Liz Bode

Hi,

Thanks for you comments. The radiographs show marked cardiomegaly with mixed interstitial-alveolar pattern predominantly in the caudodorsal lung fields but also ventrally in cranial lung fields (almost an aspiration type pattern here). The pulmonary veins and arteries are prominent. These findings are consistent with pulmonary oedema secondary to heart failure. In my experience large breed dogs can cough with pulmonary oedema, especially Dobermanns! So this could be the cause of the cough, but the cranial lung lobes do have a very ventral interstitial-alveolar pattern that could be consistent with some aspiration too. However, we treated him for CHF with furosemide, pimobendan and once stable ACE inhibitor (benazepril) and spironolactone and his cough resolved (although this could be coincidence).
This dog was markedly taurine deficient and we supplemented this. When we saw him back 3 months later his heart looked like this:

Echo

And we actually managed to wean him off furosemide and eventually pimobendan! If they have a truly taurine deficient DCM then we can see this dramatic remodelling. However, sometimes dogs (and cats) will be taurine deficient with DCM and we supplement with taurine and their hearts do not remodel like this. It is very case dependent and needs good follow-up.

Cool case 🙂

Liz

Thanks all for the discussion and questions. My answers are as follows to the case:

The views show:
1. Right parasternal 4 chamber long axis – demonstrates a dilated LV and LA, with a slightly dilated right side (in the normal animal the right side should be 1/3-1/2 the size of the left, in this dog the right side is almost a 1/3 so if the left side is big the right side must also be a little big to maintain the proportions). The LV is round and subjectively hypokinetic and this can be appreciated on the short axis view too. The mitral valve is slightly thickened and appears tethered (doesn’t open properly).
2. Right parasternal 4 chamber long axis with colour over mitral valve – shows a central jet of mitral regurgitation.
3. M-mode at level of papillary muscles shows a hypokinetic septum with relatively normal free wall (posterior wall) motion.
4. Right parasternal short axis view at the level of the left atrium/ aorta demonstrates a markedly dilated LA.

The ECG shows sinus rhythm throughout.

I’m not sure I can evaluate PA size on the last view as I can see the body of the left atrium and the auricle, which is dilated. However, there was tricuspid regurgitation at 3.7m/s indicating mild pulmonary hypertension.

There should be relatively normal cardiac output in this case as systolic blood pressure has been maintained and so this can’t explain why the aorta might be a bit smaller (if it is at all – we would need a better view of the pulmonary artery first to evaluate this).

The aortic annulus does look a little bit strange but I think that this is because there is a coronary artery appearing in this view.

Endocarditis lesions do not always produce those nodular/ thickened looking valves that we are used to seeing they can look relatively normal so cannot always exclude based on echo (I don’t particularly like ‘hunt the endocarditis’ in a pyrexia of unknown origin for this reason, unless more obvious things have been excluded first or the animal has a new murmur etc).

My echo diagnosis would be – DCM-phenotype with probable degenerative mitral valve disease. I think it is more likely a DCM-phenotype because of the central jet of MR and the depressed systolic function of the septum. Although it can be difficult in large breed dogs as MMVD can also reduce systolic function.

Our DDx for a DCM-phenotype would be:
Primary DCM
Tachycardia-induced (a dog paced at 180bpm for 4 weeks will develop heart failure. You can also develop this with intermittent tachyarrhythmias as long as they increase your mean heart rate significantly).
Myocarditis – acute or chronic (if chronic and normal troponin then you wouldn’t know this unless you did a biopsy – however the treatment is the same whatever the pathology in this case)
Diet induced (including taurine deficiency).
A shunt is possible, but less likely and I would only do a bubble study if the right side showed changes consistent with pulmonary hypertension).

Further tests:
Taurine
Thoracic radiographs
A Holter could also be considered

Results:
Taurine 7umol/l (ref range 50-180 umol/l) measured in this case due to diet AND because we know Golden Retrievers seem to suffer from taurine deficiency that causes DCM.
Thoracic radiographs:

DV
Lateral

How would you interpret these results and radiographs and what treatment would you advise?

I look forward to reading your answers.

Liz

Yes, good point about the hypovolaemia and heart rate. The heart rate is fast side of normal so dehydration rather than hypovolaemia might be possible, but these are low on the Ddx list. I try and list my DDX in order of likelihood as this is good practice when writing case reports etc and when thinking about cases (although I didn’t do that great a job for this case 😉 ).

Francois – a point-of-care ultrasound of the thorax and abdomen are ALWAYS going to be the correct answer for any case! They are some of my most favourite diagnostics. They give you so much information really quickly and then the other tests can follow them as necessary. I didn’t mention them here as the dog appeared pretty stable for further examinations (at present at least…).

I’ll answer everything else once others have had time to look through the videos.

Liz