From the Guidelines
Significant heart axis deviation is considered to be left-axis deviation beyond 30° and right-axis deviation beyond 90° in adults, as stated in the 2009 American Heart Association recommendations 1. The normal QRS axis in adults is within 30° and 90°, and any deviation beyond this range can be indicative of underlying cardiac conditions.
- Left-axis deviation is categorized into moderate (between 30° and 45°) and marked (between 45° and 90°), with the latter often associated with left anterior fascicular block.
- Right-axis deviation is also categorized into moderate (between 90° and 120°) and marked (between 120° and 180°), with the latter often associated with left posterior fascicular block. In children, the normal QRS axis shifts from a rightward orientation at birth to a more leftward orientation throughout childhood, with different age-specific ranges considered normal 1. It is essential to consider the age and body habitus of the individual when interpreting the QRS axis, as these factors can influence the normal range.
- The QRS axis can be determined by examining leads I and aVF on the electrocardiogram (ECG), with specific patterns indicating left, right, or extreme axis deviation. Significant axis deviation warrants further cardiac evaluation to identify the underlying cause, which might include echocardiography or other cardiac imaging studies, as it can be associated with various cardiac conditions, such as left ventricular hypertrophy, conduction blocks, or structural heart abnormalities 1.
From the Research
Significant Heart Axis Deviation
There is no direct information in the provided studies regarding what is considered a significant heart axis deviation.
- The studies primarily focus on the treatment and management of atrial fibrillation, heart failure, and ventricular arrhythmias using various medications such as beta-blockers, amiodarone, and sotalol 2, 3, 4, 5, 6.
- They discuss the importance of controlling ventricular rate, preventing atrial fibrillation, and managing heart failure, but do not provide specific information on heart axis deviation.
- None of the studies mention the criteria for determining a significant heart axis deviation, suggesting that this topic may not be directly related to the research presented in these studies.