Possible causes for shortness of breath and irregular heart rate 85 yo male has high bp and hiadle hernia? resting rate of 46, but was 85-130

Atrial fibrillation: Afib is a likely cause. Congestive heart failure, heart block which might need a pacemaker and coronary artery blockages are also concerns. He needs to see a doctor and get an ekg and poss some other tests as well.

Consider these: Sick sinus syndrome, atrial fibrillation, pulmonary embolism, ischemic heart disease. See an internist asap. These are not the only possible reasons.