LBBB: How low is a safe dose of metoprolol?

Please read this:
https://scienceinsights.org/are-beta-blockers-contraindicated-in-left-bundle-branch-block/
LBBB means the two ventricles, the largest and most powerful of the four chambers in a typical heart, do not beat in concert. The typical beat is: atria first, then the two ventricles. That's why a heart beat in a healthy heart sounds like 'lub-DUB...lub-DUB...............lub-Dub...lub-DUB............' With left or right, or both, partial or complete, the two large ventricles work somewhat at odds with each other, one contracting while the other remains flaccid, even if just a fraction of a second out. In time, this can lead to 'remodeling' of the heart, including thickening of the ventricular walls and with deposition of collagen and fibrosis in the substrate. A heart with thickened wall, and with fibrosis, has stiffer walls that are resistant to the contractile force, so those muscles must use more force to move blood properly. This puts a strain on the heart muscle and can lead to heart failure in time, as the article above suggests. Metoprolol has two properties: it slows the heart's rate, but it also reduces the contractile force of each beat. It is for this reason that metoprolol is often prescribed for patients with 'incipient' hypertension....you can get some modest relief from high BP by taking 12.5 mg of metoprolol BID ('bis in die', or twice a day in Latin). Or more....whatever is prescribed, that is what you should do unless you are at complete loggerheads with your physician/cardiologist, or unless that person feels it's safe to at least try reducing the dose...or raising it. If you cannot agree with your physician, then you must accept the risks inherent in what you elect to do, or find another physician who will work with you and try to find a happy medium. But, above all, I do not recommend starting or stopping a prescription unless you have a physician firmly in your back pocket and on board with what you intend to do.

Thank you gloaming - hopefully your post will be helpful to newly diagnosed LBBB patients. My issue is not hypertension or a disagreement with my cardiologist. I'm just curious to hear from other LBBB patients about their experiences and history with metoprolol doses and dose adjustments.

I have had a LBBB. I never knew I had it until 3 years ago. After reviewing my echocardiogram form the past it show it in the report. I didn’t look up what that meant and had cardiologist at Emory hospital and Duke University and no one ever mentioned it. I had Aorta stenosis which I had operated on in 1985 and replaced in 2002 both at Cleveland Clinic. I found out I had A LBBB when we moved to CO and was going to have my knee replaced. The found a problem I had and needed a pacemaker. I had been cleared by my cardiologist at CU Cardiology to have knee surgery . I was on metoprolol ER 50 mg for as t least 24 years. I ended up taking it at night because it made me very tired during the day. I was just switched to Coreg 25 mg twice a day bc the metoprolol stopped working. I wished I had read Mr echos sooner and the questioned my drs more. The only spoke of the aorta valve. Ira’s seeing doctors at big named hospitals too. So all I can say is to keep reading your reports and question what the initials mean. I have learned you have to be your own advocate.