Dysrhythmia ECG Monitoring & Analysis

Question 1

What is the normal range for a PR interval on an ECG?

Accepted Answer

0.12 - 0.20 seconds

Answer

The PR interval represents the time it takes for an electrical impulse to travel from the sinoatrial (SA) node through the atria, AV node, and His-Purkinje system to the ventricles. A normal PR interval ranges from 0.12 to 0.20 seconds (3 to 5 small squares) on standard ECG paper. Deviations outside this range can indicate conduction abnormalities.

Question 2

Which ECG finding is characteristic of myocardial infarction?

Accepted Answer

ST-segment elevation

Answer

ST-segment elevation on an ECG is a critical indicator of acute myocardial infarction (heart attack), specifically an ST-elevation myocardial infarction (STEMI). It signifies transmural ischemia, where the entire thickness of the heart muscle wall is deprived of oxygen due to a complete blockage of a coronary artery. This finding requires immediate medical intervention, such as reperfusion therapy.

Question 3

Which ECG lead placement provides a view of the heart’s electrical activity from the left lateral perspective?

Accepted Answer

Lead aVL

Answer

The 12-lead ECG provides different views of the heart's electrical activity. Lead aVL is one of the augmented unipolar limb leads and specifically offers a view of the heart from the high lateral wall, which is part of the left lateral perspective. This allows for detection of changes in this specific region of the myocardium.

Question 4

What does a prolonged QT interval indicate?

Accepted Answer

Risk for Torsades de Pointes

Answer

A prolonged QT interval indicates a delay in ventricular repolarization, making the heart more vulnerable to developing dangerous arrhythmias. This increased vulnerability specifically predisposes individuals to Torsades de Pointes, a polymorphic ventricular tachycardia that can degenerate into ventricular fibrillation and sudden cardiac death. Therefore, identifying a prolonged QT interval is crucial for risk assessment.

Question 5

Which ECG abnormality suggests hyperkalemia?

Accepted Answer

Tall, peaked T waves

Answer

Hyperkalemia, an elevated potassium level in the blood, significantly affects cardiac electrical activity. One of the earliest and most characteristic ECG changes is the appearance of tall, narrow, and peaked T waves, often described as 'tented.' This reflects altered repolarization due to the increased extracellular potassium concentration.

(DC) Dysrhythmia Certification Practice Test

(DC) Dysrhythmia Certification Practice Test

Dysrhythmia ECG Monitoring & Analysis