Palpitations at 2 am
Case:
A 20 yo male with PMH of anxiety presents with one week of chest discomfort. Symptoms began just after working out and have persisted since. At one point during his exercise, he noticed his personal heart rate monitor showed a HR of 260, associated with a few seconds of palpitations that resolved on their own. He attributes his symptoms largely due to anxiety as he has a history of this but just wanted to make sure it was nothing else. Denies dyspnea, lightheadedness, or syncope. He denies a family hx of sudden cardiac death or cardiac problems in general and does not take any medications or use any illicit drugs. He remembers similar symptoms happening twice before over the past year. He saw his primary care doctor for this who ordered an outpatient echo, scheduled for later this year.
Initial Vitals:
HR: 82 beats/min
BP: 118/70
RR: 16 breaths/min
O2: 100% on room air
T: 37°C
An EKG was obtained given the c/c:
Computer interpretation:
sinus rhythm, left ventricular hypertrophy with QRS widening and repolarization abnormality; ST elevation, consider inferior injury or acute infarct
** ACUTE MI **
Physician interpretation:
sinus rhythm, regular, narrow QRS, shortened PR (64 ms), slurred upstroke of the QRS complex, suggestive of a delta wave. worrisome for Wolff-Parkinson-White syndrome (WPW).
Pearl #1:
Always interpret your own EKG’s! It’s often easier to rely on a computer interpretation of an EKG, particularly on a busy ED shift. This one is a good reminder of that.
Pearl #2:
EKG features in this pre-excitation syndrome: delta wave (slurred upstroke of the QRS), narrow QRS if orthodromic (QRS < 120 ms) vs. wide QRS if antidromic (QRS > 120 ms), shortened PR (PR < 120 ms)
WPW refers to the presence of a congenital accessory pathway that predisposes to episodes of tachyarrhythmias and a small risk of sudden cardiac death. Incidence is 0.1 - 0.3 per 1,000 people. WPW is a ventricular pre-excitation syndrome in which an accessory conduction pathway bypasses the AV node and forms a direct electrical connection between the atria and ventricles. Because there are two pathways, a re-entry circuit can form. The delta wave is due to early slow depolarization outside the His-Purkinje system preceding the usual QRS. The isoelectric PR segment, which is created by the AV node, is absent.
In orthodromic AVRT (75%), the atrial impulse is conducted through the AV node and returns back to the atria via the accessory pathway. Since the ventricles are depolarized normally via the His-Purkinje system, the QRS complex is narrow. The pattern looks similar to a PSVT (AVNRT) and treatment is the same: vagal maneuvers, adenosine, and rate control.
In antidromic AVRT (5%), the re-entry circuit conducts down the accessory pathway and returns to the atria in a retrograde fashion via the AV node. Thus, the QRS complex is wide (> 120 ms). In WPW with atrial fibrillation (20%), there is a wide QRS but the rhythm is irregular, the rate tends to be faster, and the QRS complexes themselves often vary in morphology. In either case of wide-complex rhythm, however, we tend to avoid AV nodal blocking agents (including amiodarone) as they can incite ventricular tachycardia and fibrillation; instead, management is typically with procainamide or electrical cardioversion.
Of note, about 15% of accessory pathways only conduct retrograde (from ventricle to atrium) – in these patients, no delta wave is seen, so the accessory pathway is described as “concealed” and is not evident unless reentrant tachycardia occurs.
Pearl #3:
Consider these diagnoses on your differential in patients with palpitations, lightheadedness, and/or syncope, particularly in those of younger age: Brugada syndrome, HOCM (Hypertrophic Obstructive Cardiomyopathy), Long QT syndrome, aRVC (Arrhythmogenic Right Ventricular Cardiomyopathy), WPW (Wolff-Parkinson-White).
Case Conclusion:
Cardiology was called for concern of WPW based on the EKG and clinical history as above; the patient was admitted to telemetry and received a formal echo inpatient, which was normal. He was given close outpatient follow-up with an electrophysiology specialist for radiofrequency ablation of his accessory pathway.
Written by:
Alex Pezeshki, MD – PGY 4 | Cook County Health
Reviewed by:
Robert Feldmen, MD
Department of Emergency Medicine |Cook County Health
For More Reading:
https://litfl.com/pre-excitation-syndromes-ecg-library/
https://litfl.com/wolff-parkinson-white-syndrome-ccc/
https://hqmeded-ecg.blogspot.com/2012/03/wpw-mimicking-and-obscuring-acute-stemi.html
ECGs for the Emergency Physician by Amal Mattu and William Brady
References:
Sethi KK, Dhall A, Chadha DS, Garg S, Malani SK, Mathew OP. WPW and preexcitation syndromes. J Assoc Physicians India. 2007 Apr;55 Suppl:10-5. PMID: 18368860.
Chhabra L, Goyal A, Benham MD. Wolff Parkinson White Syndrome. [Updated 2021 Aug 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK554437/
Cain N, Irving C, Webber S, Beerman L, Arora G. Natural history of Wolff-Parkinson-White syndrome diagnosed in childhood. Am J Cardiol. 2013 Oct 1;112(7):961-5. doi: 10.1016/j.amjcard.2013.05.035. Epub 2013 Jul 2. PMID: 23827401.
Gaita F, Giustetto C, Riccardi R, Brusca A. Wolff-Parkinson-White syndrome. Identification and management. Drugs. 1992 Feb;43(2):185-200. doi: 10.2165/00003495-199243020-00005. PMID: 1372217.
“Photo From Question 133147. Category: Cardiovascular Disorders. Subcategory: Disturbance of Cardiac Rhythm.” Rosh Review, 13 July 2021, https://www.roshreview.com/.
Yealy DM, Kosowsky JM. Dysrhythmias. In: Walls RM, Hockberger RS, Gausche-Hill M, et al., eds. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 9th ed. Philadelphia, PA: Elsevier Saunders; 2018:929–958.