Cardiac MRI in Arrhythmogenic Right Ventricular Cardiomyopathy

Transcription

1 ardiopulmonary Imaging Pictorial Essay Murphy et al. ardiac MRI in ardiomyopathy ardiopulmonary Imaging Pictorial Essay Downloaded from by on 12/23/17 from IP address opyright RRS. For personal use only; all rights reserved Darra T. Murphy 1 Suzanne. Shine 1 ndrea radock 1 Joseph M. Galvin 2 Edward T. Keelan 2 John G. Murray 1 Murphy DT, Shine S, radock, Galvin JM, Keelan ET, Murray JG Keywords: arrhythmogenic right ventricular cardiomyopathy and dysplasia, RV, RVD, cardiac MRI, sudden cardiac death DOI: /JR Received ugust 9, 2009; accepted after revision October 12, Department of Radiology, Mater Misericordiae University Hospital, Eccles St., Dublin 7, Ireland. ddress correspondence to D. T. Murphy (darramurphy@me.com). 2 Department of ardiology, Mater Misericordiae University Hospital, Dublin, Ireland. WE This is a Web exclusive article. JR 2010; 194:W299 W X/10/1944 W299 merican Roentgen Ray Society ardiac MRI in rrhythmogenic Right Ventricular ardiomyopathy OJETIVE. rrhythmogenic right ventricular cardiomyopathy (RV) is a cause of sudden cardiac death in otherwise healthy young adults. This article outlines the spectrum of MRI findings in RV using a combination of static and cine images. ONLUSION. The detection of right ventricular enlargement, fatty infiltration, fibrosis, and wall motion abnormalities at MRI is useful in the diagnosis of RV. rrhythmogenic right ventricular cardiomyopathy (RV), also known as arrhythmogenic right ventricular dysplasia (RVD), is characterized by progressive fibrofatty replacement of the right ventricular myocardium. It represents an underdiagnosed cardiac entity leading to syncope, recurrent ventricular tachycardia, heart failure, and occasionally sudden cardiac death in a younger population [1]. The pathogenesis of RV is not fully established, but there appears to be a genetic basis in many patients. The prevalence in the population is estimated at 1 per 1,000 5,000. Familial occurrence can approach 50%. RV accounts for 3 4% of deaths in sports and 5% of sudden cardiac deaths in people younger than 65 years [2, 3]. Patients may present at any age but are usually young or middle-aged. There is a 3:1 maleto-female ratio. broad range of symptoms may occur, including palpitations, fatigue, syncope, and chest pain. In some cases, cardiac arrest after physical exertion, such as participation in sports, may be the initial presenting complaint [4]. Many patients are asymptomatic and are diagnosed by familial screening. The diagnosis of RV is based on established criteria determined by a task force comprising the European Society of ardiology and the International Society and Federation of ardiology [5]. Pathophysiology RV is characterized by progressive replacement of normal myocardium in the right ventricle by fibrofatty tissue. The most common location for this tissue transforma- tion is between the anterior infundibulum, the right ventricular apex, and the inferior or diaphragmatic aspect of the right ventricle, the so-called triangle of dysplasia. Dysplasia in this region may lead to dilatation or aneurysm formation with associated paradoxical motion. The left ventricle and septum are usually spared from the fibrofatty transformation, although they may be involved in more extensive cases. In addition, the conduction system of the heart is usually spared. The presence of arrhythmias and the characteristic EG findings are caused by the dispersion of myocytes that can incite tachycardic events as the dysplasia progresses. Two forms of fibrofatty replacement have been described. In fibrolipomatosis type I, there is predominantly fatty replacement with a small amount of fibrosis surrounding surviving myocardial cells. In fibrolipomatosis type II, there is a much greater amount of fibrosis [2]. Previous authors have attempted to distinguish between these two histologic forms of RV. The predominantly fatty replacement type is described as typical RVD, and the mixed fibrofatty type is described as a more cardiomyopathic form of the disease [6]. Further attempts have been made to investigate morphologic variants of RV on the basis of morphologic and MRI findings [7]. The mode of inheritance of RV in most patients is autosomal dominant with incomplete penetrance. There is also an autosomal recessive form called Naxos disease, in which there are skin (palmoplantar keratoses) and hair (woolly hair) manifestations, in addition to RV. Genetic testing has identified genetic and chromosomal muta- JR:194, pril 2010 W299

2 Murphy et al. Downloaded from by on 12/23/17 from IP address opyright RRS. For personal use only; all rights reserved tions in certain subgroups, and, more recently, RV has been increasingly attributed to a desmosomal protein disorder. This was initially described in the autosomal recessive form in 2000 [8] and subsequently in the autosomal-dominant form in 2002 [9]. t least 10 further gene mutations have since been described in the autosomal dominant form. Diagnosis Physical Examination and EG Physical examination is normal in at least 50% of patients with RV. Diagnosis is often made following a workup for tachycardia in an otherwise healthy adult; 50 90% of people with RV will have characteristic findings on a resting EG. These findings include T-wave inversion in the anterior precordial leads (V1 V6), premature ventricular beats > 200 over 24 hours, epsilon waves, and ventricular tachycardia with a left bundle branch block pattern. Epsilon waves are small deflections just beyond the QRS complex that are best seen on a signal-averaged EG in leads V1 V3. Diagnostic riteria The diagnosis of RV is based on the presence of major and minor criteria (ppendix 1). These criteria encompass structural, histologic, EG, arrhythmic, and genetic factors, as described elsewhere [5]. lthough these criteria are specific, they lack sensitivity and have never been validated, in part because there is no single definitive means of making the diagnosis. revision of these diagnostic guidelines has been proposed, aiming to improve diagnostic sensitivity, particularly in first-degree relatives of patients, for whom there may be incomplete phenotypic expression [10]. The preferred method for making the diagnosis is based on histologic evidence of fibrofatty myocardium. Unfortunately, however, biopsy lacks sufficient sensitivity because of the segmental nature of the disease process, resulting in sampling error, and because many clinicians biopsy the septum rather than the free wall of the right ventricle to avoid the risk of ventricular perforation. patient is considered to have RV if two major criteria, or one major and two minor criteria, or four minor criteria are satisfied. Imaging Techniques and Findings Imaging techniques for detection of the morphologic and functional abnormalities of RV include conventional angiography, echocardiography, MDT, and, most importantly, MRI. ngiography is invasive, does not detect fatty infiltration, and relies on wall motion abnormalities that are often missed unless multiple projections are obtained. Echocardiography, although excellent in the assessment of the left ventricle, is limited in the evaluation of the right ventricle. This is because much of the free wall lies directly behind the sternum and ribs and is not seen. Experience with T in the diagnosis of RV is limited, but it has been used in the detection of morphologic abnormalities and wall motion abnormalities, particularly in patients with implantable defibrillators [11]. MRI is established as the imaging technique of choice in the assessment of RV. Standard protocol in our institution consists of axial breath-hold double inversion recovery turbo spin-echo sequences ( black blood ) with and without fat saturation from the base of the heart to the bifurcation of the pulmonary artery; true fast imaging with steadystate precession (TrueFISP ( bright blood ) cine sequences of the right ventricular outflow tract, vertical long axis, horizontal long access, and short axis of the heart from the mitral valve to the cardiac apex; short axis breath-hold double inversion-recovery turbo spin-echo; and delayed contrast-enhanced MRI sequences using segmented recovery turbo FLSH in both the axial plane (eight axial images through the heart) and short axis images from the mitral valve the cardiac apex. Gadolinium dose is 0.2 mmol/kg. MRI can detect fatty infiltration in the right ventricle (Figs. 1 6) and occasionally in the left ventricle (Fig. 3); however, fat infiltration of the ventricles is currently only a major criterion for diagnosis of RV on cardiac biopsy. MRI can detect right ventricular dilatation and aneurysm formation (Figs. 7 9), as well as wall-motion abnormalities including right ventricular dyskinesia, a corrugated pattern to the right ventricular wall known as the accordion sign (Figs ). Focal left ventricular dyskinesia can also be present in the setting of fatty infiltration within the left ventricle. MRI is also very useful in the evaluation of myocardial fibrosis and scarring (Fig. 14). The black blood spin-echo sequences provide excellent anatomic detail and are the most important for the detection of fat in the right ventricular myocardium. The bright blood TrueFISP cine is useful for evaluation of wall motion abnormalities and ventricular size, and STIR sequences null the fat. More recently, delayed right ventricular myocardial enhancement on gadolinium-enhanced inversion recovery sequences has been used to confirm the presence of myocardial fibrosis [12]. Late left ventricular enhancement has also been described in patients with RV [13]. Suppression of arrhythmias plays a role in adequate EG triggering and optimization of image acquisition. Treatment Treatment of RV aims to prevent sudden cardiac death. Treatment options include avoidance of strenuous exercise and competitive sports or training, β blockade, antiarrhythmic medications, catheter ablation [14], implantable cardioverter defibrillator therapy [15], and cardiac transplant. The optimal treatment technique depends on the individual patient, and no one therapy is correct for every patient [16]. Further research in treatment options, as well as maintenance of international patient registries, is vital for future risk stratification and optimization of treatment of patients with RV. cknowledgments We thank Niall Mulligan for the pathological image and description included in this article and John O Dea for his assistance with obtaining the electroanatomic voltage map. References 1. orrado D, asso, Thiene G. rrhythmogenic right ventricular cardiomyopathy: an update. Heart 2009; 95: Thiene G, Nava, orrado D, Rossi L, Pennelli N. Right ventricular cardiomyopathy and sudden death in young people. N Engl J Med 1988; 318: Peters S, Peters H, Thierfelder L. Risk stratification of sudden cardiac death and malignant ventricular arrhythmias in right ventricular dysplasia-cardiomyopathy. Int J ardiol 1999; 71: Dalal D, Nasir K, omma, et al. rrhythmogenic right ventricular dysplasia: a United States experience. irculation 2005; 112: McKenna WJ, Thiene G, Nava, et al. Diagnosis of arrhythmogenic right ventricular dysplasia/ cardiomyopathy. Task Force of the Working Group Myocardial and Pericardial Disease of the European Society of ardiology and of the Scientific ouncil on ardiomyopathies of the International Society and Federation of ardiology. r Heart J 1994; 71: d mati G, Leone O, di Gioia R, et al. rrhythmogenic right ventricular cardiomyopathy: clinicopathologic correlation based on a revised definition W300 JR:194, pril 2010

3 ardiac MRI in ardiomyopathy Downloaded from by on 12/23/17 from IP address opyright RRS. For personal use only; all rights reserved of pathologic patterns. Hum Pathol 2001; 32: Dalal D, Tandri H, Judge DP, et al. Morphologic variants of familial arrhythmogenic right ventricular dysplasia/cardiomyopathy a geneticsmagnetic resonance imaging correlation study. J m oll ardiol 2009; 53: McKoy G, Protonotarios N, rosby, et al. Identification of a deletion in plakoglobin in arrhythmogenic right ventricular cardiomyopathy with palmoplantar keratoderma and woolly hair (Naxos disease). Lancet 2000; 355: Rampazzo, Nava, Malacrida S, et al. Mutation in human desmoplakin domain binding to plakoglobin causes a dominant form of arrhythmogenic right ventricular cardiomyopathy. m J Hum Genet 2002; 71: PPENDIX 1: riteria for Diagnosis of rrhythmogenic Right Ventricular ardiomyopathy 10. Hamid MS, Norman M, Quraishi, et al. Prospective evaluation of relatives for familial arrhythmogenic right ventricular cardiomyopathy/ dysplasia reveals a need to broaden diagnostic criteria. J m oll ardiol 2002; 40: omma, Dalal D, Tandri H, et al. Evolving role of multidetector computed tomography in evaluation of arrhythmogenic right ventricular dysplasia/cardiomyopathy. m J ardiol 2007; 100: Tandri H, Saranathan M, Rodriguez ER, et al. Noninvasive detection of myocardial fibrosis in arrhythmogenic right ventricular cardiomyopathy using delayed-enhancement magnetic resonance imaging. J m oll ardiol 2005; 45: Sen-howdhry S, Prasad SK, Syrris P, et al. ardiovascular magnetic resonance in arrhythmogenic right ventricular cardiomyopathy revisited: comparison with task force criteria and genotype. J m oll ardiol 2006; 48: Dalal D, Jain R, Tandri H, et al. Long-term efficacy of catheter ablation of ventricular tachycardia in patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy. J m oll ardiol 2007; 50: orrado D, Leoni L, Link MS, et al. Implantable cardioverter-defibrillator therapy for prevention of sudden death in patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia. irculation 2003; 108: Wichter T, Paul TM, Eckardt L, et al. rrhythmogenic right ventricular cardiomyopathy. ntiarrhythmic drugs, catheter ablation, or ID? Herz 2005; 30: I. Global and/or regional dysfunction and structural alterations Major Severe dilatation and reduction of right ventricular ejection fraction with no (or only mild) left ventricular impairment Localized right ventricular aneurysms (akinetic or dyskinetic areas with diastolic bulging) Severe segmental dilatation of the right ventricle Mild global right ventricular dilatation and/or ejection fraction reduction with normal left ventricle Mild segmental dilatation of the right ventricle Regional right ventricular hypokinesia II. Tissue characterization of walls Major Fibrofatty replacement of myocardium at endomyocardial biopsy III. Repolarization abnormalities Inverted T waves in right precordial leads (V2 and V3) (people > 12 years old; in absence of right bundle branch block) IV. Depolarization of conduction abnormalities Major Epsilon waves or localized prolongation (> 110 milliseconds) of the QRS complex in right precordial leads (V1 V3) Late potentials (signal-averaged EG) V. rrhythmias Left bundle branch block type ventricular tachycardia (sustained and nonsustained (EG, Holter, exercise testing) Frequent ventricular extrasystoles on Holter (1,000 > 24 hours) VI. Family history Major Familial disease confirmed at necropsy or surgery Familial history of premature sudden death (35 years) due to suspected right ventricular cardiomyopathy Familial history (clinical diagnosis based on present criteria) Note Diagnosis is made if two major, or one major and two minor, or four minor criteria are satisfied. List is adapted from [5]. JR:194, pril 2010 W301

4 Murphy et al. Downloaded from by on 12/23/17 from IP address opyright RRS. For personal use only; all rights reserved Fig year-old man who presented after episode of collapse. T1-weighted MR image shows diffuse fatty infiltration of free wall of right ventricle. Note linear high signal corresponding to fat within myocardium (arrows) in contrast to epicardial fat (arrowhead). Fig year-old girl with palpitations. lack blood breath-hold T1-weighted MR image shows diffuse fatty infiltration of right ventricle. Note increased signal intensity from fat in free wall of right ventricle (arrows), compared with intermediate signal intensity from septum and left ventricular wall (arrowheads). Fig year-old woman undergoing family screening. T1-weighted MR image shows fat infiltration of both ventricles. There is diffuse fat within right ventricular free wall (arrowhead) in addition to focal fat in left ventricular wall (arrow). Fatty infiltration of both ventricles is rare in arrhythmogenic right ventricular cardiomyopathy. Fig year-old man under investigation for tachycardia and abnormal EG., T1-weighted MR image shows fat in right ventricular outflow tract (arrows)., True fast imaging with steady-state precession image from cardiac cine shows aneurysm formation of right ventricular wall (arrow). (See also Fig. S4, cine images, which is in the JR electronic supplement to this article, available at Fig year-old man with history of palpitations and abnormal EG., T1-weighted MR image shows extensive areas of fatty infiltration in right ventricular free wall (arrows)., True fast imaging with steady-state precession image in systole shows marked dilatation of right ventricle. These findings satisfy two major diagnostic criteria for arrhythmogenic right ventricular cardiomyopathy. (See also Fig. S5, cine images, which is in the JR electronic supplement to this article, available at W302 JR:194, pril 2010

5 ardiac MRI in ardiomyopathy Downloaded from by on 12/23/17 from IP address opyright RRS. For personal use only; all rights reserved Fig year-old asymptomatic man with first-degree relative diagnosed with arrhythmogenic right ventricular cardiomyopathy., True fast imaging with steady-state precession sequence shows focal dyskinesia with aneurysm of free wall of right ventricle (arrow). and, T1-weighted MR images in diastole () and systole () show fatty infiltration of right ventricular free wall. Note also dilatation of right ventricle in systole. In all, two major criteria and one minor criterion are satisfied. Fig year-old boy who sustained out-of-hospital cardiac arrest (ventricular fibrillation) that was successfully treated. He subsequently had implantable cardioverter defibrillator implanted. Four first-degree relatives were screened and were negative., xial spin-echo (black-blood) T2-weighted image obtained during breath-hold. Note lack of contraction and wall thinning at distal right ventricular free wall close to apex (arrow), where there is systolic bulging and aneurysm formation. This is example of major dyskinesia (major criterion). Mild anterior systolic out pouching is not specific for arrhythmogenic right ventricular cardiomyopathy and can be seen in healthy subjects. It should not be confused with aneurysm formation. and, Still images from true fast imaging with steady-state precession (bright blood) cardiac cine loop in both diastole () and systole () show aneurysm formation. (See also Fig. S7, cine images, which is in the JR electronic supplement to this article, available at Fig year-old man with palpitations., True fast imaging with steady-state precession MR image shows aneurysmal bulging of right ventricular free wall., ulging becomes more prominent during systole (arrow). JR:194, pril 2010 W303

6 Murphy et al. Downloaded from by on 12/23/17 from IP address opyright RRS. For personal use only; all rights reserved Fig year-old man under investigation of tachycardia and abnormal EG., True fast imaging with steady-state precession MR images at various stages of cardiac cycle from diastole through systole show focal dyskinesia with aneurysm formation at anterior aspect of right ventricular outflow tract (arrow, ). Fig year-old woman under investigation of palpitations and abnormal EG. True fast imaging with steady-state precession images were taken at level of right ventricular outflow tract., t rest, appearances are normal., During systole, there is dyskinesia of anterior wall of right ventricular outflow tract that gives corrugated appearance, so-called accordion sign (arrows). (See also Fig. S10, cine images, which is in the JR electronic supplement to this article, available at W304 JR:194, pril 2010

7 ardiac MRI in ardiomyopathy Downloaded from by on 12/23/17 from IP address opyright RRS. For personal use only; all rights reserved Fig year-old woman under investigation of palpitations. EG was normal. T1-weighted MRI shows abnormal wall motion with corrugation and aneurysm formation at apex. Note that no fat in seen in right ventricle in this case. (See also Fig. S12, cine images, which is in the JR electronic supplement to this article, available at D Fig year-old man who presented with atypical chest pain. He had normal coronary angiogram. D, True fast imaging with steady-state precession MR images in short axis ( and ) and long axis ( and D) show right ventricular aneurysm, corrugated right ventricular wall (accordion sign), and dyskinesia. E, T1-weighted image confirms presence of fat in right ventricular wall (arrow). (See also Fig. S11, cine images, which is in the JR electronic supplement to this article, available at Fig year-old woman with history of ventricular tachycardia. and, True fast imaging with steady-state precession images in horizontal long axis () and short axis () during systole show right ventricular dilatation with secondary dilatation of right atrium from tricuspid valve incompetence. There is marked hypokinesia of right ventricle myocardium with focal areas of dyskinesia best appreciated on cine loop. Note lack of right ventricular muscle thickening and contraction in systole on shortaxis views in comparison with normal left ventricle. No fatty infiltration was identified on black blood images. Therefore, two major criteria are satisfied. (See also Fig. S13, cine images, which is in the JR electronic supplement to this article, available at E JR:194, pril 2010 W305

8 Murphy et al. Downloaded from by on 12/23/17 from IP address opyright RRS. For personal use only; all rights reserved FOR YOUR INFORMTION Fig year-old woman with syncope and family history of sudden cardiac death., Delayed contrast-enhanced MR images show delayed enhancement (arrows) confirming presence of fibrosis. Note right ventricular enlargement. True fast imaging with steady-state precession cine reveals localized dyskinesia of anterior free wall with markedly diminished ejection fraction. (See also Fig. S14, cine images, which is in the JR electronic supplement to this article, available at Three-dimensional electroanatomic voltage map of heart in right anterior oblique projection viewed inferiorly. This shows abnormal areas of low voltage (orange) in inferior and free walls of right ventricle, representing electroanatomic scar tissue. Normal voltage (purple) is seen in surrounding myocardium. and D, Endomyocardial biopsy shows myocardium with fatty infiltration (arrows, ) and patchy fibrosis (arrow, D). (H and E; original magnifications, 100 [] and 200 [D]) data supplement for this article can be viewed in the online version of the article at: D W306 JR:194, pril 2010