ECG Rhythms

Sinus Rhythms:

Normal Sinus Rhythm
Sinus Tachycardia
Sinus Bradycardia
Sinus Arrhythmia
Sinus Arrest
Sinus Block

Normal Sinus Rhythm

Rhythm: Regular
Rate: 60 to 100 bpm
Atria: Yes
PRI: Normal (.12-.20)
QRS: Normal (<.12)

Sinus Tachycardia

Rhythm: Regular
Rate: 100 to 150 bpm (can be faster)
Atria: Yes
PRI: Normal
QRS: Normal

Sinus Bradycardia

Rhythm: Regular
Rate: <60
Atria: Yes
PRI: Normal
QRS: Normal

Sinus Arrhythmia

Rhythm: Irregular
Rate: 60 to 100 bpm
Atria: Yes
PRI: Normal
QRS: Normal

Sinus Arrest

Rhythm: Irregular
Rate: Report underlying
Atria: No, the atria are not in rhythm after the pause
PRI: Underlying
QRS: Underlying
Rhythm does not stay consistent after pause

Sinus Block

Rhythm: Overall irregular
Rate: Underlying rhythm
Atria: Yes, atria remain in rhythm after delay
PRI: Underlying
QRS: Normal
Rhythm after block stays consistent after the pause

Atrial Rhythms

Wandering Atrial Pacemaker
SVT (Supraventricular Tachycardia)
Atrial Flutter
Atrial Fibrillation

Wandering Atrial Pacemaker

Rhythm: Irregular
Rate: 60 to 100 bpm
Atria: No (p-waves different, not in rhythm, typically have 3 different configurations)
PRI: Can vary or be absent
QRS: Normal

SVT (Supraventricular Tachycardia)

Rhythm: Regular
Rate: 140 to 250 bpm
Atria: No, P-wave hidden in T-wave, typically not identifiable
PRI: Indeterminate
QRS: Normal

Atrial Flutter

Rhythm: Regular or Irregular
Rate: Variable
Atria: Rapid, identical undulating waves (Flutter waves)
PRI: Baseline is absent; can’t measure
QRS: Normal
Report conduction ratio, if not consistent then it’s variable

Atrial Fibrillation

Rhythm: Always irregular
Rate: <100 - controlled; >=100 - with RVR
Atria: No - identified as fibrillation waves - course or fine
PRI: Indeterminate
QRS: Normal

Premature Contractions

PAC
Non-conducted PAC
PJC
PVC

PAC (Premature Atrial Contraction)

Rhythm: Irregular
Rate: 110?
Atria: No!
PRI: Normal
QRS: Normal

Non-Conducted PAC

Rhythm: Underlying usually regular
Rate: Underlying rhythm
Atria: Yes for p-wave, atrial rhythm is important
PRI: Indeterminate - not conducted
QRS: Indeterminate - not conducted

Junctional Rhythm

Rhythm: Regular
Rate: Intrinsic Rate 40 to 60 bpm
Atrial: No - P waves are inverted or absent
PRI: Indeterminate
QRS: Normal

Accelerated Junctional Rhythm

Rate: 60 to 100 bpm

PJC (Premature Junction Contraction)

Rhythm: Underlying (to the left of the PJC)
Rate: Underlying (to the left of the PJC)
Atria: P-waves are different - absent or inverted
PRI: Underlying
QRS: Usually normal of underlying

PVC (Premature Ventricular Contraction)

Rhythm: Report underlying
Rate: Underlying
Atria: No missing p-waves
PRI: Underlying
QRS: Wide - abnormal (>.12s)

Ventricular Rhythms

Ventricular Tachycardia
Ventricular Fibrillation
Idioventricular Rhythm
Accelerated Idioventricular Rhythm
Torsade de pointes
Asystole (Ventricular Standstill)

Ventricular Tachycardia

Rhythm: Regular
Rate: 110 to 250 bpm
Atria: Cannot see astral activity
PRI: Indeterminate
QRS: Wide >.12 s
Sustained > 30 seconds

Ventricular Fibrillation

All measures are indeterminate it is ELECTRICAL CHAOS

Idioventricular Rhythm

Rhythm: Regular
Rate: <40 (may be higher)
Atria: No
PRI: Indeterminate
QRS: Abnormal

Accelerated Idioventricular Rhythm

Rate: >40 to 110

Torsade de pointes

A form of ventricular tachycardia but the QRS complexes spiral around the baseline

Asystole (Ventricular Standstill)

Rhythm: None
Rate: If p-waves present, there may be atrial rate
Atria: Sometimes present
PRI: Indeterminate
QRS: Indeterminate

First Degree AV Block

Rhythm: Regular

Rate: Underlying

Atria: Yes

PRI: > than .2 seconds

QRS: Usually normal

The prolonged PRI is constant

2nd Degree AV Block Mobitz I

Rhythm: Irregular

Atria Rhythm: Regular

PRI: Successively longer PRIs until one QRS fails

QRS: Normal

2nd Degree AV Block Mobitz II

Rhythm: Irregular

Atria Rhythm: Regular

PRI: Normal or Prolonged

QRS: Often Abnormal

All PQRST will look the SAME

3rd Degree AV Block

Rhythm: Normal

Atria Rhythm: Regular

Rate: 40-60 bpm

PRI: Varies greatly

QRS: Varies depending on site of block

Many times the P waves will be inside the QRS complex

How to distinguish between 2nd Degree and Non conduced PAC, and Sinus block

Non conducted will have irregular P-P

AV block will have regular P-P and longer PRI

Sinus Block has no p wave and regular PRI

QRS Axis

Normal QRS Axis: +90 to -30

Right Axis Deviation: +120 to +180

Extreme Right Axis Deviation: -150 to -90

Left Axis Deviation: -60

Right Bundle Branch Block

V1, V2, & sometimes V3 produce a R,R or RsR wave

T-wave inversion and ST depression

V5, V6 and Lead I producing a deep S wave

Left Bundle Branch Block

V5, V6, aVL, and Lead I produce a R,R or blunted positive QRS

T-wave inversion and ST depression

V1, V2, and V3 are predominately negative QRS complexes

Right Atrial Enlargement

Amplitude of p-wave > 2.5 mm in II, III, and aVF

Biphasic V1 with greater portion positive

Right Ventricular Hypertrophy

V1: Mostly positive large R-wave and T-wave inversion

V6: S-wave is larger than R-wave

QRS Axis: Right Axis Deviation

Lead I: Mostly negative

Left Ventricular Hypertrophy

R-wave amplitude in V5 or V6 plus S-wave amplitude in V1 or V2 exceed 35 mm and T-wave inversion

Inferior Infarction

ST elevation in II, III, and aVF

Q-waves II, III, and aVF

Residual ST depression: Right/anterior leads V1-V3

Lateral (Left) Infarction

ST elevation in Lead I, aVL, V5, and V6

Evolving Q-waves in Lead I, aVL, V5, and V6

Residual ST depression: Inferior (II, III, aVF) and Right (V1-V3)

Anterior Infarction

ST elevation in V1-V4

Residual ST depression: Left (I, aVL, V5, V6)

NSTEMI

T-wave inversion, can be universal, and may see ST depression