What Can Be Learned?

Normally I lurk and learn. Every now and then I come out of my hidey hole with a question. 

We know the heart is both electrical and mechanical.  When your provider interrogates your PM he gets info on the device as well as the electrical aspects of the heart.  At least that is my understanding. 

My question is,  is there anything from the information the provider receives from the interrogation that would give him/ her any indications of what may be going on with the mechanical portion of the heart? Or are they so exclusive that your electrical portion could be fine and yet you could have any number of heart issues...ischemia,  atherosclerosis,  valve issues etc?

Thank you for your wisdom and insight.


5 Comments

Essentially nothing

by crustyg - 2020-04-13 03:46:50

Apart from a few clues, the electrical activity of the heart tells doctors nothing about the mechanical function/health of the heart and valves.

Note I'm not saying that an EKG doesn't provide some information which would help your PCP learn something about your heart health, but a PM interrogation is a lot less informative than a 12-lead EKG.

You might have a developing cardiomyopathy, an increasingly leaky valve, badly furred up coronary arteries and none of this would necessarily show on your PM interrogation.

Taking a look at the patient is one of the most useful things you can do in medicine.

PM check up

by Selwyn - 2020-04-13 06:34:32

You ask an interesting question which I am sure others have in mind.

A 12 lead ECG (EKG) shows some of the electrical activity of the heart but also has changes associated with the muscle. The muscle may change with problems with the valves of the heart, and so indirectly the ECG can highlight structural changes in the heart.. for example the P wave ( the first bump of the ECG is associated with atrial activity) and in mitral valve disease the left atrium can enlarge... producing a P wave loooking like a small pair of breasts! The first sign of my cardiomyopathy was a large QRS swing ( the QRS is the big spike seen on the ECG) in keeping with more muscle, the conduction of electricity in the thickened muscle is prolonged and this results in ST elevation ( the bit between the big spike and the last upwards bump, or T wave), and lastly the T waves are inverted ( this represents ventricular returning to the resting state or so called repolarisation).  

Believe me, having a 90% narrowing in my main coronary artery neither showed up on my ECG ( which is abnormal anyway due to the cardiomyopathy) or the pacemaker check ( though that is to be expected).

The PM check will show episodes of arrhythmia ( in both the atria and the ventricles) - their duration and frequency.  A change in the current needed to produce a heart contraction may indicate  heart muscle disease, thyroid disease, ischaemia, kidney disease,  fibrous changes etc. Various valve abnormalities may lead to arrhythmias, so indirectly there is a clue... hence we often end up having ECHOCARDIOGRAMS to show the internal structure and workings of the heart when we have an arrhythmia . It is fascinating to see your own heart valves flapping around on an echocardiogram.  The doppler effect is also used to assess blood flow. 

Hope this is of some help.

 

 

 

Indeed.

by crustyg - 2020-04-13 08:30:07

As I very carefully said in my initial response, there are clues in the data from an interrogation.

However I'd bet good money that most EP techs wouldn't notice the increased QRS height of LV hypertrophy, especially as the EMGs of a PM don't necessarily produce quite the familiar patterns seen in a a 12-lead EKG and the normal interpretation values are derived from the classical lead positions and not intra-cardiac leads.

It's a good question, but the answer is still no.  The ultimate demonstration of this is EMD - electro-mechanical dissociation - relatively normal ECG but no cardiac output => rapidly fatal, but the electrics look good!  Apparently it's been renamed PEA, but in my day it was EMD.  Still kills you very quickly, untreated.

Don't hope that your PM reports and interrogations will detect anything seriously wrong with the plumbing - if you don't feel right, see a doctor.  The box inside you is a brilliant piece of kit, but it's not StarTrek.

most EP techs

by AgentX86 - 2020-04-13 17:29:07

That's why the data is sent to your EP, or perhaps another EP who specializes in reading them (as is the case with EKGs).  The tech is just the first stop along the line for this information but you'd be surprised at what some of them know.  They aren't dummies to be brushed off.

My PM Check Up Nov 2019

by heartu - 2020-04-13 17:56:39

During my PM checkup last November, my interrogation picked up 4 very short lived ventricular tachycardia, which I never had before in the 9 1/2 yrs I had a PM for complete heart block. This prompted getting a nuclear stress test which was abnormal, followed by an echocardiogram which indicated I had congestive heart failure EF 35% . I had no other symptoms of heart failure. I also had an angiogram to check for heart blockages and it was negative. Got a CRT-d in late January ( my echo for late April was canceled by the facility so I won't know if heart failure has reversed/improved). So I believe your PM interrogations could possibly alert you to other heart problems.

You know you're wired when...

Your pacemaker receives radio frequencies.

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