The axis of the ECG is the major direction of the overall electrical activity of the heart. It can be normal, leftward (left axis deviation, or LAD), rightward (right axis deviation, or RAD) or indeterminate (northwest axis). The QRS axis is the most important to determine.
What is normal cardiac axis?
The normal cardiac axis is expected to lie between -30º and 90º, which means the overall direction of electrical activity is toward leads I, II, and III.
What does right axis deviation indicate?
If the electrical axis falls between the values of -30° to +90° this is considered normal. If the electrical axis is between -30° to -90° this is considered left axis deviation. If the electrical axis is between +90° to +180° this is considered right axis deviation (RAD).
What does axis deviation indicate?
Right axis deviation (RAD) involves the direction of depolarisation being distorted to the right (between +90º and +180º). The most common cause of RAD is right ventricular hypertrophy. Extra right ventricular tissue results in a stronger electrical signal being generated by the right side of the heart.
What causes heart axis deviation?
Some of the causes include normal variation, thickened left ventricle, conduction defects, inferior wall myocardial infarction, pre-excitation syndrome, ventricular ectopic rhythms, congenital heart disease, high potassium levels, emphysema, mechanical shift, and paced rhythm.
What causes left axis deviation?
Left axis deviation occurs when the QRS axis falls between -30 and -90. There are a variety of causes, including left anterior fascicular block and left ventricular hypertrophy. See the ECG basics section on determining axis for details.
What is abnormal in ECG?
An abnormal ECG can mean many things. Sometimes an ECG abnormality is a normal variation of a heart’s rhythm, which does not affect your health. Other times, an abnormal ECG can signal a medical emergency, such as a myocardial infarction /heart attack or a dangerous arrhythmia.
Is a left axis deviation serious?
Left axis deviation (LAD) is the most common “abnormality” in adults, occurring in over 8% of patients. It can be part of the criteria for LVH, but in isolation it has little significance. Marked LAD (45% or more) is calledleft anterior hemiblock orleft anterior fascicular block.
Does left axis deviation mean heart disease?
The results were that the development of left axis deviation in men 40 to 59 yr of age, independent of blood pressure is a significant predictor of ischemic heart disease events that are usually manifest 5 to 10 yr after the onset of this electrocardiographic abnormality.
Is right axis deviation serious?
Right axis deviation is a strong indicator of pulmonary hypertension in a risk population.
