Here's our case for the evening, a 6 year old MN mastiff:

Looking at the big picture, he definitely looks to be on the skinny side! Time for some history:

At the end of his usual walk today he had difficulty breathing and was brought straight to the practice. On exam, BCS 2/5, RR 60/min with an obvious abdominal component.HR >200 bpm, irregular, with pulse deficits (pulse rate about 90)

What do we think about this presentation?

Good, he's tachydysrhythmic with pulse deficits. Is this dog in heart failure?

What shall we do next?

Next up, it's time for a radiograph:

What do we think of this radiograph?

On the subject of the radiograph, James asked what lung pattern this dog had:

Next, we moved on to treatment:

What shall we do now we have this dog stabilised?

So we definitely want at least some, if not all of these suggested drugs.

As an aside:

The dog comes back for a check up:

What next?

Sounds about right!

What do we think about this ECG?

So we can see atrial fibrillation, a supraventricular tachycardia

Do we need to treat this?

So what shall we treat this with?

Excellent answers from everyone.

Do we need to do anything else at this point?

What specifically do we need to see on bloods?

Next, we have a repeat ECG:

What shall we do now?

As an aside:

An excellent set of answers, well done everyone!

Just for clarity, we do not use beta blockers much in dogs. Especially when they have congestive failure, since their sympathetic tone is probably keeping them alive! We sometimes use them once the dog is stable and out of congestive failure IF the dog has a supraventricular tachycardia which digoxin and/or diltiazem is not controlling, but use with care, start with low dose and titrate up.

For dogs with ventricular tachydysrhythmias, again once stable and decongested, we may need to use a drug like sotalol in some to control the rate and rhythm, but again, use with care, it does have some beta blocking effects but also some class 3, K channel blocking effects.

I measure digoxin levels if the dog is receiving the drug, but the heart rate is still higher than I would like, check blood levels to see if they are therapeutic, if not you can increase the digoxin dose. I don’t do them very often.