ST-T changes in PVCs, ventricular arrhythmias, and ventricular paced beats.ST-T changes seen in bundle branch blocks (generally the ST-T polarity is opposite to the major or terminal deflection of the QRS)."Secondary" ST-T Wave changes (these are normal ST-T wave changes solely due to alterations in the sequence of ventricular activation): Ventricular conduction abnormalities and rhythms originating in the ventricles.Atrial repolarization (e.g., at fast heart rates the atrial T wave may pull down the beginning of the ST segment).Metabolic factors (e.g., hypoglycemia, hyperventilation).Neurogenic factors (e.g., stroke, hemorrhage, trauma, tumor, etc.).Electrolyte abnormalities of potassium, magnesium, calcium.Drugs (e.g., digoxin, quinidine, tricyclics, and many others).Intrinsic myocardial disease (e.g., myocarditis, ischemia, infarction, infiltrative or myopathic processes).
Patient to ascertain the importance of the ECG findings.įactors affecting the ST-T and U wave configuration include: Thisĭoes not mean that the ECG changes are unimportant! It is the responsibility of the clinician providing care for the Thus the term, nonspecific ST-T waveĪbnormalities, is frequently used when the clinical data are not available to correlate with the ECG findings. In which the ECG changes are found than by the particular changes themselves. General Introduction to ST, T, and U wave abnormalitiesīasic Concept: the specificity of ST-T and U wave abnormalities is provided more by the clinical circumstances
General Introduction to ST-T and U Wave Abnormalities.The PP intervals are constant (↔) and the atrial rate is 90 beats/min. These P waves are not followed by a QRS complex (ie, they are nonconducted).
Two additional P waves (*) are seen between each QRS complex. The P waves a re positive in leads I, II, aVF, and V4-V6 and hence there is a sinus rhythm. There is a P wave before each QRS complex (+) with a stable but prolonged PR interval (0.24 sec). The QT/QTc intervals are normal (600/425 msec). This has often been called a "crista pattern." The axis is approximately +90° (biphasic QRS complex in lead I and positive in lead aVF). This pattern is consistent with an intraventricular conduction delay (IVCD) to the right ventricle. This has often been termed an incomplete right bundle branch block but this is not appropriate, as conduction through the bundles is all or none and it not incomplete. The QRS complex duration is normal (0.08 sec) and there is a normal morphology, although there is a narrow R' in lead V1. The rhythm is regular with a rate of 30 beats/min.