Critical analysis of cineangiographic criteria for diagnosis of arrhythmogenic right ventricular dysplasia

Biplane 30-degree RAO and 60-degree LAO RV selective cineangiography was performed in 21 patients with significant ventricular arrhythmias (ventricular tachycardia in 14, salvos in three, and complex PVCs in seven) and a high presumption of arrhythmogenic RV dysplasia (ARVD), and in a control group of 10 presumed normal individuals. Comparing the two series revealed the lack of specificity of some angiographic images usually reported as suggestive signs of ARVD, such as slow dye evacuation of RV during the levophase and deep fissuring in the anterior wall with a "pile of plates" image. Inversely, localized morphologic and contraction abnormalities in the RV free wall were more sensitive and specific signs for diagnosis of ARVD; these were localized akinetic or dyskinetic bulges sometimes giving a true image of aneurysm (90%), wide and deep fissuring of the apex or of the inferior wall (33%), and large areas of akinesia. By order of frequency, these abnormalities were found on the apex in 71%, on the inferior wall in 52%, on the anterior wall in 48%, in the subtricuspid area in 38%, and on the pulmonary infundibulum in 33%. These localized lesions can suffice for the diagnosis of RV dysplasia in the absence of associated pathologies, such as ischemic heart disease or congenital defects. Usually a global RV systolic dysfunction is associated in ARVD, as confirmed by greater RV volumes (134 +/- 26 vs 79 +/- 10 ml/m2 for RVEDV, p less than 0.001; 76 +/- 34 vs 32 +/- 6 ml/m2 for RVESV, p less than 0.001), and lower RV ejection fraction (58 +/- 18% vs 47 +/- 8%, p less than 0.001) in the ARVD group compared to controls. Nevertheless, normal RV volumes and ejection fraction can be observed in some localized forms with mono- or bisegmental lesions in which RV systolic dysfunction is absent or moderate, and extensive forms with multiple segmental lesions where RV systolic dysfunction is constant and often severe. Six out of 21 patients in the ARVD group exhibited obvious global or segmental LV dysfunction, indicating the possibility of biventricular forms, as previously reported in other publications.     

Electroanatomic mapping characteristics of ventricular tachycardia in patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia.

BACKGROUND: Ventricular tachycardia (VT) in arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVD) has been previously explored using entrainment mapping techniques but little is know about VT mechanisms and the characteristics of their circuits using an electroanatomical mapping system. METHODS AND RESULTS: Three-dimensional electroanatomical mapping was performed in 11 patients with well tolerated sustained VT and ARVD. Sinus rhythm mapping of the right ventricle was performed in eight patients showing areas of low bipolar electrogram voltage (<1.2 mV). In total 12 tachycardias (mean cycle length 382+/-62 ms) were induced and mapped. Complete maps demonstrated a reentry mechanism in eight VTs and a focal activation pattern in four VTs. The reentrant circuits were localized around the tricuspid annulus (five VTs), around the right ventricular outflow tract (one VT) and on the RV free lateral wall (two VTs). The critical isthmus of each peritricuspid circuit was bounded by the tricuspid annulus with a low voltage area close to it. The isthmus of tachycardia originating from the right ventricular outflow tract (RVOT) was delineated by the tricuspid annulus with a low voltage area localized on the posterior wall of the RVOT. Each right ventricular free wall circuit showed an isthmus delineated by two parallel lines of block. Focal tachycardias originated on the right ventricular free wall. Linear radiofrequency ablation performed across the critical isthmus was successful in seven of eight reentrant tachycardias. The focal VTs were successfully ablated in 50% of cases. During a follow-up of 9-50 months VT recurred in four of eight initially successfully ablated VTs. CONCLUSIONS: Peritricuspid ventricular reentry is a frequent mechanism of VT in patients with ARVD which can be identified by detailed 3D electroanatomical mapping. This novel form of mapping is valuable in identifying VT mechanisms and in guiding RF ablation in patients with ARVD.     

Value and limitations of 2-dimensional echocardiography in the identification of arrhythmogenic right ventricular dysplasia

The aim of this study was to evaluate the value and limitations of Cross-sectional Echocardiography (CSE) in the diagnosis of Arrhythmogenic right ventricular dysplasia (ARVD). Diagnosis was based on accepted clinical, electrocardiographic, electrophysiologic and angiographic criteria. CSE criteria for the diagnosis are segmental right ventricular wall motion abnormalities of unknown cause, usually associated with localized or diffuse dilatation of right ventricular (RV) chamber and with the presence of localized anomalies consisting of sacculation or bulging of RV wall. Comparison of CSE and RV angiographic findings was performed in 8 patients with ARVD (6 men and 2 women, aged 10 to 37 years, mean 28 years). CSE and angiography compared closely when diffuse RV enlargement and wall motion abnormalities were identified by both techniques. Bulging and sacculation of the RV wall at CSE predicted the presence of similar lesions at angiography, but agreement for specific location was poor and, in addition, CSE showed low sensitivity in their detection. The inherent different information provided by the two methods added to the subjectivity of the qualitative analysis probably accounts for the inconsistencies. Therefore in patients with diagnosed ARVD RV enlargement, otherwise unexplained, associated with wall motion abnormalities and localized anomalies at CSE strongly supports the diagnosis and avoids the need for angiography. By other hand, in patients with high clinical suspicion of ARVD a negative CSE study can not exclude the diagnosis and angiography should be indicated.     

Quantification of fatty tissue mass by magnetic resonance imaging in arrhythmogenic right ventricular dysplasia

INTRODUCTION: Arrhythmogenic right ventricular dysplasia (ARVD) is a heart muscle disorder in which the pathological substrate is a fatty or fibro-fatty replacement of the right ventricular (RV) myocardium. METHODS AND RESULTS: Magnetic resonance imaging (MRI) studies were performed in 10 patients with arrhythmogenic right ventricular dysplasia and in 24 matched controls in order to assess right ventricular epicardial/intramyocardial fatty tissue mass, RV myocardial mass, and RV functional parameters. Functional abnormalities were found in all ARVD cases. Patients with ARVD showed increased fatty tissue compared to controls (8.2 +/- 4 g vs. 2.0 +/- 1.0 g; P = 0.001), whereas no significant differences were found in RV myocardial mass (29.5 +/- 9.2 g vs. 23.2 +/- 6.7 g; P = NS). A correlation coefficient between 0.87 and 0.97 was found for repeated measurements. CONCLUSION: Quantification of fatty tissue with MRI is feasible and constitutes an objective method for differentiating normal from pathological conditions. This approach may lead to a complete diagnostic assessment of ARVD with the potential application for monitoring the evolution of the disease.     

Noninvasive detection of myocardial fibrosis in arrhythmogenic right ventricular cardiomyopathy using delayed-enhancement magnetic resonance imaging

OBJECTIVES: We evaluated the role of myocardial delayed-enhancement (MDE) magnetic resonance imaging (MRI) for noninvasive detection of fibrosis in Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). BACKGROUND: Arrhythmogenic right ventricular dysplasia/cardiomyopathy is characterized by fibro-fatty replacement of the right ventricle (RV) leading to arrhythmias and RV failure. Endomyocardial biopsy can demonstrate fibro-fatty replacement of the RV myocardium; however, the test is invasive and carries a risk of perforation. METHODS: Thirty consecutive patients were prospectively evaluated for ARVD/C. Magnetic resonance imaging was performed on a 1.5-T scanner. Ten minutes after intravenous administration of 0.2 mmol/kg of gadodiamide, MDE-MRI was obtained. Diagnosis of ARVD/C was based upon the Task Force criteria and did not include MRI findings. RESULTS: Twelve (40%) of 30 patients met the Task Force criteria for ARVD/C. Eight (67%) of the 12 ARVD/C patients demonstrated increased signal on MDE-MRI in the RV compared with none (0%) of the 18 patients without ARVD/C (p <0.001). Endomyocardial biopsy was performed in 9 of the 12 ARVD/C patients. Of the nine patients, four had fibro-fatty changes consistent with the diagnosis of ARVD/C. Each of these patients had increased RV signal on MDE-MRI. None of the patients without ARVD/C had any abnormalities either on histopathology or on MDE-MRI. Electrophysiologic testing revealed inducible sustained ventricular tachycardia (VT) in six of the eight ARVD/C patients with delayed enhancement, compared with none of the ARVD/C patients without delayed enhancement (p=0.01). CONCLUSIONS: Noninvasive detection of RV myocardial fibro-fatty changes in ARVD/C is possible by MDE-MRI. Magnetic resonance imaging findings had an excellent correlation with histopathology and predicted inducible VT on programmed electrical stimulation, suggesting a possible role in evaluation and diagnosis of patients with suspected ARVD/C.     

Angiographic right and left ventricular function in arrhythmogenic right ventricular dysplasia

We prospectively documented right ventricular (RV) and left ventricular (LV) volumes and ejection fractions in a large series of patients with arrhythmogenic RV dysplasia/cardiomyopathy (ARVD/C). Eighty-five patients with ARVD/C and 11 controls underwent 2 successive orthogonal right and left monoplane x-ray-digitized cineangiographies. Volumes were calculated using the hemielliptical RV and ellipsoidal LV models. All controls and 58 of 85 patients (ARVD/C-I) had a RV ejection fraction > or =35% and 27 patients had a RV ejection fraction <35% (ARVD/C-II). Tricuspid annulus plane systolic excursion (TAPSE) was lower in ARVD/C-II than in ARVD/C-I patients (6 +/- 3 vs 14 +/- 3 mm) and controls (16 +/- 2 mm) (each p <0.001). In patients with ARVD/C, TAPSE was positively related to RV ejection fraction (r = 0.79) and to crista supraventricularis shortening (r = 0.81) (each p <0.001). Sensitivity and specificity of TAPSE <12 mm in identifying patients with RV ejection fraction <35% were 96% and 78%, respectively. LV ejection fraction was > or =50% in 68 patients, 40% to 49% in 10, and <40% in 7. Diffuse RV outflow tract aneurysm was observed in 9 patients, all belonging to ARVD/C-II, and this sign identified patients with LV ejection fraction <40% with 86% sensitivity and 96% specificity. In conclusion, 68% of ARVD/C patients had normal RV ejection fraction and RV volumes, and 80% of ARVD/C patients had normal LV ejection fraction. Decreased TAPSE <12 mm and a diffuse RV outflow tract aneurysm were sensitive and specific indicators of RV ejection fraction <35% and LV ejection fraction <40%, respectively.     

Quantitative assessment of angiographic right ventricular wall motion in arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C)

Introduction: Angiography of the right ventricle (RV) is a standard, reference technique to diagnose wall motion abnormalities in arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). RV wall motion is usually assessed by qualitative, visual impression, and has lacked a quantitative basis for defining abnormalities. Since the normal RV has a markedly asymmetric movement, angiographic interpretation can differ, even among experienced clinicians. The purpose of this study was to quantify RV wall motion based on contrast ventriculography in patients with ARVD/C and to specify the severity and location of wall motion abnormalities, as compared with normal subjects.
Methods and Results: We analyzed the angiographic contours of the RV in three views from 19 normal subjects and 23 subjects with ARVD/C. Contour area movement during contraction was calculated circumferentially and further analyzed in nine zones. RV ejection fraction was also computed. Wall motion in ARVD/C was depressed by more than 30% at the tricuspid valve and inferior wall regions (P < 0.001) and significantly reduced at the apex (P = 0.003). However, the RVOT and anterior wall motion were not significantly reduced. RV ejection fraction was depressed from 60 ± 11% in normal subjects to 41 ± 12% in ARVD/C patients (P < 0.001).
Conclusion: Wall motion abnormalities in ARVD/C can be quantified and compared with normal controls, showing primarily reduced movement in the tricuspid and inferior wall regions. This study delineates objective measurements that can be used to aid in the diagnosis of ARVD/C. In addition, they may be incorporated in future refinements of criteria to diagnose ARVD/C.     

Magnetic resonance imaging findings in patients meeting task force criteria for arrhythmogenic right ventricular dysplasia

INTRODUCTION: Magnet resonance imaging (MRI) findings in patients meeting Task Force criteria for the diagnosis of arrhythmogenic right ventricular dysplasia (ARVD) have not been systematically described. We report qualitative and quantitative MRI findings in ARVD using state-of-the-art MRI. METHODS AND RESULTS: MRI was performed on 12 patients with ARVD who were prospectively diagnosed using the Task Force criteria. The imaging protocol included breath-hold double inversion recovery spin-echo and gradient-echo images. Ventricular volumes and dimensions were compared to 10 age- and sex-matched normal volunteers. High intramyocardial T1 signal similar to fat signal was observed in 9 (75%) of the 12 patients and in none of the controls. Right ventricular (RV) hypertrophy was seen in 5 (42%) patients, trabecular disarray in 7 (59%), and wall thinning in 3 (25%). Both the RV end-diastolic diameter and the outflow tract area were significantly higher in ARVD patients compared to controls (51.2 vs 43.2 mm, P < 0.01; and 14.5 vs 9.3 cm2, P < 0.01, respectively). ARVD patients had a higher RV end-diastolic volume index and lower RV ejection fraction compared with controls (127.4 vs 87.5, P < 0.01; and 41.6% vs 57%, P < 0.01, respectively). CONCLUSION: High intramyocardial T1 signal indicative of fat is seen in a high percentage (75%) of patients who meet the Task Force criteria for ARVD. Trabecular disarray is seen more frequently than wall thinning and aneurysms. RV dimensions and volumes differ significantly in ARVD compared to controls, indicating a role for quantitative evaluation in the diagnosis of ARVD.     

The clinical manifestation of arrhythmogenic right ventricular dysplasia]

Five patients, 4 male, 1 female with age ranging from 25 to 65 were included in the study. All the cases admitted into the hospital because of episodes of ventricular tachycardia (VT). Four associated with history of Adams-Stokes attacks. Their common manifestations are as followed: 1. Sustained LBBB VT associated with history of syncope and/or Adams-Stokes-Syndrome. 2. Inverted T waves in right precordial leads. 3. Positive ventricular late potential. 4. Relatively normal heart on physical examination and X-ray film. 5. Enlargement and dysfunction of right ventricle, 3 with a diverticulum-like bulging lesion at apex of right ventricle, proved by echocardiographic and nuclear angiocardiographic study. 6. Repeatedly induced VT during electrophysiological study. Our data suggest that arrhythmogenic right ventricular dysplasia (ARVD) should be suspected in patients with recurrent LBBB VT and relatively normal heart, especially, those with positive ventricular late potential. Right ventricle should be carefully investigated with echocardiography and nuclear angiocardiography to confirm the diagnosis. Four cases in the study were refractory to antiarrhythmic drug therapy and 2 of them were treated successfully with transcatheter electrical ablation, 1 with surgical intervention.     

Arrhythmogenic right ventricular dysplasia

Arrhythmogenic right ventricular dysplasia (ARVD) is an inherited cardiomyopathy characterized by ventricular arrhythmias and structural abnormalities of the right ventricle (RV). ARVD results from progressive replacement of right ventricular myocardium with fatty and fibrous tissue. The precise prevalence of ARVD in the United States has been estimated to be 1 in 5000 of the general population. Recent evidence has made it clear that ARVD is a disease of desmosomal dysfunction. The main management consideration concerns whether to implant an ICD. Catheter ablation of VT is a largely a paliative procedure that should not be considered as an appropriate strategy to eliminate VT or reduce sudden death risk. It is likely that the recent advances in the understanding of the pathophysiologic basis of this condition will result in more targeted treatment approaches in the future.     

致心律失常性右室发育不良室性心动过速的电生理检查和外科治疗（附一例报告）

报告药物治疗无效、射频导管消融失败的致心律失常性右室发育不良（ＡＲＶＤ）顽固性室性心动过速（简称室速）１例患者，在电生理导引下行右室前游离壁隔离术治疗成功。术后随访７个月无室速发作，左室收缩功能正常。提示部分右室隔离术对有生命危险和药物治疗无效及射频导管消融失败的ＡＲＶＤ室速患者是安全、有效的     

Programmed ventricular stimulation at a second right ventricular site: An analysis of 100 patients, with special reference to sensitivity, specificity and characteristics of patients with induced ventricular tachycardia

One hundred patients without ventricular tachycardia (VT) initiated from the right ventricular (RV) apex were subjected to stimulation at the RV outflow tract. Sixty-two patients had no clinical arrhythmias, and 38 had sustained VT, ventricular fibrillation (VF) or cardiac arrest. Of the 38 patients with clinical arrhythmias, 22 (58%) had VT or VF induced from the RV outflow tract. Among the 62 patients without arrhythmias, 5 (13%) had polymorphic nonsustained VT or VF induced, which occurred with triple extrastimull in all 5 patients. The 22 patients with VT initiated at the RV outflow tract were a heterogeneous group; 10 (45%) patients had cardiac diagnoses other than coronary artery disease (CAD). In contrast were patients whose VT was initiated at the RV apex (n = 84); in this group, 20 patients (22%) had diagnoses other than CAD (p <0.05). These 22 patients also were younger (mean age 46 years) than patients whose VT was initiated at the RV apex (mean age 58; p <0.01). Of the 16 patients with clinical VT and no induced arrhythmia from either RV site, 7 had CAD (4 with cardiac arrest), 5 had the long QT syndrome, 3 had dilated cardiomyopathy and 1 had valvular heart disease. In conclusion, stimuiation at a second RV site increases the sensitivity of RV stimulation in patients with known VT and seldom initiates VT in patients without cllnical VT.     

Electroanatomic mapping of arrhythmogenic right ventricular dysplasia

OBJECTIVES: We tested the hypothesis that spatial association of low-amplitude intracardiac electrograms can identify the presence, location and extent of dysplastic regions in arrhythmogenic right ventricular dysplasia (ARVD). BACKGROUND: Arrhythmogenic right ventricular dysplasia is a right ventricular (RV) cardiomyopathy characterized pathologically by fibrofatty infiltration and clinically by a spectrum of arrhythmias, sudden cardiac death and RV failure. Diagnosis of ARVD still remains a clinical challenge. METHODS: A three-dimensional electroanatomic mapping technique was used to map the RV of two groups of patients: 1) those with ARVD presenting with typical clinical, electrocardiographic and echocardiographic or magnetic resonance imaging (MRI) findings; and 2) those with structurally normal ventricles. RESULTS: The dysfunctional RV area could be identified only in the first group and was characterized by the presence of discrete areas of abnormally low-amplitude electrograms. Hence, the normal voltage values observed in the control group (unipolar: 11.9 +/- 0.3 mV; bipolar: 4.6 +/- 0.2 mV [mean +/- SEM]) and in the nonaffected zones in the ARVD group (unipolar: 10.4 +/- 0.2 mV; bipolar: 4.6 +/- 0.2 mV) were reduced significantly (p < 0.05) in the dysplastic areas (unipolar: 3.3 +/- 0.1 mV; bipolar: 0.5 +/- 0.1 mV). The pathologic process mainly involved the RV anterolateral free wall, apex and inflow and outflow tracts and ranged from patchy areas to uniform and extensive involvement. Concordance between electroanatomic findings and MRI or echocardiographic findings was noted in all patients. CONCLUSIONS: The pathologic substrate in ARVD can be identified by spatial association of low-amplitude endocardial electrograms, reflecting replaced myocardial tissue. The ability to accurately identify the presence, location and extent of the pathologic substrate may have important diagnostic, prognostic and therapeutic implications.     

Autonomic and pharmacological responses of idiopathic ventricular tachycardia arising from the left ventricular outflow tract

Background: It is well recognized that the mechanism of idiopathic ventricular tachycardia (VT) arising from the right ventricular outflow tract (RVOT) is mostly due to cyclic AMP-mediated triggered activity. The mechanism of VT arising from the left ventricular outflow tract (LVOT) has not been well clarified whether it is the same as VT of RVOT.
Methods: We studied autonomic modulations and pharmacological interventions on VT/premature ventricular contractions (PVCs) from LVOT to explore its possible mechanism in six patients (age: 49 ± 14, three males). None of them had structural heart diseases.
Results: Isoproterenol application easily induced VT and/or PVCs from LVOT. Valsalva maneuvers suppressed isoproterenol-induced VT in two and PVCs in two, and carotid sinus massage (CSM) suppressed PVCs in one patient. Adenosine triphosphate inhibited both VT and PVCs in all six patients. Propranolol, lidocaine, and procainamide eliminated VT/PVCs in four, three, and four patients, respectively. Verapamil terminated VT in one and PVCs in another one patient, but aggravated PVCs to VT in one patient.
Conclusion: The results suggest that the mechanism of VT from LVOT is mostly due to cAMP-mediated triggered activity as similar to that in VT from RVOT.     

Thromboembolic complications in patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy.

AIMS: Incidence and clinical presentation of thromboembolic complications in patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) were analysed. In reports on ARVD/C, thromboembolism is rarely mentioned. The possible risk factors are: right ventricle (RV) dilatation, aneurysms, and wall motion abnormalities. METHODS AND RESULTS: A group of 126 patients (89 male, 37 female, aged 43.6+/-14.3) with ARVD/C was retrospectively analysed for the presence of thromboembolic complications. The mean follow-up period was 99+/-64 months. Thromboembolic complications, i.e. pulmonary embolism (n=2), RV outflow tract thrombosis with severe RV failure (n=1), and cerebrovascular accident associated with atrial fibrillation (n=2) were observed in 4% of the patients. Spontaneous echogenic contrast was observed in seven patients with severe damage to RV. In four of them supraventricular arrhythmias resulting in heart failure were reported. Annual incidence of thromboembolic complications was 0.5/100 patients. CONCLUSIONS: (i) ARVD/C may be complicated by thrombosis. Annual incidence of such complications is significantly lower than reported for left ventricle failure. (ii) Anticoagulation should be used in ARVD/C patients with large, hypokinetic RV and slow blood flow. (iii) Patients with severe forms of ARVD/C, thrombus formation in the RV and/or spontaneous echocardiographic contrast are at higher risk of a poor outcome.     

A case of arrhythmogenic right ventricular cardiomyopathy-Naxos disease

We present a case of arrhythmogenic right ventricular cardiomyopathy (ARVC)-Naxos disease. The patient is 21-year-old male with no history of previous heart disease admitted in a private hospital for rhythm disorder in heart. The condition was diagnosed as ventricular tachycardia (VT) and was treated with cardioversion. The patient was referred to our hospital for further evaluation. On examination patient had palmoplantar keratoderma, wooly hair, and dystrophic nails. The cardiovascular system examination was clinically normal. His electrocardiogram showed epsilon wave in lead V1; echocardiography showed hypo-echogenic tissues in the right ventricular (RV) apex and free wall; magnetic resonance imaging (MRI) investigation revealed fibrofatty replacement of RV free wall and dyskinetic RV wall with diastolic outbulging.     

Ventricular dimensions and wall motion assesed by echocardiography in patients with arrhythmogenic right ventricular dysplasia

Twenty patients with arrhythmogenic right ventricular dysplasia(ARVD) and 20 helthy volunteers underwent cross-sectional echocardiographicexamination for the assessment of ventricular dimensions andwall motion. Right ventricular cavity diameters and wall segmentsfrom the inflow and outflow tracts and the right ventricularbody. The measurements eroor for measuring cavity dimensions was lowthroughout and the reproducibility of wall motion scoring washigh in both the normal subjects and the patients. All exceptone patient had increased dimensions and/or abnormal wall motionin the right ventricle. The right ventricular inflow tract wasdilated in nine patients, the outflow tract in 11 patients andthe short-or long-axis diameters of the right ventricular bodywere increased in seven patients, Right ventricular wall motionabnormalities, being the most frequent finding, ranged frommild hypokinesia only to dyskinesia or sacculations, and werefairly evenly distributed among the segments studied. Left ventricularabnormalities, found in eight patients, were generally mild.Cross-sectional echocardiology thus provides highly reproduciblemeasurements of right ventricular size and contraction patternseven in patients with wall shape deformities, and is théreforea feasible non-invasive method for the evaluation of right-sidedmyocardial abnormalities in patients with ARVD. The diagnosticaccuracy of this technique warrants further clarification.     

Histologic findings in patients with clinical and instrumental diagnosis of sporadic arrhythmogenic right ventricular dysplasia

OBJECTIVES: We sought to analyze the histologic findings of 30 patients with a diagnosis of arrhythmogenic right ventricular dysplasia (ARVD) based on established clinical and instrumental criteria, who did not have a family history of ARVD. BACKGROUND: The diagnostic role of endomyocardial biopsy (EMB) in patients with a clinical profile of ARVD is still debated. METHODS: Thirty patients (19 male, 11 female, mean age 27 +/- 10 years) with left bundle branch block morphology ventricular tachyarrhythmias and echocardiographic, angiographic, and magnetic resonance imaging (MRI) findings diagnostic of ARVD were studied. All patients, besides diagnostic, noninvasive, and invasive cardiac studies, underwent EMB in the apex, anterior free wall, inferior wall of the right ventricle (RV) and in the septal-apical region of the left ventricle. RESULTS: Diagnostic histologic features of ARVD were found only in 9 (30%) patients and a myocarditis, according to the Dallas criteria, in the remaining 21 (70%) patients. Morphometric evaluation of RV samples showed significant differences in fatty tissue and myocyte percent area between ARVD and myocarditis (p < 0.001). Conversely, no difference was found between the two groups in arrhythmic patterns and structural and functional echocardiographic, angiographic, and MRI RV alterations. Magnetic resonance imaging showed hyperintense signals in 67% of ARVD and in 62% of myocarditis group (p = NS). During follow-up (mean, 23 +/- 14 months), all patients with myocarditis remained stable on antiarrhythmic therapy while five patients with ARVD required implantation of an implantable cardioverter defibrillator. CONCLUSIONS: A myocarditis involving the RV can mimic ARVD. An EMB appears the most reliable diagnostic technique, with significant prognostic and therapeutic implications.     

Clinical and electrophysiological differences between patients with arrhythmogenic right ventricular dysplasia and right ventricular outflow tract tachycardia.

AIMS: Radiofrequency catheter ablation is considered first line treatment for symptomatic patients with right ventricular outflow tract tachycardia (RVOT). The role of ablation in arrhythmogenic right ventricular dysplasia (ARVD) is more limited. As such, differentiating between the two conditions is essential. METHODS AND RESULTS: This study compared non-invasive findings, magnetic resonance images (MRI), invasive electrophysiological characteristics, results of ablation and long-term outcome in 50 consecutive patients with RVOT (33) or ARVD (17). Structural abnormalities were uniform in the ARVD group; in addition 18 (54%) of the RVOT tachycardia group had MRI abnormalities. At electrophysiological study the tachycardia in the ARVD group displayed features of re-entry in over 80%, but behaved with a triggered automatic basis in 97% with RVOT. Ablation was complete or partial success in 12 (71%) patients with ARVD and ventricular tachycardia (VT) recurred in eight (48%). In the RVOT patients, ablation was a complete success in 97% with recurrent VT in 6%. Long-term success in the RVOT patients was 95% in both patients with and without MRI abnormalities. CONCLUSIONS: Electrophysiological characterization can differentiate ARVD from RVOT. The finding of abnormalities on MRI does not have any bearing on arrhythmia mechanism, acute or long-term success of RFA.     

致心律失常性右心室心肌病患者心室晚电位与室性心动过速关系

目的探讨致心律失常性右心室心肌病(arrhythmogenic right ventricular dysplasia/cardiomyopathy,ARVD/C)合并室性心动过速与心室晚电位的关系。方法ARVD/C38例,男28例,女10例,年龄(35±15)岁。心电图检查进行信号叠加,记录心室晚电位量化参数:总QRS时限(total QRS duration,QRST)、QRS终末部位电压低于40μV时限(low potential terminal signals,LPS40)、QRS最后40ms电压方根均数(root mean square of the last 40 ms,RMS40);动态心电图检查记录室性心动过速和室性期前收缩。使用χ2及Mann-Whitney秩和检验统计。结果①心室晚电位阳性25例,其中室性心动过速18例;心室晚电位阴性13例,室性心动过速3例(P=0.004);②室性心动过速阳性21例,阴性17例,QRST:室性心动过速阳性组109～233(中位数147)ms,阴性组85～158(中位数104)ms(P=0.000);LPS40:阳性组15～158(中位数53)ms和阴性...