Thank you for your query.
Your diastilic BP is 50 mm of hg.
It is not so low from normal level.
It is a frequent findings in our daily practice.
But you should concern about this because you are a pacemaker implanted patient.
Metoprolol was probably prescribed you for prevention of
arrhythmia.
But it is also a BP lowering agent.
It is better for you to consult your doctor.
Take care.