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Atrial Fibrillation

Unusual Electrocardiogram Findings After Cardioversion

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JAMA Internal Medicine

Published Online: December 5, 2022

Challenges in Clinical Electrocardiography

Article Information and Disclosures

Ramanathan Velayutham, MD¹;

Chinmay Parale, MD¹;

Sridhar Balaguru¹

Author Affiliations

¹Department of Cardiology, Jawaharlal Institute of Postgraduate Medical Education and Research, Dhanvantari Nagar, Puducherry, India

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An individual in their late 60s presented with a 4-day history of palpitations at rest and reported 2 months of exertional breathlessness. The patient’s medical history was notable for metastatic bladder carcinoma followed by palliative chemotherapy and pulmonary tuberculosis treated with antituberculous therapy for 6 months 10 years earlier. On physical examination, the patient had a pulse rate of 84 beats per minute (bpm) and blood pressure of 112/76 mm Hg. Jugular venous pressure was notable for a prominent y descent. Cardiovascular examination was otherwise unremarkable. Results of a transthoracic echocardiography showed biatrial dilatation, normal biventricular systolic function, grade III diastolic dysfunction, and significant transmitral flow variations—features suggestive of constrictive pericarditis. Findings of an electrocardiogram (ECG) at presentation were consistent with typical atrial flutter with an atrioventricular Wenckebach conduction. After ruling out atrial thrombi, the patient underwent synchronized electrical cardioversion. Results of ECGs performed before and after cardioversion are shown in the Figure.

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Interatrial block is classified into 3 types: first degree or partial, defined as a P-wave duration of more than 120 milliseconds; third degree or advanced, defined by a P-wave duration 120 milliseconds or longer and a biphasic configuration in the inferior leads; and second degree or intermittent, characterized by a variable transition between partial and advanced IAB. Advanced IAB is frequently associated with supraventricular arrhythmias, such as atrial fibrillation and atrial flutter, known as Bayés syndrome.² More recently, IAB has also been implicated in cognitive impairment, dementia, and stroke.³ The pathologic substrate of IAB has been shown to be atrial fibrosis.⁴

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Article Information

Corresponding Author: Ramanathan Velayutham, MD, Department of Cardiology, Jawaharlal Institute of Postgraduate Medical Education and Research, Jipmer Campus Rd, Dhanvantari Nagar, Puducherry 605006, India (nadalram@gmail.com).

Published Online: December 5, 2022. doi:10.1001/jamainternmed.2022.5053

Conflict of Interest Disclosures: None reported.

References

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Murariu E , Frigy A . Bayés’ syndrome: a comprehensive short review. Medicina (Kaunas). 2020;56(8):410. doi:10.3390/medicina56080410 PubMed Google Scholar Crossref

Power DA , Lampert J , Camaj A , et al. Cardiovascular complications of interatrial conduction block: JACC state-of-the-art review. J Am Coll Cardiol. 2022;79(12):1199-1211. doi:10.1016/j.jacc.2022.01.030 PubMed Google Scholar Crossref

Bisbal F , Baranchuk A , Braunwald E , Bayés de Luna A , Bayés-Genís A . Atrial failure as a clinical entity: JACC review topic of the week. J Am Coll Cardiol. 2020;75(2):222-232. doi:10.1016/j.jacc.2019.11.013 PubMed Google Scholar Crossref

Hancock EW . Differential diagnosis of restrictive cardiomyopathy and constrictive pericarditis. Heart. 2001;86(3):343-349. doi:10.1136/heart.86.3.343 PubMed Google Scholar Crossref

Ninios I , Pliakos C , Ninios V , Karvounis H , Louridas G . Prevalence of interatrial block in a general population of elderly people. Ann Noninvasive Electrocardiol. 2007;12(4):298-300. doi:10.1111/j.1542-474X.2007.00178.x 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

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