Left Anterior Fascicular Block: Should You Be Concerned?

Abnormal electrocardiogram (ECG) findings?

The recent electrocardiogram report from your health check-up indicates left anterior fascicular block (also known as left anterior hemiblock), which has been consistent in your reports for the past two years.
Is it necessary to return for a follow-up appointment? What does "left anterior fascicular block" mean, and is it serious?

Irene, 40~49 year old female. Ask Date: 2016/03/30

Dr. He Dongjin reply Cardiology

Hello, there is no need to worry.
Intraventricular conduction block refers to the conduction block located below the His bundle, generally classified into left and right bundle branch blocks, as well as anterior and posterior divisions of the left bundle branch block.
Clinically, aside from heart sound splitting, there are no other specific manifestations.
The diagnosis primarily relies on electrocardiography (ECG).

The left bundle branch is further divided into the left anterior and left posterior divisions.
The left anterior division is thinner and receives blood supply only from the left anterior descending artery, making it more susceptible to damage.
In contrast, the left posterior division is thicker and receives dual blood supply from both the left circumflex artery and the right coronary artery, making it less likely to experience conduction block; if it does, it often indicates severe pathology.

The main etiology is coronary artery disease, but it can also be seen in conditions such as hypertension, cardiomyopathy, and aortic coarctation.
Symptomatically, aside from heart sound splitting, there are no other specific manifestations.
The diagnosis primarily relies on electrocardiography.

Diagnostic criteria for left anterior fascicular block on ECG include:
1.
Left axis deviation of -45° to -90°;
2.
Leads I and aVL show a qR pattern, with the R wave in aVL greater than that in lead I;
3.
Leads II, III, and aVF show an rS pattern, with the S wave in lead III greater than that in lead II;
4.
QRS duration is less than 0.11 seconds, mostly normal.

Changhua Hospital cares about you.

Reply Date: 2016/03/30

More Info

Left Anterior Fascicular Block (LAFB) is a type of intraventricular conduction delay that affects the electrical conduction system of the heart. It occurs when there is a blockage in the left anterior fascicle of the left bundle branch, which is responsible for conducting electrical impulses to the left ventricle. This condition is often identified through an electrocardiogram (ECG) and can be a significant finding, particularly in the context of underlying heart disease.

In your case, since the LAFB has been noted in your ECG reports for two consecutive years, it is essential to understand its implications. LAFB itself is not typically considered a life-threatening condition. However, it can be associated with other cardiac issues, particularly if there are underlying conditions such as hypertension, coronary artery disease, or structural heart abnormalities. The presence of LAFB may indicate that there is some degree of left ventricular hypertrophy or other cardiac stressors that need to be evaluated.

While LAFB can occur in healthy individuals without any significant heart disease, it is crucial to monitor it, especially if you have risk factors such as a family history of heart disease, high blood pressure, diabetes, or if you experience symptoms like chest pain, shortness of breath, or palpitations. Regular follow-up with a healthcare provider, particularly a cardiologist, is advisable to assess your heart health comprehensively. They may recommend additional tests, such as echocardiograms or stress tests, to evaluate your heart's function and structure.

In terms of severity, LAFB can be classified as a benign finding in some individuals, particularly if there are no associated symptoms or other cardiac abnormalities. However, it can also be a marker for more serious conditions, and its presence should prompt further investigation to rule out any underlying issues. If you have not experienced any symptoms and your overall health is stable, your healthcare provider may suggest routine monitoring rather than immediate intervention.

In conclusion, while LAFB itself may not be a cause for alarm, it is essential to maintain regular check-ups with your healthcare provider to ensure that your heart health is monitored appropriately. If you have any concerns or if your symptoms change, do not hesitate to seek medical advice. Understanding your heart's electrical conduction system and its implications can empower you to take proactive steps in managing your cardiovascular health.

Similar Q&A

Understanding Left Axis Deviation and Left Anterior Fascicular Block in ECG

Dear Dr. Zhong, The electrocardiogram (ECG) report from our stationed technical personnel indicates "left axis deviation and left anterior fascicular block." Could you please explain what these findings signify in terms of health warnings and whether they may impact no...

Dr. Zhong Yuxun reply Cardiology
Hello, Gaoou netizen: The three findings in the electrocardiogram report you mentioned are commonly found in general health check-up reports; even normal individuals may exhibit these findings. Therefore, if the examinee has no symptoms or discomfort, these findings are likely no...

Understanding Left Posterior Fascicular Block: Do You Need Further Testing?

Hello, doctor. In my health check report, the electrocardiogram showed <left posterior fascicular block>. Should I follow up or undergo further examination? Thank you!

Dr. Huang Yinghe reply Cardiology
Hello: Simply looking at the electrocardiogram shows left posterior fascicular block, but it cannot confirm the presence of disease; it only indicates that the electrical conduction direction of the heart is abnormal. This could be related to cardiovascular disease, pulmonary iss...

Understanding Left Ventricular Hypertrophy and Its Implications

A few days ago, my health check report indicated that I have left ventricular hypertrophy and suspected left anterior fascicular block. Is this issue serious? What are the treatment options?

Dr. Lin Jixiong reply Cardiology
Hello: You may visit the cardiology outpatient clinic to discuss with the attending physician; observation can be done initially. Dr. Lin Chi-Hsiung, Taoyuan General Hospital, Ministry of Health and Welfare.

Should I Worry About a Bump on My Left Shoulder?

Hello Doctor: When I look in the mirror, it's very noticeable that there is a prominent bony protrusion above my left arm. After checking on Google, it seems to be near the upper trapezius and acromion of the left shoulder. I have been exercising consistently over the past f...

Dr. Su Hongci reply Rehabilitation
Hello: The issue you raised needs to be confirmed through a personal examination. Please visit a nearby rehabilitation or orthopedic medical facility for an evaluation. Wishing you good health!