Is On And Off Low Pulse While Having Artery Blockage A Cause For Concern?

My husband has been having a low pulse lately. Ranges from 56 to 49 n 50. This concerns him as his pulse usually in the 60 s n 70 s. He has been sick with the muscle flu. He is 71 years. He,s had a stent n he has small artery blockage in thr right side of his neck. His family dr does,nt know much about this. He has a cardiologist but very hard to to see him. Thank you