Left axis deviation
In
There are several potential causes of LAD. Some of the causes include normal variation,
Symptoms and treatment of left axis deviation depend on the underlying cause.
Defining left axis deviation
Determining left axis deviation
Determining the electrical axis can provide insight into underlying disease states and help steer the differential diagnosis.[2] There are several methods to determining the ECG axis. The easiest method is the quadrant method, where one looks at lead I and lead aVF. First, examine the QRS complex in both leads I and avF and determine if the QRS complex is positive (height of R wave > S wave), equiphasic (R wave = S wave), or negative (R wave < S wave). If lead I is positive and lead aVF is negative, then this is a possible LAD. To determine a true LAD, examine QRS in lead II. If the QRS complex is positive in lead II, then this is a normal axis. On the other hand, if QRS complex is negative in lead II, then this is a LAD.Another method of determining LAD is called the Isoelectric lead, which allows for a more precise estimation of the QRS axis.[3]
Causes
There are several potential causes of LAD. These include normal variation, left ventricular hypertrophy, conduction defects, inferior wall myocardial infarction, preexcitation syndrome, ventricular ectopic rhythms, congenital heart disease, hyperkalemia, emphysema, mechanical shift and pacemaker-generated paced rhythm. Normal variation causing LAD is an age-related physiologic change. Conduction defects such as
Signs and symptoms
Left axis deviation symptoms depend on the underlying cause.
Treatment
Left axis deviation per se does not require treatment, however the underlying cause can be treated.
See also
References
- ^ Jenkins, Dean (1996). "The electrical axis at a glance". www.ecglibrary.com. Retrieved 2016-11-12.
- ^ PMID 29262101, retrieved 2021-07-26
- ^ a b Cadogan, Mike; Buttner, Robert (2021-01-05). "ECG Axis Interpretation". Life in the Fast Lane • LITFL. Retrieved 2021-07-26.
- PMID 28231933.
- ^ a b Team, Health Jade (2020-03-19). "Heart left axis deviation causes, symptoms & treatment". Health Jade. Retrieved 2021-07-26.
- ^ "What is Left Ventricular Hypertrophy (LVH)?". www.heart.org. Retrieved 2021-07-26.
- ^ Kang MD, Steven. "Left Bundle Branch Block". Cedars-Sinai. Retrieved 2021-07-26.
- ^ "Left ventricular hypertrophy - Diagnosis and treatment - Mayo Clinic". www.mayoclinic.org. Retrieved 2021-07-26.