Question 1

In most patients, the posterior wall of the left ventricle is supplied by the circumflex coronary artery.

Accepted Answer

The posterior wall of the left ventricle is supplied by the right coronary artery in most patients; however, in some patients it is supplied by the circumflex coronary artery.

Question 2

A normal ECG rules out an MI.

Accepted Answer

The ECG is nondiagnostic in approximately 50% of patients with chest discomfort. A normal ECG does not rule out an acute MI, particularly in the early hours of a coronary artery occlusion.

Question 3

Consider the presence of right ventricular infarction (RVI) if a patient with an inferior wall infarction becomes hypotensive after the administration of nitrates.

Accepted Answer

RVI should be suspected when ECG changes suggesting an inferior infarction (ST elevation in leads II, III, and/or aVF) are observed. Nitroglycerin should be avoided in inferior wall MI with a possible associated right ventricular MI. Consider the presence of RVI if the patient with an inferior wall MI becomes hypotensive after nitrate administration.

Question 4

In a patient experiencing an acute coronary syndrome, T-wave inversion suggests the presence of:

Accepted Answer

In the later acute phase of the infarction, you may see the presence of T-wave inversion, suggesting the presence of ischemia. In fact, T-wave inversion may precede the development of ST-segment elevation, or they may occur at the same time.

Question 5

Anterior or lateral wall MIs are most often due to occlusion of the ___coronary artery.

Accepted Answer

An anterior wall MI is often due to occlusion of the left anterior descending coronary artery. A lateral wall MI occurs as a result of an occlusion of the left anterior descending, circumflex, or, in some patients, the right coronary artery.

Question 6

The clinical evidence of RVI involves three components:

Accepted Answer

The clinical evidence of RVI involves three main areas: hypotension, jugular venous distention, and clear breath sounds. This triad of signs is estimated to be present in only 10% to 15% of patients with RVI.

Question 7

Which of the following ECG changes is one of the earliest to occur during an infarction, but may have resolved by the time the patient seeks medical assistance?

Accepted Answer

Hyperacute T waves are sometimes called "tombstone" T waves and typically measure more than 50% of the preceding R wave. In addition to an increase in height, the T wave becomes more symmetric and may become pointed. These changes are often not recorded on the ECG because they have typically resolved by the time the patient seeks medical assistance.

Question 8

From what point should ST-segment deviation be measured?

Accepted Answer

The answer of From what point should ST-segment deviation be...

Question 9

Explain what is meant by the phrase anatomically contiguous leads.

Accepted Answer

The answer of Explain what is meant by the phrase...

Question 10

When should you assess a patient for a possible posterior infarction?

Accepted Answer

The answer of When should you assess a patient for...

Question 11

When should you suspect an RVI?

Accepted Answer

The answer of When should you suspect an RVI?...

Question 12

A 72-year-old woman is experiencing a possible acute coronary syndrome. A 12-lead ECG has been obtained. As the health care professional reviewing the patient's ECG, you should attempt to categorize the patient into one of three groups. Name them. 1. 2. 3.

Accepted Answer

The answer of A 72-year-old woman is experiencing a possible...

Quiz 5: Ethics