Clinical Cases And ECG MIs

Question 1

What could sinus tachycardia be due to?

What is it normal in?

Answer 1

Normal if pregnant, emotional

Could also be response to:

• drugs
• hyperthyroid
• fever
• anemia
• CHF
• hypovolemia

Question 2

What could cause sinus Bradycardia?

Answer 2

‣ Vagal response sleep apnea
		‣ Meds
		‣ MI
		‣ Increased ICP 
		‣ Hypothyroid

Question 3

When does a premature beat occur?

Answer 3

When an irritable focus spontaneously fires a single stimulus

Question 4

What is premature atrial contraction associated w/ ?

Answer 4

Stress
Alcohol
Tobacco
Coffee
Copd
Cad

Question 5

Wha will a Premature Ventricular contraction present w/ on an ECG?

Answer 5

Wide QRS

Question 6

What do multiple PVCs indicate on an ECG?

Answer 6

Ventricular Tachycardia

Question 7

What can cause VTACH?

Answer 7

CAd
Heart failure
Hypertrophic cardiomyopathy
Congenital HD
Electrolyte abnormalities

Question 8

How is a Supraventricular Tachycardia represented on an ECG?

Answer 8

Narrow QRS complex, fast HR

Question 9

What are the causes of Supraventricular Tachycardia?

Answer 9

Thyroid disease
Caffeine
Medications w/ stimulants
Stress

Question 10

Why is Atrial Fibrillation particularly dangerous?

Answer 10

Can develop clots from this

Question 11

What are the causes of atrial fibrillation?

Answer 11

‣ Hypertensive heart disease
		‣ Valvular heart disease
		‣ CHF
		‣ CAD
		‣ Obesity
		‣ DM
		‣ Metabolic syndrome
		‣ Chronic Kidney disease

Question 12

How is AFIB seen on an ECG?

Answer 12

Undulating baseline

No discernible P waves

Irregular QRS complex

Irregularly irregular ventricular rhythm

Question 13

How does a First degree AV block present on an ECG?

Answer 13

Prolonged PR interval (over .2 sec - or bigger than 1 big block)

Question 14

What are the limb leads of an ECG and what do they show?

Answer 14

Show depolarizatio of heart in frontal/coronal plane

AVR, aVL, aVF, I, II, III

Question 15

What are the precordial leads of an ECG and what do they show?

Answer 15

V1-V6

Show depolarization of heart in horiz. Plane

Question 16

What is a normal axis on an ECG? How do you determine this?

Answer 16

Normal= 0-+90

Determined by looking at leads 1 and aVF

Question 17

How common is Coronary heart disease (CHD)?

Answer 17

1/6 adults in us

Question 18

What is the common Hx and Sxs seen with CHD?

Answer 18

Chest discomfort

Sxs of nausea, vomiting, diaphoresis, dyspnea

Question 19

What is the pathophys of CHD?

Answer 19

Narrowing of coronary arteries secondary to erosion, fissure or rupture of plaque, thrombus

Question 20

If there is partial occlusion of the coronary arteries, what can occur?

Answer 20

Unstable angina or NSTEMI

Question 21

If coronary flow is completely occluded, what can occur?

Answer 21

STEMI

Question 22

What does STEMI stand for?

Answer 22

ST elevation MI

Question 23

What are most MIs caused by?

Answer 23

Atherosclerosis

Question 24

What is the progression of CAD?

Answer 24

Normal heart —> stable angina —> unstable angina —> NSTEMI —> STEMI

Question 25

What will myocardial ischemia present with on an ECG? Why?

Answer 25

Change in T wave - inverted - tall, upright - depressed Bc deficient blood supply; Impaired REpolarization (t-wave)

Question 26

What will myocardial injury present with on an ECG? Why?

Answer 26

ST elevation bc inability to fully polarize back to baseline

Question 27

How will a myocardial infarcton/necrosis present on an ECG? Why?

Answer 27

Change in Q waves Bc dead tissue cant DEpolarize

Question 28

What are the cardiac bio markers of necrosis? When will these show up? Peak?

Answer 28

-elevated Troponin I or T - show up 1-4 hours after AMI onset - peak at 10-24 hours

Question 29

What can cause a false positive elevation in troponin T?

Answer 29

Renal failure

Question 30

What does an NSTEMI present with?

Answer 30

Elevated troponin, CK, and CK/MB - no st elevation - usually st depression or t wave inversion

Question 31

How does a STEMI present on an ECG?

Answer 31

W/ a fireman’s hat -ST elevation that is 2 mm or more higher than baseline when measured at J point

Question 32

What is an Acute MI?

Answer 32

Complete interruption of blood flow *usually bc coronary occlusion

Question 33

What vessels are supplied by the Left Anterior descending a. (Ant. Interventricular a.) ? What MI is assoc.w/ occlusion of LAD?

Answer 33

V1-V7 V3 and V4 Anterior wall infarction

Question 34

What vessels are supplied by the Right Coronary a.? What MI is assoc.w/ occlusion of RCA?

Answer 34

II, III, aVF V3R-V6R Inferior wall infarction (RV)

Question 35

What vessels are supplied by the circumflex a.? What MI is assoc.w/ occlusion of Circ. A.?

Answer 35

I, aVL V5-V6 Lateral Wall infarction

Question 36

What vessels are supplied by the Posterior Desc. A.? What MI is assoc.w/ occlusion of Post. Desc. A.? How can you see this on an ECG?

Answer 36

V1-V3 Look for sharp R wave- then, turn ECG upside down to see fireman’s hat Posterior wall infarction (Most missed one)