Pacemakers

the one case i have seen in my limited student career, we called the tech to come turn off the patients internal defib. we put pacer pads on and brought in a defib machine. ours was a young guy that had a hx of a cardiac arrest from a drug overdose. stated his defib had never gone off. never had a problem in the OR and when we went to pacu, we called the tech and they came and turned it back on.
his surgery was for a tracheal resection.

Hi there. I work in a lab where we put in pacers, defib, and perform ablations. Basically, defib. need to be programmed off when a bovie is used-it can set off the defib due to false sensing by the defib.-Not fun!! Pacers are another story. The pacemakers are to be set to a mode so that they pace but do not inhibit due to the patient's rhythm because it could be the bovie it is really sensing. It can depend on the patient's underlying rhthym. If they have an underlying rhythm and don't use the pacer much then it can be turned off during the procedure. Having the magnet available to set the pacer back to it's previous settings when the procedure is over is correct. We also ALWAYS recommend having pads on the patient so the RN can pace externally if necc. You never know what can happen. I hope this helps! Pacers and defibrillators can be confusing. They come up with new stuff everyday. There is also something we are putting in for CHF that is not responding to drug therapy-it is called a BIV or biventricular pacemaker or it can be a defibrillator. There are 3 leads place into the heart-the 3rd is placed down through the coronary sinus over to the left side of the heart. This way the pacer can sort of pace both ventricles!! It is giving people 7-9 years of quality life!! Oh, one more thing some people do not realized-a defibrillator has the ability to not only deliver a shock, but to pace a patient when needed as well. It depends on the MD that programs it. Sorry, to go on and on, but I think it is amazing what is being invented!!

Thanks for the good info jebain.

qwigley:

1) pacemakers are not inserted for A-fib, primarily because with a-fib you just have an irregular rhythm and that isn't the issue.... more than likely that person had a pacer placed for sick sinus syndrome (brady/tachy syndrome - which is different from a-fib).

2) the problem with bovies: any electrical activity will be misinterpreted as cardiac activity - if the patient has a pacer, it will stop firing. In of itself that isn't a problem if the patient doesn't rely on the pacer and has a decent intrinsic rhythm - however if the patient is pacer dependent, you run into trouble because the pacer has no reason to fire as it assumes that everything is okay since it is sensing electrical activity (which in this case would be the bovie) - by using a bipolar there is no spread of electrical activity and is a lot safer.

3) AICD/ICD: they would interpret the electrical activity as v-tach and would continue to discharge over and over again (which would drain the battery quickly and cause some cardiac damage) - that is why they should always have a magnet on them, which in turn sets the AICD in to a back=up pacer mode. If true v-tach were to occur, just tell the surgeon to stop with the bovie/cautery and take the magnet off, the AICD will wake up, sense the v-tach and discharge.


4) magnets: you have to be careful about when you place magnets on a pacemaker.... most of the newer pacers (in the last 5-8 years) will reset to their previous setting without a problem. the older pacers will be stuck in their default DDO mode, or even older pacers will be stuck in their default VOO mode. In that situation it is imperative that EP cardiology/Implant rep comes and interrogates the pacer in the PACU and resets it ... this is becoming less of an issue as more and more patients have the newer pacers.

5) don't worry about all this stuff: when you start doing cardiac cases you will know pacers/ICDs by heart (no pun intended)

Just want to clear something up: Pacemakers ARE inserted for A-fib all the time. Whether or not they ablate the A-V node or not is dependent upon the pts condition and if they are chronic A-fib. We try to first perform ablations to the pulmonary veins to rid people of A-fib, but sometimes a pacer is neccessary.

jebain - i stand corrected.... however, pacemakers are not the initial treatment modality for atrial fibrillation and when they are implanted they are usually not for the atrial fibrillation but rather because of rare occurences of brady-arrhytmias or because somebody just had their arrhythmogenic areas ablated and no longer have an intact conduction system.

ICDs are considered a primary treatment modality for atrial fibrillation in certain patients as studies have shown that defibrillating the atria and resetting a normal rhythm has better outcomes...

In rare settings a ventricular pacing system will be placed to overdrive pace an afib patient, but in somebody who has poor cardiac function to begin with, this can be detrimental.

the population that you see the biggest incidence of a-fib is in the post-cardiac surgery patient: 40-50% - and so far one of the tools we use is bi-atrial overdrive pacing that seems to stabilize the rhythm within the first 3 days (however no data to show that it actually improves outcome).

so yes, pacing works for a-fib. will you see patients who have a pacer for a.fib without a hx of bradyarrhythmias or ablation? very unlikely, more than likely that person would have an ICD

i know - a lot of mumbo jumbo - i am post-call

Hey

I agree there are many misconceptions out there. Mainly because people don't realize the programing details of these devices. I see many patients with a fib, mostly 2per day. The patients with pacemakers implanted for afib are usually ppm dependant or they are on so many medications to control ventricular responce, the ventricle rate is to low for patient tolerance. Many of the patients that don't have ppm elect for catheter ablation therapy of afib. This treatment has improved greatly over the last 2 years. Success rates improved as well. I disagree with the 40-50% of afib patients have had bypass. Maybee 40 to 50 % of bypass patients develop afib post-op, I find it very difficult to believe the otherwise.

Most pacemakers have the basic modes of pacing to choose from as well as rate responsivness.(ie. exercise increases the paced rate of the heart) The Magnet does not "reprogram" the pacemaker. It does suspend sensing of the device. This makes the ppm pace reguardless of whats going on. If the ppm is in a "demand" type mode reguardless of patient dependance a bovie or electrical impulse of any kind will be detected as if it were a heart beat by the ppm. A ppm dependant pt will go pulseless in this setting. A magnet over the ppm will tell the ppm to pace reguardless. A bovie cautary will not interfere with the ppm pacing.

ICD's are different. A magnet suspends dectection of the device. (defib detection ) IT WILL NOT SHOCK after a magnet has been placed over the device. Some of these settings are changed with prolonged magnet placement. ( i.e.Guidant) Not all company magnet responses are the same. In the OR with bovi the icd will sence the bovie as vt/vf AND SHOCK INAPPROPRIATELY. This puts the patient and everyone else at risk for harm.

Now with the age of Bi-Ventricular devices implanted for heart failure management. These devices pace 100% of the time. Be sure you know what your dealing with because there are so many different devices out there now.