The term J-point elevation represents a family of ECG findings. It has been described in several metabolic disorders most notably hypothermia (abnormally low body temperature). Subtle nuances in its pattern may point to other conditions, the most common of which is termed ‘early repolarization’.
What do J waves indicate?
Although “J Wave” is supposed to be pathognomonic of hypothermia, it is seen in a host of other conditions such as hypercalcemia, brain injury, subarachnoid hemorrhage, cardiopulmonary arrest from over sedation, the Brugada syndrome, vasospastic angina, and idiopathic ventricular fibrillation.
Is J-point elevation significant?
J-point elevation of >0.1 mV in inferior leads was associated with an increased risk of death from cardiac causes (adjusted relative risk, 1.28 P = 0.03). J-point elevation >0.2 mV in inferior leads was observed in 0.3% and increased the adjusted relative risk of death from cardiac causes to 2.98 (P<0.001).
What is the J-point on an ECG?
Introduction. The J-point on the electrocardiographic waveform is historically defined as the junction between the end of the QRS complex and the beginning of the ST-segment.
What causes J waves on ECG?
There are four principal causes of J waves, namely hypothermia, Brugada syndrome, early repolarization and hypercalcemia. Figure 1. Osborn wave (J wave). These waves occur due to hypothermia, hypercalcemia, early repolarization and Brugada syndrome.
How is J wave treated?
Treatment
- Isoproterenol infusion can be useful in suppressing electrical/VT storms in patients with diagnosis of J wave/ER syndrome.
- Quinidine in addition to an ICD can be useful for secondary prevention and suppression of VT/VF in patients with a diagnosis of J wave/ER syndrome.
What causes Osborn J waves?
J waves, also known as Osborn waves or the camel-hump sign, can be caused by hypercalcemia, brain injury, subarachnoid hemorrhage, and cardiopulmonary arrest from oversedation, vasospastic angina, or ventricular fibrillation. However, the chief cause is hypothermia (body temperature, <90 °F).
How is J point elevation different from ST elevation?
ST segment / T wave morphology
- There is elevation of the J point.
- The T wave is peaked and slightly asymmetrical.
- The ST segment and the ascending limb of the T wave form an upward concavity.
- The descending limb of the T wave is straighter and slightly steeper than the ascending limb.
What does a notched J point mean?
Early repolarization syndrome ER is characterized by prominent J-point on ECG with notching/slurring of distal part of R wave which more or less appears as pseudo delta wave. J notches are known for long time and are actually present in 2–10% of general population.
What is early repolarization syndrome?
Early repolarization syndrome is diagnosed by the presence of J-point elevation ≥1 mm in ≥2 contiguous inferior and/or lateral leads of a standard 12-lead ECG in a patient resuscitated from otherwise unexplained ventricular fibrillation/ polymorphic ventricular tachycardia.
What causes ST elevation in all leads?
The most important cause of ST segment elevation is acute Ischemia. Other causes are [4][6]: Early repolarization. Acute pericarditis: ST elevation in all leads except aVR.
What does it mean when the J point is elevated?
1 Elevation or depression of the J point is seen with the various causes of ST segment abnormality . 2 Elevation of the J point occurs with benign early repolarisation 3 A positive deflection prior to the J point is termed a J wave (Osborn wave) and is characteristically seen with hypothermia.
What causes depression of the J point?
Abnormalities of the J point Elevation or depression of the J point is seen with the various causes of ST segment abnormality. It may be elevated as a result of injury currents during acute myocardial ischemia and pericarditis, as well as in various other patterns of both normal and abnormal ECGs
What is J-point elevation of QRS?
What is a J-point elevation? J-point is the point at which the QRS complex meets the ST wave. ST segment elevation with an upward convexity is usually benign, especially when seen in healthy, asymptomatic individuals. ST segment elevation with a downward concavity is more likely to be due to acute coronary syndrome.
What is early repolarization of the J point?
The condition has been recognized for decades, and it has been regarded as a benign form of ST segment elevation with slurring or notching at the J point. A notch at the J point is actually a J wave. The term “early repolarization” was used to describe what appeared to be a premature repolarization on the ECG.
