ECG quiz #3 + answer

Re: ECG quiz #3

Mike Martin — Mon, 17 Feb 2014 12:05:49 GMT

Thanks for participating. Sorry for the slow posting of the 'answer' - had a busy spell with courses elsewhere.

3 seconds are indicated by the horizontal line. 7 beats in 3 seconds = 140 per minute. Or, 10 beats in 4 seconds = 150/min.

The 'exam' answer: There is an underlying sinus rhythm at 140 to 150/min with a supraventricular premature complex (SVPC).

This is an SVPC because it is very similar to the normal QRS in this dog, ie. narrow and positive (as opposed to being very different as seen in the previous case with the VPC). It is slightly smaller in amplitude, which is just 'one of those variants'.

The arrow points to - what looks like a hidden 'ectopic P wave'. So this SVPC could be further classified as an Atrial premature complex (APC).

Arrhythmias really need at least 24 hour Holter monitoring to fully evaluate - if they are suspected to be important. Simple APCs like this can be 'adrenaline' induced in a nervous dog 'in the vets'. Often they can be secondary to atrial disease, such as atrial dilation. In this dog, it had a history of episodic weakness associated with a sustained SVT, which we found on Holter. It was the history that prompted the use the Holter in this instance.

Some did mention some other aspects on 'measurements' such as a slightly long PR interval and tall P wave, but ultrasound is now king for heart chamber enlargement (dilation/hypertrophy).

Re: ECG quiz #3

Martin Atkinson — Wed, 29 Jan 2014 10:21:57 GMT

[quote user="Robin Grimmer"]The rate is too fast for an escape beat. And if there were an escape beat, it would be a prolonged gap after the preceding QRS complex. The abnormal complex occurs earlier than anticipated, is normal in appearance so is supra-ventricular, ie is a supra-ventricular premature complex.[/quote] Partly agree. I admit trying to be clever again and using the ECG ruler only this time Mike has fooled me by changing the way the trace has been magnified on the screen. So change rate to 150 bpm and that PR interval to 0.15 sec which IMO is still prolonged. I'm thinking outside the box here and wonder why Mike would give us another trace with just a simple VPC so although I may be wrong I'm sticking with first degree heart block just to be different.

Re: ECG quiz #3

Robin Grimmer — Tue, 28 Jan 2014 22:49:57 GMT

[quote user="Martin Atkinson"]

Rate 100 bpm, Sinus rhythm, P wave looks spiked which is suggestive of right atrial enlargement although we need to know breed/size and species to determine if it is elevated, P-R interval prolonged, escape beat after 6th QRS complex with no P wave, This is first degree heart block.

[/quote]

The rate is too fast for an escape beat. And if there were an escape beat, it would be a prolonged gap after the preceding QRS complex. The abnormal complex occurs earlier than anticipated, is normal in appearance so is supra-ventricular, ie is a supra-ventricular premature complex.

Re: ECG quiz #3

vio doran — Tue, 28 Jan 2014 22:44:45 GMT

HR-140 (based on first 3 sec)

normal sinus rhythm

supra ventricular ectopic beat (7th complex) - poss PAC (premature atrial complex)

Re: ECG quiz #3

Linda Filshie — Tue, 28 Jan 2014 20:07:15 GMT

Rate 150bpm, R-R interval looks mostly regular but for a premature complex (7th) which appears to have the P wave hidden in the preceding T wave (the R wave for this compex also is shorter in amplitude). The P-Q interval looks a little longer than I would expect and the P waves seem on the taller side but possibly both are within normal limits. I'm going to go with a premature supraventricular beat on top of a regular sinus rhythm.

Re: ECG quiz #3

Martin Atkinson — Tue, 28 Jan 2014 13:24:39 GMT

Re: ECG quiz #3

Rob Davis — Tue, 28 Jan 2014 11:45:44 GMT

Heart rate 150bpm, normal sinus rhythm apart from 7th complex. This complex is smaller and premature and the P wave is superimposed on the preceding T wave. The comples is otherwise normal in shape. I would suspect some sort of atrial premature contraction. I'm not sure what would cause this...

Re: ECG quiz #3

Michael Woodhouse — Mon, 27 Jan 2014 22:39:03 GMT

I got 150 bpm too.

Re- the S-T negativity, do I have it lodged in my brain Digoxin toxicity can cause such changes?

Re: ECG quiz #3

John Flynn — Mon, 27 Jan 2014 19:00:25 GMT

Rate approx 135-150bpm in sinus ryhthm with premature supraventricular complex 5th from the right.and a marginally increased pause after it.

Doubt this one's haemodynamically important and no treatment based on just that ECG strip.

[I do often wonder how often a 5 min ECG trace actually leads to any useful treatment decisions though, as most guidelines seem to be based on 24hr Holter...]

Re: ECG quiz #3

Clive Ansell — Mon, 27 Jan 2014 15:56:54 GMT

There is a normal sinus rhythm, with normally appearing P-QRS-T complexes, with a rate of around 150pm based on 10 complexes in 4 seconds in the given trace. There is a slighly prolonged PR interval varying between 0.14s and 0.16s (normal <0.14s) Every P wave is followed by a QRS-T complex, so suggestive of a first degree AV block. Digitalis toxicity could be another cause of an extended PR interval.

The 7th complex has no preceeding P wave, is smaller in amplitude, and occurs early, or premature compared to the other complexes. Given the normal morphology (less the P wave)of this QRS-T wave, it must originate in or just prior to the AV node. So would suspect a premature supraventricular ectopic beat?

Re: ECG quiz #3

James Laidlaw — Mon, 27 Jan 2014 13:02:54 GMT

Is this an ectopic beat - generated without a p wave, but relatively normal as opposed to VPC which generally looks weird/abnormal.

Re: ECG quiz #3

Anthony Dennison — Mon, 27 Jan 2014 12:59:38 GMT

So, rate of about 180bpm? Does seem to be some variation in amplitude of QRS complex, and the T wave seems more negative than normal, with some variation in the amplitude of that also.

PQ interval looks constant, though there is one QRS complex with a much smaller P wave (7th complex)