# The ECG shows ______ contractions, where extra heartbeats originate from an irritable focus in the ventricles.

> source: MyMerci (mymerci.kr)  
> url: https://mymerci.kr/pages/nclex_q.php?qn_id=168391  
> language: ko  
> subject: Diseases of the circulatory system

## 문제

The ECG shows ______ contractions, where extra heartbeats originate from an irritable focus in the ventricles.

## 보기

1. premature **✔ 정답**
2. ectopic
3. aberrant
4. escape
5. retrograde

**정답: 1**

## 해설

Premature ventricular contractions (PVCs) occur when the ventricles contract earlier than they should in the cardiac cycle. These early beats originate from an irritable focus in the ventricles rather than following the normal conduction pathway.

## 임상 시나리오

ECG Abnormal Contractions:

1. Premature Ventricular Contractions (PVCs)
- Early beats originating from ventricles
- Wide QRS complex (>120ms)
- No preceding P wave
- Compensatory pause follows

2. Characteristics of PVCs
- Unifocal: single origin point
- Multifocal: multiple origin points
- Bigeminy: alternating normal-PVC pattern
- Trigeminy: two normal beats-one PVC pattern

3. Clinical Significance
- Common in healthy individuals
- May indicate underlying heart disease
- Risk factors: caffeine, stress, electrolyte imbalance
- Treatment needed if frequent/symptomatic

4. Related ECG Terms
- Coupling interval: time between normal and premature beat
- Interpolated PVCs: occur between normal beats
- R-on-T phenomenon: PVC during T wave
- Ventricular tachycardia: multiple consecutive PVCs

## 핵심 개념

- **premature** — Occurring earlier than normal or expected in the cardiac cycle, specifically referring to contractions that happen before the regular heartbeat sequence
- **ectopic** — Occurring in an abnormal position or place, referring to heartbeats that originate from a location other than the normal pacemaker site
- **aberrant** — Deviating from the normal or typical pattern, referring to abnormal conduction pathways in cardiac electrical activity
- **escape** — A backup heartbeat that occurs when the normal pacemaker fails to initiate a contraction, serving as a protective mechanism
- **retrograde** — Moving or conducted in a backward direction, opposite to the normal direction of cardiac electrical conduction

## 같은 주제 문제

- [The patient's EKG shows significant ST ______ in leads V2 through V4, suggesting acute ant…](https://mymerci.kr/pages/nclex_q.php?qn_id=168328)
- [Patient presents with ______ angina not responding to sublingual nitroglycerin.](https://mymerci.kr/pages/nclex_q.php?qn_id=168343)
- [Patient's telemetry shows ______ rhythm with a rate of 150, requiring immediate cardiovers…](https://mymerci.kr/pages/nclex_q.php?qn_id=168345)
- [Echo shows severe ______ regurgitation requiring valve replacement.](https://mymerci.kr/pages/nclex_q.php?qn_id=168361)
- [MRI shows acute ______ stroke in the left MCA territory.](https://mymerci.kr/pages/nclex_q.php?qn_id=168366)
- [In hypertensive crisis, the patient shows severely elevated ______ pressure, often exceedi…](https://mymerci.kr/pages/nclex_q.php?qn_id=168375)
- [During cardiac auscultation, the nurse hears an abnormal heart sound between S1 and S2, in…](https://mymerci.kr/pages/nclex_q.php?qn_id=168376)
- [The patient's ECG shows a ______ rhythm with no discernible P waves and an irregularly irr…](https://mymerci.kr/pages/nclex_q.php?qn_id=168377)

---

More free questions: [기출문제](https://mymerci.kr/)

_학습 참고용입니다. 실제 임상은 최신 지침과 소속 기관 프로토콜을 따르세요._