The patient's ECG shows ______ complexes with an intrinsicoid deflection time greater than 0.05 seconds in V5-V6, suggesting left ventricular hypertrophy.
1R✓ 정답
2QRS
3S
4T
5P
해설
Tall R waves with prolonged intrinsicoid deflection time (>0.05s) in left lateral leads V5-V6 are characteristic of left ventricular hypertrophy. This represents the increased time required for electrical activation to traverse the thickened left ventricular wall.
1. Diagnostic Criteria for LVH:
- R wave amplitude in V5/V6 > 26mm
- R wave in aVL > 11mm
- S wave in V1 + R wave in V5/V6 > 35mm (Sokolow-Lyon criteria)
- R wave in lead I + S wave in lead III > 25mm (Lewis criteria)
2. Intrinsicoid Deflection:
- Time from QRS onset to R wave peak
- Normal: < 0.05 seconds
- LVH: > 0.05 seconds in V5-V6
- Represents ventricular depolarization time
3. Additional ECG Features of LVH:
- Left axis deviation
- ST depression with T wave inversion
- Prolonged QRS duration
- Deep S waves in V1-V2
- Increased QRS voltage
5. Voltage Criteria:
- Cornell criteria: R in aVL + S in V3
- Modified Cornell criteria
- Romhilt-Estes point score system
핵심 개념
R — A positive deflection in the ECG that represents ventricular depolarization, typically the largest upward wave in the QRS complex
QRS — The combination of waves representing ventricular depolarization on an ECG, consisting of Q wave (downward), R wave (upward), and S wave (downward)
S — The negative deflection following the R wave in the QRS complex, representing the final phase of ventricular depolarization
T — The wave representing ventricular repolarization, typically appearing as a rounded upward deflection after the QRS complex
P — The first wave in the ECG cycle representing atrial depolarization, appearing as a small rounded upward deflection before the QRS complex