MultipleQuestion_fromVideo_text_ECG Basics.docx

**Question:** Which lead placement is used to record the heart's electrical activity in the frontal plane? A) Chest leads (V1-V6) B) Limb leads (I, II, III, AVR, AVL, AVF) C) Septal leads (VI, V2) D) Anterior leads (V3, V4) **Answer:** B) Limb leads (I, II, III, AVR, AVL, AVF) **Explanation:** The t...

**Question:** Which lead placement is used to record the heart's electrical activity in the frontal plane? A) Chest leads (V1-V6) B) Limb leads (I, II, III, AVR, AVL, AVF) C) Septal leads (VI, V2) D) Anterior leads (V3, V4) **Answer:** B) Limb leads (I, II, III, AVR, AVL, AVF) **Explanation:** The text mentions that six limb leads (I, II, III, AVR, AVL, AVF) are used to record the heart's electrical activity in the frontal plane. Chest leads (V1-V6), septal leads (VI, V2), and anterior leads (V3, V4) are used in other planes and have different purposes. **Question:** Which wave represents ventricular repolarization in an ECG? A) P wave B) PR interval C) QRS complex D) T wave **Answer:** D) T wave **Explanation:** The T wave in an ECG represents ventricular repolarization. The text explains that the T wave represents the phase in which the ventricles are repolarizing, which is the recovery of their electrical activity after depolarization. The other options are incorrect as follows: A) P wave represents atrial depolarization. B) PR interval represents the time from the beginning of atrial contraction to the beginning of ventricular contraction. C) QRS complex represents ventricular depolarization. **Question:** Which part of the ECG represents the time taken for ventricular depolarization and repolarization? **A. P wave B. PR interval C. QRS complex D. QT interval** **Answer:** C. QRS complex **Explanation:** In the text, it is mentioned that the QRS complex represents ventricular depolarization, which is the electrical activity related to the contraction of the ventricles. The QRS complex is followed by the T wave, which represents ventricular repolarization. The other options (A, B, and D) represent different parts of the ECG, but they are not specifically related to ventricular depolarization and repolarization. Question: What does a prolonged PR interval signify in an ECG? A) Atrial dilation B) Ventricular hypertrophy C) AV node dysfunction D) Sinus tachycardia Answer: C) AV node dysfunction Explanation: A prolonged PR interval on an ECG signifies a delay in the conduction of electrical impulses between the atria and ventricles, which is typically indicative of AV (atrioventricular) node dysfunction. This can result in various types of heart blocks and can be a cause of irregular rhythms and heart rate abnormalities. It is not associated with atrial dilation, ventricular hypertrophy, or sinus tachycardia. **Question:** Which ECG characteristic is typically associated with acute myocardial infarction (MI)? A) ST depression B) T wave inversion C) ST elevation D) Pathologic Q waves **Answer:** C) ST elevation **Explanation:** Acute myocardial infarction (MI) is typically associated with ST elevation on the ECG. This ST elevation is one of the early signs of MI and represents complete artery blockage (STEMI). Other ECG characteristics like ST depression and T wave inversion can be seen in cases of ischemia or unstable angina, but they are not specific to MI. Pathologic Q waves appear in ECG after an MI as a sign of necrosis, but they are not an early indicator. **Question:** What does the presence of elevated ST segments on an ECG indicate? A) Partial artery blockage B) Normal sinus rhythm C) Myocardial infarction D) Bundle branch block **Answer:** C) Myocardial infarction **Explanation:** Elevated ST segments on an ECG are a key characteristic of myocardial infarction (heart attack), denoted by the term "STEMI" (ST-Elevation Myocardial Infarction). This signifies a complete artery blockage that results in myocardial damage. Elevated ST segments are one of the earliest ECG signs of infarction and typically return to baseline over time. Option A is incorrect because partial artery blockage is associated with non-ST-elevation MI (NSTEMI) and does not cause elevated ST segments. Option B is incorrect because normal sinus rhythm refers to the normal electrical activity of the heart and is not related to ST segment elevation. Option D is incorrect because bundle branch blocks are unrelated to elevated ST segments; they are characterized by QRS complex abnormalities. **Question:** Which lead configuration records electrical activity in both the frontal and horizontal planes of the heart during an ECG? A) Limb leads B) Chest leads C) Precordial leads D) Bipolar leads **Answer:** B) Chest leads **Explanation:** The text mentions that chest leads, also known as precordial leads, provide information on cardiac activity in both the frontal and horizontal planes of the heart. These leads are labeled V1 to V6 and record electrical activity from different angles across the chest. The other options, limb leads, and bipolar leads do record electrical activity, but they do not cover both the frontal and horizontal planes as comprehensively as chest leads. **Question:** What is the normal range for the PR interval in an ECG? **A) 0.04-0.10 seconds B) 0.10-0.20 seconds C) < 0.12 seconds D) > 0.12 seconds** **Answer:** C) < 0.12 seconds **Explanation:** The PR interval is the time from the beginning of the P wave to the beginning of the QRS complex in an ECG. According to the provided text, the normal PR interval duration is between 0.12-0.20 seconds. Therefore, the correct answer is option C, which indicates that the normal PR interval is less than 0.12 seconds. **Question:** What does a prolonged PR interval signify in an electrocardiogram (ECG)? A. Atrial depolarization B. Ventricular depolarization C. Signifies AV nodal delay D. Ventricular repolarization **Answer:** C. Signifies AV nodal delay **Explanation:** In the context of an ECG, the PR interval represents the time between the beginning of atrial contraction (P wave) and the beginning of ventricular contraction (QRS complex). A prolonged PR interval indicates a delay in the electrical conduction at the atrioventricular (AV) node. This delay could be due to various reasons, such as heart block or other conduction abnormalities, and is often considered a sign of AV nodal delay. Option C is the correct answer. Options A, B, and D are incorrect: - Atrial depolarization is represented by the P wave. - Ventricular depolarization is represented by the QRS complex. - Ventricular repolarization is represented by the T wave. **Question:** Which part of the ECG represents ventricular repolarization? A) P wave B) PR interval C) QRS complex D) T wave **Answer:** D) T wave **Explanation:** In an ECG (Electrocardiogram), the T wave represents ventricular repolarization. The T wave is the portion of the ECG that reflects the electrical activity as the ventricles recover and prepare for the next cardiac cycle. The other options are as follows: A) P wave: Represents atrial depolarization. B) PR interval: Reflects the time from the beginning of atrial contraction to the beginning of ventricular contraction and signifies the AV nodal delay. C) QRS complex: Represents ventricular depolarization. So, option D, the T wave, is the correct answer as it corresponds to ventricular repolarization. Here's a multiple choice question along with the answer and an explanation based on the provided text: **Question:** Which component of the ECG represents the ventricular repolarization? A) P wave B) PR interval C) QRS complex D) T wave **Answer:** D) T wave **Explanation:** In the provided text, it is mentioned that the T wave represents ventricular repolarization. The P wave represents atrial depolarization, the PR interval signifies the time between the beginning of atrial contraction and the beginning of ventricular contraction, and the QRS complex represents ventricular depolarization. Therefore, the correct answer is the T wave, which represents ventricular repolarization.