rhythm: regular

P waves: usually not visible

PR interval: not measurable

QRS duration: <0.10 seconds

management of supraventricular tachycardia

stable - vagal maneuver, IV adenosine

unstable - synchronized cardioversion, IV beta blockers, IV diltiazem, IV verapamil

premature ventricular complex

rate: depends on underlying rhythm

rhythm: regular

P waves: may be absent

PR interval: <0.12 seconds

QRS duration: >0.12 seconds, wide, bizzare, abnormal

bigeminy

every other complex is premature

couplet

two sequential complexes

run

three or more successive PVCs (Vtach)

multifocal

PVCs that differ in size, shape, and direction

R-on-T phenomenon

PVC occurring on or near T wave

management of PVCs

treat underlying cause (stimulants, cardiac ischemia, hypoxia, etc.)

ventricular tachycardia

rate: 100-250 bpm

rhythm: regular

P waves: not visible

PR interval: none

QRS duration: >0.12 seconds, wide and bizzare

management of ventricular tachycardia

ensure patient has a pulse; correct H+T's, IV amiodarone if stable, synchronized cardioversion if symptomatic

ventricular fibrillation

rate: cannot be determined

rhythm: irregular

P waves: not visible

PR interval: not visible

QRS duration: not visible

no cardiac output, no pulse

management of pulseless V-tach or V-fib

CPR, defibrillation, IV epi, establish an airway

asystole

no pulse, no waveforms, absence of cardiac electricity

management of asystole

CPR,, identify underlying cause, correct H and T's

pulseless electrical activity (PEA)

organized electrical activity present on the cardiac monitor, but there is a mechanical failure of the heart

patient has NO PULSE, NOT BREATHING, UNCONSCIOUS

management of PEA

CPR, ABCs, identify and treat causes

first degree AV block

atrial conduction delayed through AV node, prolonged PR interval

rate: depends on underlying rhythm

rhythm: regular

P waves: present before each QRS, consistent in size and shape

PR interval: >0.20 seconds

QRS duration: <0.10 seconds

first degree AV block poem

If the R is far from P, then you have a FIRST DEGREE

second degree type 1 AV block (Wenckebach)

repeating pattern where all but one of a series of atrial impulses are conducted through AV node;

each impulse takes a longer time for conduction than the one before, until one is blocked

second degree type 1 AV block poem

Longer-longer-longer-dropped! Now you have a Wenckebach!

second degree type 2 AV block (Mobitz II)

only some of the atrial impulses are conducted through AV node into the ventricles

PR interval: consistent until a QRS is dropped

P waves not followed by a QRS

third degree AV block

no atrial impulse is conducted through the AV node into the ventricles

two separate impulses are happening at the same time

third degree AV block poem

If P's and Q's don't agree, then you have a THIRD DEGREE

atrial pacing

pacer spike happens immediately before p wave

ventricular pacing

pacer spike happen immediately before QRS

failure to sense

pacer fails to sense patient's own intrinsic beat and fires causing competition problems

failure to capture

pacer spike occurs but no depolarization of muscle detected with QRS complex