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Atrial Fibrillation

Challenged Atrioventricular Node Ablation in a Patient With Atrial Fibrillation With Rapid Ventricular Rate and Wide QRS Complex

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JAMA Internal Medicine

Published Online: October 31, 2022

Challenges in Clinical Electrocardiography

Article Information and Disclosures

Xiaobo Pu, MD¹;

Bosen Yang, MSc¹;

Author Affiliations

¹Department of Cardiology, West China Hospital, Sichuan University, Chengdu, China

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A patient in their 60s was referred to our hospital (West China Hospital) for atrial fibrillation (AF) ablation, with a history of palpitations for more than 10 years and dyspnea for 3 years. This patient had undergone a single-chamber pacemaker implant 10 years prior for sick sinus syndrome with paroxysmal AF. Two months prior, the patient was admitted to a local hospital for worsening dyspnea because of persistent AF with a poorly controlled ventricular rate even though they were taking metoprolol, 47.5 mg, and digoxin, 0.125 mg, once daily, and diltiazem, 30 mg, 3 times a day. Echocardiography results showed an enlarged left atrium (51 mm) and left ventricle (66 mm) with a reduced left ventricular ejection fraction (31%). A 12-lead electrocardiogram (ECG) was obtained on admission (Figure). Physicians interpreted the ECG as AF with a rapid ventricular response and left bundle branch block (LBBB) and made the diagnosis of tachycardia-induced cardiomyopathy. The treatment strategy was to ablate the atrioventricular (AV) node and then upgrade the single-chamber pacemaker to cardiac resynchronization therapy. However, AV block was not achieved after more than 3 hours’ ablation around the His bundle area.

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For patients with AF, regular WCT is more likely to be VT, whereas irregular WCT indicates pre-excited AF or AF with aberrant conduction. Usually, AF with pre-excitation manifests as irregular tachycardia with varying QRS morphologies and a very rapid ventricular rate owing to the short refractory period of the AP. The changing QRS morphology results from varying degrees of fusion owing to the ventricular activation by the AP and AV node.¹ For this patient, it was most likely that the AV nodal blocking agents resulted in monomorphic QRS complexes by inhibiting the conduction through the AV node, and AV conduction was occurring mostly over the AP. Therefore, physicians were misled to exclude the diagnosis of pre-excited AF and make the wrong diagnosis of AF with LBBB.

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Article Information

Corresponding Author: Hua Fu, MSc, Department of Cardiology, West China Hospital, Sichuan University, 37 Guoxue St, Chengdu 610041, China (fuhua0108@qq.com).

Published Online: October 31, 2022. doi:10.1001/jamainternmed.2022.4712

Conflict of Interest Disclosures: None reported.

Additional Contributions: We thank Song-wen Chen, MD, Shanghai General Hospital, for his linguistic assistance. He was not compensated for this contribution.

Additional Information: Drs Pu and Yang contributed equally to this work as co–first authors.

References

Katritsis DG , Brugada J . Differential diagnosis of wide QRS tachycardias. Arrhythm Electrophysiol Rev. 2020;9(3):155-160. doi:10.15420/aer.2020.20 PubMed Google Scholar Crossref

Neiger JS , Trohman RG . Differential diagnosis of tachycardia with a typical left bundle branch block morphology. World J Cardiol. 2011;3(5):127-134. doi:10.4330/wjc.v3.i5.127 PubMed Google Scholar Crossref

Willems JL , Robles de Medina EO , Bernard R , et al; World Health Organizational/International Society and Federation for Cardiology Task Force Ad Hoc. Criteria for intraventricular conduction disturbances and pre-excitation. J Am Coll Cardiol. 1985;5(6):1261-1275. doi:10.1016/S0735-1097(85)80335-1 PubMed Google Scholar Crossref

Kindwall KE , Brown J , Josephson ME . Electrocardiographic criteria for ventricular tachycardia in wide complex left bundle branch block morphology tachycardias. Am J Cardiol. 1988;61(15):1279-1283. doi:10.1016/0002-9149(88)91169-1 PubMed Google Scholar Crossref

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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 CME points in the American Board of Surgery’s (ABS) Continuing Certification program

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