ECG Application - Jones

Review: Describe each of the following parts of an ECG

• P- wave

• QRS- wave

• T- wave

• PR interval

• QRS interval

• QT interval

• P- wave: atria depolarizing

• QRS- wave: ventricles depolarizing

• T- wave: ventricles repolarizing

• PR interval: measures the conduction system- the SA node through AV node right before ventricles

• QRS interval: measures how rapidly we are depolarizing

• QT interval: measures how long our action potential takes

Depolarization generates a dipole. How is the net dipole determined?

1. magnitude of depolarization (how many cells)

2. orientation of the dipoles (same direction=stronger)

What does the net dipole of atrial depolarization look like?

This net dipole belongs to which of the following?

a. Q wave

b. S wave

c. ST segment

d. R wave

Q wave

This net dipole belongs to which of the following?

a. Q wave

b. S wave

c. ST segment

d. R wave

ST segment (no dipole!)

This net dipole belongs to which of the following?

a. Q wave

b. S wave

c. ST segment

d. R wave

S wave

This net dipole belongs to which of the following?

a. Q wave

b. S wave

c. ST segment

d. R wave

R wave

The mean electrical axis measures the largest dipole during the ___-wave.

R

What are the common causes of left axis deviation?

LVH, right MI

What are the common causes of right axis deviation?

RVH, left MI

An ______________ is an abnormal heart rhythm.

arrhythmia

What arrhythmias are “supraventricular”?

1. tachycardia (a flutter)

2. atrial fibrillation

3. heart block

What arrhythmias are “ventricular”?

1. bundle branch block

2. premature ventricular contractions (PVC’s)

3. ventricular fibrillation

4. Long QT

5. myocardial infarction

6. electrolyte disturbances

In a patient with supraventricular tachycardia, what is seen on the ECG?

P and T waves may overlap

What are the symptoms of supraventricular tachycardia?

• dizzy

• low BP

What are the 3 causes of supraventricular tachycardia?

1. SA node over activity

2. ectopic focus (cells outside SA start to fire)

3. reentry phenomenon (circus) (abnormal electrical currents)

What is the most likely rhythm in the following ECG trace?

supraventricular tachycardia

• the T+P are overlapping

What rhythm is present on the ECG below?

atrial flutter

• hallmark sawtooth pattern

• no T+P

What rhythm is present on the ECG below?

Atrial fibrillation

• P waves not making it to QRS

In sinus tachycardia, the ____ node discharges at a __________ rate.

SA node discharges at a faster rate.

Cause of a fib and a flutter:

a fib- reentry and ectopic

a flutter- usually reentry

A heart block is a conduction block at the _____ node.

AV node

Does a heart block cause tachycardia or bradycardia?

bradycardia

Describe each kind of heart block:

• first

• second

• third

• first- slowed conduction thru AV node

• second- some but not all signals thru AV node

• third- no signals thru AV node

What rhythm is present on the patient’s ECG trace?

1st degree heart block

• prolonged PR interval

What rhythm is likely present on the following ECG trace?

3rd degree heart blcok

What rhythm is present on the ECG?

2nd degree heart block

• always gonna be a ratio! so 2:1 or 4:1

What rhythm is present on the ECG?

bundle branch block

• widened QRS

• double R

What is the typical cause of a bundle branch block?

MI

What rhythm is likely present on the following ECG trace?

Premature Ventricular Contractions (PVCs)

• huge dip followed by a pause!

What is the cause of PVC’s?

ectopic cells in the ventricle

In ventricular tachycardia, _____________ drive electrical activity.

ectopic foci

Ventricular Tachycardia progresses to….

ventricular fibrillation

What rhythm is present on the ECG?

ventricular fibrillation

What rhythm is present on the ECG?

ventricular tachycardia

What 2 rhythms are present on this ECG?

• Long QT syndrome

• Torsade de pointes

Long QT syndrome is caused by what?

• inappropriate opening of Na+ channels

• prolonged closure of K+ channels (maybe by meds)

With what condition is the blood supply to the myocardium interrupted and mainly effects ventricular repolarization?

myocardial infarction

What is seen on the ECG of a STEMI acute MI during the following times:

• acute

• hours

• day 1-2

• days later

• weeks later

• acute- ST ELEVATION

• hours- ST elevation, decrease R wave, Q wave begins

• day 1-2- T-wave inversion, Q wave

• days later- ST normalize, T wave inverted

• weeks later- ST and T normal, Q wave persists

What is seen on the ECG of a Non-STEMI Myocardial Infarction?

• ST depression

• T wave inversion

What electrolyte disturbance would cause the ECG shown?

hyperkalemia

What electrolyte disturbance would cause the ECG shown?

severe hyperkalemia

What electrolyte disturbance would cause the ECG shown?

Hypocalcemia

What electrolyte disturbance would cause the ECG shown?

Hypercalcemia

What electrolyte disturbance would cause the ECG shown?

Hypokalemia

JONES IN CLASS ASSIGNMENT QUESTIONS:

What does ST-elevation suggest?

a. Bundle Branch Block

b. Long QT syndrome

c. Myocardial infarction

d. Second degree heart block

c

JONES IN CLASS ASSIGNMENT QUESTIONS:

Which of the following is a common cause of right axis deviation?

a. Right Ventricular MI

b. atrial fibrillation

c. Right ventricular hypertrophy

d. left ventricular hypertrophy

c

JONES IN CLASS ASSIGNMENT QUESTIONS:

An ECG is performed and reveals a normal PR interval and dropping of QRS complexes at regular intervals. Which of the following is the most likely diagnosis?

a. third degree heart block

b. hyperkalemia

c. first-degree heart block

d. second-degree heart block

d

JONES IN CLASS ASSIGNMENT QUESTIONS:

a. sinus tachycardia

b. atrial flutter

c. atrial fibrillation

d. PVC

a.

JONES IN CLASS ASSIGNMENT QUESTIONS:

a. hypokalemia

b. second degree heart block

c. bundle branch block

d. hypocalcemia

a

JONES IN CLASS ASSIGNMENT QUESTIONS:

Apart from ventricular tachycardia, what is an important cause of wide QRS complexes?

a. AV nodal reentrant tachycardia

b. atrial flutter

c. bundle branch block

d. hypokalemia

c.

(think: if depolarization not occurring at the same time= longer QRS)

JONES IN CLASS ASSIGNMENT QUESTIONS:

a. sinus rhythm

b. second degree heart block

c. STEMI

d. first degree heart block

d

JONES IN CLASS ASSIGNMENT QUESTIONS:

a. complete heart block

b. non-STEMI

c. Atrial fibrillation

d. atrial flutter with 4:1 transmission

c

JONES IN CLASS ASSIGNMENT QUESTIONS:

a. ventricle

b. atria

c. SA node

d. AV node

a

JONES IN CLASS ASSIGNMENT QUESTIONS:

a. second degree heart block

b. complete heart block

c. sinus tachycardia

d. Long QT syndrome

b

JONES IN CLASS ASSIGNMENT QUESTIONS:

a. current angina event

b. severe MI several minutes ago

c. severe MI 2 days ago

d. MI several weeks ago

d

JONES IN CLASS ASSIGNMENT QUESTIONS:

a. Torsades de pointes

b. PVC

c. Ventricular fibrillation

d. bundle branch block

d

JONES IN CLASS ASSIGNMENT QUESTIONS:

SATA:

a. pharmalogical administration of a K+ channel blocker

b. hyperkalemia

c. ectopic ventricular foci firing

d. hypocalcemia

e. reactivation of ventricular muscle Na+ channels

a, d, e