Evaluation

I went to a new cardiologist for check up after mine died.   He checked me vaguely and had me wear a halter overnite I have stable heart failure.    He said  that during the test I suffered a type 2  AV Heart Block and wanted to change all my medicines. He did no other tests.    I contacted a superior clinic and they did a photo-chem stress test, echo and full EKG - THis doctor said he saw no signs of any heart blocks - that my CHF was fine - EF of 44.
I am still concerned -  Is it possible that my second doctor more thoroughly tested me and that I can be assured that I am not potential heart block patient

[Cleveland Clinic]

I cannot comment on what the first  heart doctors saw on your Holter. If he says he saw high degree AV block, then I must believe him. And if so he is correct in changing your medications, and if symptoms of heart block ( lightheadedness or dizziness and passing out) occur even to recommend the placement of a pacemaker. Simply because the second cardiologist did not see heart block does not mean that it wasn't there at other times. Internittent heart block usually occurs in the early stages of disease, and it progresses to more prolongued periods as the disease progresses.
An EF of 44% is not normal and shows moderate impairment of systolic function, but CHF is a clinical diagnosis and you may not have any at the present but should be on medications to prevent further development of CHF symptoms or cardiac events such as heart attacks or sudden cardiac death.