ECG Analysis Mannual

7/28/2019 ECG Analysis Mannual

1/24

ECG ANALYSIS

Normal Electrical Conduction of the Heart:

The electrical impulse that stimulates and paces the cardiac muscle normally originates in the sinus (SA) Node .The

electrical impulse quickly travels from the sinus node through the atria to the atrio-ventricular (AV) node. The

electrical stimulation of the muscle cells of the atria causes them to contract. The structure of the AV node

slows the electrical impulse, which allows time for the atria to contract and fill the ventricles with blood. This is

called AV delay. The electrical impulse then travels very quickly through the bundle of His to the right and

left bundle branches and the Purkinjie fibers, located in the ventricular muscle. The electrical stimulation of

the muscle cells of the ventricles, in turn causes the mechanical contraction of the ventricles (systole).the cell

repolarize and the ventricles then relax (Diastole).

The electrical stimulation causes contraction is called depolarization (Systole)

The electrical relaxation is called repolarization (Diastole).

ELECTROCARDIOGRAM (ECG)

The electrical impulse that travels through the heart can be viewed by means of electrocardiography; each phase

of the cardiac cycle is reflected by specific waveforms on a strip of ECG graph.

Recording of the ECG:

Standard ECG's utilize 12 leads which are composed of 6 limb leads and 6 precordial leads (chest leads).

6 Standard Limb leads: I, II, III, aVR, aVL, and aVF.

6 Standard Precordial / Chest leads: V1, V2, V3, V4, V5, and V6.

1


2/24

Limb Leads are located on the extremities: right arm (RA), left arm (LA), and left leg (LL).

The right leg electrodes serve as aground to prevent display of background interference on ECG tracing.

Leads I, II, III are bipolar leads, using both positive and negative electrodes.

Leads aVR, aVL, and aVF are augmented unipolar leads that use the center of the heart as their negative

electrode.

2


3/24

The six standard precordial/chest leads are distributed in an arch around the left side of the chest.

Precordial or chest (Unipolar) leads:

V1 - 4th

intercostal space at Rt sternal boarder V2 - 4th

intercostal

space at Lt sternal boarder V3 - midway between V2 and V4

V4 - 5th

intercostal space in midclavicular line

V5 - 5th

intercostal space in anterior axillary line

V6 - 5th

intercostal space in midaxillary line

The positive electrode on the skin acts as a camera. If the wave of depolarization travels towards the camera,

3


4/24

positive deflection is written on the ECG paper.

If the wave of depolarization travels away from the camera negative deflection is recorded.

When depolarization travel perpendiculars to camera biphasic complex occur (isoelectric line).

The wave of ventricular depolarization in healthy heart travels from right to left and from head to toe. The

appearance of the wave form in different ECG leads will vary, depending on location of positive electrode.

4


5/24

Cardiac V ectors vs ECG

The wave of depolarization that spreads through the heart during each cardiac cycle has vector

properties defined by its direction and magnitude. At any instant depolarization occurs in multiple

directions as the activation wave is propagated. Thus the instantaneous direction of the wave recorded at

the skin surface is the resultant of multiple minivectors through the heart.

Cardiac vectors of each cardiac cycle include:

1. Atrial depolarization vector

2. Septal depolarization vector

3. Apical and early ventricular depolarization vector

4. Late ventricular depolarization vector

5. Ventricular repolarization vector

5


6/24

Interpretation of Electrocardiogram

The ECG wave form represents the function of the heart's conduction system, which normally initiates and

conducts the electrical activity, in relation to the lead.

1. ECG waveforms are printed on graph paper that is divided by light and dark vertical and horizontallines at standard intervals.

2. Time and rate are measured on the horizontal axis of the graph.

3. Amplitude or voltage is measured on the vertical axis.

6


7/24

P wave: represents the electrical impulse starting in the sinus node and spreading through the atria. Therefore,

the P wave represents atrial muscle depolarization.

- Normal P wave morphology: Upright in I, II, aVF; upright or biphasic in III, aVL, V1, V2.

- Amplitude/height: up to 2.5mm (2.5 small square)

QRS complex: Represents ventricular muscle depolarization

- Normal voltage: Amplitude of the QRS has a wide range of normal limits, depending on the lead, age of the

individual, and other factors

Q wave: The first negative deflection after the P wave

- Normal: less than 25% of the R wave amplitude

- Normal Duration: < 0.03 seconds (0.75 of one small square)

- Common in most leads, except aVR, V1-V3

R wave: the first positive deflection after the P wave

S wave: is the first negative deflection after the R wave

- When a wave is less than 5 mm in height, small letters (q, r, s) are used; when a wave is taller than 5 mm,

capital letters (Q, R, S) are used.

T wave: represents ventricular muscle repolarization

- Morphology: Upright in I, II, V3-V6; inverted in aVR, V1; may be upright, flat or biphasic in III, aVL, aVF,

V1, V2.

- Normal duration: not exceeds 0.2 sec- Normal amplitude: Usually < 6 mm in limb leads and 10 mm in precordial leads

U wave: Controversial: Afterpotentials of ventricular muscle vs. repolarization of Purkinje fibers

- Normal U wave: Not always present.

- Morphology is upright in all leads except aVR

- Amplitude is 5-25% the height of the T wave (usually < 1.5 mm= 1.5 small square)

- U waves are typically most prominent in leads V2, V3

- It sometimes is seen in patients with hypokalemia (low potassium levels), hypertension, or heart disease.

PR interval:From the beginning of the P wave to the first deflection of the QRS complex.

- PR interval represents conduction time from the onset of atrial depolarization to the onset of ventricular

repolarization

- Normal PR segment: Usually isoelectric. May be displaced in a direction opposite to the P wave

- Elevation is usually < 0.5 mm; depression is usually < 0.8 mm

ST segment:Interval between the end of ventricular depolarization (QRS complex) and the beginning of

repolarization (T wave)

- It is identified as the segment between the end of the QRS complex and the beginning of the T wave

- Normal ST segment: Usually isoelectric, but may vary from 0.5 mm below to 1 mm above baseline in limb

leads, and up to 3 mm concave upward elevation may be seen in the precordial leads in early repolarization

7


8/24

The PP interval: measured from the beginning of one P wave to the beginning of the next P wave.

Used to determine atrial rhythm and atrial rate

The RR interval: measured from one QRS complex to the next QRS complex.The RR interval is used to determine ventricular rate and rhythm

Analysis of the ECG - 5 step Method

STEP 1: Evaluate the rhythm (atrial and ventricular)

1. Compare the P-P and R-R intervals in several cycles.

2. If the P-P (R-R) intervals are consistently the same, the atrial (ventricular) rhythm is regular.

3. If the P-P (R-R) intervals are not consistently the same, the atrial (ventricular) rhythm is irregular.

4. If there is a pattern to the irregularity, the atrial (ventricular) rhythm is considered to be regularly

irregular.

STEP 2: Calculate the rate (atrial and ventricular)

There are several ways to calculate heart rate. Some are given to use with regular rhythms and one to

use with irregular rhythms.

Regular rhythms

1. Count the number of small squares between two R waves.

2. Divide the number of small squares into 1500 or

1. Count the number of large squares (one large square = 0.20 second) between two R waves.

2. Divide that number of large squares into 300

Irregular rhythms

1. Count the number of R waves in a 6 second strip and multiply by 10

2. Count the number of R waves in a 3 second strip and multiply by 20

STEP 3: Evaluate the P wave

1. Are P waves present?

2. Do the P waves have a normal shape? (Small and rounded)

3. Are all the P waves similar in size and shape?

4. Do you see a one-to-one relationship between the P waves and the QRS complexes?

STEP 4: Calculate the duration of the PR interval1. Does the duration of PR interval fall within normal limits?

8


9/24

2. Is the PR interval constant?

STEP 5: Calculate the duration of the QRS complex

1. Does the duration of the QRS complex fall within normal limits?

2. Are all the QRS complexes the same size and shape?

3. Are any QRS complexes present that appear different from the other QRS complexes on the strip?

4. Is there a QRS complex for each P wave?

Normal Sinus Rhythm

Normal sinus rhythm occurs when the electrical impulse starts at a regular rate and rhythm in the sinus

node and travels through the normal conduction pathway.

The following are the ECG criteria for normal sinus rhythm:

Ventricular and atrial rate:60 to 100 in the adult Ventricular and atrial rhythm:Regular/equal RR intervals

Regular/equal PP intervals

QRS:All QRS complex must look like (similar)QRS duration: between 0.06 - 0.10 second (1.5 to 2.5 small squares)

P wave: Present, identifiable and are of the same morphology, round in shape, and always in front of

the QRS

Duration: 0.08 - .11 seconds (3 small squares)

PR interval:Consistent intervalDuration: Between 0.12 and 0.20 seconds (3 to 5 small squares)

ST segment:isoelectric line P: QRS ratio: 1:1

Rate: 60-100 per minute

Rhythm: R- R =

P waves: Upright, similar

P-R: 0.12 -0 .20 second & consistent

qRs: 0.04 0.10 second

P:qRs: 1P:1qRs

9


10/24

CARDIAC DYSRHYTHMIAS

Cardiac Dysrhythmias: are disturbances in regular heart rate and/or rhythm due to change in electrical

conduction or refers to abnormal cardiac rhythms.

Types of Dysrhythmias:

1. Sinus node.

2. Atrial.

3. Junctional.

4. Ventricular .

10


11/24

1. Sinus Node Dysrhythmias

A. Sinus Bradycardia:

- Sinus bradycardia occurs when the sinus node creates an impulse at a slower-than-normal rate.

- Causes may include:1. Lower metabolic needs (e.g., sleep, athletic training, hypothermia,. Hypothyroidism,

2. Vagal stimulation (from vomiting, suctioning, severe pain, extreme emotions),

3. Medications (e.g., calcium channel blockers, Amiderone, beta-blockers)

4. Increased intracranial pressure and myocardial infarction (MI), especially of the inferior wall

- Characteristics of Sinus Bradycardia:

Ventricular and atrial rate: Less than 60 in the adult

Ventricular and atrial rhythm: Regular.

QRS shape and duration: Usually normal, but may be regularly abnormal -P wave: Normal and

consistent shape; always in front of the QRS

PR interval: Consistent interval, between 0.12 and 0.20 seconds

Rate: < 60

Rhythm: R- R =

P waves: Upright; similar



P:qRs: 1P:1qRs

11


12/24

B- Sinus Tachycardia:- Sinus tachycardia occurs when the sinus node creates an impulse at a faster-than-normal rate. It may be

caused by acute blood loss, anemia, shock, hypovolemia, congestive heart failure, pain, Hyper

metabolic states, fever, exercise, anxiety, or sympathomimetic medications.

- All aspects of sinus tachycardia are the same as those of normal sinus rhythm, except for the rate. As theheart rate increases, the diastolic filling time decreases, possibly resulting in reduced cardiac output and

subsequent symptoms of syncope and low blood pressure. If the rapid rate persists and the heart cannot

compensate for the decreased ventricular filling, the patient may develop acute pulmonary edema.

- Characteristics of Sinus Tachycardia:

Ventricular and atrial rate: Greater, than 100 in the adult

Ventricular and atrial rhythm: Regular

QRS shape and duration: Usually normal, but may be regularly abnormal

P wave: Normal and consistent shape; always in front of the QRS, but may be buried in the preceding T

wave

PR interval: Consistent interval between 0.12 and 0.20 second P: QRS ratio is 1:1.

Rate: > 100

Rhythm: R- R =

P waves: Upright, similar



P:qRs: 1P:1qRs

12


13/24

C. Sinus Arrhythmia:- Sinus arrhythmia occurs when the sinus node creates an impulse at an irregular rhythm; the rate usually

increases with inspiration and decreases with expiration.

- Non respiratory causes include heart disease and valvular disease, but these are rarely seen.

- Characteristics of Sinus Arrhythmia:

Ventricular and atrial rate: 60 to 100 in the adult

Ventricular and atrial rhythm: Irregular

QRS shape and duration: Usually normal, but may be regularly abnormal

P wave: Normal and consistent shape; always in front of the QRS

PR interval: Consistent interval between 0.12 and 0.20 seconds

P: QRS ratio: 1:1

- Sinus arrhythmia does not cause any significant hemodynamic effect and usually is not treated.

13


14/24

2. ATRIAL DYSRHYTHMIAS

A. Premature Atrial Complex:

- A premature atrial complex (PAC) is a single ECG complex that occurs when an electrical impulse starts in the

atrium before the next normal impulse of the sinus node.

- The PAC may be caused by caffeine, alcohol, nicotine, stretched atrial myocardium (as in hypervolemia),

anxiety, hypokalemia (Low potassium level), hyper metabolic states, or atrial ischemia, injury, or infarction.

- PACs are often seen with sinus tachycardia.

- Characteristics of PACs:

Ventricular and atrial rate: Depends on the underlying rhythm (e.g., sinus tachycardia)

Ventricular and atrial rhythm: Irregular due to early P waves, creating a PP interval that is shorter than

the others. This is sometimes followed by a longer-than-normal PP interval, but one that is less than

twice the normal PP interval. This type of interval is called a non-compensatory pause.

QRS shape and duration: The QRS that follows the early P wave is usually normal, but it may be

abnormal (aberrantly conducted PAC), or it may even be absent (blocked PAC).

P wave: An early and different P wave may be seen or may be hidden in the T wave; other P waves in

the Strip are consistent.

PR interval: The early P wave has a shorter-than-normal PR interval, but still between 0.12 and 0.20

seconds.

P: QRS ratio is usually 1:1.

Rate: usually < 100, dependent on underlying rhythm

Rhythm: irregular

P waves: Early & upright, different from Sinus

PR: 0.12 0.20 second; different from Sinus


P:qRs = 1:1

14


15/24

B. Atrial Flutter:

- Atrial flutter occurs in the atrium and creates impulses at an atrial rate between 250 and 400 times per minute.

- Because the atrial rate is faster than the AV node can conduct, not all atrial impulses are conducted into the

ventricle, causing a therapeutic block at the AV node. This is an important feature of this dysrhythmia. If all atrial

impulses were conducted to the ventricle, the ventricular rate would also be 250 to 400, which would result in

ventricular fibrillation, a life-threatening dysrhythmia.

- Atrial flutter can cause serious signs and symptoms, such as chest pain, shortness of breath, and low blood

pressure.

- Characteristics of Atrial Flutter:

Ventricular and atrial rate: Atrial rate ranges between 250 and 400; ventricular rate usually ranges

between 75 and 150.

Ventricular and atrial rhythm: The atrial rhythm is regular; the ventricular rhythm is usually regular but

may be irregular because of a change in the AV conduction.

QRS shape and duration: Usually normal, but may be abnormal or may be absent.

P wave: Saw-toothed shape. These waves are referred to as F waves.

PR interval: Multiple F waves may make it difficult to determine the PR interval.

P: QRS ratio: 2:1, 3:1, or 4:1

Rate: Atrial rate 250-350 Vent 150 common

Rhythm: Atrial = Regular

Vent = Reg. or irreg P waves: Not identifiable

F waves: Uniform (sawtooth or picket fence )

PRI: not measurable


-

15


16/24

C. Atrial Fibrillation:

- Atrial fibrillation causes a rapid, disorganized, and uncoordinated twitching of atrial musculature.

- It may start and stop suddenly.

- Atrial fibrillation may occur for a very short time (paroxysmal), or it may be chronic.

- Atrial fibrillation is usually associated with advanced age, valvular heart disease, coronary artery disease,

hypertension, cardiomyopathy, hyperthyroidism, pulmonary disease, acute moderate to heavy ingestion ofalcohol ("holiday heart" syndrome), or the aftermath of open heart surgery.

- A rapid ventricular response reduces the time for ventricular filling, resulting in a smaller stroke volume.

Because this rhythm causes the atria and ventricles to contract at different times, the atrial kick (the last part of

diastole and ventricular filling, which accounts for 25% to 30% of the cardiac output) is also lost. This leads to

symptoms of irregular palpitations, fatigue, and malaise.

- Characteristics of Atrial Fibrillation:

Ventricular and atrial rate: Atrial rate is 300 to 600. Ventricular rate is usually 120 to 200 in untreated

atrial fibrillation

Ventricular and atrial rhythm: Highly irregular QRS shape and duration: Usually normal, but may be

abnormal P wave: No discernible P waves; irregular undulating waves are seen and are referred to as fibrillatory or f

waves

PR interval: Cannot be measured

P: QRS ratio: many: l

Rate: Atrial: 400-700 Vent. 160-180/minute

Rhythm: Atrial: irregular; Vent.: irregular

P waves: No identifiable Ps

f waves: may be seen.

PRI: unable to measure (No identifiable P) qRs: usually normal

16


17/24

3. Ventricular Dysrhythmias

A. Premature ventricular contraction (PVC):- Its a single ectopic impulse originates from any ectopic focus in the ventricles, and therefore it may take

unlimited number of shapes and patterns.

- It is a relatively common happened when the impulse is in initiated by the ventricles rather than by the SA

node.

- A PVCs may be perceived as a "skipped beat" or felt as palpitations in the chest.

- In a normal heartbeat, the ventricles contract after the atria have helped to fill them by contracting; in this way

the ventricles can pump a maximized amount of blood both to the lungs and to the rest of the body.

- In a PVC, the ventricles contract first, which means that circulation is inefficient. However, single beat PVC

arrhythmias do not usually pose a danger and can be asymptomatic in healthy individuals, it happened more

frequent in the elderly

- Possible causes: Ischemia, Certain medicines such as digoxin, which increases heart contraction, Myocarditis,

Hypoxia, Smoking; and electrolyte imbalance.

- Characteristics of PVC:

Rate: Dependent upon underlying rhythm

Rhythm: R R P waves: Usually absent, if present, not associated with PVC

qRs: 0.12 second or greater (wide); bizarre and notched

ST & T: Often opposite in direction to the qRs.

Morphology:

Similar shape = Uniformed, if PVC originates from the same irritable focus it will take the same

shape

Different shape = Multiformed, if PVC originates from various foci it will take different shapes, it is

more dangerous than uniformal

Pattern:

When PVC follows each normal beat it is called ventricular bigemeny (every other). If PVC follows every two normal beat it is called ventricular trigeminy (every third).

Location: R on T = PVC falls on the T wave of the complex before the PVC

Timing:

One on a strip = Rare

One in a row = Isolated

Two in a row = Pair, couplet

Three in a row = V Tachycardia

17
http://en.wikipedia.org/wiki/Ventricle_(heart)http://en.wikipedia.org/wiki/Sinoatrial_nodehttp://en.wikipedia.org/wiki/Palpitationshttp://en.wikipedia.org/wiki/Arrhythmiahttp://en.wikipedia.org/wiki/Digoxinhttp://en.wikipedia.org/wiki/Hypoxia_(medical)http://en.wikipedia.org/wiki/Ventricle_(heart)http://en.wikipedia.org/wiki/Sinoatrial_nodehttp://en.wikipedia.org/wiki/Palpitationshttp://en.wikipedia.org/wiki/Arrhythmiahttp://en.wikipedia.org/wiki/Digoxinhttp://en.wikipedia.org/wiki/Hypoxia_(medical)


18/24

B. Ventricular Tachycardia (VT):- Ventricular tachycardia (VT) is defined as three or more PVC in row, occurring at a rate exceeding 100

beats per minute. The causes are similar to those for PVC.

- VT is usually associate d with coronary artery disease and may precede ventricular fibrillation, VT is an

emergency because the patient is usually, (although not always) unresponsive and pulseless.

- The patient's tolerance or lack of tolerance for this rapid rhythm depends on the ventricular rate andunderlying disease.

- ECG characteristics of VT:

Ventricular and atrial rate: Ventricular rate is 100 to 200 beats per minute; atrial rate depends on the

underlying rhythm.

Ventricular and atrial rhythm: Usually regular; atrial rhythm may also be regular.

QRS shape and duration: Duration > 0.12 sec (wide); bizarre.

P wave: Very difficult to detect, so atrial rate and rhythm may be indeterminable

PR interval: Very irregular, if P waves seen.

P: QRS ratio: Difficult to determine, but if P waves are apparent, there are usually more QRS

complexes than P waves.

18


19/24

Rate: > 100 per minute and usually not > 220

Rhythm: Usually regular

P Waves: No P waves or if present, not associated with qRs

qRs: Wide ( 0.12 sec), bizarre

ST/T wave: Opposite direction of qRs

C. Ventricular Fibrillation (VF):

- Ventricular fibrillation is a rapid but disorganized ventricular rhythm that causes ineffective quivering of the

ventricles. There is no atrial activity seen on the ECG.

- Causes of ventricular fibrillation are the same as for VT; it may also result from untreated or unsuccessfully

treated VT. Other causes include electrical shock

- This dysrhythmia is always characterized by the absence of an audible heartbeat, a palpable pulse, and

respirations.

- Because there is no coordinated cardiac activity, cardiac arrest and death are imminent if ventricular

fibrillation is not corrected.- ECG characteristics of Ventricular Fibrillation:

Ventricular rate: Greater than 300 per minute

Ventricular rhythm: Extremely irregular, without specific pattern

QRS shape and duration: Irregular, undulating waves without recognizable QRS complexes

19


20/24

CONDUCTION ABNORMALITIES

1. First-Degree Atrioventricular Block:

- All the atrial impulses are conducted through the AV node into the ventricles at a rate slower than normal.

- Causes: may be according to coronary artery disease,vulvular disease myocarditis,drug toxicity or

electrolyte imbalance

- ECG characteristics of 1st degree AV Block:

Ventricular and atrial rhythm: Depends on the underlying rhythm -QRS shape and duration: Usually

normal, but may be abnormal

P wave: In front of the QRS complex; shows sinus rhythm, regular shape

PR interval:greater than 0.20 seconds,PR intervals meaures is constant

P: QRS ratio: 1:1

1P : 1 qRs

Prolonged PRI (> 0.20 sec not > 0.40 sec)

20


21/24

2. Second-Degree Atrioventricular Block, Type I:

- Occurs when all but one of the atrial impulses are conducted through the AV node into the ventricles.

- Each atrial impulse takes a longer time for conduction than the one before, until one impulse is fully blocked.

- Because the AV node is not depolarized by the blocked atrial impulse, the AV node has time to fully

repolarize, so that the next atrial impulse can be conducted within the shortest amount of time.- ECG Characteristics of 2nd degree AV Block, Type I:

Ventricular and atrial rate: Depends on the underlying rhythm

Ventricular and atrial rhythm: The PP interval is regular if the patient has an underlying normal sinus

rhythm; the RR interval characteristically reflects a pattern of change. Starting from the RR that is the

longest, the RR interval gradually shortens until there is another long RR interval.

QRS shape and duration: Usually normal, but may be abnormal P wave: In front of the QRS complex;

shape depends on underlying rhythm

PR interval: PR interval becomes longer with each succeeding ECG complex until there is a P wave not

followed by QRS. The changes in the PR interval are repeated between each "dropped" QRS, creating a

pattern in the irregular PR interval measurements.

P: QRS ratio: 3:2, 4:3, 5:4, and so forth

More P waves than qRs

PRI progressively increases in a cycle until P appears w/o qRs.

Cyclic pattern reoccurs

R R

21


22/24

PR PR

3. Second-Degree Atrioventricular Block, Type II:

- Second-degree, type II heart block occurs when only some, of the atrial, impulses are conducted through the AVnode into the ventricles- ECG characteristics of 2nd degree AV Block,Type II:

Ventricular and atrial rate: Depends on the underlying rhythm

Ventricular and atrial rhythm: The PP interval is regular if the patient has an underlying normal sinus

rhythm.

The RR interval is usually regular but may be irregular, depending on the P:QRS ratio.

QRS shape and duration: Usually abnormal, but may be normal

P wave: In front of the QRS complex; shape depends on underlying rhythm.

PR interval: PR interval is constant for those P waves just before QRS complexes.

P: QRS ratio: 2:1, 3:1, 4:1, 5:1, and so forth


PRI consistent (regular)

qRs normal or wide (bundle branch block)

R - R or R R =

22


23/24

4. Third-Degree Atrioventricular Block:

- Third-degree heart block occurs when no atrial impulse is conducted through the AV node into the

ventricles.- In third-degree heart block, two impulses stimulate the heart: one stimulates the ventricles (eg, Junctional or

ventricular escape rhythm), represented by the QRS complex, and one stimulates the atria (eg, sinus rhythm,

atrial fibrillation), represented by the P wave. P waves may be seen, but the atrial electrical activity is not

conducted down into the ventricles to cause the QRS complex, the ventricular electrical activity. This is called

AV dissociation.

- ECG characteristics of 3rd degree AV Block:

Ventricular and atrial rate: Depends on the escape and underlying atrial rhythm

Ventricular and atrial rhythm: The PP interval is regular and the RR interval is regular; however, the PP

interval is not equal to the RR interval.

QRS shape and duration: Depends on the escape rhythm; in junctional escape, QRS shape and durationare usually normal, and in ventricular escape, QRS shape and duration are usually abnormal.

P wave: Depends on underlying rhythm

PR interval: Very irregular

P: QRS ratio: More P waves than QRS complexes


P not r/t qRs (P too close, P too far)

PRI varies greatly

qRs normal or wide

R R =

23


24/24

Date post:	03-Apr-2018
Category:	Documents
Upload:	ahmad-khalil-al-sadi
View:	225 times
Download:	0 times

ECG Analysis Mannual

Documents