Hypertrohpic Obstructive Cardiomyopathy ( HOCM)

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Hypertrohpic Obstructive Cardiomyopathy ( HOCM)

Hi guys, 

Just wanted some advise on treatment for a 3y.o cat with HOCM and syncope episodes.

Cat presents with

Severe concentric hypertrophy of the LV,

Systolic Anterior motion of the MV

Mitral regurgitation

Severe enlargement of the LA.

I know we use atenolol to help with HOCM. however, my understanding is not to use beta blockers if cat has CHF. O has financial constraints hence thoracic rads were not done.

Questions:

1. Can you tell if cat is in Left sided CHF based on just Echo images?

Hi guys, 

Just wanted some advise on treatment for a 3y.o cat with HOCM and syncope episodes.

Cat presents with

Severe concentric hypertrophy of the LV,

Systolic Anterior motion of the MV

Mitral regurgitation

Severe enlargement of the LA.

I know we use atenolol to help with HOCM. however, my understanding is not to use beta blockers if cat has CHF. O has financial constraints hence thoracic rads were not done.

Questions:

1. Can you tell if cat is in Left sided CHF based on just Echo images?

2. How do i know when it is safe to start on atenolol if O doesn’t want to take repeat X-rays 

3. How do i know if a cat that is on atenolol develops CHF?

Comments

randyhermandvm

Do you have a good M Mode of

Do you have a good M Mode of the L ventricle. In the 3rd still picture 

showing SAM the IVS and VFW did not look all that thickened to me.

If there is not concentric hypertrophy but rather eccentric hypertrophy or even no hypertrophy I would consider starting this cat on diuretics and +/- Pimobendan (off label)

I don’t know that you can diagnose CHF on Echo alone.

I know there are financial constraints- but a chest x-ray and EKG are indicated.

OK – I put my 2 cents in here. Wait and see what others have to say.

EL

yeh he has a 2 cm left atrium

yeh he has a 2 cm left atrium which is kocking on the door to chf depends if wet lung or not from traditional definition of chf. In my opinion many would tx differently here. Correct you are not supposed ot use b blockade in chf because they need th elevated HR to stay alive basicly. So what I do with these is BID lasix and stat and acei 0.25-0.5 mg/kg and sit on it for about a week and then reecho. Im a proactive plavix user too so I would add that. If you reduce the volume overload and starlings laws come back home the HR may drop under 200 on its own but if the vlume overload reduces to say an LA of 1.6 or so and the HR is still > 200 then I would add atenolol. Again its just how I have managed these cats and many may do it differently but the key is minor adjustments… treat what you can see and here I see volume overload and have always lived by treat the volume issue first then see if the heart gets happier or not before trying to control the rate.

note the contractility is not elevated here even if the LV is thick… Im eyeballing a 35% fs or so which is a tendency toward restrictive cmy… but things change once volume issues are adjusted and fs% may go up to true hcm range > 45-50%.

Hope this helps

lookpris

Thank you for the

Thank you for the feedback.

 

Here are the LV measurements. Based on the measurements for LVIDd, there is no evidence of volume overload but FS% is ~30%. Base on the ‘lowish’ FS%, so i still presumed volume overload is present due to the large atrium?

 

randyhermandvm

Thank you for the updated

Thank you for the updated images.

Below is Dr Chris Stauthammers take on treatment of HCM.

Congestive heart failure:

Acute Therapy:

Cats that present in respiratory distress secondary to CHF require prompt and aggressive

therapy. The primary treatment is parenteral furosemide. Most cats also benefit from

supplemental oxygen (e.g., oxygen cage). Topical nitroglycerine may also be applied, but

its efficacy in cats is unknown. Cats with significant pleural effusion require

thoracocentesis. It is important remember that cats with severe heart failure are usually in

severe respiratory distress, and must be managed with the utmost care and with minimal

stress. Stress and excessive handling exacerbate dyspnea, and this can prove fatal.

Chronic Therapy:

After resolution of the acute crisis, the therapeutic objective is to prevent a recurrence of

pulmonary edema. Furosemide is the most important and efficacious drug available to

achieve this objective. Most cats require life-long furosemide therapy. However,

furosemide can occasionally be discontinued, usually in those cats in which the heart

failure that was precipitated by a reversible event (e.g., fluid or corticosteroid

administration). Cats are more sensitive to furosemide than dogs, and are more likely to

develop azotemia or electrolyte abnormalities with overzealous administration. Cats with

pleural effusion may require periodic thoracocentesis.

Two classes of drugs have been advocated to improve left ventricular filling in feline

cardiomyopathy; calcium channel blockers and-blockers. Published information that

addresses this issue in an objective manner is scant. However, an abstract was presented

at the 2003 ACVIM Forum from a prospective, double-blinded, multicenter study

evaluating chronic therapies for CHF in cats with either HCM or restrictive/unclassified

cardiomyopathy. Cats were entered into the study after having survived an acute episode of

CHF. In addition to furosemide, the cats were randomly assigned to receive placebo, a

calcium channel blocker (extended-release diltiazem), a beta-blocker (atenolol), or an ACE

inhibitor (enalapril). Cats receiving atenolol did significantly worse than cats receiving

placebo (in terms of time to recurrence of CHF or death). The cats receiving diltiazem had

a similar outcome to cats receiving placebo, but there was a relatively high incidence of

side effects (predominately gastrointestinal signs). Cats receiving enalapril appeared to

have a better outcome than cats receiving placebo, but this difference did not achieve

statistical significance in this study.

Based on these results, we currently recommend that cats in CHF be treated with either

furosemide alone, or furosemide and an ACE inhibitor (e.g., enalapril or benazepril). The

ACE inhibitor is carefully added to a cat’s treatment protocol once it is eating well and is

not azotemic. In addition to furosemide and an ACE inhibitor, therapy aimed at

preventing systemic arterial thromboembolism (e.g., aspirin or clopidogrel) is

recommended in cats with HCM (see arterial thromboembolism lecture). Positive inotropic

medications (digoxin, pimobendan) are not recommended as myocardial contractility is

generally normal and these medications may exacerbate the diastolic dysfunction and

myocardial hypoxia. Positive inotropic

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