Question 1

Left axis deviation is between
A)0 and +90 degrees.
B)0 and -90 degrees.
C)+90 and 180 degrees.
D)-90 and 180 degrees.

Accepted Answer

Left axis deviation (LAD) reflects a leftward anatomical shift in the overall direction of ventricular depolarization, indicating an abnormality in the conduction system. The normal QRS axis lies between -30 degrees and +90 degrees, with most individuals having a QRS axis between -30 and +70 degrees. Therefore, if the QRS axis deviates significantly to the left of -30 degrees, it is referred to as LAD, and the most negative axis would be -90 degrees. Hence the correct option is B, i.e., between 0 and -90 degrees.

Question 2

Ventricular hypertrophy is
A)excessive growth of ventricular myocardial tissue.
B)excessive growth of atrial tissue.
C)characterized by low-voltage QRS complexes.
D)characterized by tall,pointy P waves.

Accepted Answer

Ventricular hypertrophy is the excessive growth of ventricular myocardial tissue, resulting in a thickened and enlarged ventricular wall. It can occur as a response to various conditions such as hypertension or valve disease.

Question 3

If the QRS in I is negative and the QRS in aVF is positive,the axis is
A)normal.
B)right axis deviation.
C)left axis deviation.
D)indeterminate axis.

Accepted Answer

A negative QRS in lead I and a positive QRS in lead aVF indicates right axis deviation.

Question 4

Indeterminate axis is between
A)0 and +90 degrees.
B)0 and -90 degrees.
C)+90 and 180 degrees.
D)-90 and 180 degrees.

Accepted Answer

An indeterminate axis is the line of an object that has an undefined direction of rotation about that axis. This occurs when the object has symmetry in its shape along that axis. For example, a cylinder has an indeterminate axis that lies along its central axis. The angle of rotation about this axis can be any angle between -90 degrees and +90 degrees, as flipping it upside down or rotating it by 180 degrees would result in the same orientation. Thus, the correct answer is option D, which covers the range of angles from -90 to 180 degrees.

Question 5

Bundle branch block is characterized by
A)a QRS complex at least 0.12 seconds wide.
B)more P waves than QRS complexes.
C)cardiac arrest.
D)sudden onset of symptoms of decreased cardiac output.

Accepted Answer

Bundle branch block is characterized by a QRS complex that is wider than normal, usually greater than or equal to 0.12 seconds. The other answer choices are not consistent with the definition of bundle branch block.

Question 6

A disorder in which there is too much potassium in the bloodstream is called
A)hyperkalemia.
B)hypokalemia.
C)hypercalcemia.
D)hypocalcemia.

Accepted Answer

Hyperkalemia refers to the condition in which there is an excess of potassium in the bloodstream. This can be caused by a variety of factors, including certain medications, kidney disease, or adrenal gland disorders. Symptoms can include muscle weakness, abnormal heart rhythms, and fatigue. Hypokalemia, on the other hand, is the opposite condition in which there is too little potassium in the bloodstream.

Question 7

Low voltage EKGs can be caused by ALL BUT which of the following?
A)Obesity
B)Thyroid gland malfunction
C)Emphysema
D)Hypertension

Accepted Answer

Low voltage EKGs can be caused by obesity, thyroid gland malfunction, and emphysema. However, hypertension is not a known cause of low voltage EKGs.

Question 8

Digitalis effect is characterized by
A)shortened PR intervals.
B)widened QRS.
C)sagging ST segments.
D)prolonged ST segments.

Accepted Answer

Digitalis effect on the electrocardiogram (ECG) is characterized by sagging ST segments. This is a classic sign of digitalis effect, reflecting its impact on the myocardial tissue.

Question 9

Left ventricular hypertrophy is most commonly caused by
A)atrial fibrillation.
B)heart attack.
C)hypertension.
D)chronic lung disease.

Accepted Answer

Left ventricular hypertrophy is most commonly caused by hypertension. The increased pressure in the arteries puts extra stress on the heart, causing it to work harder and leading to the thickening of the left ventricle.  Atrial fibrillation and heart attacks can also contribute to left ventricular hypertrophy, but they are not the most common causes. Chronic lung disease is not typically associated with left ventricular hypertrophy.

Question 10

If the QRS in leads I and aVF are both positive,the axis is
A)normal.
B)right axis deviation.
C)left axis deviation.
D)indeterminate axis.

Accepted Answer

When both leads I and aVF have positive QRS complexes, it indicates that the electrical activity is primarily heading towards the positive electrode of lead I and towards the bottom of the heart (i.e. the positive electrode of aVF). This is consistent with a normal axis.

Question 11

If the QRS in I and aVF are both negative,the axis is
A)normal.
B)right axis deviation.
C)left axis deviation.
D)indeterminate axis.

Accepted Answer

If the QRS complexes in both lead I and lead aVF are negative, it indicates an indeterminate axis, also known as extreme axis deviation.

Question 12

Left bundle branch block (LBBB)
A)is almost always indicative of heart disease.
B)is more serious than RBBB.
C)is characterized by a QS or RS pattern in V₁.
D)all of the above.

Accepted Answer

LBBB is almost always indicative of heart disease, is more serious than RBBB, and is characterized by a QS or RS pattern in V₁.

Question 13

Normal axis is between
A)0 and +90 degrees.
B)0 and -90 degrees.
C)+90 and 180 degrees.
D)-90 and 180 degrees.

Accepted Answer

The normal axis of the heart's electrical activity in an electrocardiogram (ECG) is between 0 and +90 degrees. This range indicates a normal direction of the heart's electrical impulse from the atria to the ventricles.

Question 14

Which of the following is NOT a step in 12-lead EKG interpretation?
A)Assess the basics-rhythm,rate,and intervals
B)Determine the axis quadrant
C)Check for ventricular hypertrophy
D)Check the patient for symptoms

Accepted Answer

Checking the patient for symptoms is not typically considered a step in 12-lead EKG interpretation, as the EKG is primarily used to evaluate the electrical activity of the heart itself rather than the patient's symptoms. However, it is important for the interpreting physician to take into account the patient's medical history and any reported symptoms when interpreting the EKG findings in order to make an accurate diagnosis.

Question 15

Right ventricular hypertrophy is most commonly caused by
A)atrial fibrillation.
B)heart attack.
C)hypertension.
D)chronic lung disease.

Accepted Answer

Chronic lung disease, particularly conditions such as pulmonary hypertension, can increase pressure in the lungs and cause the right ventricle of the heart to work harder to pump blood, leading to hypertrophy. Atrial fibrillation and heart attack may also contribute to right ventricular hypertrophy, but they are not the most common causes. Hypertension primarily affects the left ventricle.

Question 16

Right axis deviation is between
A)0 and +90 degrees.
B)0 and -90 degrees.
C)+90 and 180 degrees.
D)-90 and 180 degrees.

Accepted Answer

Right axis deviation (RAD) is defined as a QRS axis in the frontal plane deviating between +90 and 180 degrees.

Question 17

A disorder in which there is a deficit of calcium in the bloodstream is called
A)hyperkalemia.
B)hypokalemia.
C)hypercalcemia.
D)hypocalcemia.

Accepted Answer

Hypocalcemia is a disorder in which there is a deficit of calcium in the bloodstream. Hyperkalemia refers to an excess of potassium in the bloodstream, while hypokalemia refers to a deficit of potassium. Hypercalcemia refers to an excess of calcium in the bloodstream.

Question 18

Right bundle branch block (RBBB)is characterized by
A)RSR configuration in V₁.
B)tall,pointy P waves.
C)symptoms of decreased cardiac output.
D)more P waves than QRS complexes.

Accepted Answer

RBBB usually shows an RSR' pattern in V1, with a wide S wave in V6. This is due to delayed depolarization of the right ventricle, leading to a delayed R wave in V1 and a wider S wave in V6. Tall, pointy P waves may indicate left atrial enlargement, not RBBB. While decreased cardiac output is possible with any block or arrhythmia, it is not a characteristic feature of RBBB. Finally, RBBB should have the same number of P waves as QRS complexes, as the atrial and ventricular rates should match.

Question 19

Hypercalcemia is a disorder in which there is too much ________ in the bloodstream.
A)cholesterol
B)calcium
C)calcitonin
D)potassium

Accepted Answer

Hypercalcemia is a disorder in which there is too much calcium in the bloodstream.

Question 20

If the QRS in Lead I is positive and the QRS in aVF is negative,the axis is
A)normal.
B)right axis deviation.
C)left axis deviation.
D)indeterminate axis.

Accepted Answer

If QRS is positive in lead I and negative in aVF, it indicates that the electrical axis of the heart is directed towards the left lower quadrant of the body (i.e. Left Inferior) - a pattern suggestive of Left Axis Deviation. Therefore, the correct answer would be C.

Quiz 13: How to Interpret a 12-Lead EKG

Left axis deviation is between

Ventricular hypertrophy is

If the QRS in I is negative and the QRS in aVF is positive,the axis is

Indeterminate axis is between

Bundle branch block is characterized by

A disorder in which there is too much potassium in the bloodstream is called

Low voltage EKGs can be caused by ALL BUT which of the following?

Digitalis effect is characterized by

Left ventricular hypertrophy is most commonly caused by

If the QRS in leads I and aVF are both positive,the axis is

If the QRS in I and aVF are both negative,the axis is

Left bundle branch block (LBBB)

Normal axis is between

Which of the following is NOT a step in 12-lead EKG interpretation?

Right ventricular hypertrophy is most commonly caused by

Right axis deviation is between

A disorder in which there is a deficit of calcium in the bloodstream is called

Right bundle branch block (RBBB) is characterized by

Hypercalcemia is a disorder in which there is too much ________ in the bloodstream.

If the QRS in Lead I is positive and the QRS in aVF is negative,the axis is