General Cardiology General Medicine ICD/Pacemaker

A malignant arrhythmia from an antibiotic? Lessons to be had…

What can an interesting case of a simple infection which nearly led to sudden cardiac death teach us about health care, health care reform and our ways of knowing?

Dr Wes’ blog recently described a post from a geriatrics (specialist in the care of the elderly) doctor that highlighted the challenges of caring for the elderly in today’s medical climate.  Obviously, we all know the elderly often have multiple medical problems, take multiple medications and thus are at increased risk for drug interactions.  No matter how thorough you try to be, on completing an evaluation of a complicated elderly patient, there is always this uneasiness that something was missed.  A 22 year old with SVT cured for life with a 60 minute ablation it is not.  

An illustration…

An 82year old women was admitted a few days prior to my visit with abdominal pain from a simple urinary tract infection (UTI).  At night she had multiple episodes of loss of consciousness and the following cardiac rhythm was recorded.

These fast rhythms are life threatening episodes of ventricular tachycardia which are basically 3-6 second episodes of sudden death occurring episodically.  Sound smart and call this “torsades de pointes.”

Before this recent UTI, she was living at home with her family and doing reasonably well.  I had placed a pacemaker many years before and this also was without problems.

What is the cause of this malignant rhythm?  It must be horrible; a blockage, a heart attack or some other atrocity.  No, this near death experience is from a commonly used antibiotic, Levaquin.  Come on Doc, antibiotics are safe, aren’t they?

For the most part, it is true, antibiotics are safe, but like any medicine, especially when administered to the elderly there are potential dangers.  It turns out this patient had mild kidney disease which meant the antibiotic was not cleared as well, thereby resulting in higher levels of the drug.  The antibiotic dose given was the “normal” dose which would typically be given to a younger patient with healthy kidneys.  She was also taking the anti-depressant trazodone.  Trazodone and levaquin both have effects on the same cardiac channel which controls cardiac relaxation. Heart relaxation time is termed the QT interval.  These two medicines are QT prolonging agents.  Excessive QT prolongation leads to the above pictured malignant arrhythmia.  Additionally, women are more susceptible to QT prolongation then men.

Here is a very functional elderly women who is doing well with a pacemaker and an anti-depressant who unfortunately develops a common urinary tract infection.  A simple problem for a younger healthier patient, but in the elderly, not so much. This case demonstrates a near perfect storm:  not one, but two drugs with the same cardiac effect, plus female gender and finally depressed drug clearance from kidney disease.  Just one or two of these issues would not likely have caused any adverse outcome, but all the above combined to cause a near death situation.

This particular case concluded with a positive outcome.  The treatment was to change the antibiotic to a non-QT prolonging agent (obviously) and to increase the pacing rate (increased heart rate decreases the QT interval).  The crisis was averted.  I wrote on a prescription pad to “always avoid QT prolonging medicines.”


A geriatrics specialist might have known to adjust the dose of an antibiotic in this elderly patient with a decreased ability to clear the drug.

Considering she was already on an anti-depressant drug which affects the cardiac rhythm, the use of an antibiotic without QT prolongation would have been a better choice.  This seems obvious, but Levaquin is commonly used and most often well tolerated. 

A computer entry system that flags these potential interactions may have prevented this event.

Although, I knew both drugs were QT prolongers, it took just 3 minutes with a 300 dollar laptop and google to know these drugs both inhibit the same cardiac channel.  For those wondering, it is the HERG channel, which controls potassium channels.  The same channel affected in Long QT -2 patients.

The big picture…

On learning:  discovery is still fun.  These were indeed beautiful tracings.  A good outcome was accomplished.  I felt like a resident again- good sensations.  It is sad there are no medical students (“learners”) at this private hospital.  I could have “schooled them.”

On reform:  When our health care system is reformed, it seems obvious to me that caring for the increasingly elderly population should be emphasized.  The elderly use medicare.  Medicare reimbursement looks to be going south.  How is this an incentive?

Maybe stories like a simple infection threatening a life will help illustrate the importance of recruiting and maintaining talented care givers for our elderly patients.


6 replies on “A malignant arrhythmia from an antibiotic? Lessons to be had…”

Great tracings (provided, of course, they're not yours). The issue you raised here is not just with geriatric patients, but extends to our younger generation, too.

From a health care policy perspective, business looks at health care as a vast new growth industry since 30 million more patients will soon be piled on the seemingly infinite government dole. Politicians, eager to please their constituents, offer back room deals to industry while assuring the public that $480 billion in Medicare cuts will balance the books.

While I've got some ocean-front property in Arizona I'd like to sell, guess who ultimately loses?

Thanks Wes,

Your comments are appreciated.

There is much to worry about in the impending "reform," but what is spoken so little about is the disincentive to the talented pool of future doctors. Although, at 46 and for various reasons, I can afford the luxury of working for (a little) less money, it is clear to me that medicine is increasingly less attractive to the young. Concurrently, medicine is way more complicated now -there is more to know, more that can be done and importantly, more decisions on when not to do.

Nothing illustrates the importance of talented doctors better than becoming a consumer of health care yourself. We doctors seem to garner little sympathy from the general public, but as we "rich" doctors become much less rich, there will be fewer of us when needed.


Good "Doctoring" John; as usual. Part of the problem is the younger doctors don't believe "work" is the master word of Medicine ala Sir William Osler.

Patients may doctors (their own and in general) as "rich" because we see so many of them driving cars that cost as much as our houses.

Most patients only see their doctors one a year or even less; I had one PCP I went to for four years (very infrequently; perhaps six or seven times)and only actually met once, as I was always seen by his Nurse Practitioner. When I did finally see "my doctor," he barely looked at me, never smiled, and gave me all of four minutes of his time.

We patients tend to forget that our doctors gave up many years of their youth to achieve "MD" at the end of their name and did so only by taking on a huge financial burden. Yet when our doctors (by their own fault or not) cannot or will not spend more than five or six minutes with us when we need them, the negative perception naturally solidifies.

I'm not sure what will happen when health insurance reform takes effect and continues to evolve over the coming years. I can only hope that young people more interested in helping and healing others than becoming wealthy will be the ones going to medical school. It's a conundrum, isn't it.

I don't know what sort of car that long-ago PCP of mine drove, but I can guess. And eventually I fired him.

Too many prescriptions written by doctors spending too little time with each patient results in a dysfunctional system of patients receiving one-size-fits-all drugs, despite their unique differences.

After I quit taking all medications, I stopped having all the drug-induced life-threatening side-effects.

The only problem now is high blood pressure and fits of uncontrolled anger.

No, not my blood pressure and anger. My doctors suffer those symptoms because I am a happily non-compliant patient.


I drove a Mercury Tracer for the first 5 years of practice, then an upgrade to a Honda Civic. My buds call me a "chiseler," which always makes me grin as that phrase was coined by my late grandmother. My father in law, a wealthy dermatologist, drove an old oldsmobile; now I know why. For years one of the best surgeons at my hospital had the junkiest Ford Escort. I have expensive carbon fiber bikes which are much cheaper than cars and bring much more pleasure. Oh, that feeling of a 15lb carbon bike with Zipp 303's and good legs – there are some, but few better sensations.


Grin. Though, do not misunderstand me, there are many meds that extend and enhance lives of patients. It takes caution and some doctoring skills to use them effectively. Take Atrial Fib for example, a small dose of a benign medicine that works without side effects is still better than a complicated ablation with the possibility of scary complications.


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