Cardiac & Resuscitation, Columns, Patient Care

Syncopal Episodes Can Warn of Cardiac Conditions

Issue 1 and Volume 40.

You’ve been dispatched to care for a person who’s unconscious. As you walk in, you’re directed to a young male lying on a couch. He appears to be in his late 20s or early 30s. The patient, Mark, is awake and acknowledges you as you approach. Your initial assessment identifies no respiratory distress or signs of trauma or hemorrhage. His pulse is tachycardic but strong, and his skin is warm and dry.

Mark tells you he and his wife had just arrived at his parents’ home. Soon after, he became light-headed and felt like his heart was racing. He laid himself down on the couch but doesn’t remember much after. His wife tells you he was unresponsive for about a minute until he began to move and answer to his name.

Nothing like this has happened to him before. Your assessment reveals no neurological deficits, a pulse of 120, blood pressure of 132/78 and a breathing rate at about 12 times a minute without difficulty.

Mark denies any previous medical history, takes no medications and says he hasn’t had anything to drink this evening. He says he’s feeling better and is able to sit up without feeling dizzy. He doesn’t want to go to the hospital, though his mother is encouraging him to go. She’s concerned because she had an older brother who died when he was about 20 years old—he had no known medical history but passed out a couple of times prior to his death, when he was found dead in his bed one morning. Mark agrees to go be evaluated and is transported without incident.

Discussion

Why did a healthy, young adult male pass out, and is there any correlation between Mark’s syncopal episode and the untimely death of his uncle? When EMS is evaluating a patient who has experienced a syncopal episode, they should attempt to identify a cause. Commonly, syncope is caused by a transient loss of blood supply to the brain, which can be due to dehydration, blood loss, cardiac dysrhythmias or neurologic events such as transient ischemic attacks. The fact the patient is young and healthy doesn’t negate the fact something caused him to lose consciousness.

Another potential cause of syncope and sudden cardiac death in young persons are a group of heart conditions known as channelopathies. Channelopathies are congenital (born with) problems on cardiac cells. The ion channels on the wall of cardiac cells fail to properly regulate the exchange of electrolytes, such as sodium. Two common channelopathies are long QT syndrome (LQTS) and Brugada syndrome (BrS). Both of these conditions are difficult to diagnosis because there are no structural changes seen in the heart. The first symptom can be sudden cardiac death. In some cases there are changes in the ECG suggestive of the conditions.

There are currently 13 different types of LQTS and it’s estimated LQTS is seen in one out of every 2,500 people.1 The condition can be congenital or acquired. Acquired LQTS is most commonly associated with medications. The condition can result in sudden cardiac arrhythmias, causing syncope or cardiac arrest. Faster heart rates can be associated with the arrhythmias so it’s not uncommon to see patients with LQTS show symptoms during physical activity, such as collapsing on a soccer field.

Once identified, LQTS can be treated with beta blockers, which are medications that work to keep heart rates from becoming tachycardic. These patients may also be placed with an internal cardiac defibrillator (ICD).

BrS exists in an estimated four out of every 1,000 persons2 with prevalence in men over women 8:1.3 Similar to LQTS, the first presentation of BrS can be sudden syncope or sudden cardiac death. Many medications can be harmful to patients with BrS,  and the only treatment is an ICD.

Conclusion

Both channelopathies briefly mentioned here are congenital and can be seen in multiple family members. In this case, the fact Mark’s uncle died unexplainably at a young age is very relevant to Mark’s syncopal episode. If one member of a family is thought to have a channelopathy, other family members are commonly tested.

EMS providers, although perhaps not versed in all potential channelopathies, should keep in mind the possibility of a cardiac condition as a cause of syncope, especially if there’s no other explainable cause. It’s easy to consider a heart problem when the patient who passes out is older, but even young, healthy people can have cardiac conditions causing syncope or sudden cardiac death. In many instances, your interaction with them may be the first indication they have a condition requiring evaluation.

References
1. Vincent GM. The molecular genetics of the long QT syndrome: Genes causing fainting and sudden death. Annu Rev Med. 1998;49:263–274.
2. Patel SS, Anees S, Ferrick KJ. Prevalence of a Brugada pattern electrocardiogram in an urban population in the United States. Pacing Clin Electrophysiol. 2009;32(6):704.
3. Benito B, Sarkozy A, Mont L, et al. Gender differences in clinical manifestations of Brugada syndrome. J Am Coll Cardiol. 2008;52(19):1567.