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

Analysis of statistical biases in studies used to formulate guidelines: the case of arrhythmogenic right ventricular cardiomyopathy (ARVC) the case of ARVC

RATIONALE AND OBJECTIVES

To analyze the statistical biases in the studies used to derive cardiac magnetic resonance-based major and minor criteria for the diagnosis of arrhythmogenic right ventricular cardiomyopathy (ARVC).

MATERIALS AND METHODS

ARVC is a rare disorder of the heart that can lead to sudden death in young adults. Cardiac magnetic resonance imaging (CMR) plays a role in the diagnosis by contributing to the criteria set by experts. The original criteria emphasized qualitative analysis of CMR. The criteria were modified in 2010 to provide quantitative cutoffs.

RESULTS

We apply the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool for systematic review of diagnostic accuracy to the studies cited in the guidelines written in 1994 and revised in 2010. We use the signaling questions in QUADAS-2 to identify different types of statistical bias.

CONCLUSIONS

The studies have understandable biases that affect the sensitivity and specificity of CMR in the diagnosis of ARVC, as well as the truth of the disease state. There is potential to overdiagnose ARVC particularly in low prevalence populations.

Arrhythmogenic right ventricular cardiomyopathy a still underrecognized clinic entity

Arrhythmogenic right ventricular cardiomyopathy is a new morbid entity that was discovered thanks to the study of sudden death in the young. This heart muscle disease is characterized by myocardial atrophy, mostly of the right ventricle, with massive fibro-fatty infiltration, accounting for ventricular electrical instability at risk of severe arrhythmias and even cardiac arrest. The disease was found to be the major cause of sudden death in young people and athletes in the Veneto Region, Italy. A familial occurrence with autosomal dominant transmission was then discovered, and the prevalence was estimated to be higher than 1 in 5000. The disease is genetically heterogeneous: Linkage analysis, carried out in a large family with recurrence of sudden deaths, led to map the gene to chromosome 14q23-q24. Linkage analysis in a second family allowed mapping of another gene to chromosome 1q42-q43. Clinical diagnosis can be achieved through electrocardiography, echocardiography, angiocardiography, magnetic resonance imaging, and endomyocardial biopsy. Diagnostic criteria have been put forward by a committee of the International Society and Federation of Cardiology. The disease was recently included among the cardiomyopathies in the revised World Health Organization (WHO) classification. Study of the natural history allowed us to distinguish (a) a covert phase in apparently normal subjects who have a risk of abrupt electrical instability and sudden death, (b) an overt arrhythmic phase with palpitations and impending cardiac arrest, (c) congestive heart failure with pump depression, sometimes so severe as to require heart transplantation. Both the etiology and pathogenesis of the disease are unknown. In particular, the mechanisms leading to progressive loss of myocardium and fibro-fatty replacement are still speculative. Apoptosis in the right ventricle occurring not only in infancy, as in the normal heart, but also in childhood and adulthood might account for the progressive disappearance of myocardial tissue. (Trends Cardiovasc Med 1997;7:84-90). © 1997, Elsevier Science Inc.

Long-term follow-up in arrhythmogenic right ventricular cardiomyopathy using tissue Doppler imaging

AIM

To study patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) and describe different echocardiographic parameters and their change over time during almost 10 years follow-up period.

METHODS

Fifteen patients (9 male, 6 female), aged 22-58 years (mean 40) with a diagnosis of ARVC, were followed up for a period of 6-10 years (mean 8.7). Twelve-lead and a signal- averaged ECG was recorded. Tricuspid and mitral annular motion and tissue Doppler imaging were registered by echocardiography. Wall motion score index (WMSI) was calculated for the left and right ventricles.

RESULTS

We registered significant reduction in systolic tissue velocity on right ventricle free wall between the first and last investigations: 7-17 cm/s (mean 11.8) to 4-15 (mean 9.1), p=0.005. WMSI increased by at least 0.2 in 10/14 patients for the right and in 8/15 patients for the left ventricle. A decrease in velocity time integral for the left ventricular outflow was observed (16-30 to 13-21, p=0.009).

CONCLUSION

ARVC is a progressive disease with individual variation. Left ventricular involvement may occur early in the disease. Tissue Doppler imaging is a useful tool to follow-up right ventricular abnormalities.

Utility of tissue Doppler and strain echocardiography in arrhythmogenic right ventricular dysplasia/cardiomyopathy

Arrhythmogenic right ventricular dysplasia (ARVD) is a heritable cardiomyopathy characterized by the fibrofatty replacement of right ventricular (RV) myocardium leading to RV failure and arrhythmias. This study evaluated the potential utility of tissue Doppler echocardiography (TDE) and strain echocardiography (SE) to quantitatively assess RV function and their potential role in diagnosing ARVD. Images of 30 patients with ARVD (diagnosed by task force criteria) and 36 healthy controls were obtained. Peak systolic velocity, early diastolic velocity, displacement, strain rate, strain, outflow tract diameter, and fractional RV area change were measured in all subjects. Peak RV systolic velocity (6.4 +/- 2.2 vs 9 +/- 1.6 cm/s, p <0.0001), early diastolic velocity (-6.7 +/- 2.7 vs -9.4 +/- 2 cm/s, p <0.0001), displacement (13.7 +/- 5.8 vs 18.7 +/- 3.5 mm, p <0.0003), strain rate (-1 +/- 0.7 vs -2 +/- 1 s(-1), p = 0.002), and strain (-10 +/- 6% vs -28 +/- 11%, p = 0.001) were significantly lower in patients with ARVD compared with controls, respectively. Sensitivity and specificity, respectively, were 67% and 89% for systolic velocity, 77% and 71% for displacement, 73% and 87% for strain, 50% and 96% for strain rate, 53% and 93% for outflow tract diameter, and 47% and 83% for fractional area change. RV systolic velocity and displacement were significantly lower than in controls, even in the subset of patients with ARVD with apparently normal right ventricles by conventional echocardiography. Inter- and intraobserver agreement was high. In conclusion, TDE and SE enable the detection of ARVD via the quantification of RV function and may have potential clinical value in the assessment of patients with suspected ARVD. Peak RV systolic velocity <7.5 cm/s and peak RV strain <18% best identify patients with ARVD.

Plakophilin-2 missense mutations in arrhythmogenic right ventricular cardiomyopathy

BACKGROUND

Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is an inherited cardiac disorder characterized by life-threatening ventricular arrhythmias and fibrofatty replacement of myocardial tissue. Recent data suggest a dominant mode of inheritance in ARVD due to mutations in desmosomal proteins, plakophilin-2 (PKP2) in particular. We carried out a search for PKP2 mutations in the Finnish population representing a genetic isolate.

METHODS

Mutations were detected by direct sequencing of PKP2 exons in 29 unrelated ARVD patients. Subcellular changes in ARVD associated with PKP2 mutations were searched for using immunohistochemistry and electron microscopy.

RESULTS

We identified three PKP2 amino acid substitutions, absent in controls, in three (10%) cases. Two of them (Q62K and N613K) co-occurred in a patient with arrhythmia and structural changes of the heart. Visualized with plakophilin-2 antibodies, the intercalated disks in this compound heterozygous ARVD sample appeared wavier than in non-ARVD controls. Partial irregularities were occasionally seen in the organization and distribution of the cell-cell junctions. Relatives carrying one of these mutant alleles were phenotypically normal or showed only limited electrocardiographic (ECG) changes. The third substitution (Q59L) was detected in two ARVD probands with ventricular tachycardias, ECG abnormalities and right ventricular structural alterations.

CONCLUSIONS

We identified two novel plakophilin-2 missense mutations associated with 10% of ARVD, and a previously reported Q62K variant with a possible disease modifying role. The low prevalence of predominantly missense mutations may present population-specific differences in the pathogenesis of ARVD. Our preliminary data also suggest that ultrastructural cell junction abnormalities may associate with plakophilin-2 mutations.

Advanced quantitative echocardiography in arrhythmogenic right ventricular cardiomyopathy

BACKGROUND

Arrhythmogenic right ventricular (RV) cardiomyopathy (ARVC) is a regional disease of the RV myocardium with variable degrees of left ventricular involvement. Three-dimensional echocardiography and Doppler tissue imaging (DTI) are new echocardiographic modalities for the evaluation of global and regional function, but the diagnostic potential remains to be assessed.

METHODS

Twenty patients with previously established ARVC were evaluated by 3-dimensional echocardiography and DTI, and compared with 32 age- and sex-matched control subjects.

RESULTS

Using 3-dimensional echocardiography, patients with ARVC had a decreased RV ejection fraction (0.47 +/- 0.08 vs 0.53 +/- 0.05, P < .01), and a decreased peak lateral systolic annular velocity by pulsed wave imaging of both the RV (11.9 +/- 2.6 vs 15.1 +/- 3.7 cm/s, P < .01) and the left ventricle (7.0 +/- 2.6 vs 9.5 +/- 1.9 cm/s, P < .01). DTI showed decreased regional systolic strain, but with wide variation in the measurements.

CONCLUSION

Three-dimensional echocardiography identifies decreased RV ejection fraction in ARVC. Assessment of regional contractility by DTI is limited by wide variation. Echocardiographic evaluation of the longitudinal motility appears to be a sensitive marker of preclinical left ventricular involvement.

Serial Reevaluation for ARVD/C Is Indicated in Patients Presenting with Left Bundle Branch Block Ventricular Tachycardia and Minor ECG Abnormalities

INTRODUCTION

Diagnosis of arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is based on a set of criteria proposed by the International Task Force (TF) for Cardiomyopathies in 1994. To fulfill these criteria, presence of both electrocardiographic and anatomical abnormalities must be assessed with ECG and imaging techniques, respectively. This may be difficult in patients with early/mild forms of the disease as detectable structural abnormalities may still be absent. We evaluated in which patients presenting with right ventricular tachycardia (VT) serial reevaluation for ARVD/C is indicated.

METHODS AND RESULTS

Sixty consecutive patients (41 men, mean age 40+/-15 years) were evaluated by the TF criteria for possible ARVD/C because of presentation with a left bundle branch block (LBBB) VT, representing 1 minor criterion. The presence on the ECG of a T-wave inversion beyond lead V2 (1 minor), right precordial QRS prolongation (1 major), or an epsilon wave (1 major) was assessed together with the visualization of severe regional/global right ventricle dysfunction (1 major) or mild segmental dilatation/regional hypokinesia (1 minor) by standard imaging techniques. Initially, 22 (37%) patients were diagnosed as having ARVD/C. After 47+/-39 (range 6-146) months, 23 initially TF-negative patients were reevaluated because of recurrent symptoms, with 12 (52%) additional patients now meeting the TF criteria. Eleven of these 12 (92%) patients presented initially with ECG abnormalities only, but developed structural abnormalities on imaging at follow-up.

CONCLUSION

ECG abnormalities may precede structural abnormalities warranting serial reevaluation for ARVD/C in initially TF-negative patients presenting with LBBB VT with only ECG abnormalities.

Left ventricular involvement in arrhythmogenic right ventricular cardiomyopathy - a scintigraphic and echocardiographic study

BACKGROUND

Left ventricular involvement in arrhythmogenic right ventricular cardiomyopathy (ARVC) is a common finding in autopsy studies. In clinical studies using myocardial scintigraphy, MRI and echocardiography, contradictory results have been reported. In this study, we therefore investigated a group of 15 patients with ARVC using thallium-201 (Tl) single-photon emission tomography (SPECT) and echocardiography including assessment of mitral annular motion with M-mode and pulsed tissue Doppler.

METHODS

Exercise and rest Tl-201 SPECT were performed in 15 patients with ARVC. The time from diagnosis of the disease varied from less than 1-16 years. All patients fulfilled the established diagnostic criteria for ARVC. An echocardiographic examination, including assessment of left and right ventricular motion and measurements of the mitral annulus motion with M-mode and pulsed tissue Doppler was performed in the patients and in 25 normal subjects.

RESULTS

Tl-201 uptake defects in the left ventricular myocardium were present in all except one patient (93%). The uptake defects were predominantly located to the anteroseptal and basal posterior segments. Wall motion abnormalities were seen in the same segments, and in addition to this, in the septal area. In line with this, the total amplitude and the peak systolic velocity of mitral annular motion at the septal point were significantly decreased in the patients compared with the control group.

CONCLUSIONS

Our data show that left ventricular involvement is common in ARVC. Tl-201 SPECT and echocardiographic abnormalities were seen not only in patients with long-lasting symptoms but also in asymptomatic patients and in those with short duration of symptoms.

Echocardiographic findings in patients meeting task force criteria for arrhythmogenic right ventricular dysplasia: new insights from the multidisciplinary study of right ventricular dysplasia

OBJECTIVES

The purpose of this study was to quantify the echocardiographic abnormalities in probands who were newly diagnosed with arrhythmogenic right ventricular dysplasia (ARVD).

BACKGROUND

The diagnosis of ARVD remains challenging. The Multidisciplinary Study of Right Ventricular Dysplasia was initiated to characterize the cardiac structural, clinical, and genetic aspects of ARVD.

METHODS

Detailed echocardiograms were performed in 29 probands and compared with echoes from 29 normal control patients matched for age, gender, body size, and year of echo. Right atrial (RA) and right ventricular (RV) chamber dimensions, RV regional function, and the presence of morphologic abnormalities (hyper-reflective moderator band, trabecular derangement, and sacculations) were assessed. The RV systolic function was calculated as RV fractional area change (FAC).

RESULTS

The RV dimensions were significantly increased, and RV FAC was significantly decreased in probands versus control patients (27.2 +/- 16 mm vs. 41.0 +/- 7.1 mm, p = 0.0003). The right ventricular outflow tract (RVOT) was the most commonly enlarged dimension in ARVD probands (37.9 +/- 6.6 mm) versus control patients (26.2 +/- 4.9 mm, p < 0.00001). A RVOT long-axis diastolic dimension >30 mm occurred in 89% of probands and 14% of controls. The RV morphologic abnormalities were present in many probands (trabecular derangement in 54%, hyper-reflective moderator band in 34% and sacculations in 17%) but not in controls.

CONCLUSIONS

Probands with ARVD have significant RA and RV enlargement and decreased RV function, which can be easily assessed on standard echocardiographic imaging. These parameters should be measured when ARVD is suspected and compared with normal values.

Usefulness of electroanatomical mapping to differentiate between right ventricular outflow tract tachycardia and arrhythmogenic right ventricular dysplasia

Differentiation between the different right ventricular rhythm disorders and specifically between arrhythmogenic right ventricular dysplasia (ARVD) and right ventricular outflow tract (RVOT) tachycardias has important clinical implications but remains a clinical challenge. We tested the hypothesis that the spatial association of local electrographic parameters may be used to discriminate between these 2 entities. Electroanatomic mapping of the right ventricle was performed in 3 groups: patients who had typical RVOT tachycardia, a control group of patients who had no ventricular arrhythmias, and patients who had a diagnosis of ARVD based on clinical, electrocardiographic, and structural findings. Electroanatomic mapping in the RVOT tachycardia group showed normal electrographic parameters throughout the right ventricle (unipolar electrographic amplitude 9.9 +/- 0.9 mV, duration 55 +/- 1 ms, amplitude/duration 0.193 +/- 0.022) that were no different from those in the control group. In contrast, dysplastic regions in the ARVD group were characterized by significantly lower amplitude (unipolar 3.6 +/- 0.4 mV), prolonged electrographic duration (unipolar 73 +/- 4 ms), and a decreased amplitude/duration ratio (unipolar 0.054 +/- 0.008) compared with the unaffected zones in the same hearts and with all regions in the RVOT and control groups. Thus, endocardial electrographic parameters do not differ between patients who have RVOT and control patients. RVOT tachycardia can be differentiated from ARVD by the absence of abnormal right ventricular electrographic findings. This ability may have important clinical implications and supports the concept of different underlying mechanisms for these 2 entities.

Helical CT features of arrhythmogenic right ventricular cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC), also known as arrhythmogenic right ventricular dysplasia, is a disorder of the heart muscle of unknown origin. It is characterized by electrical instability of the heart as a result of replacement of the right ventricular myocardium with fatty or fibrous fatty tissue. Dilatation of the right ventricle; fatty tissue in conspicuous trabeculae of the right ventricle, especially in the anterior wall, apex, and inferior (diaphragmatic) wall; and a scalloped appearance (bulging) of the right ventricular wall are characteristic findings at helical computed tomography (CT) that may be used to diagnose ARVC. Fatty tissue in the left ventricle and ventricular septum is seen relatively frequently in ARVC, and fat in the ventricular septum is another useful finding for diagnosis of ARVC with helical CT. ARVC is usually diagnosed on the basis of clinical or pathologic findings, and electron-beam CT is superior to nongated helical CT in assessment of abnormal right ventricular function. However, with knowledge of the characteristic findings, standard nongated helical CT can be helpful in diagnosing ARVC.

Electrophysiological characteristics and outcome in patients with idiopathic right ventricular arrhythmia compared with arrhythmogenic right ventricular dysplasia

BACKGROUND

Idiopathic right ventricular arrhythmias (IRVA) are responsive to medical and ablative treatment and have a benign prognosis. Arrhythmias caused by right ventricular dysplasia (ARVD) are refractory to treatment and may cause sudden death. It is difficult to distinguish between these two types of arrhythmia.

OBJECTIVE

To differentiate patients with IRVA and ARVD by a conventional electrophysiological study.

METHODS

56 patients with a right ventricular arrhythmia were studied. They had no history or signs of any cardiac disease other than right ventricular dysplasia. They were classified as having IRVA (n = 41) or ARVD (n = 15) on the basis of family history, ECG characteristics, and various imaging techniques. They were further investigated by standard diagnostic electrophysiology.

RESULTS

The two groups were clearly distinguished by the electrophysiological study in the following ways: inducibility of ventricular tachycardia by programmed electrical stimulation with ventricular extrastimuli (IRVA 3% v ARVD 93%, p < 0.0001); presence of more than one ECG morphology during tachycardia (IRVA 0% v ARVD 73%, p < 0.0001); and fragmented diastolic potentials during ventricular arrhythmia (IRVA 0% v ARVD 93%, p < 0.0001). Data from the clinical follow up in these patients supported the diagnosis derived from the electrophysiological study.

CONCLUSIONS

Patients with IRVA or ARVD can be distinguished by specific electrophysiological criteria. A diagnosis of ARVD can be made reliably on the basis of clinical presentation, imaging techniques, and an electrophysiological study.

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.

Genotype-phenotype assessment in autosomal recessive arrhythmogenic right ventricular cardiomyopathy (Naxos disease) caused by a deletion in plakoglobin

OBJECTIVES

The purpose of this study was to examine the genotype-phenotype relation with respect to penetrance, age and severity of expression, disease progression and prognosis in a recessively inherited arrhythmogenic right ventricular cardiomyopathy (ARVC).

BACKGROUND

Naxos disease is a recessively inherited ARVC caused by a mutation in the gene encoding plakoglobin (cell adhesion protein) in which the cardiac phenotype is associated with palmoplantar keratoderma and woolly hair.

METHODS

Twelve families with Naxos disease underwent cardiac and molecular genetic investigation. Serial cardiac assessment with annual resting 12-lead and 24-h ambulatory electrocardiogram (ECG) and two-dimensional echocardiography was performed during 1 to 16 years, median 7 +/- 6 years in all 78 surviving members.

RESULTS

Twenty-eight surviving members were homozygous and 40 were heterozygous for the mutation. All adults who were homozygous (n = 26) fulfilled the diagnostic criteria for ARVC, the youngest by the age of 13 years. In eight who were heterozygous, minor ECG or echocardiographic abnormalities were observed. Of the 26 subjects who were affected homozygotes, 92% showed ECG abnormalities, 92% ventricular arrhythmias, 100% right ventricular structural alterations and 27% left ventricular involvement. During follow-up (10 +/- 6 years), 16 (62%) developed structural progression, 12 (46%) arrhythmic events and 7 (27%) heart failure. The annual disease-related and sudden death mortality was 3% and 2.3%, respectively.

CONCLUSIONS

Autosomal recessive ARVC caused by a mutation in plakoglobin was 100% penetrant by adolescence. Affected subjects who were homozygous experienced progressive disease with adverse prognosis. A minority of subjects who were heterozygous showed minor ECG/echocardiographic changes, but clinically significant disease did not develop.

Arrhythmogenic right ventricular cardiomyopathy: current diagnostic and management strategies

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a heart muscle disease of unknown etiology characterized by the peculiar right ventricular (RV) involvement. Distinctive pathologic features are myocardial atrophy and fibro-fatty replacement of the RV free wall, and clinical presentation is usually related to ventricular tachycardias with a left bundle branch block pattern or ventricular fibrillation leading to cardiac arrest, mostly in young people and athletes. Later in the disease evolution, progression and extension of RV muscle disease and left ventricular involvement may result in right or biventricular heart failure. The diagnosis of ARVC may be difficult because of several problems with specificity of ECG abnormalities, different potential etiologies of ventricular arrhythmias with a left bundle branch morphology, assessment of RV structure and function, and interpretation of endomyocardial biopsy findings. Therefore, standardized diagnostic criteria have been proposed by the Study Group on ARVC of the European Society of Cardiology. According to these guidelines, the diagnosis of ARVC is based on the presence of major and minor criteria encompassing electrocardiographic, arrhythmic, morphofunctional, histopathologic, and genetic factors. Since the assessment of sudden death risk in patients with ARVC is still not well established, there are no precise guidelines to determine which patients need to be treated and what is the best management approach. The therapeutic options include beta-blockers, antiarrhythmic drugs, catheter ablation, and implantable cardioverter defibrillator (ICD). The ICD is the most effective safeguard against arrhythmic sudden death. However, its precise role in changing the natural history of ARVC by preventing sudden and nonsudden death needs to be evaluated by a prospective study of a large series of patients. In patients in whom ARVC has progressed to severe RV or biventricular systolic dysfunction with risk of thromboembolic complications, treatment consists of current therapy for heart failure including anticoagulant therapy. In cases of refractory congestive heart failure, patients may become candidates for heart transplantation.

Echocardiographic assessment of arrhythmogenic right ventricular cardiomyopathy

OBJECTIVE

To evaluate new echocardiographic modes in the diagnosis of arrhythmogenic right ventricular cardiomyopathy (ARVC).

DESIGN

Prospective observational study.

SETTING

University Hospital.

SUBJECTS

15 patients with ARVC and a control group of 25 healthy subjects.

METHODS

Transthoracic echocardiography included cross sectional measurements of the right ventricular outflow tract, right ventricular inflow tract, and right ventricular body. Wall motion was analysed subjectively. M mode and pulsed tissue Doppler techniques were used for quantitative measurement of tricuspid annular motion at the lateral, septal, posterior, and anterior positions. Doppler assessment of tricuspid flow and systemic venous flow was also performed.

RESULTS

Assessed by M mode, the total amplitude of the tricuspid annular motion was significantly decreased in the lateral, septal, and posterior positions in the patients compared with the controls. The tissue Doppler velocity pattern showed decreased early diastolic peak annular (E(A)) velocity and an accompanying decrease in early (E(A)) to late diastolic (A(A)) velocity ratio in all positions; the systolic annular velocity was significantly decreased only in the lateral position. Four patients had normal right ventricular dimensions and three were judged to have normal right ventricular wall motion. The patient group had also a significantly decreased tricuspid flow E:A ratio.

CONCLUSIONS

Tricuspid annular measurements are valuable, easy to obtain, and allow quantitative assessment of right ventricular function. ARVC patients showed an abnormal velocity pattern that may be an early but non-specific sign of the disease. Normal right ventricular dimensions do not exclude ARVC, and subjective detection of early changes in wall motion may be difficult.

Echocardiographic assessment of arrhythmogenic right ventricular cardiomyopathy

OBJECTIVE

To evaluate new echocardiographic modes in the diagnosis of arrhythmogenic right ventricular cardiomyopathy (ARVC).

DESIGN

Prospective observational study.

SETTING

University Hospital.

SUBJECTS

15 patients with ARVC and a control group of 25 healthy subjects.

METHODS

Transthoracic echocardiography included cross sectional measurements of the right ventricular outflow tract, right ventricular inflow tract, and right ventricular body. Wall motion was analysed subjectively. M mode and pulsed tissue Doppler techniques were used for quantitative measurement of tricuspid annular motion at the lateral, septal, posterior, and anterior positions. Doppler assessment of tricuspid flow and systemic venous flow was also performed.

RESULTS

Assessed by M mode, the total amplitude of the tricuspid annular motion was significantly decreased in the lateral, septal, and posterior positions in the patients compared with the controls. The tissue Doppler velocity pattern showed decreased early diastolic peak annular (EA) velocity and an accompanying decrease in early (EA) to late diastolic (AA) velocity ratio in all positions; the systolic annular velocity was significantly decreased only in the lateral position. Four patients had normal right ventricular dimensions and three were judged to have normal right ventricular wall motion. The patient group had also a significantly decreased tricuspid flow E:A ratio.

CONCLUSIONS

Tricuspid annular measurements are valuable, easy to obtain, and allow quantitative assessment of right ventricular function. ARVC patients showed an abnormal velocity pattern that may be an early but non-specific sign of the disease. Normal right ventricular dimensions do not exclude ARVC, and subjective detection of early changes in wall motion may be difficult.

Clinical diagnosis and management strategies in arrhythmogenic right ventricular cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a myocardial disease, often familial, that is characterized by fibro-fatty replacement of the right ventricular (RV) myocardium. The most common clinical manifestations of ARVC consists of ventricular arrhythmias of RV origin, which may lead to sudden death mostly in young people and athletes, electrocardiograph depolarization/repolarization changes mostly localized to right precordial leads, and global and/or regional dysfunction and structural alterations of the RV. The diagnosis of ARVC may be difficult due to several problems with the specificity of the electrocardiograph abnormalities, the different potential etiologies of ventricular arrhythmias with a left bundle branch morphology, the assessment of the RV structure and function, and the interpretation of endomyocardial biopsy findings. Therefore, standardized diagnostic criteria have been proposed by the Study Group on ARVC of the European Society of Cardiology. According to these guidelines, the diagnosis of ARVC is based on the presence of major and minor criteria encompassing electrocardiograph, arrhythmic, morphofunctional, histopathologic, and genetic factors. Because the assessment of sudden death risk in patients with ARVC is still not well established, there are no precise guidelines to determine which are the patients who need to be treated and which is the best management approach. The therapeutic options include beta blockers, antiarrhythmic drugs, catheter ablation, and implantable cardioverter defibrillator. The implantable defibrillator is the most effective safe-guard against arrhythmic sudden death. However, its precise role in changing natural history of ARVC by preventing sudden and nonsudden death needs to be evaluated by a prospective study of a large series of patients. In patients in whom ARVC has progressed to severe RV or biventricular systolic dysfunction with risk of thromboembolic complications, treatment consists of current therapy for heart failure including anticoagulant therapy. In case of refractory congestive heart failure, the patients may become candidates for heart transplantation.

Arrhythmogenic right ventricular dysplasia/cardiomyopathy: need for an international registry. European Society of Cardiology and the Scientific Council on Cardiomyopathies of the World Heart Federation

Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is a heart muscle disease characterized by peculiar right ventricular involvement and electrical instability that precipitates ventricular arrhythmias and sudden death. The purpose of the present consensus report of the Study Group of the European Society of Cardiology and the Scientific Council on Cardiomyopathies of the World Heart Federation is to review the considerable progress in our understanding of the etiopathogenesis, morbid anatomy, and clinical presentation of ARVD/C since its first description in 1977. This article will focus on the important but still unanswered issues, mostly regarding risk stratification, clinical outcome, and management of affected patients. Because ARVD/C is relatively uncommon and any one center may have experience with only a few patients, an international registry is being established to accumulate information and enhance the numbers of patients that can be analyzed to answer the pending questions. The registry also will facilitate pathologic, molecular, and genetics research on the etiology and pathogenesis of the disease. Furthermore, availability of an international database will enhance awareness of this largely unrecognized condition among the medical community. Physicians are encouraged to enroll patients in the International Registry of ARVD/C.

Arrhythmogenic right ventricular dysplasia/cardiomyopathy: need for an international registry. Study Group on Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy of the Working Groups on Myocardial and Pericardial Disease and Arrhythmias of the European Society of Cardiology and of the Scientific Council on Cardiomyopathies of the World Heart Federation

Arrhythmogenic right ventricular (RV) dysplasia/cardiomyopathy (ARVD/C) is a heart muscle disease characterized by peculiar RV involvement and electrical instability that precipitates ventricular arrhythmias and sudden death. The purpose of the present consensus report of the Study Group on ARVD/C of the Working Groups on Myocardial and Pericardial Disease and Arrhythmias of the European Society of Cardiology and of the Scientific Council on Cardiomyopathies of the World Heart Federation is to review the considerable progress in our understanding of the etiopathogenesis, morbid anatomy, and clinical presentation of ARVD/C since it first was described in 1977. The present article focuses on important but still unanswered issues, mostly regarding risk stratification, clinical outcome, and management of affected patients. Because ARVD/C is relatively uncommon and any one center may have experience with only a few patients, an international registry is being established to accumulate information and enhance the numbers of patients that can be analyzed and thus answer pending questions. The registry also will facilitate pathological, molecular, and genetics research on the causes and pathogenesis of the ARVD/C. Furthermore, availability of an international database will enhance awareness of this largely unrecognized condition among the medical community. Physicians are encouraged to enroll patients in the International Registry of ARVD/C.

Autosomal dominant myofibrillar myopathy with arrhythmogenic right ventricular cardiomyopathy linked to chromosome 10q

Twenty-one members of a Swedish family suffering from myopathy and cardiomyopathy underwent neurological and cardiological investigations. Medical charts of 2 affected deceased patients were reviewed. Twelve patients had myopathy. The distribution of weakness was axial in mildly affected, axial and predominantly distal in moderately affected, and generalized in severely affected patients. The electromyogram showed signs of myopathy in 10 patients. Muscle biopsy specimens showed myopathic changes, rimmed vacuoles, and accumulation of desmin, dystrophin, and other proteins. Electron microscopy revealed granulofilamentous changes and disorganization of myofibrils. Several patients had episodes of chest pain or palpitations. Three men had arrhythmogenic right ventribular cardiomyopathy. Nonsustained ventribular tachycardia, atrial flutter, and dilatation of the ventricles mainly affecting the right ventricle were documented. Two of them had a pacemaker implanted because of atrioventricular block and sick sinus syndrome. Inheritance is autosomal dominant with variable onset and severity of skeletal muscle and cardiac involvement. Linkage analysis of candidate chromosomal regions showed a maximum 2-point LOD score of 2.76 for marker locus D10S1752 on chromosome 10q. A multipoint peak LOD score of 3.06 between markers D10S605 and D10S215 suggests linkage to chromosome 10q22.3, and this region may harbor a genetic defect for myofibrillar myopathy with arrhythmogenic right ventricular cardiomyopahty.

An echocardiographic study of right ventricular adaptation to physical exercise in elite male orienteers

Considerably more publications appear on left ventricular morphology than on the right ventricle. The reasons for this imbalance are related to the complex shape of the right ventricular cavity and its position beneath the sternum, making imaging, measurement and functional assessment much more complex than the left ventricular chamber. Little attention has been directed towards right ventricular changes because of training, therefore the present study was designed to assess right ventricular changes due to extensive training by comparing cavity and wall dimensions in 29 sedentary men (mean age 23 years) and 82 elite male orienteers (mean age 22 years). The elite orienteers had on average significantly larger right ventricular outflow (10%) and right ventricular inflow (12%) tract 2 and 3 dimensions. The right ventricular wall measurements were on average 13% larger in the orienteers than the sedentary men. The right ventricular enlargement in endurance athletes probably reflects the increased haemodynamic loading that is caused by prolonged and extensive physical training. The thicker right ventricular wall in endurance athletes increases the contractile reserve and decreases wall stress in the right ventricle.

[Arrhythmogenic right ventricular cardiomyopathy. Etiology, diagnosis and therapy]

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is characterized by regional atrophy of right ventricular myocardium and subsequent replacement by fatty and fibrous tissue. The disease manifests in young adulthood with a predominance of males. Hallmarks of ARVC are ventricular tachyarrhythmias of left bundle branch block pattern which frequently occur during exercise. However, sudden death may also be the first manifestation of the disease. Characteristic findings are repolarization abnormalities and QRS prolongation in the right precordial leads of the surface ECG and regional abnormalities of right ventricular structure and wall motion. Left ventricular involvement may occur in later stages of the disease but rarely leads to progressive biventricular heart failure. Therapeutic efforts are mainly directed to the treatment of ventricular tachyarrhythmias and the prevention of sudden death. A tailored treatment strategy including antiarrhythmic drug therapy, catheter ablation and implantation of cardioverter-defibrillators may be used to improve the long-term prognosis of patients with ARVC.

[Arrhythmogenic dysplasia of the right ventricle]

Arrhythmogenic right ventricular dysplasia is a disease of the cardiac muscle of unknown etiology. Landmarks of this disease are the presence of muscular atrophy and replacement of ventricular myocardium by adipous and fibroadipous tissue. This disease was originally described by Fontaine et al in 1977 during surgical ablation of drug refractory ventricular tachycardias in patients without evident structural heart disease. During surgery anomalies in contractility of the right ventricle and the presence of adipous tissue were documented. Some years later, Markus et al reported the first clinical series of patients with arrhythmogenic right ventricular dysplasia. Since then, this disease has been widely recognized and must be considered in the differential diagnosis of all patients with ventricular arrhythmias originating in the right ventricle.

An echocardiographic study comparing male Swedish elite orienteers with other elite endurance athletes

Between 1979 and 1992, there were 16 known cases of sudden unexpected cardiac death among young Swedish orienteers, whose autopsies showed myocarditis to be a common finding. Therefore, 96 elite orienteers and 47 controls underwent echocardiography, showing left ventricular wall motion abnormalities in 9% of the orienteers compared with 4% in the controls.

Ventricular tachycardia: pathophysiology and radiofrequency catheter ablation

Limitations of pharmacological therapy for VT have led to great interest in alternative nonpharmacological therapies. The appeal of a curative therapy for VT initially led to the search for operative techniques to identify and destroy the underlying substrate, and more recently, has resulted in the development of catheter techniques to achieve the same goal in the electrophysiology laboratory. Investigations into the pathophysiology of VT have resulted in the recognition that this arrhythmia reflects a mechanistically and anatomically heterogeneous set of disorders. Recent growth in our understanding of these distinctions has both led to, and resulted from, simultaneous advances in catheter ablation techniques. The clinical electrophysiology laboratory has served as a testing ground for theories derived from in vitro and animal experiments while also providing its own set of human experimental data regarding the pathophysiology and treatment of VT. As a result of this process, several distinct forms of VT that are amenable to catheter ablation have been characterized. This article will summarize current knowledge of the pathophysiology of various VT subtypes and of techniques for catheter mapping and ablation.

Spin-echo nuclear magnetic resonance for tissue characterisation in arrhythmogenic right ventricular cardiomyopathy

OBJECTIVE

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a myocardial disorder characterised clinically by ventricular arrhythmias that can cause cardiac arrest and morphologically by fatty or fibro-fatty myocardial atrophy of the right ventricle. In vivo tissue characterisation without endomyocardial biopsy would be useful. The aim of this study was to investigate the diagnostic accuracy of spin-echo nuclear magnetic resonance (NMR) for tissue characterisation in ARVC.

PATIENTS AND METHODS

Twenty three subjects (15 men and eight women, aged 18-49, mean 34) were studied with spin-echo T1-weighted NMR and multislice scan. Fifteen had a clinical diagnosis of ARVC and eight were controls (age and sex matched subjects). Data were independently evaluated by two expert observers.

RESULTS

In the control group NMR was always negative (100% specificity). Ten of the 15 patients with ARVC had an abnormal NMR result (67% sensitivity), with areas that had a signal intensity close to that of pericardial or subcutaneous fat. In the remaining five cases the NMR signal was inadequate. Nine patients underwent both NMR and endomyocardial biopsy; biopsy was positive in eight (89%) and NMR was positive in five (56%).

CONCLUSIONS

NMR is a useful non-invasive diagnostic tool in the evaluation of fatty replacement in ARVC. The technique can be used with other procedures in the initial diagnostic evaluation and is a useful alternative tool in the long term follow up of patients with ARVC.

Arrhythmogenic right ventricular cardiomyopathy. Dysplasia, dystrophy, or myocarditis?

BACKGROUND

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a frequent cause of sudden death in young individuals and athletes. Although familial occurrence has been documented and a gene defect was recently localized on chromosome 14q23-q24 the etiopathogenesis of the disease is still obscure.

METHODS AND RESULTS

A pathological study was conducted in 30 hearts with ARVC (age range, 15 to 65 years; mean, 28 years). In the 27 autopsy cases, the mode of death was sudden in 24 and congestive heart failure in 3. ECG, available in 19 cases, showed inverted T waves in the right precordial leads in 15 cases (79%) and ventricular arrhythmias in 15 (79%). Right ventricular aneurysms were present in 15 hearts (50%) and located in the inferior wall in 12. Left ventricle and ventricular septum were involved in 14 (47%) and 6 (20%) cases, respectively. Scattered foci of lymphocytes with myocardial death were observed in 20 cases (67%). Electron microscopy studies, although confirming the myocardial death and lymphocyte infiltrates, did not show any specific ultrastructural substrate. Two pathological patterns, fatty (40%) and fibrofatty (60%), were identified. The fibrofatty pattern was associated with a thinner right ventricular wall (P < .0001) and a higher occurrence of focal myocarditis (P < .001). In sections of right ventricular free wall with maximal fatty infiltration, the mean percentage area of fatty tissue was 35.9 +/- 11.1% in control versus 80.4 +/- 9.6% in the ARVC, fatty variety (P < .00001). Involvement of the left ventricle and/or ventricular septum, right ventricular aneurysms, and inflammation were found almost exclusively in the fibrofatty variety.

CONCLUSIONS

In the fibrofatty variety of ARVC, the myocardial atrophy appears to be the consequence of acquired injury (myocyte death) and repair (fibrofatty replacement), mediated by patchy myocarditis. Whether the inflammation is a primary event or a reaction to spontaneous cell death remains unclear.

Usefulness of electron-beam computed tomography in arrhythmogenic right ventricular dysplasia. Relationship to electrophysiological abnormalities and left ventricular involvement

BACKGROUND

Electron-beam computed tomography (CT) may be useful for detecting myocardial fat infiltration and diagnosing arrhythmogenic right ventricular dysplasia (ARVD). There are several characteristic electron-beam CT findings of ARVD. However, the incidence, their relation to electrophysiological abnormalities, and the usefulness of electron-beam CT for evaluating left ventricular involvement are unknown. This study aimed to clarify these issues.

METHODS AND RESULTS

Electron-beam CT was performed in 14 patients with ARVD (ARVD group), 16 age- and sex-matched patients with right ventricular enlargement and/or dysfunction without ARVD (RV enlargement group), and 13 control subjects (control group). The incidences of abnormal electron-beam CT findings in the three groups were examined. Furthermore, we examined the endocardial fat-infiltrated areas detected by electron-beam CT (CT-A) and electrophysiologically abnormal areas detected in the mapping electrophysiology study (EPS-A) and compared the relationship between them in the ARVD group. (1) The frequencies of abundant epicardial adipose tissue, low-attenuation trabeculations, scalloping of the right ventricular free wall, and intramyocardial fat deposits were 86%, 71%, 79%, and 50%, respectively, in the ARVD group, whereas these findings were not observed in the RV enlargement and control groups. (2) Three ARVD patients (21%) had adipose tissue involvement of the left ventricle. (3) The relationship between CT-A and EPS-A was as follows: CT-A > EPS-A, 71%; CT-A = EPS-A, 14%; and EPS-A only, 14%.

CONCLUSIONS

Characteristic electron-beam CT findings are frequently observed only in patients with ARVD. Electron-beam CT is useful for evaluating for left ventricular involvement and can estimate EPS-A.

Usefulness of Biplanar Transesophageal Echocardiography in Arrhythmogenic Right Ventricular Dysplasia: Clinical Experience with Seven Cases

This study evaluated the clinical usefulness of biplanar transesophageal echocardiography (TEE) in suspected arrhythmogenic right ventricular dysplasia (ARVD). Seven symptomatic subjects (3 male and 4 female: ages 18-64 years, mean 45) with clinical features of ARVD (typical ventricular arrhythmias) underwent comprehensive noninvasive assessment including transthoracic echocardiography (TTE), nuclear magnetic resonance (NMR), and TEE. Other systemic and cardiac diseases were reasonably excluded. TEE identified a significant right ventricular regional alteration in one subject with negative TTE and NMR, and nonsignificant abnormalities in two subjects with negative or no TTE and positive NMR. TEE confirmed the pathological findings detected by TTE in the four remaining patients and visualized several more abnormalities that approximately corresponded to NMR results. On the basis of these initial results, biplanar TEE appears to be comparable to NMR in the assessment of ARVD and a promising technique in identifying ARVD morphological alterations. (ECHOCARDIOGRAPHY, Volume 13, January 1996)

Relation of right ventricular morphology and function in pectus excavatum to the severity of the chest wall deformity

Although pectus excavatum (PE) is thought to impair right ventricular (RV) performance, the degree of RV dysfunction, if any, produced by this chest wall deformity remains controversial. To address this issue, we performed 2-dimensional echocardiography and chest wall radiography in 28 subjects with mild-to-severe degrees of PE to assess RV morphology and function in relation to the degree of the chest wall deformity. Measurements of RV anatomy and function obtained in these patients were compared to those of 24 normal control subjects of similar age and sex. In subjects with PE, mean RV outflow tract diameter at the aortic root level was narrower (1.4 +/- 0.3 cm/m2) and end-diastolic (10 +/- 2.3 cm2/m2) and end-systolic (5.8 +/- 1.4 cm2/m2) areas were larger than those in normal controls (1.6 +/- 0.3, 8.6 +/- 1.7, and 4.5 +/- 1.2 cm2/m2, respectively; p < 0.013). The magnitude of these abnormalities was related to the degree of the chest wall deformity evaluated on the chest radiogram (r = 0.54, 0.51, and 0.49, respectively). RV planar emptying fraction, an index of RV systolic function, was reduced in subjects with PE (42 +/- 10%) compared to the normal controls (48 +/- 10%; p = 0.047). No relation could be found, however, between this index and the severity of the chest wall deformity.(ABSTRACT TRUNCATED AT 250 WORDS)

Ventricular tachycardias with left bundle branch block morphology

The differential diagnosis of VTs with LBBB morphology includes several well-defined syndromes. Although the majority of cases are attributable to acquired structural heart disease, including ischemia, prior infarction, or dilated cardiomyopathy, consideration of specific right ventricular processes is essential to proper evaluation and treatment. The approach to older patients or those with evidence for heart disease should begin with an evaluation for coronary artery disease and an assessment of biventricular function. Careful evaluation for bundle branch reentry should be performed during electrophysiological study, especially when there is underlying conduction system disease. Younger patients, those without overt heart disease, or those with isolated right ventricular disease, should receive a complete noninvasive evaluation of right and left ventricular size and function. An abnormal SAECG or identification of intracardiac late potentials suggest right ventricular dysplasia or cardiomyopathy, whereas responsiveness to adenosine and absence of detectable heart disease support the diagnosis of idiopathic right VT. Newer techniques, including MRI, show promise in identifying subtle right ventricular disease not otherwise detectable even in the setting of presumed idiopathic right VT. Following surgical repair of selected congenital heart defects, particularly tetralogy of Fallot, symptoms of recurrent palpitations, near syncope, syncope, or aborted sudden death may be attributable to recurrent VT, and diagnostic electrophysiological study should be considered for these patients. Finally, SVTs with LBBB morphology, particularly cases associated with right-sided or septal accessory pathways, should always be considered in this differential diagnosis.

Diagnosis of arrhythmogenic right ventricular dysplasia/cardiomyopathy. Task Force of the Working Group Myocardial and Pericardial Disease of the European Society of Cardiology and of the Scientific Council on Cardiomyopathies of the International Society and Federation of Cardiology

Images

Magnetic resonance imaging in right ventricular dysplasia

Fifteen patients with right ventricular dysplasia were investigated by T1-weighted spin- and gradient-echo pulse sequences, using a protocol that enabled both a subjective analysis of myocardial signal intensity and a quantitative/qualitative analysis of right and left ventricular function. In 8 patients, 3 investigators independently recognized abnormally hyperintense areas in the anatomic sites usually affected by the disease. In 7 of these patients, these areas showed an overlap with a-dyskinetic areas imaged by both magnetic resonance imaging (MRI) and echocardiography. In 1 patient who underwent a cardiac transplant, MRI of the explanted heart showed an excellent correlation between the distribution of the lesions and the in vivo/in vitro features. The data were compared with those from an equivalent sample of patients affected by dilated cardiomyopathy. In the latter patients, no focal hyperintensities were attributed to any anatomic sites in the right ventricule, and no focal a-dyskinetic foci were observed. Furthermore, the 2 groups of patients were significantly different in regard to dimensional and functional quantitative parameters. The results suggest that MRI is useful in integrating echocardiographic data and can be helpful in diagnosing this disease in late stages.

Efficacy of antiarrhythmic drugs in patients with arrhythmogenic right ventricular disease. Results in patients with inducible and noninducible ventricular tachycardia

BACKGROUND

Ventricular tachyarrhythmias are the major clinical manifestation of arrhythmogenic right ventricular disease. Although antiarrhythmic therapy has been widely advocated, there is only limited information available on the efficacy of antiarrhythmic drugs in these patients.

METHODS AND RESULTS

The short- and long-term efficacies of various antiarrhythmic agents were retrospectively and prospectively analyzed in 81 patients (mean age, 39 +/- 14 years; range, 16-68 years; 61.7% males) with arrhythmogenic right ventricular disease. In 42 patients with inducible ventricular tachycardia during programmed ventricular stimulation, the following efficacy rates were obtained: class Ia and Ib drugs (n = 18), 5.6%; class Ic drugs (n = 25), 12%; beta-blockers (n = 8), 0%; sotalol (n = 38), 68.4%; amiodarone (n = 13), 15.4%; verapamil (n = 5), 0%; and drug combinations (n = 26), 15.4%. Only one of the 10 patients not responding to sotalol was treated effectively by amiodarone, whereas the remaining nine patients proved to be drug refractory toward all other drugs tested (3.8 +/- 2.3 drugs, including amiodarone in five cases) and underwent nonpharmacological therapy. During a follow-up of 34 +/- 25 months, three of the 31 patients (9.7%) discharged on pharmacological therapy had nonfatal recurrences of ventricular tachycardia after 0.5, 51, and 63 months, respectively. In 39 patients with noninducible ventricular tachycardia during programmed ventricular stimulation, the following efficacy rates were observed: class Ia and Ib drugs (n = 16), 0%; class Ic agents (n = 23), 17.4%; beta-blockers (n = 7), 28.6%; sotalol (n = 35), 82.8%; amiodarone (n = 4), 25%; verapamil (n = 24), 50%; and drug combinations (n = 11), 9.1%. During a follow-up of 14 +/- 13 months, four of 33 patients (12.1%) discharged on antiarrhythmic drugs had nonfatal relapses of their clinical ventricular arrhythmia.

CONCLUSIONS

Thus, in arrhythmogenic right ventricular disease, sotalol proved to be highly effective in patients with inducible as well as noninducible ventricular tachycardia. Patients with inducible ventricular tachycardia not responding to sotalol are likely to not respond to other antiarrhythmic drugs and should be considered for nonpharmacological therapy without further drug testing. Amiodarone did not prove to be more effective than sotalol and may not be an alternative because of frequent side effects during long-term therapy, especially in young patients. Verapamil and beta-blockers were effective in a considerable number of patients with noninducible ventricular tachycardia and may be a therapeutic alternative in this subgroup. Class I agents appear to be rarely effective in the treatment of both inducible and noninducible ventricular tachycardia in arrhythmogenic right ventricular disease.

Left ventricular involvement in right ventricular dysplasia

Right ventricular dysplasia, a heart muscle disease of unknown cause, anatomically characterized by variable replacement of myocardial muscle with adipose or fibroadipose tissue, is usually considered a selective disorder of the right ventricle. However, concomitant left ventricular involvement has been noted in a few cases. The aim of this study was to evaluate the prevalence and characteristics of left ventricular involvement in right ventricular dysplasia, as well as possible progression of the disease. Thirty-nine patients with right ventricular dysplasia were studied by M-mode and two-dimensional echocardiography; 28 of them also underwent cardiac catheterization, and in 25 endomyocardial biopsy was performed. On first examination the left ventricle was normal in 25 patients, whereas in the remaining 14 right ventricular abnormalities were associated with left ventricular involvement, characterized by asynergic areas (12 patients) or diffuse mild hypokinesis (two patients). During follow-up (27 patients, 84.1 +/- 66.1 months) 10 patients showed worsening of right ventricular function; in nine the appearance or worsening of left ventricular abnormalities was observed. Five patients died (four in congestive heart failure and one suddenly). Results of postmortem examination (available in two patients) showed atrophy of myocells and a massive fatty and fibrous infiltration of the right ventricular wall, associated with degenerative changes and fibrosis of the left ventricle. In conclusion, right ventricular dysplasia may be associated with left ventricular involvement and the disorder appears to be progressive in some instances.

Monomorphic repetitive rhythms originating from the outflow tract in patients with minor forms of right ventricular cardiomyopathy

We studied in detail 17 patients presenting with monomorphic repetitive ventricular rhythms having left bundle branch block morphology and right axis deviation. All had an apparently normal heart at physical examination. At chest radiography, three patients had mild cardiomegaly, and at electrocardiography, five patients had inverted T waves beyond V2. Five patients had syncope or near syncope. In seven patients the tachycardia occurred on effort. One patient died suddenly. The patients were extensively investigated, using cross-sectional echocardiography, complete haemodynamic and angiographic studies, electrophysiology and histology, to search for any structural basis of the arrhythmias. Tachycardia was sustained in 8 patients, nonsustained in 3, and consistent with accelerated idioventricular rhythm and repetitive paroxysmal ventricular tachycardia in 5 and 1 patients, respectively. Despite the differences in clinical and arrhythmologic features, similar abnormalities of right ventricular structure and/or wall motion were detected in all patients, consistent with localized forms of right ventricular cardiomyopathy. Different antiarrhythmic drugs were successfully used in twelve patients (the four patients with accelerated idioventricular rhythm were not treated). The patient who died suddenly had previously had a sustained ventricular tachycardia and was being treated by beta-blockade. Postmortem study revealed massive fibro-adipose substitution of the right ventricular free wall and pulmonary infundibulum.