Diagnostic features of EKG - disorders

Question 1

EKG findings of LV hypertrophy

Answer 1

1. Bigger R waves in Left-sided Leads (due to larger muscle mass)
   → I, aVL, V5, V6
2. T wave can be inverted

Question 2

EKG findings of Right Ventricular Hypertrophy

Answer 2

Big R waves in Right-sided Leads

→ V1,V2

Question 3

EKG findings of Myocardial ischemia

Answer 3

ST depression

T wave inversion - sometimes

Question 4

EKG findings of ischemia during acute coronary syndrome

Answer 4

T wave inversion

Question 5

What is transmural injury and what are the

EKG findings of transmural injury

Answer 5

ST elevation

Note: Transmural injury: death of myocardial tissue that extends from the endocardium to the epicardium as a result of a myocardial infarction.

Question 6

Coronary artery most responsible for MI seen in inferior Leads

Answer 6

inferior Leads are II, III, av1

RCA

Question 7

Coronary artery most responsible for MI seen in anteroseptal leads

Answer 7

anteroseptal: V1-V2

LAD

Question 8

Coronary artery most responsible for MI seen in anteroapical leads

Answer 8

V3-V4

LAD (distal)

Question 9

Coronary artery most responsible for MI seen in anterolateral leads?

Answer 9

V5, V6, I, aVl

CFX

Question 10

Coronary artery most responsible for MI seen in posterior leads

Answer 10

V1-V2

RCA

(note: V1-V2 is also anteroseptal and responsible for LAD)

Question 11

EKG findings of myocardial injury/infarction

Answer 11

Pathological/sizable Q waves
(>1 small box)

• Q waves in inferior leads (II,III, aVF) are due to inferior infarcts.
• Q waves in anterior leads (V1-V4) are due to anterior wall infarcts.

Question 12

Can Q waves differentiate between acute MI and one that happened years ago?

Answer 12

No, but ST elevation along with Q wave can

ST elevation can.

• Acute: see ST elevation
• Hours: see ST elevation AND ↓ R wave and Q deeper waves
• Weeks: normal ST and persistent Q waves

(note: Q waves are usually the last ECG findings to develop)

Question 13

What the the giant upright t waves called that are rarely seen in MI?

Answer 13

Hyperacute/peaked T waves

- lasts only a few minutes and rarely caught bc usually people dont have an MI while they are hooked up to an EKG

Question 14

ECG findings in MI in:
Transmural MI
Subendocardial MI

Answer 14

transmural:

• ST elevation
• With Q waves

Subendocardial:

• ST depression (lasting 2/3 days)
• no Q waves

(note: ST depression may reflect transient ischemia w/o necrosis)

Question 15

Difference between Stenosis and regurge sounds:

Answer 15

Stenosis: hear the sound before the closing of valves
Regurge: hear the sound after closing of the valves

Question 16

How can you tell if you have a prolonged QT interval? Why is this important?

Answer 16

If you look peak to peak, divide in half = if you don’t see the T wave, you have a prolonged QT interval

• When the QT interval is altered susceptibilities to arrhythmias increase - especially likely with QT prolongation.

Question 17

Causes of prolonged QT interval

Answer 17

hypocalcemia
hypokalemai
hypomagnesemia
hypothermia
Class 1A or 3 anti-arrythmic drugs
Congenital Long QT syndrome

Question 18

How do calcium levels affect the QT intervals?

Answer 18

Hypercalcemia shortens the QT interval.
§ The commonest cause is hyperparathyroidism.

Hypocalcemia lengthens the QT interval (is more common)
§ Has many causes (life threatening ventricular arrhythmias)

Question 19

EKG findings of hypokalemia

- what can this cause?

Answer 19

Prolonged QT

T wave merging with U wave

• Hypokalemia is a common cause of arrhythmias.

Question 20

Common causes of hypokalemia?

Answer 20

overuse of diuretics and vomiting or diarrhea

Question 21

EKG findings in:
mild hyperkalemia (5.5-7.5)

Answer 21

increased T wave voltages with a distinctive peaked, symmetrical appearance.

Question 22

EKG findings in:
highish hyperkalemia (7.5-9.0)

Answer 22

P waves may flatten and the QRS & T waves widen.

A broad S wave often appears.

Question 23

EKG findings in:
highhh hyperkalemia (>9.0)

Answer 23

sinusoidal pattern appears without P or R waves.

Question 24

most common cause of hyperkalemia?

Answer 24

renal failure

If unrecognized hyperkalemia often causes fatal arrhythmias (and cardiac arrests)

Question 25

sinus arrest

Answer 25

Failure of sinus node discharge;

absent atrial depolarization and periods of ventricular asystole

Question 26

Intermittent episodes of slow and fast rates from SA node or atria

Answer 26

Bradycardia-Tachycardia Syndrome

Question 27

Inability to mount age-appropriate HR with exercise

Answer 27

Chronotropic Incompetence

Question 28

First-Degree AV block

how long is the PR interval?

Answer 28

AV conduction is delayed, and the PR interval is prolonged (> 200 ms)

Question 29

Mobitz I (Wenckebach)
- how is the QRS duration?

Answer 29

Progressive prolongation of PR interval until a VENTRICULAR (QRS) beat is dropped;
QRS duration is normal

• AV node is affected

Question 30

Infranodal diseases

Answer 30

Mobitz II 2nd degree AV block

3rd degree AV block = complete heart block

Question 31

Mobitz II

Answer 31

2nd degree AV block

intermittently dropped ventricular beats (QRS) preceded by constant PR intervals

Question 32

Irregular supraventricular tachycardias (SVT)

Answer 32

i. Atrial fibrillation (no discrete Ps, and irregularly irregular)
ii. Multifocal atrial tachycardia (3 or more P waves)
iii. Atrial flutter with variable conduction (flutter waves, sawtooth)
* note: supraventricular (above the ventricles)

Question 33

5 C’s of Atrial Fibrillation

Answer 33

1. Cause: Reverse
2. Control Rate
3. antiCoagulation
4. Control Rhythm
5. Cure: ablation

Question 34

medications that control rate

Answer 34

1. betablockers
2. digoxin
3. verapamil
4. diltiazem
5. Amiodarone

Question 35

EKG findings of cardiac tamponade

Answer 35

caused by: rapidly accumulating moderate sized or large effusions (can be caused by pericardial effusion)- Heart is unable to fill (sim to restrictive CM)

1. Low voltage with sinus tachycardia
2. Electrical alternans with sinus tachycardia

Note: Heart is in a Sea of fluid that causes changes with each beat