Dear Dr. John,

Our family is heartbroken after we had to put our elderly mother’s 13-year-old Terrier to sleep. We are thinking about getting her a new dog and would welcome any thoughts about what might be good for a woman who is 90. We have some questions about what happened to our old family dog. He was in reasonable health except for having developed a heart murmur about two years ago. It had progressed but was being managed by a cardiologist. Just before things turned badly, the dog had not been eating for two days and was more tired than usual. We called our vet and sent him a video. He noticed the dog was panting and had labored breathing and referred us into an emergency facility. There, we were told that the dog had a heart rate of 20, and it was determined that not much could be done short of surgery to place a pacemaker. We opted not to put the dog through the difficulty given the risks, life expectancy, and cost. What causes a dog’s heart to slow down so much? H.S.

Dear H.S.,

Sorry for your loss. The normal heart rate for an elderly dog, somewhat dependent on the size of the dog, is somewhere between 60-140 with larger dog size associated with slower heart rates. With a rate of 20, your mother’s dog had what is called bradycardia and at that level it is high risk for collapse or death unless emergency intervention is done. Short term, injectables such as atropine or glycopyrrolate can be given but the underlying condition needs to be addressed. The suggestion of a pacemaker suggests to me that a primary cardiac issue was at hand and was probably the only true means to help the dog. Likely causes of a primary cardiac issue include sinus node problems such as sick sinus syndrome or some kind of atrioventricular block of electrical conductivity.

From what you describe, the dog already had a cardiac issue for some time and eventually the heart simply started to fail. As for getting another dog for your mother, be sure that she not only wants another companion but can care for it. I would suggest a small dog that might be easier to care for.

Dr. John de Jong owns and operates the Boston Mobile Veterinary Clinic.He can be reached at 781-899-9994.