Could a pericardial effusion cause a heart block?

Peicardial effusion. Pericardial effusions can be small and not hemodynamicallly significant (inflamed lining) and in such cases they cause pain mostly. If effusion is large and prevents filling of the heart, low BP results. It can occasionally be assorted with slow heart rates (example hypothyroidism), or. When vagal reflexes are stimulated.