[CARDIO] ECG

0.12-0.20 seconds [3-5 small boxes]

Normal PR interval duration & boxes

0.04-0.12 seconds [1-3 small boxes]

Normal QRS complex duration & boxes

0.08 second [2 small boxes]

Normal ST segment duration & boxes

0.10-0.25 seconds [2½-6¼ small boxes]

Normal T wave duration & boxes

0.04

ECG

1 small box = ___ second

0.2

ECG

5 small boxes = ___ second

0.2

ECG

1 big box = ___ second

1

ECG

5 big boxes = ___ second

3

ECG

15 big boxes = ___ seconds

6

ECG

30 big boxes = ___ seconds

0.5

ECG

1 big box = ___ mV

ischemia

Implications of T wave inversion

hyperkalemia

Implications of tall/peaked/pointed T wave

myocardial ischemia

Implications of ST depression

myocardial infarction

Implications of ST elevation

sinus bradycardia

ECG Interpretation

below 60 bpm

sinus tachycardia

ECG Interpretation

below 100 bpm

Premature Atrial Contractions (PACs)

ECG Interpretation

Atrial cells can fire occasionally from a focus

Atrial Flutter

ECG Interpretation

Atrial cells can fire continuously due to a looping re-entrant circuit

Premature Atrial Contractions (PACs)

ECG Interpretation

Occasional irregular

P waves different contour and interval

Atrial Fibrillation

ECG Interpretation

Irregularly irregular

No P waves

Atrial Flutter

ECG Interpretation

Regular

P waves flutter

Paroxysmal Supraventricular Tachycardia

ECG Interpretation

The AV junction fire continuously due to a looping re-entrant circuit

AV Junctional Blocks

ECG Interpretation

The AV junction

Premature Ventricular Contractions (PVCs)

ECG Interpretation

Ventricular cells fire occasionally from 1 or more foci

Ventricular Fibrillation

ECG Interpretation

Ventricular cells fire continuously from multiple foci

Ventricular Tachycardia

ECG Interpretation

Ventricular cells fire continuously due to a looping re-entrant circuit

1st Degree AV Block

ECG Interpretation

60 bpm

Regular

Prolonged PR interval

2nd Degree AV Block, Type I

ECG Interpretation

50 bpm

regularly irregular

some have no QRS

PR interval lengthens

2nd Degree AV Block, Type II

ECG Interpretation

40 bpm

regular

some have no QRS

PR interval short

3rd Degree AV Block

ECG Interpretation

40 bpm

regular

P waves far from QRS

QRS interval wide

Premature Ventricular Contractions (PVCs)

ECG Interpretation

occasionally irregular

P wave some missing

QRS wave some wide

Paroxysmal Supra Ventricular Tachycardia (PSVT)

ECG Interpretation

> 100 bpm

regular

P waves absent

Ventricular Fibrillation

ECG Interpretation

All waves irregular

Ventricular Tachycardia

ECG Interpretation

> 100 bpm

P wave absent or inverted

QRS bizarre > 0.12s