You can feel a cat’s pulse in two places. The first is by feeling the femoral artery in the cat’s groin. You feel along the inside of the cat’s thigh. You press with your fingers to locate the pulsation. Feel along the inside of the thigh where the leg and body join. The other place is over your cat’s heart. Take the pulse by pressing against the cat’s rib cage. Be cautious about pressing. Don’t fight your cat when doing this! You can use both methods with your cat standing or lying semi-belly up.
The pulse rate can be worked out by counting the number of beats every 15 seconds and then multiplying by four. Alternatively if your cat is passive enough you can count the number of beats in a minute. I’ve never done this but as an adult cat has a normal pulse rate of 140-240 bpm (beats per minute), it may be quite difficult to maintain an accurate count.
The pulse should be regular, steady and strong. If the pulse is rapid it may indicate: blood loss, anaemia, fever, shock, dehydration, infection, heatstroke, excitation or heart and lung disease.
Alternatively a slow pulse will indicate hypothermia, pressure on the brain, heart disease or the collapse of the cat’s circulation due to an advanced morbid (unhealthy) condition.
If the pulse is erratic or irregular this indicates arrhythmia (irregular hearbeat). Always see a vet when necessary.
Source: Cat Owner’s Home Veterinary Handbook and (for image (modified)) from The American Animal Hospital Association Enyclopedia of Cat Health and Care.