Alternating P Wave Morphology

HomeCirculationVol. 139, No. 9Alternating P Wave Morphology Free AccessCase ReportPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessCase ReportPDF/EPUBAlternating P Wave MorphologyWhat is The Mechanism? Xiaozhi Qin, MD, Ennan Fang, MD, Megumi Narisawa, MD and Xian Wu Cheng, MD, PhD Xiaozhi QinXiaozhi Qin Department of Cardiology, Yanbian University Hospital, Yanji, Jilin Province, China (X.Q., E.F., X.W.C.). Search for more papers by this author , Ennan FangEnnan Fang Department of Cardiology, Yanbian University Hospital, Yanji, Jilin Province, China (X.Q., E.F., X.W.C.). Search for more papers by this author , Megumi NarisawaMegumi Narisawa Department of Cardiology, Nagoya University Graduate School of Medicine, Aichiken, Japan (M.N.). Search for more papers by this author and Xian Wu ChengXian Wu Cheng Xian Wu Cheng, MD, PhD, Department of Cardiology and Hypertension/Heart Center, Yanbian University Hospital, Yanji 133000, Jilin Province, China. Email E-mail Address: [email protected]Xian Wu Cheng, MD, PhD, Department of Cardiology and Hypertension/Heart Center, Yanbian University Hospital, Yanji 133000, Jilin Province, China. Email E-mail Address: [email protected] Department of Cardiology, Yanbian University Hospital, Yanji, Jilin Province, China (X.Q., E.F., X.W.C.). Department of Cardiology, Kyung Hee University Hospital, Seoul, Republic of Korea (X.W.C.). Search for more papers by this author Originally published25 Feb 2019https://doi.org/10.1161/CIRCULATIONAHA.118.038396Circulation. 2019;139:1225–1227ECG ChallengeA 59-year-old man was admitted to the surgery department for the surgical treatment of esophageal cancer. He had no cardiovascular disease or notable medication history. At the hospital, his heart rate was 61 bpm and his blood pressure was 120/80 mm Hg, with no detectable heart murmurs or other cardiac signs. The echocardiography data were as follows: left atrium diameter, 28 mm; left ventricle end-diastolic diameter, 44 mm; left ventricle end-systolic diameter, 25 mm; interventricular septum thickness, 10/15 mm; main pulmonary artery inner diameter, 22 mm; left ventricular ejection fraction, 63%; fraction shortening, 32; systolic volume, 73 mL; cardiac index, 5.6 L/min (3.5–8.0 L/min). Chest x-ray combined with echocardiography data indicated a normal heart size without gross structural abnormalities. The 12-lead ECG shown in Figure 1 was obtained before surgical therapy. What is the cardiac arrhythmia and what is the clinical implication?Download figureDownload PowerPointFigure 1. ECG obtained at admission: 12 leads synchronously recorded the ECG.Please turn the page to read the diagnosis.Response to ECG ChallengeThe ECG showed sinus rhythm with 2 alternating different P-wave morphologies (Figure 2): the narrow P-wave duration was 100 ms, the wide P-wave duration was 170 ms, and the peak appeared to have bifid morphology. The PR intervals also exhibited 2 types: the short interval was 160 ms, and the long interval was 230 ms. The P wave in the I, II, III, and aVF leads was upright, whereas the P wave in the aVR lead was the inverse (Figure 1). The QRS duration was 100 ms, the QT interval was 380 ms, and the ST-T segment was normal. The patient’s previous ECG record was not available. Based on the characteristics of the ECG results, the ECG diagnosis was sinus rhythm, with alternating first-degree (type I) intra-atrial conduction block.Download figureDownload PowerPointFigure 2. ECG obtained at admission: Standard I and II leads synchronously recorded the ECG.An intra-atrial conduction block is a conduction disturbance from the right atrium to the left atrium that occurs mainly across the Bachmann bundle,1 which is 1 of 4 tracks of specialized fibers that act as the interatrial conduction system and the preferential path for electric activation of the left atrium. In general, the conduction time of the right to left atrium is ≈60 to 70 ms. When the P-wave duration is >100 ms, it meets criteria for intra-atrial conduction block.2 The incidence of intra-atrial conduction block in the general population is <1%, and it increases with age.3 Intra-atrial conduction blocks can usually be divided 2 ways: (1) degrees I, II, and III; and (2) partial (including degree I) and progressive (including degrees II and III).3 The width and shape of P waves are also often used to classify intra-atrial conduction blocks. For example, in cases with a partial degree I intra-atrial conduction block, the P waves exhibit broadening and an upright shape with a bimodal appearance and peak spacing ≥40 ms in I, II, III, and aVF leads. In cases with a progressive intra-atrial conduction block, there is a positive and negative bidirectional P wave at the II, III, and aVF leads, indicating that left atrial excitation is in the direction from the feet to the head.All the data from the present patient’s laboratory examinations (x-ray, color Doppler ultrasound, and ECG) strongly suggested the presence of an intra-atrial conduction block without gross structural abnormalities (eg, left atrial hypertrophy). To the best of our knowledge, this is the first reported case of ECG showing an alternating degree I atrial block and the P wave appearing in bigeminal alternation.Intra-atrial conduction block can have clinical consequences because it has been associated with an increased incidence of various atrial arrhythmias, such as premature atrial contractions, atrial flutter, atrial fibrillation, and atrioventricular nodal block, as well.In the differential diagnosis between intra-atrial conduction block and other atrial arrhythmia, the possibility of premature atrial beats exists, yet we did not feel that was the case, because the alternating P waves were not early and there was no compensatory interval.Finally, we have not followed up on this patient’s case. Further study is needed regarding intra-atrial conduction blocks, including alternating degree I intra-atrial conduction blocks, especially regarding their underlying molecular mechanisms, clinical progression, and implications.Sources of FundingThis work was supported in part by grants from the National Natural Science Foundation of China (Nos. 81560240 and 81770485).DisclosuresNone.Footnoteshttps://www.ahajournals.org/journal/circXian Wu Cheng, MD, PhD, Department of Cardiology and Hypertension/Heart Center, Yanbian University Hospital, Yanji 133000, Jilin Province, China. Email [email protected]nagoya-u.ac.jpXian Wu Cheng, MD, PhD, Department of Cardiology and Hypertension/Heart Center, Yanbian University Hospital, Yanji 133000, Jilin Province, China. Email [email protected]comReferences1. Chugh A, Yokokawa M, Baman T, Bogun F, Wu A. Intra-atrial conduction block mimicking atrioventricular nodal block after multiple catheter ablation procedures for atrial tachycardia in a patient with cardiomyopathy.J Cardiovasc Electrophysiol. 2012; 23:1258–1261. doi: 10.1111/j.1540-8167.2012.02347.xCrossrefMedlineGoogle Scholar2. Weiss C, Willems S, Hoffmann M, Meinertz T. Impact of the ECG for detection of intraatrial conduction block after atrial flutter ablation.Pacing Clin Electrophysiol. 1999; 22:1457–1465. doi: 10.1111/j.1540-8159.1999.tb00349.xCrossrefMedlineGoogle Scholar3. Mairesse GH, Lacroix D, Klug D, Le Franc P, Kouakam C, Kacet S. The usefulness of surface 12-lead electrocardiogram to predict intra-atrial conduction block after successful atrial flutter ablation.J Electrocardiol. 2003; 36:227–235. doi: 10.1016/S0022-0736(03)00047-5CrossrefMedlineGoogle Scholar Previous Back to top Next FiguresReferencesRelatedDetailsCited By Li Y, Narisawa M, Huang Z, Meng X, Wang H, Jin X, Shen X and Cheng X (2021) Expanding role for single‐pill combination drug therapy in the initial treatment of hypertension?, The Journal of Clinical Hypertension, 10.1111/jch.14378, 23:11, (1984-1986), Online publication date: 1-Nov-2021. Ezeani M and Prabhu S (2021) Pathophysiology and therapeutic relevance of PI3K(p110α) protein in atrial fibrillation, Pharmacological Research, 10.1016/j.phrs.2020.105415, 165, (105415), Online publication date: 1-Mar-2021. Zhang S, Li P, Xin M, Jin X, Zhao L, Nan Y and Cheng X (2021) Dipeptidyl peptidase-4 inhibition prevents lung injury in mice under chronic stress via the modulation of oxidative stress and inflammation, Experimental Animals, 10.1538/expanim.21-0067, 70:4, (541-552), . Zhao L, Xin M, Piao X, Zhang S, Li Y and Cheng X (2022) Prognostic Implications of the Admission Cardiac Troponin I Levels and Door-to-Balloon Time on Clinical Outcomes in Patients with ST-Segment Elevation Myocardial Infarction Undergoing Percutaneous Coronary Intervention, Therapeutics and Clinical Risk Management, 10.2147/TCRM.S335045, Volume 18, (31-45) February 26, 2019Vol 139, Issue 9 Advertisement Article InformationMetrics © 2019 American Heart Association, Inc.https://doi.org/10.1161/CIRCULATIONAHA.118.038396PMID: 30802173 Originally publishedFebruary 25, 2019 PDF download Advertisement SubjectsArrhythmiasElectrophysiology