|INTERESTING CASE REPORT
|Year : 2019 | Volume
| Issue : 2 | Page : 85-87
Arrhythmogenic isolated left atrial cardiomyopathy
Madhu Shukla1, Vishwas Mohan1, Jagdish Chander Mohan2
1 Department of Cardiology, Institute of Heart and Vascular Diseases, Jaipur Golden Hospital, Rohini, Delhi, India
2 Department of Cardiology, Jaipur Golden Hospital, Delhi, India
|Date of Web Publication||29-Aug-2019|
Jagdish Chander Mohan
Jaipur Golden Hospital, Sector 3, Rohini, Delhi - 110 088
Source of Support: None, Conflict of Interest: None
The atrial structure or substrate of patients with atrial arrhythmias can present very differently, and also, the “phenotype” of the arrhythmia cannot explain these differences. Idiopathic isolated atrial cardiomyopathy is a novel subtype of cardiomyopathy characterized possibly by atrial fibrosis that does not involve the ventricular myocardium and is associated with significant atrial tachyarrhythmia and no systemic, inflammatory, or infiltrative disease. We report a 57-year-old female doctor who presented with recurrent palpitations of 2-week duration and was shown to have normal left ventricular size, function, longitudinal strain, and filling pressures as judged by E/e' ratio and mitral early diastolic Doppler tissue velocities. The study of atria revealed markedly enlarged left atrium (LA), significantly reduced left atrial reservoir strain, and increased LA stiffness index. Frequent atrial ectopy may be manifestation of a structural atrial disease which could be termed arrhythmogenic isolated LA cardiomyopathy.
Keywords: Atrial cardiomyopathy, atrial fibrillation, left atrial strain
|How to cite this article:|
Shukla M, Mohan V, Mohan JC. Arrhythmogenic isolated left atrial cardiomyopathy. J Indian Acad Echocardiogr Cardiovasc Imaging 2019;3:85-7
|How to cite this URL:|
Shukla M, Mohan V, Mohan JC. Arrhythmogenic isolated left atrial cardiomyopathy. J Indian Acad Echocardiogr Cardiovasc Imaging [serial online] 2019 [cited 2020 Feb 25];3:85-7. Available from: http://www.jiaecho.org/text.asp?2019/3/2/85/265747
| Introduction|| |
The term “atrial cardiomyopathy” is not a recent entity. The first case of atrial cardiomyopathy presenting with supraventricular arrhythmias and atrioventricular block was described in 1972. Initially, it was considered that long-standing atrial fibrillation can produce morphological changes which could be termed tachycardia-induced atrial cardiomyopathy. However, recently, it has been proposed that isolated atrial cardiomyopathy is a well-defined specific entity with non-scar fibrosis and is the denominator for atrial arrhythmias. We herein describe a middle-aged female who had relatively benign atrial arrhythmias but was found to have significant left atrial (LA) disease. There are important clinical implications which prompted us to report this case.
| Clinical Presentation|| |
A 57-year-old female physician presented with a history of recurrent palpitations of 2-week duration. She denied any history of exertional dyspnea/fatigue, diabetes, hypertension, hypothyroidism, and cerebral ischemic events. On examination, she weighed 61 kg with a standing height of 168 cm (body surface area: 1.6 m 2), blood pressure: 110/76 mmHg, and pulse rate: 84/min irregular. There was no pedal edema, and jugular venous pressure was not elevated. Examination of the cardiovascular system was unremarkable except for frequent premature beats. Her 12-lead electrocardiogram showed atrial trigeminy [Figure 1]. Routine biochemistry was normal. Brain natriuretic peptide level was 57 pg/mL. A 24-h Holter monitoring revealed frequent atrial ectopy (1% of all beats), atrial bigeminy, trigeminy, a single episode of short self-terminating atrial fibrillation, and asymptomatic sinus pauses of 2 s or less [Figure 2]. Transthoracic echocardiography revealed normal left ventricular size and function (ejection fraction – 62% and global longitudinal strain – 21%), enlarged LA [anteroposterior diameter 42 mm, superoinferior diameter – 55.7 mm, mediolateral diameter – 49 mm, and biplane LA maximum volume – 47 mL/m 2, [Figure 3]. Average E/e' of 9 was noted [Figure 4]. There was no mitral or tricuspid regurgitation. Right ventricular systolic function was normal (tricuspid annular S' – 13 cm/s). There was no right atrial enlargement. Postectopic cardiac cycles in tissue Doppler tracings (lateral mitral edge) showed prominent L' waves [Figure 5]. Global LA longitudinal reservoir strain was +27%, and LA stiffness index (E/e'/LA reservoir strain) was 0.34 [normal values <0.2, [Figure 6].
|Figure 1: A 12-lead surface electrocardiogram showing supraventricular trigeminy. There is no P-wave abnormality|
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|Figure 2: An electrocardiogram strip from Holter monitoring showing sinus pauses (upper panel) and frequent atrial premature beats (lower panel)|
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|Figure 3: Transthoracic echocardiographic parasternal long-axis view (a) and apical four-chamber view (b) showing significantly enlarged left atrium. LV: Left ventricle, LA: Left atrium, RV: Right ventricle, RA: Right atrium|
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|Figure 4: Upper panel shows pulsed-wave Doppler interrogation at the tips of mitral valve leaflets and the lower panel shows tissue Doppler velocities at medial edge of the mitral annulus. E/e' =9. Note the mitral S' of 10 cm/s. E: Early diastolic flow at mitral leaflet tip, A: Late diastolic flow at mitral leaflet tip, S': Peak systolic velocity at medial mitral annulus|
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|Figure 5: Tissue Doppler evaluation at the lateral edge of the mitral annulus. E/e' was 9 but every postectopic beat shows L' wave (arrow) which could be related to longer cardiac cycle or impaired left ventricular relaxation|
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|Figure 6: (a) Acoustic speckle tracking in apical four-chamber view showing global longitudinal strain of −23.5%. (b) Acoustic speckle tracking of the left atrium showing left atrial reservoir strain of +27%. GS: Global strain, GLS: Global longitudinal strain, LA: Left atrium|
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| Discussion|| |
The patient described in this report has predominantly LA disease presenting with atrial arrhythmias. Arrhythmic load alone cannot explain atrial enlargement and atrial dysfunction. Hence, it has to be some form of atrial cardiomyopathy. Ventricular cardiomyopathies of different types with variable atrial involvement are well-described. There are limited data on isolated atrial cardiomyopathy. The joint expert panels of most heart rhythm societies  have defined atrial cardiomyopathy as “any complex of structural, architectural, contractile or electrophysiological changes affecting the atria with the potential to produce clinically-relevant manifestations.” Our patient fits into this definition. This expert panel consensus report describes principally four types of atrial cardiomyopathy: (1) involving mainly atrial cardiomyocytes, (2) mainly interstitial fibrosis, (3) combined disease of cardiomyocytes and fibrosis, and (4) noncollagen infiltration of the extracellular matrix. Clinically, all four types may not be distinguishable.
LA remodeling may be defined as an increase in chamber size with or without reduced function. Atrial fibrosis is a hallmark of structural remodeling that contributes to the arrhythmic substrate. LA tissue has been found to contain deposits of fibrillar collagen, expansion of the extracellular matrix, and disorganized myocyte architecture in those with atrial arrhythmias, especially atrial fibrillation. Atrial fibrosis may lead to disruption of normal electric conduction and establishment of reentry circuits and thereby contribute to an increased susceptibility to and maintenance of arrhythmia. There is a close relationship between LA structural remodeling assessed by delayed enhancement magnetic resonance imaging and LA functional remodeling assessed by strain and strain rate imaging in patients with atrial arrhythmias. Our patient also showed decreased LA reservoir strain (27% vs. normal about 40% indicating possibility of fibrosis being present). Increased LA stiffness index may also be an indicator of fibrosis.
| Conclusion|| |
The atria and ventricles move in opposite directions during the cardiac cycle, so the atrial myocardium lengthens during ventricular systole (positive strain), while the ventricular myocardium shortens during ventricular systole (negative strain). This reciprocal relationship is tightly coupled both in health and disease. Normally, LA reservoir strain is numerically twice of left ventricular longitudinal strain. Isolated reduced LA lengthening as denoted by reduced reservoir strain in our patient (+27% in four-chamber view) in association with a left ventricular longitudinal four-chamber strain of −23.5% probably points toward the presence of isolated or dominant LA cardiomyopathy. These functional changes in conjunction with morphological changes are associated with a higher chance of future heart failure, stroke, thromboembolism, and persistent atrial fibrillation.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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