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The last half of the T wave is referred to as the relative refractory period or vulnerable period. The T wave contains more information than the QT interval. The T wave can be described by its symmetry, skewness, slope of ascending and descending limbs, amplitude and subintervals like the T peak –T end interval. [1] In most leads, the T wave ...
The TWA test uses an ECG measurement of the heart's electrical conduction using electrodes attached to one's torso. It takes approximately a half-hour to perform on an outpatient basis. The test looks for the presence of repolarization alternans (T-wave alternans), which is variation in the vector and amplitude of the T wave component of the ...
Wellens' syndrome is an electrocardiographic manifestation of critical proximal left anterior descending (LAD) coronary artery stenosis in people with unstable angina. Originally thought of as two separate types, A and B, it is now considered an evolving wave form, initially of biphasic T wave inversions and later becoming symmetrical, often ...
T wave: The T wave represents the repolarization of the ventricles. It is generally upright in all leads except aVR and lead V1. Inverted T waves can be a sign of myocardial ischemia, left ventricular hypertrophy, high intracranial pressure, or metabolic abnormalities. Peaked T waves can be a sign of hyperkalemia or very early myocardial ...
Only chest impacts occurring on a narrow band of the ECG during the upslope of the T wave (40 milliseconds (ms) before the peak of the T wave to the instant of the actual peak) will cause the ventricular fibrillation of commotio cordis, with an increased probability occurring when an impact happens from 30 to 10 ms before the peak of the T wave ...
Diagnosis is based on an ECG showing ST-segment depression at the J-point of 1 to 3 mm in leads V1 to V6, with tall and symmetrical T waves. [1] The ST-segment is upsloping and there is also often ST-segment elevation of 0.5 to 2 mm in lead aVR. [1] [2] The QRS complex is either normal or slightly wide. [1]
Hyperacute T waves need to be distinguished from the peaked T waves associated with hyperkalemia. [16] In the first few hours the ST segments usually begin to rise. [17] Pathological Q waves may appear within hours or may take greater than 24 hr. [17] The T wave will generally become inverted in the first 24 hours, as the ST elevation begins to ...
Long QT intervals predispose the patient to an R-on-T phenomenon, wherein the R-wave, representing ventricular depolarization, occurs during the relative refractory period at the end of repolarization (represented by the latter half of the T-wave). An R-on-T can initiate torsades. Sometimes, pathologic T-U waves may be seen in the ECG before ...