A Tachycardia in Disguise

HomeCirculationVol. 145, No. 13A Tachycardia in Disguise Free AccessCase ReportPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyRedditDiggEmail Jump toFree AccessCase ReportPDF/EPUBA Tachycardia in Disguise Giacomo Mugnai, MD, PhD, Alessia Gambaro, MD and Flavio Luciano Ribichini, MD Giacomo MugnaiGiacomo Mugnai Correspondence to: Giacomo Mugnai, MD, PhD, Division of Cardiology, Department of Medicine, School of Medicine, University of Verona, Piazzale Aristide Stefani, 1 – 37126 Verona, Italy. Email E-mail Address: [email protected] Division of Cardiology, Department of Medicine, School of Medicine, University of Verona, Verona, Italy. *G. Mugnai and A. Gambaro contributed equally. Search for more papers by this author , Alessia GambaroAlessia Gambaro Division of Cardiology, Department of Medicine, School of Medicine, University of Verona, Verona, Italy. *G. Mugnai and A. Gambaro contributed equally. Search for more papers by this author and Flavio Luciano RibichiniFlavio Luciano Ribichini https://orcid.org/0000-0002-6662-0304 Division of Cardiology, Department of Medicine, School of Medicine, University of Verona, Verona, Italy. Search for more papers by this author Originally published28 Mar 2022https://doi.org/10.1161/CIRCULATIONAHA.121.058997Circulation. 2022;145:1024–1028ECG ChallengeA 66-year-old woman presented in the emergency department reporting asthenia, weight gain (6 kg in the past month) and increasing edema in both legs, and dyspnea for minimal efforts. Her history included the so-called arrhythmogenic cardiomyopathy1 characterized by a predominant right ventricular (RV) fibrofatty replacement with partial involvement of the left ventricle (LV; apical and inferior wall) diagnosed 17 years before through cardiac magnetic resonance (CMR), cardiac electrophysiology 3-dimensional mapping system, and right and left heart catheterization.1 Over time, the patient did not undergo a regular clinical follow-up, consulting different outpatient clinics sporadically. Furthermore, she had repeatedly refused the placement of an implantable cardioverter defibrillator in primary prevention. The patient did not experience or report any arrhythmias during her follow-up. No family history of sudden cardiac death was reported.Structural conditions mimicking a biventricular arrhythmogenic cardiomyopathy such as myocarditis, sarcoidosis, and amyloidosis were ruled out at the moment of the diagnosis and by a recent CMR. The latest CMR confirmed the arrhythmogenic cardiomyopathy with an important progression of the LV involvement together with a severe RV derangement.The physical examination revealed clear signs of congestive heart failure, and blood tests showed severe impairment of renal and liver functions with metabolic acidosis and increased levels of lactates. Blood pressure was 115/70 mm Hg and the patient was asymptomatic at rest. The heart rate was ≈125 bpm.The ECG in Figure 1 was recorded on admission.Download figureDownload PowerPointFigure 1. The presenting ECG.What type of tachycardia does the patient present? Where is the QRS?Please turn the page to read the diagnosis.Response to ECG ChallengeBaseline ECG (Figure 2) helps to make the diagnosis. The tracing has been extrapolated from a previous ECG 24-hour Holter that shows sinus rhythm with big and sharp atrial P waves (amplitude of 3–4 mm) and diffuse, very small QRS voltages (amplitude of 1 mm).Download figureDownload PowerPointFigure 2. Tracing from a previous ECG 24-hour Holter. The ECG shows sinus rhythm with tall and sharp atrial P waves (as shown in lead II) and tiny QRS voltages (as marked in lead II). Of note, a single ventricular extrasystole coming from the apex of the right ventricle, typical for arrhythmogenic right ventricular cardiomyopathy (marked in the picture as a black box), was recorded.The very small amplitude of QRS was probably related to the very advanced arrhythmogenic cardiomyopathy attributable to a severe and widespread myocardial replacement with fibrofatty tissue.1 The term “arrhythmogenic cardiomyopathy” has been recently proposed1 to include a spectrum of conditions involving the RV, the LV, or both, whose common denominator is the prominent nonischemic ventricular myocardial scarring. Although other severe pathological conditions of the RV such as pulmonary hypertension and chronic pulmonary heart disease might be associated with big and sharp P waves, a decrease in QRS is not usually observed. Low QRS voltages commonly indicate LV involvement (regardless of the RV disease severity) and reflect loss of myocardium/electric voltages of the LV wall and replacement by electrically inert fibrofatty scar tissue.1 Structural conditions mimicking arrhythmogenic cardiomyopathy, such as myocarditis, sarcoidosis, and amyloidosis, were ruled out by a more recent CMR performed before the patient’s hospital admission. The latest CMR showed an important progression of the LV and RV involvement. Furthermore, no pulmonary diseases or large pericardial effusion were detected on computer tomography and echocardiogram.Because the myocardium in both ventricles was severely diseased, the complete architecture of the heart was altered and, consequently, the ECG. RV was severely dilated (Figure 3A and 3B) and dyskinetic (Figure 3D and 3E), and signs of volume and pressure overload were detected (Figure 3C). In consequence of fibrofatty tissue replacement, the patient’s ECG lost myocardial vectors almost completely (QRS ≈1 mm in all leads). However, the atrial depolarization was still preserved and showed a typical P pulmonale pattern (tall and sharp in the inferior leads) because of severe right atrium enlargement2 (Figures 2 and 4B).Download figureDownload PowerPointFigure 3. Transthoracic cardiac bidimensional echocardiography of the patient. A, Severely dilated and dyskinetic right ventricle with thickened and echo-bright moderator band. Severe functional tricuspid regurgitation with almost equalization of RV and right atrium pressure gradient. B, Parasternal short axis showing a severely dilated right ventricular outflow tract. C, Parasternal short axis at the level of papillary muscles showing signs of pulmonary hypertension. D, Severely reduced right ventricle S′ tissue Doppler imaging (≈ 6 cm/sec). E, Severely reduced tricuspid plane systolic excursion.Download figureDownload PowerPointFigure 4. Comparison between the ECGs during the arrhythmia and in sinus rhythm. A, On admission, the ECG apparently showed a wide complex tachycardia with diffuse low voltages. The complexes presented a very fast cycle length (240 ms); they were regular, negative in the inferior leads and positive in V1 with clear evidence of fragmentation. The sawtooth pattern (highlighted by the black box, lead II) represented a typical common flutter running in severely dilated right structures. The atrial flutter was conducted to the ventricle in a 2:1 fashion resulting in a ventricular heart rate of 125 bpm. The QRS complexes are tiny, as known from the Holter tracing, hidden by the prominent flutter waves but still perceived in the lateral leads (I, aVL, V4 through V6; black arrows). B, A previous 12-lead ECG helps to make the diagnosis. The P waves are highlighted by a black spot (tall and sharp waves showing a typical P pulmonale pattern), whereas the QRS waves (exhibiting low and fragmented voltages) are marked with a black asterisk.Therefore, the initial ECG has been explained in Figure 4. Although the initial presentation raised the suspicion of ventricular tachycardia, the pulse, blood pressure, and hemodynamic stability were actually clues for a supraventricular tachycardia. As a matter of fact, the sawtooth pattern (negative waves in the inferior leads with slow descent and sharp ascent) represented a typical common flutter running in severely dilated right structures. The atrial flutter was conducted to the ventricle in a 2:1 fashion resulting in a ventricular heart rate of 125 bpm (Figure 4A). As already known from the previous tracings, the QRS complexes were very small, hidden by the prominent flutter waves, but still perceived in the lateral leads (I, aVL, V4 through V6; black arrows). The diagnosis was made clear by just examining previous ECG recordings (Figure 4B): the P waves were found tall and sharp (black spot) and the QRS waves were tiny and hard to see (black asterisk).In a short time, the patient dramatically evolved into a frank cardiogenic shock and died.Article InformationSources of FundingNone.Disclosures None.Footnotes*G. Mugnai and A. Gambaro contributed equally.For Sources of Funding and Disclosures, see page 1028.https://www.ahajournals.org/journal/circCorrespondence to: Giacomo Mugnai, MD, PhD, Division of Cardiology, Department of Medicine, School of Medicine, University of Verona, Piazzale Aristide Stefani, 1 – 37126 Verona, Italy. Email mugnai.[email protected]comReferences1. Corrado D, van Tintelen PJ, McKenna WJ, Hauer RNW, Anastastakis A, Asimaki A, Basso C, Bauce B, Brunckhorst C, Bucciarelli-Ducci C, et al.; International Experts. Arrhythmogenic right ventricular cardiomyopathy: evaluation of the current diagnostic criteria and differential diagnosis.Eur Heart J. 2020; 41:1414–1429. doi: 10.1093/eurheartj/ehz669MedlineGoogle Scholar2. Harrigan RA, Jones K. ABC of clinical electrocardiography. Conditions affecting the right side of the heart.BMJ. 2002; 324:1201–1204. doi: 10.1136/bmj.324.7347.1201CrossrefMedlineGoogle Scholar Previous Back to top Next FiguresReferencesRelatedDetails March 29, 2022Vol 145, Issue 13Article InformationMetrics © 2022 American Heart Association, Inc.https://doi.org/10.1161/CIRCULATIONAHA.121.058997PMID: 35344408 Originally publishedMarch 28, 2022 PDF download Advertisement SubjectsArrhythmiasCardiomyopathy