Left anterior fascicular block diagnosis causes alarm

DEAR DR. ROACH: I am a 66-year-old woman who recently had an ECG prior to my knee surgery. The interpretation I received stated that I had an abnormal ECG with a “left anterior fascicular block.” Needless to say, this alarmed me. I saw a nurse practitioner who stated: “Don’t be concerned by the language; your doctor viewed the ECG and said it was fine.” Your thoughts, please?

— M.M.

ANSWER: Anytime a person hears that there is a problem with their heart, it causes concern, so I understand why you were unsatisfied with an answer that doesn’t explain what your condition really is.

The heart is a wonderful pump, but when the pump function is bad, it is called heart failure.

The heart has arteries that provide it with blood, containing the oxygen and fuel the heart needs, and when the arteries are blocked, it is called coronary artery disease, which can lead to heart attack. But the heart also has an electrical supply, with a natural pacemaker and specialized cells that act like wires, called the bundle branches (two of them, right and left), which in turn give rise to smaller divisions called fascicles (the left bundle branch has two fascicles; the left anterior and left posterior fascicles).

Just like in a bundle of wires, electrical transmission through the fascicles and the bundle branches can be blocked. This is quite common as people age. The blockage causes delays in conduction through the heart, which can be seen on the electrocardiogram. But, it seldom causes any symptoms.

In people who otherwise have no heart disease, the presence of left anterior fascicular block (also called left anterior hemiblock) does not increase the risk of heart attack or the need for a pacemaker (although there is a small increased risk in the development of atrial fibrillation, a common abnormal heart rhythm).

People like you, with only left anterior fascicular block, also are not likely to develop additional blocks, but if multiple conducting pathways do become blocked, a pacemaker is often put in. Without any conducting system, the heart will beat at a dangerously slow rate.

You should let your doctor know if you notice fast or irregular heartbeats or of any new symptoms such as shortness of breath.

DEAR DR. ROACH: What causes the breasts to act like they have a heartbeat? It happens to me any time, any place. Is there a problem?

— L.B.

ANSWER: The breasts are, of course, directly over the heart, and when a person is lying down, both men and women may see the chest move with the pulse. This is especially true in people with forceful heartbeats, such as those after exercise. It is very likely that you are seeing your normal heartbeat transmitted through your breast tissue.

There are certain unusual and rare heart conditions that can cause the heart to beat more forcefully, such as a leaky valve that lets the blood back into the heart after the heart pumps the blood into the aorta. This makes the heart work extra hard.

A careful physical exam by your doctor would be enough to make sure you don’t have one of these worrisome conditions.