Generally speaking, LBBB should be followed with anual echocardiograms. You are correct that people with symptoms of heart failure (shortness of breath, leg swelling, feeling tired, etc) and a low ejection fractio associated with a LBBB have options that may improve things for them (a special type of pacemaker called cardiac resynchronization therapy, or CRT). On the other hand, many people with a LBBB never have any consequences. Either way, it should not be "forgotten", and you should follow with a cardiologist.
Thank you very much for the response. Question: what does the cardiologist look for in the annual echo cardiogram? LVEF?
And this is a side question: does CRT replace your heart's internal pacing completely, or does it synchronize with the heart's internal pace? I.e., with LBBB, would it essentially replace only the broken bundle branch, or does it replace all the electrical pacemaking and wiring in the heart?
An echocardiogram can look at a variety of things, including LVEF, right ventricular function, valve function, diameters/volumes of heart chambers, vessels going into and out of the heart (such as the IVC and aorta), etc.
CRT works by placing a pacemaker lead in the right ventricle, as well as the left ventricle. These two leads pace at the same time, ensuring that your heart pumps in a synchronous manner (as opposed to the right ventricle pumping before the left ventricle, as in LBBB). There are a variety of ways in which the two leads can pace; they can be programmed to pace in sync with your internal pacing (which is preferred) or in it's own rhythm (as in certain people with more complex arrhythmias and conduction disease). Your electrophysiologist would make this determination.