$$\text{Heart Rate} = \frac{300}{\text{number of large boxes between R waves}}$$

Question 1

Which of the following best describes the primary function of an EKG in clinical practice?

Accepted Answer

Detects and records electrical signals from the heart

Question 2

Which ions are primarily responsible for cardiac depolarization?

Accepted Answer

Sodium and calcium

Question 3

A patient presents with a flattened or inverted T wave on their EKG. Which electrolyte abnormality is most likely responsible?

Accepted Answer

Hypokalemia

Question 4

Which part of the heart acts as the primary pacemaker?

Accepted Answer

SA node

Question 5

Fill in the blank: The EKG provides a $$	ext{graphic}$$ representation of the heart's electrical activity.

Accepted Answer

graphic

Question 6

Which cardiac event corresponds to the P wave on an EKG?

Accepted Answer

Atrial depolarization

Question 7

True or False: The QRS complex represents atrial repolarization.

Accepted Answer

False

Question 8

Fill in the blank: The period between the start of the P wave and the start of the QRS complex is called the $$	ext{PR interval}.$$

Accepted Answer

PR interval

Question 9

Which of the following statements about cardiac cells is true?

Accepted Answer

They conduct impulses through sodium and potassium channels.

Question 10

Fill in the blank: The resting membrane potential of a cardiac cell is approximately $$-90\ 	ext{mV}.$$

Accepted Answer

$$-90\ 	ext{mV}$$

Question 11

A standard EKG paper speed is $$25\ 	ext{mm/sec}. If $$each large box represents $$0.20$$ seconds, how many seconds does five large boxes represent?

Accepted Answer

Question 12

Which property allows cardiac cells to generate impulses without external stimulation?

Accepted Answer

Automaticity

Question 13

Which of the following EKG findings is most consistent with ventricular repolarization?

Accepted Answer

T wave

Question 14

A patient with hyperkalemia is most likely to show which EKG change?

Accepted Answer

Peaked T waves

Question 15

Which of the following is the correct formula for calculating heart rate from an EKG using the large box method?

Accepted Answer

$$	ext{Heart Rate} = \frac{300}{	ext{number of large boxes between R waves}}$$

Question 16

A widened QRS complex (duration $$\u003e0.12$$ seconds) is most commonly associated with which condition?

Accepted Answer

Bundle branch block

Question 17

Which EKG segment is most useful for detecting myocardial ischemia?

Accepted Answer

ST segment

Question 18

A patient presents with chest pain and an EKG showing ST segment elevation in leads II, III, and aVF. Which coronary artery is most likely involved?

Accepted Answer

Right coronary artery

Question 19

True or False: The U wave is always abnormal on a normal EKG.

Accepted Answer

False

Question 20

Which of the following is the correct formula for calculating the QTc interval using Bazett's formula?

Accepted Answer

$$QTc = \frac{QT}{\sqrt{RR}}$$

EKG Fundamentals and Cardiac Cell Physiology: Study Notes for Anatomy & Physiology

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