My Mothers Is Wearing A Heart Monitor And Her Heart

My mothers is wearing a heart monitor and her heart rate has been dropping into the 30's frequently. she also has a leaky valve and flunked a stress test. she is suppose to go in for a cardio cath but we just found out about the heart rate and now they say she may need a pace maker. Should I be very concerned? she is 71 and has been fairly active until just recently and consistently tired now.