Maine Coons get a heart check once a year from age 1 through age 5, using 2 tests: an echocardiogram and the MyBPC3 A31P DNA test. A cat that reaches 5 with 5 clean echoes and a clear swab can drop to 1 scan every 24 months. Starting at 1 matters because of timing: hypertrophic cardiomyopathy (HCM) in this breed most often surfaces between 2 and 7 years, and a share of affected cats, commonly quoted as 1 in 3 to 1 in 2, have no murmur loud enough for a stethoscope to catch.
What the yearly screen is looking for
HCM means the heart muscle wall thickens without a pressure load to explain it. The first number on the report is left ventricular wall thickness in diastole, read at the free wall and the septum. Under 5 mm is normal for most cats, 5 to 5.9 mm is a grey zone that earns a recheck in 6 months, and 6 mm or more meets the usual echocardiographic definition. The second number is the left atrium to aorta ratio (LA/Ao): 1.5 or below is fine, 1.5 to 1.7 is equivocal, and above 1.7 means the atrium is dilating and the plan changes the same week.
The 2 tests, and what each one misses
The echo is the functional test. It shows wall thickness, chamber size, whether the outflow tract is obstructed, and whether the mitral valve is being pulled forward (SAM). It cannot tell you what the cat looks like in 3 years, and one normal scan at 12 months in a young cat proves very little, which is exactly why the schedule repeats for 4 more years. The DNA test is a cheek swab or blood sample for the A31P variant in MYBPC3. Positive raises risk and justifies a scan every 12 months for life. Negative does not clear the cat: other variants and non-genetic causes produce the same thick wall, so a clean swab buys information, not a discharge. Budget 60 to 120 dollars for the swab, 220 to 450 dollars for the echo, and 10 to 21 days for results.
The schedule on one page
| Age | Echo | DNA swab | Decision rule |
|---|---|---|---|
| 12 months | 1 | 1 | baseline; wall under 5 mm, LA/Ao under 1.5 |
| 2 to 3 years | 1 per year | 0 | compare to baseline; wall up 1.5 mm or more means recheck in 6 months |
| 4 to 5 years | 1 per year | 0 | the scan at 5 years sets the next interval |
| 6 to 8 years | every 12 months | optional retest | add blood pressure and SDMA to the annual panel |
| 9 years and up | every 12 months | 0 | same scan, plus a 2 view abdominal ultrasound every 24 months |
Four numbers to ask for in writing
Ask the cardiologist to type 4 values into the report: maximal wall thickness in mm, LA/Ao ratio, presence or absence of SAM, and any outflow gradient in mmHg. A resting gradient above 30 mmHg is the kind of finding that changes anesthesia planning and dental decisions. Keep every report in one folder and read the trend, not the snapshot: a wall that travels from 4.6 to 5.4 mm across 24 months says more than either single value. Inter-operator variation of 0.5 to 1 mm is real, so use the same clinic when you can.
The home test the calendar cannot replace
Sleeping respiratory rate (SRR) is the cheapest instrument you own. Count chest movements for 30 seconds while the cat is deeply asleep, twice a week, and log it. The line is 30 breaths per minute. Three readings in a row at or above 30, or any single reading above 40, means a call today rather than at the next scheduled echo. Add the visible signs: open-mouth breathing at rest, hiding in a cool bathroom, and hind-limb weakness with cold paw pads, which can mean a thromboembolism and is an emergency measured in hours.
Booking it so it actually happens
Book the next echo before you leave the building, and set the date 11 months out so a 12 month interval survives one reschedule; the rest of the year's routine sits on the Maine Coon care calendar. Fast for 4 to 6 hours if sedation is planned, bring the last 2 reports, and ask for the same operator. If a 3 hour drive is the reason the scan keeps slipping, a mobile cardiology service that visits every 6 to 8 weeks is a reasonable substitute, and a shared clinic visit with another cat in the house cuts the trip in half.
When to skip the calendar entirely
Do not wait for the annual slot if the cat breathes with its mouth open at rest, faints, or drags a back leg. Those 3 signs move a Maine Coon from screening to workup the same day. A murmur first heard at 8 years in a cat with no prior scans also deserves an echo within 2 weeks, not 2 months, because new murmur plus age is a different problem from a breed screen, and the senior murmur workup lists the order those tests run in.
Five steps for this month
- Book the 12 month echo and the A31P swab in the same visit, 60 to 120 dollars plus 220 to 450 dollars.
- Start an SRR log tonight: 30 seconds, twice a week, 30 per minute as the ceiling.
- Photograph all previous reports into one album on your phone, so trend data travels with the cat.
- Ask for wall thickness in mm and LA/Ao written on the discharge sheet, not just a verbal summary.
- Set the next appointment 11 months out, and diarise the 6 month recheck if the wall reads 5 to 5.9 mm.
None of this diagnoses anything by itself. HCM is confirmed by a veterinarian with ultrasound, and the DNA test only refines risk. The screening calendar is there to make the diagnosis early enough to matter, and a cat screened at 1, 2, 3, 4 and 5 years is a cat whose baseline is already known.
Terms mentioned in this article
Frequently asked
Does a negative A31P test mean my Maine Coon will not get HCM?
No. The swab only reads one variant in MYBPC3, and other genes plus non-genetic causes produce the same thick wall, so a negative cat still needs the yearly echo from age 1 to 5 and every 12 to 24 months after that.
Is one echo at 12 months enough to stop screening?
It is a baseline, not a clearance. Wall thickness can look normal at 12 months and cross 6 mm by year 3, so most cardiologists repeat the scan every 12 months until age 5, then set the interval from that exit exam.
How much does the yearly screen cost?
Plan on 220 to 450 dollars for the echocardiogram, 60 to 120 dollars for the DNA swab, and 10 to 21 days for results. A mobile cardiology visit every 6 to 8 weeks usually costs the same and saves a long drive.