Tall and symmetrical T waves

Introduction Subendocardial myocardial ischemia results in a tall and symmetrical T wave. After exercise causes acute coronary insufficiency, the subendocardial ischemia can be induced, and the T wave vector leads to the V4 and V5 leads (back to the endocardial surface). Therefore, the T wave is increased and symmetric in these leads and adjacent leads. And changed by an arrow.

Cause

Exercise-induced coronary insufficiency causes acute myocardial ischemia in the subendocardial and subepicardum of the heart muscle, resulting in T wave morphology and directional changes.

an examination

Related inspection

ECG chest B-ultrasound

ECG check:

(1) subendocardial ischemia

T wave is towering and symmetrical

After exercise causes acute coronary insufficiency, the subendocardial ischemia can be induced, and the T wave vector leads to the V4 and V5 leads (back to the endocardial surface). Therefore, the T wave is increased and symmetric in these leads and adjacent leads. And changed by an arrow. Such changes are often accompanied by a decrease in the ST segment of subendocardial injury and a shortening of Q Tc. At this time, the amplitude of the T wave increases, and 10% of patients with coronary heart disease can exceed 0.5 mV or 3 times the amplitude of calm.

(2) epicardial ischemia

T wave inversion

In the subepicardial ischemia, the T wave vector is back-centrifuged to the outer membrane surface, and the back of the V4 and V5 leads. The lead and its adjacent leads appear T-wave inversion, showing double-symmetry and arrow-like changes. The T wave inversion can occur alone or simultaneously with the ST segment and the U wave anomaly. That is, in the same lead (V4, V5), if the ST segment falls and the symmetry inversion of the T wave is present at the same time, it indicates that there is both subendocardial damage and subepithelial ischemia. The T wave inversion of the V5 lead often occurs later, usually occurring a few minutes after the end of the exercise test, and lasts for a long time, sometimes as long as 40 minutes with Q Tc prolongation. A separate T wave inversion often indicates coronary insufficiency in the following situations:

1 inverted T wave is obviously arrow-shaped, symmetrical, and the ST segment stays on the equipotential line for a long time (>0.12 seconds);

2Q T interval extension;

3 The degree of T wave inversion after exercise is greater than the electrocardiogram record of standing and quiet ventilation for 30 seconds;

4 T wave inversion after exercise is accompanied by a relatively slow heart rate;

5 T wave inversion occurs in the I lead (indicating that the QRS T angle increases). When the inverted T wave is accompanied by the ST segment falling, the inverted T wave often appears later, that is, the T wave inversion occurs in the ST segment. After that, the T wave inversion occurs only after the ST segment has disappeared or disappeared after the exercise.

(3) Physiological T wave inversion

T wave inversion is sometimes a normal physiological response caused by exercise, which is characterized by:

The 1T wave is an asymmetrical arrow-like change;

2 no QT interval extension;

The 3ST segment stays on the baseline for a short time;

The depth of the 4T wave inversion is <0.2mV.

Physiological T wave inversions are seen in the following factors:

1 excessive ventilation;

2 increased sympathetic tone;

3 The effect of tachycardia on the myocardium;

4 The normal wide QRS-T angle is further widened. At this time, the electrocardiogram has the following characteristics: the calming electrocardiogram has a higher R wave accompanied by a lower T wave; the T wave is lower or inverted during exercise, especially when the tachycardia is overspeed Oral potassium salt can prevent the occurrence; more common in the elongated and weak form, T wave inversion can also be found in obese young people.

Differential diagnosis

Towering and symmetrical T waves need to be identified as follows:

The positive rate of 1T wave change was 6.34% (523/8 248), and 95.60% (500/523) was under 50 years old.

2T wave changes occurred in II.III, aVF leads accounted for 43.02% (225/523), II, III, aVF and V4~V6 leads accounted for 53.35% (279/523), and other leads accounted for 3.63% (19/ 523). The single T wave change accounted for 72.85% (381/523), and the ST segment mild downshift accounted for 27.15% (142/523).

3T wave low level accounted for 89.87% (470/523), and double peak or inverted accounted for 10.13% (53/523).

The 4T wave change was judged as functional accountability of 99.24% (519/523), of which 144 cases were spontaneously recovered by T wave, 14 cases were normal T wave, 195 cases were negative in treadmill exercise test, and 166 cases were positive in propranolol test. Pathological T wave changes accounted for 0.76% (4/523), which was positive for exercise test. Conclusion T-wave changes in the special service personnel are common, and are more common in people under the age of 50, most of which are functional. The use of "four-step identification method", that is, "finding physiological incentives, identifying normal mutations, doing a good identification test, and characterization of comprehensive data" can be accurately identified and can be used as a reference indicator for health identification.

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