Asphyxiation-t

The De Winter sign was first described in 2008 by the Dutch cardiologist Robbert Jan de Winter and named after him (Gollwitzer 2020).

Asphyxia T is an elevation of the T wave in the ECG, which can be symmetrical, isosceles, positive or narrow with a prominent peak (Levis 2015 / von Olshausen 2005). Depending on the cause, it can be pathological, but also without pathological significance (von Olshausen 2005).

Choking T presents differently depending on the cause:

• Myocardial infarction: A choking T occurs in the ischemic zone in acute transmural myocardial infarction. It is the earliest change to be derived in the ECG and usually escapes detection because it lasts for a very short time, i.e., only a few minutes (Herold 2022 / Kasper 2017 / Börger 1994). In myocardial infarction, asphyxial T shows broad-based, symmetric, isosceles positive (Börger 1994) T- waves in the ECG. The amplitude is increased. Often the T- waves are associated with a lowered ST- take- off (Levis 2015). Under balloon occlusion, there may be a change in the polarity of the T- waves (Goldberger 1982), i.e., a choking T may be fully reversible (von Olshausen 1995).
• Volume overload: In this case, large, symmetric, concordant T is found (von Olshausen 2005).
• Hyperkalemia: In contrast, in hyperkalemia, the T- waves in the ECG are narrow with a prominent peak (Levis 2015). In addition, the intraventricular conduction disturbance leads to a deformation and broadening of the QRS complex (von Olshausen 2005). The typical T-wave is the earliest ECG sign of hyperkalemia (Ohly 2019).
• Carbon monoxide poisoning: Here, as in myocardial infarction, a broad-based, symmetrical, isosceles positive T- wave (Börger 1994) with increased amplitude is found (Levis 2015).
• In vagotonia, vegetative lability, bradycardia and after a longer compensatory pause, the concordant T-wave is always asymmetric and has no pathological significance (von Olshausen 2005).

The occurrence of a choking T- wave may be caused by:

- acute myocardial infarction

- hyperkalemia

- cerebrovascular damage

- left ventricular volume overload e.g. mitral or aortic regurgitation (Kasper 2015), aortic valve regurgitation, patent ductus arteriosus (von Olshausen 2005)

- as a norm variant (Kasper 2015)

- Increased vagotonus in young adults (Gollwitzer 2020).

- carbon monoxide poisoning

- bradycardia (von Olshausen 2005)

The vector of the T- wave is an expression of repolarization (Ohly 2019).

• Myocardial ischemia: In myocardial ischemia, a choking T occurs seconds to minutes after the event. Due to ischemia, repolarization of the inner layer of the myocardium occurs more slowly than in the relatively more perfused parts of the myocardial outer layer (von Olshausen 1996). As a consequence of this slowing, the outer layers of the myocardium have already repolarized, whereas the process of repolarization in the inner layers has not yet proceeded (Halhuber 1978). Thus, the vector is amplified and makes the positive T- wave appear higher than in the normal state (von Olshausen 1996). As the infarct progresses, the outer layer also becomes less well perfused and the T- wave transitions to its terminal negative state (Halhuber 1978).
• Hyperkalemia: Hyperkalemia leads to positive bathmo-, chrono-, and inotropy (excitability, frequency, contractility [Thierbach 2002] [Silbernagl 2009]). Discrete depolarization makes myocardial cells more rapidly excitable. The membrane potential is strongly positive above a certain amount of potassium, so that the cell can no longer repolarize below a threshold of about - 40 mV. As a result, the voltage-gated sodium channels that would allow renewed action potentials can no longer open, and cardiac actions are ultimately arrested (von Karais 2020).

- Myocardial infarction:

Asphyxiation T manifests in ST- elevation myocardial infarction = STEMI myocardial infarction in the initial stage (Jensch 2018).

- Hyperkalemia:

As of serum potassium levels of > 6 mval / l, choking T waves usually occur (von Olshausen 2005).

- De Winter's sign: Changes similar to those of the asphyxia T are found. The De Winter sign is an atypical sign in patients with LAD stenosis. It is an equivalent of anterior wall STEMI, but without ST stretch elevation (Gollwitzer 2020).

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