Complex cardioversion?

[zzyzx]

I recently read an article in JEMS by James F. Goss about cardioversion of atrial fibrillation with a rapid ventricular response rate being contraindicated for a severe underlying pulmonary disorder. I'm not sure if I agree. What do you guys think? Check out the article below (all spelling mistakes are mine, not the author's, as I had to retype it since I could not find a link!)

Complex Cardioversion

By James F. Goss

You’re dispatched to the residence of an elderly male with difficulty breathing. On arrival, you find a 74-y/o male in severe respiratory distress. He has altered mental status and appears to need to sit up to breath. His wife reports he has a two-day history of progressive dyspnea much worse than his baseline, as well as a history of emphysema, atrial fibrillation (AF), CHF, and continued smoking.

The patient is cachectic, appears wasted, and has dry, flaky skin except around his lips, which are blue. Your assessment reveals significant suprasternal and intercostal retractions, absent breath sounds bilaterally, and use of accessory muscles. Vitals: BP 92/48; pulse thready and unable to count at fast rate; RR 44. Also observed is 4+ pitting pedal edema, extending to mid-calf, and mild abdominal distention.

A cardiac monitor reveals an unusually high tachyarrhythmia with an irregular rate of around 220. (Note: rates are usually significantly lower.) Due to the increased heart rate, it’s difficult to discern the underlying rhythm.

Your partner, also a paramedic, insists on attempting synchronized cardioversion per local protocol for symptomatic tachyarrhythmia with rates greater than 150. You think the respiratory compromise should be treated first, and you contact your base station. The base station agrees that cardioversion isn’t the best approach in this case and directs code 3 transport with respiratory care, including high-flow 02 and albuterol.

Although the monitor reveals a tachyarrhythmia with a ventricular rate of 220, this isn’t the primary problem. The tachyarrhythmia is secondary to the severe exacerbation of the patient’s emphysema and the attendant hypoxemia and myocardial ischemia.

This patient has a history of COPD and chronic AF, as well as CHF....[i’m leaving out some of the authors explanations of these diseases.]……and increased symptomatic tone usually worsens that condition, as do the hypoxia and increased anxiety and stress of respiratory decompensation. Exacerbation of your patient’s respiratory condition, along with hypoxemia and hypercapnia, contribute to increased sympathetic tone and subsequent increase in heart rate.

AF can be accompanied by ventricular response rates up to 300. Most cases of AF are chronic and shouldn’t be cardioverted due to the high risk of post-conversion embolic stroke along with the fact that chronic AF will reoccur within a very short time.

So would cardioversion by the best choice for a patient with poor air movement and hypoxemia? After all, when we hit the “reset button” on the heart through cardioversion, the cardiac cells require oxygen to restart. Thus, cardioversion of AF with a rapid ventricular response rate is contraindicated for a severe underlying pulmonary disorder.

Treatment to improve oxygenation should be initiated immediately. Improving ventilation and oxygenation will likely result in a decrease in sympathetic tone and heart rate. Although CPAP would be a better choice, IV diltiazem or verapamil may be indicated to slow the heart rate, improve ventricular filling, and decrease myocardial oxygen demand.

During transport, the patient’s respiratory status improved mildly as reflected by an increase in audible air movement on auscultation of the lungs, improved saturation, and a mildly decreased heart rate. Despite these changes, the patient remains in severe distress on ED arrival. In the Ed, his heart rate is slowly reduced and his status improves, and that patient is later transferred to the ICU.

[Thunderchild145]

Normally, I would tend to agree with you, but I do understand where the article is coming from. For the same reason that we're now doing CPR prior to defibrillation/intubation/intravenous access in ACLS, it's saying that myocardial hypoxia needs to be corrected before cardioversion takes place. Also, there's always the risk when cardioverting A-fib patients who havn't been on blood thinners that they well throw a clot, so the cardioversion is something better left to a hospital anyway.

[zzyzx]

of course you'd also treat the respiratory distress, but why not do both at the same time?

[JPINFV]

^

Why not treat the problem (hypoxia) instead of the symptom (tachycardia)? If you don't fix the hypoxia then you won't decrease sympathetic nervous activity. If you don't decrease the sympathetic nervous activity then the patient would just reenter tachycardia.

[AZCEP]

Reasonable suggestion to manage the hypoxia first, however, what would be the best way to do this?

Poor tidal volume and cardiac output are going to add to the ventilatory issues. His oxygenation status is already remarkably poor, so you will be fighting a losing battle quickly. Controlling the heart rate might be a consideration, but the oxygenation status takes a bit more importance.

I notice that the author doesn't discuss the options for actually solving the problem, or maybe it just wasn't included.

Are you going to be able to assist ventilations for this patient? Tough to say from the information given.

Can you use a rate controlling medication, rather than cardioversion? Not with the perfusion status this patient shows.

This is a difficult situation, but with the multitude of options that can be justified, not entirely unmanageable.

[zzyzx]

this guy has two things going on, respiratory distress and a dangerously fast heart rate. the heart rate is not just a response to the respiratory distress (like a sinus tach, of, say, 130, might be); rather, it's a problem in itself. there's no question that you're going to do everything you can to treat the respiratory problem. the question that the author asks is do you also treat the uncontrolled AF. he is saying no, you shouldn't. i think his case is well argued, but it just seems reasonable to me that you would try to cardiovert. if he's hypoxic and at the same time his heart is beating that quickly, it seems like it's only a matter of time before his oxygen-starved myocardium will go into V-fib.

[sledogg1]

This guy is clearly a reoccuring unstable afib pt who is probably on every med out there..........has been cardioverted before?? or has a implanted pacemaker.

So, O2, sedate with valium or versed if enought time have your intubation gear, suction on sandby or just cardiovert 100 200 300 360.

[Thunderchild145]

I think the main idea in trying to treat the hypoxia first is that if you attempt to cardiovert without treating the hypoxia, then the heart won't respond or will respond poorly to the attempt. This article says that the heart needs oxygen to restart, so if you cardiovert and the myocardium is hypoxic, you may just send them into asystole. That's what I gather anyway.

[ERDoc]

I would treat what sounds like a COPD exacerbation as such. I don't think you can ignore the rate though. As someone else said, this isn't a little STach. This guys heart is working harder than a prosititue at a sex addict convention. It is going to need some help or else it is not going to keep ticking. If this guy was on coumadin, I'd hit him with some etomidate and shock him. If he was not I would use IV cardizem to get the rate down. I would also push some calcium gluconate to help maintain the BP. He'll be better off if we don't give him a stroke.

[firefighter523]

Doc, you take the fun out of a good debate, LOL. However, I think it is not such a good idea to ignore his HR. This rate indicates that his cardiac ejection fraction is probably a bit low, creating pulmonary hypertension, hence pulmonary edema, hence hypoxemia. If you were in the hospital, I could see the cartizem if he wasn't on coumadin. Out in the field this person will not last much longer. You need to cardiovert this person asap to hopefully fix his problem. I know you run the risk of throwing a clot, this situation is grim anyway you look at it. Definately fix the rate first, while on high flow 02!