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Cardiology

The Imposter Dance of Alternating QRS Complexes

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JAMA Internal Medicine

Published Online: September 26, 2022

Challenges in Clinical Electrocardiography

Article Information and Disclosures

An-Li Yu, MD¹;

Ying-Hsien Chen, MD¹;

Po-Chih Lin, MD¹

Author Affiliations

¹Cardiovascular Center, Division of Cardiology, Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan

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A patient in their late 50s presented to the emergency department for acute onset chest pain with diaphoresis. The patient reported having had chest tightness followed by mild dyspnea after rushing down a set of stairs 2 days prior. The pain had gradually subsided after resting. In addition, on the evening of admission, just after finishing a meal, the patient experienced a fairly sudden onset of severe nonradiating pressure-like pain in the central portion of the chest accompanied by cold sweating; the pain persisted and progressed. Self-reported medical history included smoking 1 pack of cigarettes daily for more than 3 decades and taking medications for type 2 diabetes and hypertension.

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An ECG with alternating QRS complex morphologic findings has numerous potential causes and invokes an electrocardiographic differential diagnosis including but not limited to ventricular bigeminy, electrical alternans, atrial bigeminy with aberrant conduction, bidirectional ventricular tachycardia, sinus rhythm with alternating bundle-branch block, and WPW alternans. Electrical alternans are classically associated with substantial pericardial effusion with or without cardiac tamponade. True electrical alternans should draw early and aggressive investigation and correlation with the physical examination findings. In this case, alternating QRS complexes of differing amplitude were observed but the width of the QRS complexes and the PR intervals varied from beat to beat, which would not be expected with electrical alternans.

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Article Information

Corresponding Author: Po-Chih Lin, MD, Cardiovascular Center, Division of Cardiology, Department of Internal Medicine, National Taiwan University Hospital, No. 7 Zhongshan S Rd, Zhongzheng, Taipei 100, Taiwan (juipeter@gmail.com).

Published Online: September 26, 2022. doi:10.1001/jamainternmed.2022.3965

Conflict of Interest Disclosures: None reported.

References

Hindman MC , Last JH , Rosen KM . Wolff-Parkinson-White syndrome observed by portable monitoring. Ann Intern Med. 1973;79(5):654-663. doi:10.7326/0003-4819-79-5-654 PubMed Google Scholar Crossref

Kinoshita S , Katoh T . Alternans Wolff-Parkinson-White syndrome: supernormal conduction as an alternative mechanism. J Electrocardiol. 2007;40(5):448-449. doi:10.1016/j.jelectrocard.2007.01.004 PubMed Google Scholar Crossref

Ortega-Carnicer J , Benezet-Peñaranda J . Bradycardia-dependent block in the accessory pathway in a patient with alternans Wolff-Parkinson-White syndrome. J Electrocardiol. 2006;39(4):419-420. doi:10.1016/j.jelectrocard.2006.02.013 PubMed Google Scholar Crossref

AMA CME Accreditation Information

Credit Designation Statement: The American Medical Association designates this Journal-based CME activity activity for a maximum of 1.00  AMA PRA Category 1 Credit(s)™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Successful completion of this CME activity, which includes participation in the evaluation component, enables the participant to earn up to:

1.00 Medical Knowledge MOC points in the American Board of Internal Medicine's (ABIM) Maintenance of Certification (MOC) program;;
1.00 Self-Assessment points in the American Board of Otolaryngology – Head and Neck Surgery’s (ABOHNS) Continuing Certification program;
1.00 MOC points in the American Board of Pediatrics’ (ABP) Maintenance of Certification (MOC) program;
1.00 Lifelong Learning points in the American Board of Pathology’s (ABPath) Continuing Certification program; and
1.00 credit toward the CME [and Self-Assessment requirements] of the American Board of Surgery’s Continuous Certification program

It is the CME activity provider's responsibility to submit participant completion information to ACCME for the purpose of granting MOC credit.