Can pulmonary fibrosis cause heart trouble?

At the very end. At the end stages of pulmonary fibrosis, it can cause elevated blood pressure in the lungs, which can affect the heart. Also, the lack of oxygen from the fibrosis can also affect the heart. But, again, this occurs in the very end stages of the disease, usually.
It can. Pulmonary fibrosis over time can cause high blood pressure in the lungs (pulmonary hypertension) which can lead to strain and even dysfunction of the right side of the heart.