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Cardiology

Incorrect ECG Diagnoses?—Follow the Leads

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JAMA Internal Medicine

Published Online: March 6, 2023

Challenges in Clinical Electrocardiography

Article Information and Disclosures

Xingli Xin, MD¹;

Xuanxuan Li, MD²;

Qingjie Xin, MD³

Author Affiliations

¹Department of Cardiology, Huanghua Boai Hospital, Affiliate of Oriental College of Beijing University of Traditional Chinese Medicine, Huanghua, Hebei, China
²Department of Cardiology, Shijiazhuang Great Wall Hospital of Integrated Traditional Chinese and Western Medicine, Shijiazhuang, Hebei, China
³Center for Coronary Artery Disease, Division of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Chaoyang District, Beijing, China

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An individual in their early 70s presented to the emergency department with frequently recurring paroxysmal chest pain; each episode had a duration of 3 to 5 minutes. The patient had a medical history of hypertension and diabetes mellitus; vital signs were normal, except for elevated blood pressure (153/92 mm Hg). Chest auscultation revealed normal breath and heart sounds with no murmurs. The laboratory test results (hemogram, serum electrolytes, and troponin I and D-dimer levels) were all within normal limits. A chest radiograph showed no abnormality, and transthoracic echocardiography findings revealed normal left ventricular systolic function (ejection fraction, 60%). The electrocardiogram (ECG) tracing obtained on admission is shown in the Figure, A.

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When electrodes are placed in the wrong anatomic locations or clipped on the radial artery, they can produce incorrect ECG diagnoses. If the electrodes of leads V₁ to V₆ are placed on the right side of the chest, the amplitude of the QRS complex will gradually decrease from lead V₁ to V₆. When the left and right arm leads are placed inversely, the ECG manifests as follows¹: (1) the P-QRS-T waves are inverted in lead I, ie, lead I is flipped (P wave is negative); (2) lead aVR resembles a normal aVL (P wave of aVR is positive), and lead II resembles a normal lead III; and (3) the precordial leads and aVF are unaffected. When the 2 aforementioned electrode misplacements occur simultaneously, the ECG characteristics will be the same as those of mirror-image dextrocardia.² No mirror-image dextrocardia was found after performing a physical examination and chest radiography of the patient; therefore, these ECG changes denoted an instance of electrode misplacement.

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Article Information

Corresponding Author: Qingjie Xin, MD, Center for Coronary Artery Disease, Division of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Anzhen Rd, Chaoyang District, Beijing 100029, China (qingjiexingood@126.com).

Published Online: March 6, 2023. doi:10.1001/jamainternmed.2022.6944

Conflict of Interest Disclosures: None reported.

References

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