Tuesday, August 28, 2018

The Importance of Electrocardiography In Psychiatric Practice....

The US Preventive Services Task Force came out with general recommendations for resting and exercise electrocardiography a few days ago in JAMA Cardiology.  I posted the above comments on Twitter to emphasize the importance of the ECG in psychiatric practice.  I was also pleased to hear the word I frequently hear when patients, families, and other staff question the need for electrocardiography and my refusal to start of continue certain medications without seeing that ECG. That word is that the ECG is an expensive test and why do we want to incur the additional expense?  It is not an expensive test and the information it yields for the money spent is high.  The actual guidelines are available free online and if you are a psychiatrist or any other practicing physician I encourage you to read them.

The interesting aspect of this publication is that the accompanying editorial by Joseph S. Alpert, MD is more informative that the USPSTF document.  The conclusion of the USPSTF document is that screening asymptomatic individuals with resting or exercise electrocardiography does not provide useful information for predicting or preventing events due to cardiovascular disease. Dr. Alpert points out that this is a straw man argument and provides a very handy list of 15 clinical indications for resting or exercise electrocardiogram (ECG) recording.

Over the past 30 years I have ordered hundreds of ECGs and in reviewing that list, I found 6 of the common indications.  Admittedly some of these tests were in suboptimal conditions.  I am thinking primarily of the patient on a psychiatric unit with chest pain. In settings where I have practiced, several factors led to situations where I was getting the ECG and doing the early work before the consultant arrived.  In some rare cases, the troponins were being collected while the patient was still on the psychiatric unit.  In those cases the indication was to rule out acute ischemia pending additional biomarkers. 

If you examine patients, I found it was a common occurrence to makes diagnoses of arrhythmias - that were previously unknown to the patient - most commonly atrial fibrillation.  In some cases, ventricular arrhythmias and rhythms due to conduction disturbance are also noted.  An ECG is a very inexpensive test to determine what is happening. It is also a good way to get consultants interested in the problem.

The advent of concern about the QTc interval in psychopharmacology was probably the biggest driver for psychiatrists to order ECGs.  According to Dr. Alpert this is a legitimate indication for ordering the ECG and the bulk of ECGs I have ordered have been focused on matters of cardiac conduction.  The majority of those orders are based on the characteristics of the medication.  The FDA has made this problem a lot harder than I think it needs to be.  It would be useful to have a screening test for rapidly identifying patients who might be at higher risk for this abnormality but that would probably not take into account anatomical abnormalities that can affect the problem.  There is a certain amount of mystery in this area - when I see medications like haloperidol flagged for QTc prolongation and I have consulted on ICU patients taking haloperidol on telemetry and never seen a case - it tells me that some of this screening and concern may not be that well founded.

I also use the ECG (in addition to the cardiac review of systems) in cases of polypharmacy when the patient is taking multiple QTc prolonging medications.  That may involve a baseline ECG and repeat ECGs over the course of treatment.  On the front end of the evaluation, I often show the patient a drug interaction profile with all of the QTc prolongation flags, discuss the plan with them, and advise them to attend to cardiac symptoms suggestive of rhythm problems.  Even though the USPSTF is usually against screening I have picked up many problems with screening ECGs including QTCs of greater that 510 msec and complete heart block.  I think the problem with characterizing ECGs as screening seem to imply that the patient is asymptomatic and has no cardiac risk factors.  Adding a Bayesian term for the patients psychiatrists see would generally taken them out of that low risk category.  That fact and the low cost of the ECG make this an ideal test for the above problems. 

When I consider the ECG issue and the fact that I have ordered more and more of these tests over the years - I also think back to the 1980s and 1990s when it was not uncommon to see a QTc of 500 msec on a person taking thioridazine.  The Cardiology consultants would ask the high risk threshold question: "Does he really need the medication?"  Any affirmative answer usually resulted in leaving the medication in place.

As psychiatry has evolved, I think that psychiatrists are now in a place where they are (or can be) much more proactive about cardiac conduction problems - both in the initial pharmacological approach and in reacting to ECG abnormalities. The only consistent problem I see is the availability of ECG machines and technicians if the clinic is isolated from medical resources.  It may be impossible to get ECGs when you need them for the above purposes.

If you are a resident or an experienced psychiatrist, I think it will pay to get a copy of Dr. Alpert's editorial and take a look at the list.  I think it is also useful to remember there is screening and there is screening.  While you are at it - consider Cardiology Twitter and follow the Cardiologists there who post ECG tracings, how to read them, and what the clinical findings and treatment was. It is an outstanding learning resource in this skill.

Carefully consider all of the cardiac risk factors affecting the patients that you treat and I am sure you will agree with me - the threshold for obtaining ECGs in patients with severe psychiatric disorders should be low. 

George Dawson, MD, DFAPA


1: Alpert JS. Does Resting or Exercise Electrocardiography Assist Clinicians in Preventing Cardiovascular Events in Asymptomatic Adults?. JAMA Cardiol. 2018;3(8):678–679. doi:10.1001/jamacardio.2018.1800.

No comments:

Post a Comment