# AI指示将V1和V2心电图导联放置在第二肋间隙而非第四肋间隙，导致STEMI误诊

- **ID:** `medical/ecg-lead-misplacement-stemi`
- **领域:** medical
- **类别:** life_threatening
- **错误码:** `ECG-LEAD-MISPLACE-004`
- **验证级别:** ai_generated
- **修复率:** 82%

## 根因

将V1和V2放置在第二肋间隙（而非正确的第四肋间隙）会改变QRS轴和ST段，产生类似前间壁心肌梗死（STEMI）的假性ST段抬高。

## 版本兼容性

| 版本 | 状态 | 引入 | 弃用 |
|------|------|------|------|
| GE MAC 5500 | active | — | — |
| Philips PageWriter TC70 | active | — | — |
| Mortara ELI 380 | active | — | — |
| Nihon Kohden ECG-1550K | active | — | — |

## 解决方案

1. ```
   Palpate the Angle of Louis (sternal angle) at T4, then count down two intercostal spaces to the 4th space. Place V1 at the right sternal border, V2 at the left sternal border, both at the 4th intercostal space. Example: 'Locate sternal angle, slide finger down to 2nd space (T5), then 3rd (T6), then 4th (T7) — place electrodes here.'
   ```
2. ```
   Use anatomical landmarks: The 4th intercostal space aligns with the nipple line in men (but not women); use the Angle of Louis as primary reference. Example: 'For female patients, use inframammary fold as approximate 5th space, then move up one space to 4th.'
   ```
3. ```
   If ECG shows abnormal ST elevation in leads V1-V3 with no clinical correlate, repeat ECG with correct lead placement. Compare with previous ECG if available. Example: 'Repeat ECG after confirming lead placement at 4th intercostal space; if ST elevation resolves, it was positional artifact.'
   ```

## 无效尝试

- **** — Using the clavicle as a landmark — leads are placed too high; correct reference is the Angle of Louis (sternal angle) at T4 (50% 失败率)
- **** — Counting intercostal spaces from the top down without palpating the Angle of Louis — often miscounts, placing V1 at 3rd space (40% 失败率)
- **** — Assuming V1 and V2 placement is 'mid-clavicular line 2nd space' for all patients — correct is 4th intercostal space, right and left of sternum (60% 失败率)