My dad (66) has lbbb since 4 yrs ago on several ekg's. his mom had cad. cardiologist did lots of test 2 times, found nothing. cause? is it fatal?

Left bundle block: The heart has specialized electrical pathways to make the heart pump properly. The right heart is activated by the right bundle, the left heart by the left bundle. The risk of left bundle branch block alone is determined by any other associated heart problems. It is good if his cardiologists did testing and did not find other issues

NEEDS MONITORING: There are numerous causes for LBBB. It sounds as though the cardiologist has looked for those and come up with negative results. In those cases, we usually recommend monitoring with intermittent EKGs-most of the time it does not progress, but if it does , thenmedications or pacemakers are used.

Maybe, maybe not: There're quite a few causes of LBBB. Aortic stenosis, dilated cardiomyopathy, acute heart attack, coronary artery disease, disease of the cardiac electrical conduction system, long standing untreated hypertension, lyme disease etc...even some viral infections can cause this. Since his testing=negative, he is NOT more likely to die than other men his age. Regular follow up is advisable. Good luck!