Introduction

Heart murmurs in cats are diagnosed through a physical examination using a stethoscope, grading the heart murmur based on severity, and identifying what type of heart murmur is occurring based on the heart’s sound. An electrocardiogram may help to distinguish the grade and type of heart murmur, and complete blood tests and ultrasound examinations can be used to determine why the heart murmur is occurring.

Types of Heart Murmurs in Cats

There are many different types of heart murmurs, and they are distinguished by their specific sounds that occur on an up or down beat and by their intensity. In many cases, it is difficult to determine exactly what the heart is doing by sound alone, and an echocardiogram (ECG) is often used to get a view of the heart’s patterns.

Heart murmurs can be caused by a variety of conditions, and blood tests and ultrasound examinations are often used to determine if a treatable medical condition is causing the murmur, or if the murmur is caused by a physical defect in the heart or an inherited genetic condition.

Grading the Severity of Heart Murmurs in Cats

Heart murmurs are diagnosed based on grades one through six.

• A grade one heart murmur is the least severe and it can barely be heard.
• A grade two heart murmur is a faint murmur that occurs only in a specific area of the heart.
• A grade three heart murmur can be heard immediately once an examination with a stethoscope begins and the sound is widely projected.
• A grade four heart murmur can also be immediately heard during an examination and it is accompanied by a vibration known as a thrill
• A grade five heart murmur is the loudest murmur
• A grade six heart murmur can still be heard when the stethoscope has just been removed from the chest wall