Heart murmers are simply abnormal heart sounds. Many aged dogs have clinically insignificant heart murmers. But heart disease does occur and its progression and signs can be mitigated with medications and monitoring. Heart disease is a generic term which groups many different forms of heart ailment, many of which are treated and managed somewhat differently. To decide what is required, the following process is utilized.
A thorough history (any coughing?, tiring easily? etc) examination (rate, rhythm, lung sounds, pulse strength other signs) and diagnostic tests (blood, urine) and chest x-rays constitute a minimum database for suspected heart disease. An echocardiogram may also be suggested. This gets you to the diagnosis, a first and most important step in deciding on a treatment plan.
Commonly, achieving a normal body weight, dietary salt reduction and regular followup examinations and testing will allow matching the medications required to the disease as it progresses. The objective is good quality of life, minimal disease progression and symptom alleviation as they occur.
Expect and accept that regular monitoring and less frequently, medication changes, are a normal and expected part of managing heart disease. Your dog can expect good quality of life well into congestive heart failure should that occur (defined as fluid accumulations, particularly in lungs as heart becomes inefficient) if you ensure that the little things are done at the right time. Your doctor is best situated to advise you in this regard. Ensure an open honest communicative relationship and your dog will benefit from the longest possible period of good quality of life with heart disease.
Regards and good luck,
Dr G