Understanding ECG Axis and Axis Deviation | Heart | ECG скачать в хорошем качестве

Understanding ECG Axis and Axis Deviation | Heart | ECG

What is axis deviation on an ECG? 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 causes ECG axis deviation? Most causes can be attributed to one of four main mechanisms. These include right ventriular hypertrophy, reduced muscle mass of left ventricle, altered conduction pathways and change in the position of the heart in the chest. What is a normal axis deviation? The electrical axis of the heart (heart axis). As evident from the figure, the normal heart axis is between –30° and 90°. If the axis is more positive than 90° it is referred to as right axis deviation. If the axis is more negative than –30° it is referred to as left axis deviation. How do you calculate ECG axis deviation? The most efficient way to estimate axis is to look at LEAD I and LEAD aVF. A positive QRS in Lead I puts the axis in roughly the same direction as lead I. A positive QRS in Lead aVF similarly aligns the axis with lead aVF. Should I be worried about left axis deviation? In conclusion, among patients with left bundle branch block, those with left axis deviation have a greater incidence of myocardial dysfunction, more advanced conduction desease and greater cardiovascular mortality than those with a normal axis. What is the most common cause of left axis deviation? Left anterior fascicular block (LAFB): LAFB probably is the most common cause of left axis deviation and is common in persons without overt cardiac disease. Should I be worried about right axis deviation? [12,13,14] Right axis deviation can be considered a normal variant or can be associated with a right bundle branch block, causes of right ventricular hypertrophy and infarction of the left side of the heart, among the more likely differential diagnoses Can left axis deviation be cured? Treatment. Left axis deviation per se does not require treatment, however the underlying cause can be treated. If left ventricular hypertrophy is the cause of LAD, treatment depends on the underlying cause of the hypertrophy What conditions cause right axis deviation? Right axis deviation occurs when the QRS axis is shifted between 90 and 180 degrees. A number of things can result in right axis deviation which include lung disease, right sided heart strain, right bundle branch block, and right ventricular hypertrophy.