Low Ejection Fraction. Of his heart.

My father is an Ex-Serviceman, in 1985 he was diagnosed to have low heart rate 40~45ppm, Cardiologists suggested him for a pacemaker however he went in for pacemaker only on 2015 when he suddenly started feeling giddy. His heart rate was around 30~35ppm at that time. It's been 18 months since the pacemaker was implanted, in the last week he's had couple of incidents where he suddenly became very weak, couldn't stand, couldn't talk, he felt very thirsty however he did not have chest pain during these incidents. I went in for full body checkup at a laboratory and his ECHO showed that his heart's ejection fraction had dropped to 34%. I have visited a couple of cardiologist since then however I do not want to share their opinion here so that I can get unbiased consultation. I am be attaching 2D ECHO Cardiogram report and MRI Brain reports here. Can you please tell me what should be the best plan of action at this situation. Also what can help improve the ejection fraction of his heart.