Dilated cardiomyopathy in dogs and pet insurance: two codes for one heart, and the screening record that dates it

The silent years before the signs

The Merck Veterinary Manual (page modified September 17, 2024, reviewed here November 3, 2026) defines DCM as the progressive loss of heart muscle cells or function with falling contractility. It is most common in large-breed dogs, and the manual names Doberman Pinschers, Boxers, Great Danes, German Shepherd Dogs, Irish Wolfhounds, Scottish Deerhounds, Newfoundlands, Saint Bernards and Labrador Retrievers as particularly at risk. Causes it lists are chemical (doxorubicin, for example), viral (parvovirus), nutritional (taurine deficiency), genetic in Doberman Pinschers and Boxers, or idiopathic. Echocardiography is "the best test to definitively diagnose DCM", and the manual adds that "the occurrence of ventricular premature complexes on a routine ECG in a Doberman Pinscher is highly suggestive of DCM."

A European cohort study shows how quiet the early years can be. Wess and colleagues (Journal of Veterinary Internal Medicine, 2010) followed 412 Doberman Pinschers through 775 examinations, each with an echocardiogram and a 24-hour Holter recording. They counted a dog as affected when the Holter showed more than 100 ventricular premature contractions in 24 hours or the echocardiogram was abnormal, and they describe Doberman DCM as an autosomal dominant inherited disease. Males showed echocardiographic changes earlier, while females had significantly more premature contractions. The authors recommend yearly Holter and echocardiographic screening from 2 years of age.

The step from 12.5 percent at 4 to under 6 years to 43.6 percent at 6 to under 8 is a factor of about 3.5, and the abstract does not say what share of the affected dogs in any group had a sign of heart failure. The paper is a European cohort, so its percentages describe those dogs and not every American Doberman. For insurance the useful reading is narrower: a screened Doberman has a real chance of a Holter or echocardiogram report in its file well before it is ill, and the later the dog is first insured, the higher the chance that a report already exists.

This guide follows the disease by phase, silent and then failing, because that is how the veterinary sources it uses describe DCM. The stage-by-stage bill ladder belongs to valve disease, and the mitral valve disease guide prices it with the consensus stages. Nothing here rebuilds that ladder.

Three diseases behind one name

A dilated heart on an ultrasound screen is a finding, and the cause behind it changes which clause an insurer reaches for. The veterinary sources separate at least three. The first is the inherited disease of Dobermans. The second is the rhythm disease of Boxers, which the Merck manual files under arrhythmogenic right ventricular cardiomyopathy (ARVC) and also calls "Boxer cardiomyopathy". The third is nutritional or taurine-responsive DCM, which the manual says occurs in "some dogs (usually small breeds or those on grain-free diets)".

The Boxer disease is the one most likely to be coded as a rhythm problem first. Merck says the most common sign is fainting, from a very fast non-sustained ventricular tachycardia of more than 400 beats per minute, and that the diagnosis rests on the Holter count (more than 100 to 300 premature ventricular contractions in 24 hours is generally considered diagnostic) or on ventricular tachycardia itself. The heart looks normal on chest radiographs and on echocardiograms in most affected Boxers; about 10 percent in the United States go on to develop true dilated cardiomyopathy and heart failure, and about 90 percent of Boxers with DCM carry the striatin gene mutation. A gene test is commercially available, according to the manual. For Boxers that faint without DCM the manual says the outlook is often good, with many living several years on rhythm medication.

The cause in a given dog is a clinical judgment for a cardiologist, and the insurer classifies the claim separately from the veterinarian. Two reports describing the same dilated heart can still differ in wording, which the next section shows can move a payment by hundreds of dollars on a printed schedule.

Two codes, one heart: the VS-G-3-CA schedule

Nationwide's Major Medical Plan form VS-G-3-CA (02-15), a California form, pays from a benefit schedule instead of a percentage of the bill. Each diagnosis code carries a Column A primary allowance and a Column B secondary allowance. Section 4.B says: "We will apply your deductible to covered veterinary expenses that you incur during the policy term. We will pay covered veterinary expenses that exceed your deductible, up to the limit of one Column A Primary Diagnosis Allowance and any Column B Secondary Diagnosis Allowance that applies to your pet's condition. These Diagnosis Allowances are the most that we will pay during the policy term for any condition covered by this policy, regardless of the number of incidents or treatments during the policy term." A dog with a chronic heart disease therefore meets the same ceiling every policy term, however many visits it needs.

Code 1103, Acquired Cardiomyopathy, is on the covered schedule at $835 primary and $330 secondary. The inherited version is not on that schedule at all. Section 6.H excludes "any hereditary disorder or any condition caused by or resulting from a hereditary disorder, except as provided in section 7 of this policy" and says the insurer lists the conditions it regards as hereditary on its website, which was not saved with the form. Section 6.I excludes the conditions in the ineligible lists on page 10 of the schedule, and those lists contain 6003 Inherited Cardiomyopathy and 6006 Cardiac Arrhythmia of Boxers on the medical list, plus 6002 Atrial Standstill. Sick Sinus Syndrome (6014) is on the surgical list.

Section 7.A then restores a little money: up to $275 per policy term for the diagnosis or medical treatment of any condition on the page-10 ineligible list, nothing in the first twelve months, and no more than $275 whatever the number of incidents (the glaucoma guide quotes sections 7.A and 7.B whole). The $275 is one pool for every ineligible medical condition combined, not $275 per condition. Section 7.B does the same for surgery at $550.

Section 4.E closes a second door. In full: "We will pay for Specialized Diagnostic Tests conducted by your veterinarian, up to the limits of the Specialized Diagnostic Test amounts listed in the Major Medical Plan Benefit Schedule. We will only pay for Specialized Diagnostic Tests resulting in the diagnosis of a condition that is: (1) covered by this policy and (2) not an ineligible condition listed on page 10 of this policy. We will not pay more than $1,650 in Specialized Diagnostic Tests per policy term." The $440 echocardiogram allowance therefore exists only on the acquired path. If the cardiologist's report ends in an ineligible diagnosis, the echocardiogram is not a Specialized Diagnostic Test payable under 4.E, and, on the editors' reading, the only money left is the shared pool in 7.A.

The form prints no rule for which code a Doberman's dilated heart receives, and it does not define "acquired". Its definition of a hereditary disorder (section 2.I) is "an abnormality that is genetically transmitted from parent to offspring and may cause illness or disease". Chronic condition (2.B) means "a condition that can be treated or managed, but not cured". A heart finding recorded before the policy can also be written onto the Declarations Page as an Additional Excluded Condition under 6.B, and section 13 allows a review request only with records showing the condition "was cured at least six months before the date of your request", adding: "Chronic conditions are not eligible for removal." A progressive genetic DCM fits the chronic definition on Merck's description. A taurine-responsive case that recovers may not.

What each code pays on that ledger

Under the acquired code, the five lines other than the echocardiogram total $1,950. After a $250 deductible that leaves $1,700, and the primary allowance for 1103 stops payment at $835. The echocardiogram ($600) is a Specialized Diagnostic Test that pays up to its listed $440. The form pays $835 plus $440, or $1,275, which is 50.0 percent of the $2,550 invoice, and the owner carries $1,275.

Under the inherited code, section 4.E removes the echocardiogram from the Specialized Diagnostic Test route, and every line falls under the diagnosis-or-medical-treatment pool in 7.A. On the editors' reading that 7.A also reaches diagnostic tests, the whole invoice less the deductible is $2,300, and the pool stops payment at $275, which is 10.8 percent of the invoice. The owner carries $2,275. The gap between the two labels is $1,000 on this invoice, and the figure does not depend on where the deductible is applied: on the acquired path both the $835 and $440 limits bind either way, and on the inherited path the $275 limit binds either way. If this term fell in the first twelve months of the policy, the inherited path would pay $0.

Two points the form text does not settle would move the acquired figure upward. Whether a heart-failure admission would draw a Column B allowance on top of the primary one, such as the $255 for 1107, is a question about how the insurer reads the definition of an illness in section 2.J ("All clinical signs or symptoms of an illness constitute one illness, regardless of the number of affected areas of your pet's body") against section 4.C, which says the insurer "will not pay both a Column A Primary Diagnosis Allowance and a Column B Secondary Diagnosis Allowance under any Diagnosis Code that applies to the same condition." The second question is whether a second echocardiogram in the same term would be paid, since 4.E states a per-test amount and a $1,650 cap for the term but no count. The calculation above uses one echocardiogram so that it needs no answer to either.

The arithmetic compares two labels on one dog's invoice, and it does not predict that any dog receives either label. A dog might also be coded 1101, Arrhythmia or Syncope, at $530 primary, which is where the Boxer discussion below begins.

A Holter result as a dated record

The Orthopedic Foundation for Animals (OFA) runs two cardiac registries. Its Advanced Cardiac Database requires an examination by a board-certified veterinary cardiologist, and since October 1, 2020 it has required an echocardiogram. A notice on the OFA page headed as reminders from the ACVIM cardiology group (December 2022) states: "ALL Advanced Cardiac Exams REQUIRE an ECHO as part of the exam REGARDLESS of breed" and "HOLTER tests within 90 days of the Advanced Cardiac Exam are ONLY REQUIRED for DOBERMANS and BOXERS". The page explains the clearance: "The congenital clearances are considered permanent. The adult-onset clearances are valid for one year from the date of the exam." The page adds: "Additionally, for an adult-onset clearance, Boxers and Doberman Pinschers also require a Holter test within 90 days of the cardiologist's examination."

In those two breeds, then, the registry route to a clean certificate produces two dated reports within 90 days of each other, and an owner who repeats them every year produces two more each year. That is good practice for a breeder and a fair question for a pet owner, but the reports are medical records with thresholds attached. The Wess cohort treated more than 100 ventricular premature contractions in 24 hours as diagnostic of Doberman cardiomyopathy, and Merck says more than 100 to 300 in 24 hours is generally considered diagnostic of ARVC in Boxers. An above-threshold Holter in a dog that has never fainted or coughed is therefore a diagnosis on those authors' criteria, dated the day the recorder came off. Interpretation belongs to the cardiologist, and these thresholds are the cited authors', not a rule for any individual dog.

The registry's own privacy rule does not help with an insurer. The OFA page says "Abnormal information will not be released into the public domain unless the owner gives permission for this release by initialing the appropriate line on the application form," which keeps a result off the public database. It does not seal the chart at the clinic. VS-G-3-CA section 8.B says "You must provide us with all medical and surgical records relating to any claim under your policy, upon our request." Figo Part II, item 1 says: "Upon submission of Your first Claim, You must include twenty-four (24) months of medical or adoption records unless the Claim is for routine care only. You also agree, that by purchasing this Policy, You give Us permission to gather all medical information for Your Pet from all Your Veterinary Providers, as We deem necessary."

The record works in the owner's favor when it is clean. Figo defines a pre-existing condition with a twelve-month look-back, and adds a rule about baselines: "If You cannot provide medical records showing Your Pet's annual health exam by a Veterinarian occurring within the twelve (12) months prior to the Original Start Date of this Policy, the first documented veterinary examination after the effective date of the Policy will be used as the basis for determining any Pre-existing Condition(s)." A normal cardiologist examination and Holter dated before enrollment is the one document that shows the heart on the day coverage began. The OFA adult-onset clearance lapses after a year, and the Wess percentages climb with age, so a normal result at age three is evidence for age three. Whether a given insurer accepts such a record in underwriting is not stated in any of the nine forms.

The same screen done after the policy is in force and past its waiting period is a different event, and the next section shows why the answer then depends on the wording of the pre-existing clause and not on the date alone.

Nine wordings that date a heart finding

Nine sample or filed forms were compared on one question: what makes a heart condition pre-existing, and where would a Holter result taken ten days after the start date fall. They sort into three families. Three forms (AKC, VS-21 and PetPartners) reach back to when the disease existed or began, whether or not anyone had found it. Three (VS-G-3-CA, MetLife and Pets Best) turn on medical advice, treatment, diagnosis or signs before the start date or during the wait. Trupanion, Figo and Spot use a look-back window or an occurrence date and say what counts as evidence inside it.

The family decides whether a screening matters by its date or by what it proves. Under the first family a Holter taken at day 40 can still be a pre-existing finding if it shows a disease that existed on the start date. Under the second family a day-40 abnormality is clean on its date, because advice, treatment and signs all come after the start. Only Trupanion names screening outright in the clause: 5.c(4) excludes "Abnormalities that are present at, or during the 18 months prior to, the policy enrollment date. This includes conditions that are detectable by a routine physical exam by your veterinarian or those that have been noted from diagnostic testing, screening or radiographs."

Of the seven forms that print an illness wait, six (Figo, Spot, Trupanion, MetLife, Pets Best, PetPartners) run 14 or 30 days, and a Holter on day 10 lands inside all six; AKC's five-day wait is the exception. A Holter on day 40 lands inside none of the seven. These are mechanics of the wording and not a scheduling plan: when and how often a Doberman or Boxer is screened is the veterinarian's call, and Wess and colleagues recommend yearly screening from age 2. A finding cannot be set aside either. VS-G-3-CA section 15 says "By accepting this policy, you agree that all the statements in your application and the declarations are true and that you have provided us with all material information about your pet's health." Section 16 says "We will void your policy from its inception if we discover that you have misrepresented or omitted any material fact and we relied on your misrepresentation or omission in issuing this policy to you."

State endorsements can narrow the wording. PetPartners' Washington amendatory endorsement replaces the definition of pre-existing condition with one that requires that the disease "occurred or existed, whether or not diagnosed and that the policyholder knew about, or reasonably should have known about prior to the original effective date of the policy." The Declarations Page and any endorsement for the owner's state come before the base form.

Who pays for the screening itself

The annual cardiologist visit, echocardiogram and Holter that produce these records are routine screening of a dog with no sign of illness, and every one of the nine forms has language that reaches such a claim; MetLife's sample also lists a Preventive Care benefit. The table gives the clause in each form that an adjuster could cite for a screening claim; none of the nine forms uses the word Holter, and VS-21 and VS-G-3-CA are the only two that name an echocardiogram, both in their schedules.

The two sides of the screening trap are therefore uneven. The owner pays for the screen out of pocket in the forms compared here, unless an optional wellness benefit says otherwise, and an abnormal result still goes into a file the insurer can request. A normal result protects nothing that the forms promise, though it does supply the baseline. Once a sign appears and the cardiologist is diagnosing a suspected condition, the picture changes: under VS-G-3-CA section 4.D the form says "We will only pay veterinary expenses for diagnostic testing resulting in the diagnosis of a condition that is covered by this policy", so the same echocardiogram that was routine in March can become a covered diagnostic in September, if the diagnosis it reaches is a covered one.

The pre-existing conditions guide compares five definitions across other forms, and the exam fee guide covers the visit charge that sits on top of a cardiology consultation.

Inherited, congenital, genetic: where the class is excluded

Merck calls DCM genetic in Doberman Pinschers and Boxers, and Wess and colleagues call the Doberman form autosomal dominant. A policy that excludes inherited or hereditary disease as a class therefore sits directly in the path of the two breeds most associated with DCM. Four of the nine forms contain a class exclusion, and two of those sell an optional rider that removes it; five do not.

Where a class exclusion exists, the definitions matter. AKC defines Inherited as "an Illness, disease or condition whose presence is determined by genetic factors", and PetPartners' version is "an illness whose presence is determined by genetic factors". The VS-G-3-CA definition is "an abnormality that is genetically transmitted from parent to offspring and may cause illness or disease". Figo's Genetic Condition is "an Illness whose presence is determined by hereditary factors." The FDA describes non-hereditary DCM as "a complex medical condition that may be affected by the interplay of multiple factors such as genetics, underlying medical conditions, and diet." Whether a dog whose heart disease involves a diet and a susceptible genotype has a condition whose presence is "determined by" genes is a question no form answers, and it is the question to put in writing to an insurer that excludes the class.

None of the nine forms mentions a DNA result, a genotype or a gene test as an event that makes a condition pre-existing, so a Boxer with a positive striatin test and no Holter finding has no clause in these forms that dates the disease by the test alone. Figo goes the other way on the test itself, listing among its exclusions the cost of "Genetic/chromosome testing". The hereditary and bilateral exclusions guide reads these clauses across more forms, and the Doberman Pinscher page and Boxer page put the breed risks beside the premium anchors.

Grain-free headlines and the FDA notice

The FDA opened its inquiry in July 2018 after reports of DCM in dogs eating certain foods, many labeled grain-free, with a high proportion of peas, lentils, other legume seeds or potatoes among the first ten ingredients. The investigation page carries a December 23, 2022 notice and a footer reading "Content current as of: 12/23/2022". The notice says "FDA does not intend to release further public updates until there is meaningful new scientific information to share" and adds: "While adverse event numbers can be a potential signal of an issue with an FDA regulated product, by themselves, they do not supply sufficient data to establish a causal relationship with reported product(s)."

The newest-dated FDA page on the topic is the companion Q&A page, "FDA's Work on Potential Causes of Non-Hereditary DCM in Dogs", which carries "Content current as of: 08/19/2024". It reports 1,382 DCM reports in dogs between January 1, 2014 and November 1, 2022 (329 to November 30, 2018; 190 from December 1, 2018 to April 30, 2019; 608 from May 1, 2019 to July 31, 2020; 255 from August 1, 2020 to November 1, 2022), counts that the agency says are voluntary, unverified and not a true incidence. A search of the FDA site on November 3, 2026 found no 2025 or 2026 notice on the subject. The editors treat the Q&A page, dated August 19, 2024, as the newest FDA word and the December 2022 notice as the last investigation update.

The Q&A page says most diets in the reports have legumes high on the ingredient list, "FDA has received reports of non-hereditary DCM associated with both grain-free and grain-containing diets", that "Legumes, including pulse ingredients, have been used in pet foods for many years, with no evidence to indicate they are inherently dangerous," and that "FDA has no definitive information indicating that the diets are inherently unsafe and need to be removed from the market, but we are continuing to work with stakeholders in assessing how the diets may interact with other factors that may be impacting non-hereditary DCM." It also says: "Reports from veterinary cardiologists demonstrate some good results in improving heart function in non-hereditary DCM cases, unlike genetic forms of DCM, with appropriate veterinary treatment and dietary modification, when caught early in the progression of the disease." Merck matches the framing, saying some dogs "can also have taurine-responsive DCM" and that such dogs have "a fair to good prognosis once clinical signs of CHF abate."

For a policy, the diet-linked case lands differently from the inherited one. It is not hereditary on the FDA's description, so a class exclusion has less to say about it. Its treatment is a change of food and, as Merck's term taurine-responsive implies, possibly a supplement, although neither source gives a regimen. Those are the lines forms fence off most. VS-G-3-CA exclusion N removes "Special diets, pet foods, or dietary or nutritional supplements used to treat or manage a condition or to preserve or improve general nutrition or health, even if prescribed by a veterinarian", VS-21 exclusion O and Figo exclusion 17 remove diets and supplements, and AKC exclusion l removes "All diets, Pet food, whether prescribed or not. This does not include a prescription diet used as the sole Treatment of a covered condition." Spot pays "Supplements to treat a covered condition; not for general health maintenance, or prevention even if prescribed or dispensed by a veterinarian" and "Prescription pet food to treat a covered condition; not for general health maintenance, or prevention, even if prescribed or dispensed by a veterinarian", and Trupanion says "We will cover dietary supplements that are prescribed and dispensed by your veterinarian in the treatment of injuries and symptomatic illnesses covered by this policy and not for routine/preventive care." A commercial food bought at a store appears in MetLife's Not Medically Necessary clause. The echocardiograms, cardiology visits and medications of a taurine-responsive dog can be a good claim while the food bill stays the owner's. The prescription food guide compares six forms on that one line.

Seven heart records, seven outcomes

Seven positions an owner can check against the policy and the chart. Each reflects the sample wording above; the policy in hand and its Declarations Page govern.

Wording to request before the next Holter

• Does the policy treat a Holter or echocardiogram taken for screening as routine care that is not reimbursed, and what does it say if the same test is repeated after a sign appears?
• Does a cardiologist's recommendation to recheck, or to start a medication before heart failure, count as medical advice or treatment for the pre-existing clause?
• Is dilated cardiomyopathy in a Doberman or arrhythmogenic right ventricular cardiomyopathy in a Boxer on the insurer's list of hereditary or inherited conditions, and is that list attached to the policy or only posted online?
• If the form has separate acquired and inherited codes, which one does an insurer assign to a dilated heart when the report mentions breed risk but no genetic test?
• When a rider such as HereditaryPlus or InheritedPlus has its own waiting period (AKC's is 30 days), what counts as symptoms before that wait ends, and does a Holter taken during it count?
• Are heart medications covered when started before heart failure, and does the form test the drug's approval, its label indication, or the standard of care?

Pimobendan before failure, and the label question

Merck's treatment sentence for dogs with DCM reads: "Pimobendan treatment may be indicated in Doberman Pinschers with DCM before the onset of heart failure, and concurrent antiarrhythmic treatment is also frequently indicated in this breed especially." Pimobendan is the active ingredient in Vetmedin. The Vetmedin chewable tablet label on DailyMed (Boehringer Ingelheim, revised 11/2025) carries two indications: delay of onset of congestive heart failure in dogs with Stage B2 preclinical myxomatous mitral valve disease, and "management of the signs of mild, moderate, or severe congestive heart failure (CHF) in dogs due to clinical MMVD or dilated cardiomyopathy (DCM)". The first indication is valve disease only. So a Doberman started on pimobendan while it has no heart failure is using an FDA-approved drug for a purpose the label does not list.

That gap would matter only if a form tested the use against the label. None of the nine forms uses the word "label". Medication definitions ask about approval: VS-G-3-CA defines drug as medication or other substance "undergoing clinical trials for or approved by the U.S. Food and Drug Administration (FDA) that is used to treat a condition", and Figo defines Medication as prescribed by a Veterinarian and "approved by the Food and Drug Administration (FDA) of the United States or accepted for inclusion in the Homeopathic Pharmacopoeia of the United States for veterinary use". Spot pays "Prescription medications prescribed by a veterinarian and approved by the Food and Drug Administration (FDA)". Each tests the drug, not the indication. The nearest clauses that test the use are the experimental exclusions: VS-G-3-CA exclusion S for treatment "that is experimental, investigational, or otherwise not within the standard of care accepted by the board of veterinary medicine of your state" and Spot exclusion i. Whether early pimobendan counts under either is an open question for the insurer, and the mitral valve guide covers the B2 version of the same drug, with its own label indication, in detail.

The date of the first prescription can matter as much as the drug. A pimobendan prescription written before the policy starts is treatment before the start date, which VS-G-3-CA, MetLife and Pets Best each name as a trigger. The same prescription written after the policy and its wait, for a disease first found after them, is ordinary treatment of a covered illness unless a class exclusion applies. That is why the screening date in the earlier sections carries more weight than the drug.