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Wide QRS Complex Tachycardia Change to Narrow QRS Complex Tachycardia After β-Blocker Administration

To identify the key insights or developments described in this article
1 Credit CME

A patient in their 80s with a history of paroxysmal atrial fibrillation presented to the emergency department with palpitation, dizziness, nausea, and vomiting. The patient was treated with propafenone 3 × 150 mg/d and discontinued metoprolol use a week ago due to low blood pressure. The patient remained mentally clear. Physical examination revealed a blood pressure of 82/60 mm Hg and heart rate of 160 beats/min. Serum potassium level was 5.2 mmol/L. A 12-lead electrocardiogram (ECG) was obtained (Figure, A).

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A patient in their 80s with a history of paroxysmal atrial fibrillation presented to the emergency department with palpitation, dizziness, nausea, and vomiting. The patient was treated with propafenone 3 × 150 mg/d and discontinued metoprolol use a week ago due to low blood pressure. The patient remained mentally clear. Physical examination revealed a blood pressure of 82/60 mm Hg and heart rate of 160 beats/min. Serum potassium level was 5.2 mmol/L. A 12-lead electrocardiogram (ECG) was obtained (Figure, A).

Questions: What is the ECG diagnosis, and how should this patient’s treatment be managed?

The ECG revealed a regular monomorphic wide QRS complex tachycardia (162 beats/min) with a right bundle-branch block (RBBB) pattern and a reversed (<1.0) R/S ratio in lead V6. The possible differential diagnoses include (1) ventricular tachycardia (VT) from the mid to apical left ventricle or idiopathic fascicular VT, (2) supraventricular tachycardia (SVT)/atrial flutter (AFL) with aberration, (3) SVT with preexcitation, and (4) SVT/AFL with QRS widening due to electrolyte disturbance or antiarrhythmic drugs (AADs). Several features supported the diagnosis of VT: in lead II, the R wave peak time (80 milliseconds) was greater than 50 milliseconds (specificity, 99%; sensitivity, 93%).1 In lead aVR, there was an initial dominant R wave (accuracy, 98.6%).2 In lead V6, the R/S ratio was less than 1.0 (specificity, 78.3%; sensitivity, 82.1%).3 However, several features argue against this: in leads V5 and V6, the R to S interval (80 milliseconds) was not more than 100 milliseconds.4 Atrioventricular (AV) dissociation was not found.

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Article Information

Corresponding Author: Hua Wang, MD, Department of Cardiology, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, No. 1, Da Hua Rd, Dongcheng District, Beijing 100730, People’s Republic of China (wh74220@aliyun.com).

Published Online: January 30, 2023. doi:10.1001/jamainternmed.2022.6096

Conflict of Interest Disclosures: None reported.

Funding/Support: This work was supported by grants from the Capital’s Funds for Health Improvement and Research (CFH 2022-1-4052).

Role of the Funder/Sponsor: The funder had no role in the preparation, review, or approval of the manuscript and decision to submit the manuscript for publication.

References
1.
Pava  LF , Perafán  P , Badiel  M ,  et al.  R-wave peak time at DII.   Heart Rhythm. 2010;7(7):922-926.PubMedGoogle ScholarCrossref
2.
Vereckei  A , Duray  G , Szénási  G , Altemose  GT , Miller  JM .  New algorithm using only lead aVR for differential diagnosis of wide QRS complex tachycardia.   Heart Rhythm. 2008;5(1):89-98.PubMedGoogle ScholarCrossref
3.
Griffith  MJ , Garratt  CJ , Mounsey  P , Camm  AJ .  Ventricular tachycardia as default diagnosis in broad complex tachycardia.   Lancet. 1994;343(8894):386-388.PubMedGoogle ScholarCrossref
4.
Brugada  P , Brugada  J , Mont  L , Smeets  J , Andries  EW .  A new approach to the differential diagnosis of a regular tachycardia with a wide QRS complex.   Circulation. 1991;83(5):1649-1659.PubMedGoogle ScholarCrossref
5.
Brembilla-Perrot  B , Laporte  F , Sellal  JM ,  et al.  1:1 Atrial-flutter.   Int J Cardiol. 2013;168(4):3287-3290.PubMedGoogle ScholarCrossref
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Bergonti  M , Assanelli  E , Agostoni  P .  The wrong drug that led to the right diagnosis.   Circulation. 2019;140(19):1601-1604.PubMedGoogle ScholarCrossref
7.
Lopez Perales  CR , Fernandez Corredoira  PM , Chabbar Boudet  M .  Wide complex tachycardia and flecainide.   JAMA Intern Med. 2022;182(9):988-989.PubMedGoogle ScholarCrossref
8.
Kim  M , Kwon  CH , Lee  JH ,  et al.  Right bundle branch block-type wide QRS complex tachycardia with a reversed R/S complex in lead V6.   Heart Rhythm. 2021;18(2):181-188.PubMedGoogle ScholarCrossref
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