Maybe Kitty was snuggling close to your face and you heard the thumping of his little heart. His tiny ticker probably sounded like it was racing a mile a minute. While it may seem fast in comparison to our own heart rate, a rapid heartbeat is normal for him.
Healthy Heart Rate
A healthy human heart clocks between 60 and 80 beats per minute at rest. Kitty's heart pumps considerably faster. As an adult, his heartbeat will be between 120 and 140 beats per minute. As a kitten, it's even faster at 200 to 260 beats per minute. If it seems like his little heart is racing, it's probably because it does go over three times as fast as yours. If you want to check his pulse, place your hand or ear over his chest and count the beats for 15 seconds. Multiply that number by four to determine how many beats in one minute.
Supra-ventricular tachycardia is when Kitty's heart beats too fast all the time, even when he's just napping. If his heart is racing for long periods of time, it could lead to heart failure. When kitty is exercising or stressed out, it's healthy for his heart to up the speed. SVT can be genetic or a side effect of heart disease, electrolyte imbalance or other preexisting condition. If Kitty's heart rate is elevated, he should see his vet for emergency treatment. His vet will also probably put him on prescription medicine to regulate his heart and recommend a low-sodium diet.
If Kitty has an electrocardiogram and his vet sees missing P-waves, then he has a rare heart rhythm disorder called atrial standstill. P-waves are an electrical measure of Kitty's atria, the top two chambers of his heart. His heart rate will be slow and possibly become irregular. If Kitty seems tired all the time or looks like he's losing muscle mass, he should visit his vet for an ECG. Atrial standstill could be caused by high potassium in his blood or another heart condition. For some felines, the disease is slight and won't cause him any further issues. If it is caused by another condition, treatment for that disease could return his heartbeat to normal. He may need a pacemaker to regulate his heartbeat. Make sure Kitty's life is low-stress and he gets plenty of time to nap.
A heart murmur is a sound heard in Kitty's heartbeat that indicates abnormal blood flow through his heart. They're rated on a scale of I to VI by severity and how loud they are. A murmur can be labeled “innocent,” meaning it won't negatively affect his health and is probably very faint and intermittent. This kind of heart murmur can happen when he's a very young kitten and his heart is growing rapidly, disappearing when he's full grown. More serious heart murmurs are caused by structural deformities in his heart, like a leaky valve or a hole between two sections. Heart murmurs can be detected by his vet with a stethoscope. Treatment will depend on what type of murmur Kitty has. Innocent murmurs require no treatment at all, but a more severe murmur will mean treating the underlying cause, such as a repairing a hole in his heart.