Human Anatomy and Physiology : Help with Evaluation Methods for the Heart

Study concepts, example questions & explanations for Human Anatomy and Physiology

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Example Questions

Example Question #1 : Help With Evaluation Methods For The Heart

Multiple “sawtooth” P waves on an EKG suggest what pathology?

Possible Answers:

First degree atrioventricular (AV) block 

Ventricular tachycardia

Premature ventricular contraction (PVC)

Atrial flutter

Atrial fibrillation

Correct answer:

Atrial flutter

Explanation:

"Sawtooth" P waves are characteristic of atrial flutter.

Example Question #2 : Help With Evaluation Methods For The Heart

You are looking at your patient's EKG, and you suspect he may be experiencing a first degree atrioventricular (AV) block. What EKG findings would lead you to this conclusion?

Possible Answers:

“Sawtooth” shaped P waves

Prolonged P-R interval

Multiple QRS complexes prior to a P wave

Absent P wave

Multiple P waves prior to the QRS complex

Correct answer:

Prolonged P-R interval

Explanation:

A prolonged P-R interval, that does not get progressively longer is typical of a type I A-V block.

Example Question #3 : Help With Evaluation Methods For The Heart

What does an inverted or absent P wave (as an early beat) represent?

Possible Answers:

Premature atrial beat

Bundle branch block

Premature ventricular contraction

Premature junctional/nodal beat

Paroxysmal atrial tachycardia

Correct answer:

Premature junctional/nodal beat

Explanation:

A premature junctional/nodal beat would be represented on an ECG as an inverted or absent P wave. In a premature junctional/nodal beat, the atrioventricular (AV) node is firing before the sinoatrial (SA) node. Since the AV node is at the bottom of the right atrium, the net vector of atrial depolarization is occurring in a more upward direction, causing the P wave to be absent or inverted. Note that there would be a compensatory pause after the premature beat.The answer could not be a premature atrial contraction because the P wave is absent or inverted (P wave would be normal in a premature atrial contraction (PAC)).

Example Question #4 : Help With Evaluation Methods For The Heart

Which of the following conditions is the most serious?

Possible Answers:

Atrial fibrillation

Ventricular fibrillation

First degree AV block

Bundle branch block

Third degree AV block

Correct answer:

Ventricular fibrillation

Explanation:

Ventricular fibrillation is a very serious issue that requires immediate defibrillation. Ventricular fibrillation is the result of ventricular beats originating from many different automaticity foci, so the QRS looks squiggly, very fast, and incoherent. There are no P waves since the beats are originating in the ventricles. 

Example Question #5 : Help With Evaluation Methods For The Heart

Which of the following is a difference between Bundle Branch Block (BBB) and a Premature Ventricular Contraction (PVC)?

Possible Answers:

PVC has a P wave, BBB does not

None of these

BBB has a P wave, PVC does not

PVC has a wide QRS, PVC does not

BBB has a wide QRS, PVC does not

Correct answer:

BBB has a P wave, PVC does not

Explanation:

A bundle branch block is a block in one of the bundle branches, causing a long QRS (>.10 seconds). It is different than a PVC in that a bundle branch block will show a P wave since the beats are still originating in the atria. Bundle Branch Blocks also tend to show a notched QRS.

Example Question #6 : Help With Evaluation Methods For The Heart

Which AV block is characterized by a longer than normal PR interval (of consistent length)?

Possible Answers:

Second Degree AV Block, Mobitz Type 2

Third Degree AV Block

All of these

Second Degree AV Block, Mobitz Type 1 (Wenckebach)

First Degree AV Block

Correct answer:

First Degree AV Block

Explanation:

In First Degree AV Block, there is a longer than normal PR interval (>.20s) due to slowed AV node conduction. Second degree, Mobitz Type 1 (Wenckebach) is progressive lengthening of the PR interval followed by a dropped QRS. Second Degree, Mobitz Type 2 is sudden dropping of the QRS (no lengthening of PR interval). Third Degree AV Block is when there is no relationship between the P and the QRS. 

Example Question #7 : Help With Evaluation Methods For The Heart

What is a normal PR interval length?

Possible Answers:

.14 seconds

.06 seconds

.24 seconds

.10 seconds

.22 seconds

Correct answer:

.14 seconds

Explanation:

The normal PR interval length is .12 - .20 seconds. The PR interval represents the time lag from the onset of atrial depolarization to the onset of ventricular depolarization. Most of the time lag occurs in the AV node, and it allows atrial systole to occur. This allows the ventricles to have time to fill before ventricular systole.

Example Question #8 : Help With Evaluation Methods For The Heart

What is the criteria for tachycardia?

Possible Answers:

>120 beats/minute

>90 beats/minute

<80 beats/minute

<60 beats/minute

>100 beats/minute

Correct answer:

>100 beats/minute

Explanation:

Tachycardia is an abnormally rapid heart rate of rate >100 beats per minute.

Example Question #9 : Help With Evaluation Methods For The Heart

Which of the following would warrant the most investigation by a health care professional?

Possible Answers:

Resting heart rate = 45 bpm, patient is an endurance athlete

Resting heart rate = 65 bpm, patient is not an endurance athlete

Resting heart rate = 65 bpm, patient is an endurance athlete

Resting heart rate = 45bpm, patient is not an endurance athlete

Resting heart rate = 60 bpm, patient is an endurance athlete

Correct answer:

Resting heart rate = 45bpm, patient is not an endurance athlete

Explanation:

Bradycardia is defined as heart rate <60 bpm. In an endurance athlete, there tends to be higher stroke volume/higher vagal tone, so it is typical for an endurance athlete to have a resting heart rate below 60 and still meet normal cardiac output. It a non-endurance athlete, a resting heart rate of 45 bpm may warrant some investigation.

Example Question #10 : Help With Evaluation Methods For The Heart

Which of the following would be characteristic of congestive heart failure?

Possible Answers:

Ejection fraction < 45%

Ejection fraction < 40%

Ejection fraction <55%

Ejection fraction < 60%

Ejection fraction < 50%

Correct answer:

Ejection fraction < 40%

Explanation:

Ejection fraction is a measurement of how much blood blood the ventricles pump out with each contraction as a fraction of the end-diastolic volume. Mathematically, this is (stroke volume) divided by (end-diastolic volume). In congestive heart failure, the heart is weakened and quivers, and it has a hard time pumping blood out. An ejection fraction (EF) < 40% may be evidence of congestive heart failure.

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