# The patient presents with acute chest pain, and the ECG shows ______ waves in leads V1-V3, indicating myocardial injury.

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> url: https://mymerci.kr/pages/nclex_q.php?qn_id=168387  
> language: ko  
> subject: Diseases of the circulatory system

## 문제

The patient presents with acute chest pain, and the ECG shows ______ waves in leads V1-V3, indicating myocardial injury.

## 보기

1. Q **✔ 정답**
2. R
3. S
4. T
5. U

**정답: 1**

## 해설

Q waves are abnormal deflections that appear first in the QRS complex. Pathological Q waves in leads V1-V3 suggest anterior wall myocardial damage, as they represent the absence of normal electrical activity in that region of the heart muscle.

## 임상 시나리오

ECG Wave Patterns and Interpretation:
- Q waves: Initial downward deflection of QRS complex
- Normal Q wave: 25% of R wave depth
- Anterior MI: Q waves in V1-V4
- Inferior MI: Q waves in II, III, aVF
- Lateral MI: Q waves in I, aVL, V5-V6
- QRS complex: Represents ventricular depolarization
- ST elevation: Acute myocardial injury
- T wave inversion: Ischemia
- Minnesota Code: Standardized ECG classification
- Leads V1-V3: Anterior wall monitoring
- Cardiac axis: Direction of electrical activity
- Bundle branch blocks: Altered QRS morphology
- R wave progression: Normal R wave increases V1-V6

## 핵심 개념

- **Q wave** — The first negative deflection of the QRS complex in an ECG, representing ventricular depolarization. When pathological, it indicates myocardial necrosis or scarring
- **R wave** — The first positive deflection in the QRS complex of an ECG, representing the main wave of ventricular depolarization
- **S wave** — The negative deflection following the R wave in the QRS complex, representing the final phase of ventricular depolarization
- **T wave** — The wave representing ventricular repolarization in an ECG, normally appearing as a rounded, positive deflection after the QRS complex
- **U wave** — A small, rounded deflection sometimes seen following the T wave, believed to represent repolarization of the Purkinje fibers or late repolarization of ventricular cells

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