Heart Disease Management
As a board-certified cardiologist, I am often asked by owners whose pets are either at risk for developing congestive heart failure, or who have had a bout of congestive heart failure that is currently controlled, what they can do to maximize their pet's longevity. My reply is to follow our recommendations for medications in their pets' heart disease management plan and to count the home breathing rate.
One of the most easily monitored signs associated with congestive heart failure is an increase in the resting respiratory rate (RRR), which can be measured at home by the owner. By educating the owner of an at-risk dog or cat how to recognize the signs of heart failure (such as coughing) and how to measure the RRR, we can facilitate detection of heart failure in its early stages. This costs owners nothing and yet can save them hundreds to thousands of dollars if we can institute prompt therapy before the patient becomes oxygen dependent.
Of course, if you are trying to determine whether a patient is in congestive heart failure, the best diagnostic test is always a good quality chest radiograph. In a study conducted at The Ohio State University College of Veterinary Medicine, home surveillance of resting respiratory rate was compared to other tools, including advanced echocardiographic measures and the biomarker NT-proBNP (Schober et al., JAVMA 2011:239;468-479). The test that was most useful and correlated highest to the radiographs was the RRR. An elevation of the RRR to higher than 35 rpm was highly suggestive of heart failure in dogs with both mitral valve disease and dilated cardiomyopathy.
I recommend teaching every client who has a pet that is at risk for heart failure or who is on medications for heart failure how to monitor the resting respiratory rate. This can be quickly taught in the examination room by the veterinarian or technician. I advise the owner to take the RRR daily for one week to establish the baseline and then monitor it periodically. When the resting respiratory rate rises above 30 rpm, or increases greater than 25% from baseline, the owner should schedule a re-evaluation. For dogs or cats that have heart enlargement but are not yet in failure, I usually recommend that the RRR be recorded weekly. For pets that are recently diagnosed with heart failure, I recommend that RRR be recorded daily until the next recheck. It is important that the respiratory rate be performed when the animal is quietly resting or sleeping. If results are abnormal, the RRR monitoring should be repeated in about one hour. I also counsel owners to make sure that a noted increase in the RRR is consistent, to avoid over-interpretation due to the patient dreaming or being excited.
I send a paper chart with these instructions home with the owners and I'm happy to share it with veterinarians if you email me at firstname.lastname@example.org. There are also great apps designed for both the Android and Apple platforms. Look for either "Your Dog's Heart Resting Respiratory Calculator" app from Boehringer-Ingelheim, or the "Cardalis" app by Ceva.
As always, if you have questions, or need help with a difficult case, I am available to help.
Please call me or contact me via email at email@example.com.