Canine congestive heart failure - medication question

Re: Canine congestive heart failure - medication question

Mike Martin — Sun, 08 Aug 2010 10:23:12 GMT

[quote user="Amanda Magrath"]murmur is a grade 5/6 pansystolic murmur, point of maximal intensity L apex[/quote]

So its reasonable to assume in an old JRT this is MVD. I was wondering if there is a murmur on the right (I presume not from your reply) because pulmonary hypertension might fit with all those symptoms - but usually you would then hear a loud tricuspid murmur.

[quote user="Amanda Magrath"]syncope and coughing [/quote]

Syncope on exertion is common with pulmonary hypertension. However, is the syncope linked to the cough, ie. its a tussive syncope? In which case cough suppression is important. My first drug is codeine, either linctus or tabs. Assuming the murmur has been there a long time, it would be reasonable to assume the heart is pretty big and squeezing the L mainstem bronchus. So x-rays can be useful to confirm if this is the case.

[quote user="Amanda Magrath"]Resp rate and effort are normal, and lung sounds are clear - no oedema detected on ausc. [/quote]

If the dog is not breathless it should mean there is no pulmonary oedema - of course nature is not always consistent, some dogs are stoical and some owners unobservant. I find ausc of lung sounds for oedema unreliable, in that the absence of pulm crackles does not mean there is not oedema. Good X-rays are useful to assess the severity of oedema - or absence of. If there is no oedema, adding diuretics would be contraindicated and only exacerbate pre-renal azotaemia, subclinical dehydration and electrolyte depletion = sad dog, dull, depressed and off food. If there is oedema, then a very short trial of frusemide is reasonable, often best by injection initially and oral tabs at 2mg/kg - would be enough of an increase in this case - just for 2-3 days - see if there is a response. But just to reiterate, if it really is not breathless - then I doubt there is oedema.

[quote user="Amanda Magrath"] Exercise tolerance is worsening - dog tired now most days and not coping with walks.[/quote]

So this is a curious symptom (and not be breathless). Is it worth running a blood profile to check for any of the above. Is there something else going on, would be my thoughts. If its just heart - then I'd double that dose of Vetmedin - as well as cardiac effects, I feel it seems to have a general stimulant, 'pick me up' effect. Its also a pulm artery vasodilator, so if there was pulm hypertension - it might help that too. But I would also have already started an ACE inhibitor too in this case - so a consideration here.

As also mentioned, a proBNP is worth considering if you are unsure there is cardiomegaly or not - if you have done your x-rays then that should become apparent.

What's the heart rate like BTW? Any hint of ascites / jugular distension?

Hope this helps a little. Don't forget to post the x-rays when you can.

Re: Canine congestive heart failure - medication question

Martin Atkinson — Sat, 07 Aug 2010 12:07:26 GMT

Have you considered proBNP? If this is not above 1800pmol/l the cough may not be entirely cardiogenic so you're wasting your time pumping in diuretics. its relatively cheap from a simple blood sample.

Re: Canine congestive heart failure - medication question

Amanda Magrath — Fri, 06 Aug 2010 17:40:11 GMT

Mike,

Thank you for your reply. The murmur is a grade 5/6 pansystolic murmur, point of maximal intensity L apex - no radiation of murmur. The diagnosis is based on clinical presentation, no diagnostic tests have been carried out as the owner in the past has not consented to any...

Re: Canine congestive heart failure - medication question

Mike Martin — Thu, 05 Aug 2010 21:03:46 GMT

[quote user="Amanda Magrath"]16 year old JRT with moderate to severe CHF[/quote]

Amanda,

Can you describe the murmur/s and how long it / they have been present? Is the diagnosis based on clinical presentation only so far, or have there been diagnostics performed in the past?

Re: Canine congestive heart failure - medication question

Amanda Magrath — Thu, 05 Aug 2010 20:06:31 GMT

thank you very much everyone for your replies - interested reading. I have now managed to convince the owner in this case to allow me to go ahead with radiographs so hopefully I should get a better picture...fingers crossed!

Re: Canine congestive heart failure - medication question

Rob Reid — Thu, 05 Aug 2010 18:52:27 GMT

[quote user="robloxley"]

How well does lack of audible pulmonary crackles correlate with lack of pulmonary oedema that needs treatment with further diuresis, however?

[/quote]

I find it corrleates pretty well clinically but of course, it is not the same in every case. In this case I have made a clinical suggestion based on the fact that it seems like the owner will not pursue further investigation, but you are correct it is not the gold standard.

Re: Canine congestive heart failure - medication question

Julian Earl — Thu, 05 Aug 2010 18:39:14 GMT

It is always worthwhile doing x rays, as long as you can get the dog to stay still - diazepam and low-dose ACP are okay for a cardiac dog. I have the doses somewhere but but I'm on hols at the moment so am trying not to visit the practice too often!

Also frusemide can be used up to 12mg/kg as long as (a) you monitor the urea, and (b) you spread the dose over the day; it works far better as lots of small doses than as once or twice daily. If the dose seems alarmingly high, I have it on good authority that it is better than drowning. Alternatively, the addition of spironolactone as others have mentioned works well in addition to frusemide.

Thirdly, an ACE-inhibitor of your choice should help but I admit to always being a bit disappointed by these. You just don't get the more dramatic benefit that you see with pimendoban. I sometimes feel that I am giving them because I should, rather than because of any noticeable benefits.

Finally, I have little faith in theophylline, although it is probably better than nothing?

Re: Canine congestive heart failure - medication question

Rob Loxley — Thu, 05 Aug 2010 18:31:22 GMT

[quote user="Rob Reid"]Certainly if you are happy that there are no crackles on ausc, then you shouldn't need to increase diuresis at this stage[/quote]

How well does lack of audible pulmonary crackles correlate with lack of pulmonary oedema that needs treatment with further diuresis, however?

Re: Canine congestive heart failure - medication question

Rob Reid — Thu, 05 Aug 2010 18:18:16 GMT

I would go for adding in an ACEi and spironolactone initially. I tend to use moduret later on - I find it works particularly well for cases that develop ascites. Certainly if you are happy that there are no crackles on ausc, then you shouldn't need to increase diuresis at this stage and can hold that in reserve for later. Spironolactone has been proven to be of benefit for it's other effects so worth adding in for these, as a diuretic it has minimal action I find.

Re: Canine congestive heart failure - medication question

Bob Russell — Thu, 05 Aug 2010 17:44:12 GMT

[quote user="robloxley"]

[quote user="Bob Russell"]Rather than increase frusemide dose if you consider pulmonary oedema is present I have had some quite surprising results with the addition of moduret / moduretic[/quote]

The current dose of <1mg/kg frus BID is pretty low however. Have equally had good success with Moduretic, would however consider again spironolactone as much for its other effects than pure diuresis - some interesting studies on extended survival adding this in.

Given the further information, as far as drugs I'd probably go with upping the pimobendan and frusemide, and discuss also adding an ACEi and spironolactone for longterm management. Would tend to leave off moduretic until options with frus/spironolac exhausted, but that's just my opinion.

If no improvement or other signs pushed that way then I'd reconsider coexisting resp dx.

[/quote]

Frusemide dose is rather low - missed this!

Re: Canine congestive heart failure - medication question

Rob Loxley — Thu, 05 Aug 2010 17:35:44 GMT

[quote user="Bob Russell"]Rather than increase frusemide dose if you consider pulmonary oedema is present I have had some quite surprising results with the addition of moduret / moduretic[/quote]

If no improvement or other signs pushed that way then I'd reconsider coexisting resp dx.

Re: Canine congestive heart failure - medication question

Anne Christison — Thu, 05 Aug 2010 16:41:37 GMT

If this is infact true syncope would it be because of inadequate oxygenation of the brain, either due to underlying respiratory disease and/or insufficient cardiac force of contraction to overcome any vasodilation/diuretic effects resulting in the brain not receiving adequate oxygen supply?

If so, Theopylline with brochodilator properites could assist with respiratory difficulties plus provide a mild ionotropic effect?

Re: Canine congestive heart failure - medication question

Mark Holmes — Thu, 05 Aug 2010 16:17:06 GMT

I find that a trial incease in frusemide for 24-48 hrs useful as high as 4mg/kg potentially, concurrent respiratory disease is possible but I think less likely than deterioration of CHF. According to Craig Devine cardiologist an animal should never die of chf but renal failure secondary to frusemide usage. Moduretic useful, works on the collecting duct which can take up some of the function of the convulated tubule in the face of frusemide. At

Re: Canine congestive heart failure - medication question

Bob Russell — Thu, 05 Aug 2010 15:48:44 GMT

Rather than increase frusemide dose if you consider pulmonary oedema is present I have had some quite surprising results with the addition of moduret / moduretic (amiloride hydrochloride and hydrochlorothiazide). An old product but has improved the quality of life of a number of patients over the years.

Re: Canine congestive heart failure - medication question

Amanda Magrath — Thu, 05 Aug 2010 15:41:23 GMT

Thank you for your advice! Exercise tolerance is worsening - dog tired now most days and not coping with walks. Resp rate and effort are normal, and lung sounds are clear - no oedema detected on ausc. No arrythmia detected either.

The dog is 7kg - currently on 1.25mg Vetmedin bid, so could certainly increase this.

I think cost would be fine in terms of adding in an Ace inhibitor....

In terms of cough suppression, if the cough continues after increase of other meds, is codeine better or theophylline?

Re: Canine congestive heart failure - medication question

Rob Loxley — Thu, 05 Aug 2010 15:28:38 GMT

What is exercise tolerance, resp rate, resp effort and lung sounds like - these will all help towards deciding whether the dog needs more diuretics (and a chest xray would also help)? Is there any dysrhythmia? ACE inhibitor would be reasonable to add in, especially as using furosemide, but are costs an issue (you say o doesn't want more work-up)? Likewise re spirololactone as an aldosterone antagonist. Are you at the max (0.3mg/kg BID) dose of pimobendan? Hard to start to comment on diuretic dose without knowing the dog's weight.

The cough could be due to cardiomegaly pushing on the mainstem bronchus maybe, and these can improve with codeine? There could be concurrent primary respiratory disease, but given the syncope (if truly syncope) I'd be looking at further cardiac treatment to address the collapsing and see if the cough improves.

Lots to consider!