heart blocks

Question 1

What does a bundle branch block (BBB) represent?

Answer 1

A delay or obstruction in the electrical pathways (bundle branches) of the heart.

Question 2

What does the heart’s electrical system control?

Answer 2

Timing and coordination of heartbeats.

Question 3

What happens in BBB?

Answer 3

The conduction impulse is delayed or blocked in the bundle branches, altering ventricular contraction.

Question 4

Are BBBs always pathologic?

Answer 4

No — they can be chronic, intermittent, or occur in healthy individuals.

Question 5

What is a Right Bundle Branch Block (RBBB)?

Answer 5

Impulse delayed/blocked in right bundle → right ventricle contracts later.

Question 6

What is the EKG hallmark of RBBB?

Answer 6

“M” shape / Bunny ears on top of QRS.

Question 7

What is a Left Bundle Branch Block (LBBB)?

Answer 7

Impulse delayed/blocked in left bundle → left ventricle contracts later.

Question 8

What is the EKG hallmark of LBBB?

Answer 8

“W” at the bottom of QRS.

Question 9

Causes of RBBB?

Answer 9

Heart disease (congenital: ASD; acquired: valvular, ischemic).

Question 10

Causes of LBBB?

Answer 10

1) Coronary heart disease with LV dysfunction, 2) Hypertensive heart disease, 3) Aortic valve disease, 4) Cardiomyopathy.

Question 11

What EKG finding is seen in both BBB types?

Answer 11

Prolonged QRS interval.

Question 12

What do BBB QRS complexes look like?

Answer 12

Two points, one side higher than the other, still with underlying rhythm.

Question 13

What is First-Degree Heart Block?

Answer 13

Impulse delayed through AV node, but all impulses reach ventricles.

Question 14

Key EKG feature of first-degree heart block?

Answer 14

PR interval > 0.20 sec (more than 5 boxes), consistent PR/QRS/QT.

Question 15

Symptoms of first-degree heart block?

Answer 15

Usually none; incidental finding (pre-op or routine EKG).

Question 16

Causes of first-degree heart block?

Answer 16

Normal aging, meds (BB, CCB), electrolyte imbalance, heart inflammation.

Question 17

Treatment of first-degree heart block?

Answer 17

Typically benign: monitor, treat cause, adjust meds, cardiology follow-up if worsens.

Question 18

What is Second-Degree Type I (Wenckebach/Mobitz I)?

Answer 18

Progressive delay of atrial signals until one is blocked (dropped QRS).

Question 19

EKG hallmark of Type I?

Answer 19

Gradual PR prolongation until drop: “longer, longer, longer, drop.”

Question 20

Symptoms of Type I block?

Answer 20

Usually asymptomatic; can cause dizziness, fatigue, lightheadedness, syncope.

Question 21

Causes of 2nd degree Type I block?

Answer 21

CAD, HTN, ischemia, meds (BB, CCB, digoxin), ↑ vagal tone.

Question 22

Treatment of 2nd degree
Type I block?

Answer 22

Monitor if stable/asymptomatic. If bradycardic/symptomatic → atropine. Rarely pacemaker.

Question 23

NCLEX exam note for Type I?

Answer 23

Pacemaker treatment is too rare to be an exam answer.

Question 24

What is Second-Degree Type II (Mobitz II)?

Answer 24

Some atrial signals blocked, but PR interval remains constant.

Question 25

Key EKG feature of Type II?

Answer 25

Fixed PR interval with intermittent dropped beats.

Question 26

Symptoms of Type II block?

Answer 26

Dizziness, fatigue, syncope; severe cases → cardiac arrest.

Question 27

Causes of Type II block?

Answer 27

CAD, MI, cardiomyopathy, fibrosis, structural heart damage, meds (BB, CCB, digoxin).

Question 28

Why is Mobitz II more serious than Mobitz I?

Answer 28

It often progresses to complete heart block and is unstable.

Question 29

Treatment of Type II block?

Answer 29

Transcutaneous pacing → permanent pacemaker. Atropine not effective (may worsen block).

Question 30

What is Third-Degree Heart Block (Complete Heart Block)?

Answer 30

Complete block of conduction: atria and ventricles beat independently.

Question 31

Key EKG feature of third-degree block?

Answer 31

P waves march out, QRS marches out, but no relationship between P and QRS (“P’s are having a party”).

Question 32

Symptoms of third-degree block?

Answer 32

Severe bradycardia, fatigue, dizziness, SOB, syncope, cardiac arrest.

Question 33

Causes of third-degree block?

Answer 33

CAD, MI, meds (BB, CCB, digoxin).

Question 34

Treatment of third-degree block?

Answer 34

Immediate transcutaneous pacing → permanent pacemaker; treat underlying cause (CAD, meds).

Question 35

What is the overall danger of Mobitz II and Third-Degree block?

Answer 35

Risk of sudden cardiac arrest, require pacing intervention.

Question 36

Memory phrase for Wenckebach (Type I)?

Answer 36

“Longer, longer, longer, drop, that’s a Wenckebach.”

Question 37

Memory phrase for Third-Degree block?

Answer 37

“P’s are having a party” (atria and ventricles not talking).

Question 38

What is the memory phrase for First-Degree Heart Block?

Answer 38

“If the R is far from P, then you have a FIRST DEGREE.”

Question 39

What is the memory phrase for Second-Degree Type I (Wenckebach)?

Answer 39

“Longer, longer, longer, drop! Then you have a WENCKEBACH.”

Question 40

What is the memory phrase for Second-Degree Type II (Mobitz II)?

Answer 40

“If some P’s don’t get through, then you have a MOBITZ II.”

Question 41

What is the memory phrase for Third-Degree Heart Block?

Answer 41

“If P’s and Q’s don’t agree, then you have a THIRD DEGREE.”