II. Definitions
-
J Point (Junction Point)
- Junction between end of QRS Complex and begining of ST Segment
- J Wave
- Terminal slurring of the QRS Complex
- Deflection that forms at junction of QRS Complex and ST Segment, esp. lateral and precordial leads
- May appear as slurring or notch within the QRS (prior to the J Point and onset of ST Segment)
- J Wave may be upright or inverted
III. Causes: J Wave Syndromes
- Early Repolarization Syndrome
- Brugada Syndrome
-
Hypothermia (Temperature <32 C)
- J Wave amplitude increasing as core Temperature drops, and resolves with rewarming
- Associated with prolonged intervals (PR, QRS, QT), Sinus Bradycardia or Atrial Fibrillation
IV. Causes: Other J Wave causes
- Myocardial Ischemia
- Sepsis
- Hypercalcemia
- Normal variant in some young patients
- CNS disorder
V. Differential Diagnosis
-
Right Bundle Branch Block (RBBB)
- J Wave Type I (wide, large J Wave in leads V1-3) may appear similar to RBBB
- However, QRS Duration is not wide in lateral leads in J Wave (contrast with wide in RBBB)
VI. References
- Mattu (2018) Crit Dec Emerg Med 32(7): 14
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| Concepts | Pathologic Function (T046) |
| English | j waves, j wave |
