Characteristics and outcome in arrhythmogenic right ventricular dysplasia

Arrhythmogenic right ventricular dysplasia: a United States experience

BACKGROUND

Arrhythmogenic right ventricular dysplasia (ARVD) is an inherited cardiomyopathy characterized by right ventricular dysfunction and ventricular arrhythmias. The purpose of our study was to describe the presentation, clinical features, survival, and natural history of ARVD in a large cohort of patients from the United States.

METHODS AND RESULTS

The patient population included 100 ARVD patients (51 male; median age at presentation, 26 [interquartile range {IQR}, 18 to 38; range, 2 to 70] years). A familial pattern was observed in 32 patients. The most common presenting symptoms were palpitations, syncope, and sudden cardiac death (SCD) in 27%, 26%, and 23% of patients, respectively. Among those who were diagnosed while living (n=69), the median time between first presentation and diagnosis was 1 (range, 0 to 37) year. During a median follow-up of 6 (IQR, 2 to 13; range, 0 to 37) years, implantable cardioverter/defibrillators (ICD) were implanted in 47 patients, 29 of whom received an appropriate ICD discharge, including 3 patients who received the ICD for primary prevention. At follow-up, 66 patients were alive, of whom 44 had an ICD in place, 5 developed signs of heart failure, 2 had a heart transplant, and 18 were on drug therapy. Thirty-four patients died either at presentation (n=23: 21 SCD, 2 noncardiac deaths) or during follow-up (n=11: 10 SCD, 1 of biventricular heart failure), of whom only 3 were diagnosed while living and 1 had an ICD implanted. On Kaplan-Meier analysis, the median survival in the entire population was 60 years.

CONCLUSIONS

ARVD patients present between the second and fifth decades of life either with symptoms of palpitations and syncope associated with ventricular tachycardia or with SCD. Diagnosis is often delayed. Once diagnosed and treated with an ICD, mortality is low. There is a wide variation in presentation and course of ARVD patients, which can likely be explained by the genetic heterogeneity of the disease.

Arrhythmogenic right ventricular dysplasia/cardiomyopathy. A review and update

The arrhythmogenic right ventricular dysplasia/cardiomyopathy is an important cause of sudden arrhythmic death, often exertional, in young individuals and athletes. Although the aetiology remains partially unknown, genetic abnormalities have been demonstrated. Reported prevalence is 1 in 5000 individuals but it is considered there are many non-diagnosed cases. The characteristic pathologic finding is the progressive fibro-fatty replacement of the right ventricular myocardium. The clinical manifestations vary from asymptomatic patients with an episode of sudden cardiac death as first symptom to chronically symptomatic patients with recurrent palpitations and/or right or biventricular failure. Approximately a third of the patients show the characteristic Epsilon wave in the 12-lead ECG which is a useful screening test. Signal-averaged ECG frequently demonstrates late potentials. The two-dimensional echocardiography, magnetic resonance imaging, computerized tomography and right ventricular cineangiography show morphologic abnormalities in the right ventricle. Therapy is directed to prevent and/or treat malignant ventricular tachyarrhythmias with medications, implantable cardioverter defibrillator and radiofrequency ablation in selected cases.

Natural history and risk stratification of arrhythmogenic right ventricular dysplasia/cardiomyopathy

BACKGROUND

Management of patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is complicated by the incomplete information on the natural history of the disease and by the lack of risk stratification for cardiovascular death. The aim of the study was the identification of risk factors related to long-term prognosis.

METHODS AND RESULTS

Data were collected from 130 patients (100 men; age at onset of symptoms, 31.8+/-14.4 years) from a tertiary center between 1977 and 2000 who fulfilled the international standardized diagnostic criteria for ARVD/C. Risk factors for cardiovascular death were determined by a logistic regression model. After a mean follow-up of 8.1+/-7.8 years, 24 deaths were recorded, with a mean age at death of 54+/-19 years (annual mortality rate, 2.3%). There were 21 deaths with a cardiovascular origin (progressive heart failure for 14 patients and sudden death for the remaining 7 patients). All patients who died had a history of ventricular tachycardia. Multivariate analysis showed that after adjustment for sex, history of syncope, chest pain, inaugural ventricular tachycardia, recurrence of ventricular tachycardia, and QRS dispersion, clinical signs of right ventricular failure and left ventricular dysfunction both remained independently associated with cardiovascular mortality. The combined presence of one of these risk factors and ventricular tachycardia identifies high-risk subjects for cardiovascular mortality, whereas patients without ventricular tachycardia displayed the best prognosis.

CONCLUSIONS

The information on the natural history of patients with ARVD allowed us to identify risks factors for cardiovascular mortality. An analysis of a large international registry is needed to refine these results.

Ocular genetics: current understanding

Over the past decade, there has been an exponential increase in our knowledge of heritable eye conditions. Coincidentally, our ability to provide accurate genetic diagnoses has allowed appropriate counseling to patients and families. A summary of our current understanding of ocular genetics will prove useful to clinicians, researchers, and students as an introduction to the subject.

Prognostic value of radionuclide angiography in patients with right ventricular arrhythmias

BACKGROUND

The prognosis of patients with right ventricular (RV) arrhythmias remains uncertain. This study prospectively evaluated the prognostic value of RV and left ventricular (LV) involvement assessed by radionuclide angiography (RNA) as predictors for sudden death.

METHODS AND RESULTS

Patients (n=188) with severe arrhythmias originating from the RV were followed up for a mean of 45+/-34 months. Data on clinical presentation, resting and stress ECG, signal-averaged ECG, 24-hour Holter monitoring, and programmed stimulation were collected along with RNA. Patients were classified as group I (n=82) with normal RNA or group II (n=106) with an abnormal RV suggestive of arrhythmogenic RV cardiomyopathy, classified as diffuse or localized disease, with or without associated LV abnormalities. During follow-up, 14 patients died suddenly, all in group II. None of the clinical and electrical data were predictive of death. An abnormal RNA study was a highly predictive factor for death (P<0.005), as well as the presence of LV abnormalities (P<0.01).

CONCLUSIONS

The present study confirms that arrhythmogenic RV cardiomyopathy is a severe disease with a high risk for cardiac death. Evidence of RV abnormalities in patients presenting with RV arrhythmias is highly predictive for sudden death, as is its association with LV involvement.

Clinical profile and long-term follow-up of 37 families with arrhythmogenic right ventricular cardiomyopathy

OBJECTIVES

We sought to define the clinical picture and natural history of familial arrhythmogenic right ventricular cardiomyopathy (ARVC).

BACKGROUND

Arrhythmogenic right ventricular cardiomyopathy is a myocardial disease, often familial, clinically characterized by the impending risk of ventricular arrhythmias and sudden death.

METHODS

Thirty-seven ARVC families of northeast Italy were studied. Probands had a histologic diagnosis of ARVC, either at autopsy (19 families) or endomyocardial biopsy (18 families). Protocol of the investigation included basal electrocardiogram (ECG), 24-hour ECG, signal-averaged ECG, stress test and two-dimensional Doppler echocardiography. Invasive evaluation was performed when deemed necessary.

RESULTS

Of the 365 subjects, 151 (41%) were affected, 157 (43%) were unaffected, 17 (5%) were healthy carriers, and 40 (11%) were uncertain. Mean age at diagnosis was 31+/-13 years. By echocardiography, 64% had mild, 30% had moderate, and 6% had severe form. Forty percent had ventricular arrhythmias, 49 were treated with antiarrhythmic drugs, and two were treated with implantable cardioverter defibrillators. Sport activity was restricted in all. Of the 28 families who underwent linkage analysis, 6 mapped to chromosome 14q23-q24, 4 to 1q42-q43, and 4 to 2q32.1-q32.3. No linkage with known loci was found in four families and 10 had uninformative results. During a follow-up of 8.5+/-4.6 years, one patient died (0.08 patient/year mortality), and 15 developed an overt form of ARVC.

CONCLUSIONS

Arrhythmogenic right ventricular cardiomyopathy is a progressive disease appearing during adolescence and early adulthood. Systematic evaluation of family members leads to early identification of ARVC, characterized by a broad clinical spectrum with a favorable outcome. In the setting of positive family history, even minor ECG and echocardiographic abnormalities are diagnostic.

Abnormalities of cardiac sympathetic innervation in arrhythmogenic right ventricular cardiomyopathy : quantitative assessment of presynaptic norepinephrine reuptake and postsynaptic beta-adrenergic receptor density with positron emission tomography

BACKGROUND

The frequent provocation of ventricular tachycardia by stress or catecholamines and the efficacy of antiarrhythmic drugs with antiadrenergic properties suggest an involvement of the cardiac adrenergic system in arrhythmogenesis in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC). Previous studies demonstrated abnormalities of the presynaptic uptake-1 assessed by (123)I-MIBG-single-photon emission computed tomography.

METHODS AND RESULTS

This study investigated neuronal reuptake of norepinephrine (uptake-1) and beta-adrenergic receptor density in 8 patients with ARVC and 29 age-matched control subjects. All subjects underwent positron emission tomography with the volume of distribution (V(d)) of [(11)C]hydroxyephedrine ((11)C-HED) used to assess presynaptic norepinephrine reuptake, the maximum binding capacity (B(max)) of [(11)C]CGP-12177 ((11)C-CGP-12177) to assess postsynaptic beta-adrenergic receptor density, and [(15)O]H(2)O for quantification of myocardial blood flow. Patients with ARVC demonstrated a highly significant global reduction in postsynaptic beta-adrenergic receptor density compared with that in control subjects (B(max) of (11)C-CGP-12177: 5.9+/-1.3 vs 10.2+/-2.9 pmol/g tissue, P<0.0007), whereas the presynaptic uptake-1 tended toward reduction only (V(d) of (11)C-HED: 59.1+/-25.2 vs 71.0+/-18.8 mL/g tissue, NS). There were no differences in myocardial blood flow between the groups, and plasma norepinephrine was within normal limits in patients and control subjects.

CONCLUSIONS

The findings demonstrate a significant reduction of myocardial beta-adrenergic receptor density in patients with ARVC. This may result from a secondary downregulation after increased local synaptic norepinephrine levels caused by increased firing rates of the efferent neurons or as the result of impaired presynaptic catecholamine reuptake. These findings give new insights into the pathophysiology of arrhythmogenesis in ARVC, with potential impact on diagnostic evaluation and therapeutic management.

[Arrhythmogenic cardiomyopathy as cause of sudden death in Spain. Report of 21 cases]

INTRODUCTION AND OBJECTIVES

Arrhythmogenic cardiomyopathy is a myocardial disease of unknown origin characterized by progressive replacement of right and/or left ventricular myocardium by fibrofatty tissue. Young adult people are more frequently affected and symptoms include palpitations, syncopes or sudden death. The objective of this study is to assess the frequency and characteristics of arrhythmogenic cardiomyopathy as a cause of sudden death in a series of cases in Spain.

MATERIAL AND METHODS

Among the sudden death cases studied at the Toxicology Institute of Madrid between 1991 and 1997, those with arrhythmogenic cardiomyopathy diagnosis were analysed.

RESULTS

21 cases were diagnosed (0.62% of all sudden deaths and 6.8% of sudden deaths under 35 years). There were 20 males and one female (mean age 24.5 +/- 9.37 years); eleven (52.3%) died during sport activity and 8 (38%) had previous exercise related symptoms. In only two cases other members of the family had died suddenly and only one had been diagnosed in life. Biventricular involvement was observed in 13 cases; isolated involvement of the left ventricle in 4, and isolated involvement of the right ventricle in 4.

CONCLUSIONS

Arrhythmogenic cardiomyopathy is a relatively frequent cause of sudden death in the young population in Spain. It is very often the first manifestation of the disease. The myocardial involvement is more frequently biventricular than isolated in the right ventricle. The diagnosis could be difficult for cardiologists, pathologists and forensic doctors.

Increased atrial vulnerability in arrhythmogenic right ventricular disease

Supraventricular tachyarrhythmias (SVTA) may occur in patients with the arrhythmogenic right ventricular dysplasia (ARVD). The purpose of the study was to evaluate the incidence of SVTA in 47 patients with ARVD proved by right ventricular angiography. Thirty-three men and 14 women, aged 21 to 72 years (mean 44 +/- 18) were admitted for nonsustained or sustained ventricular tachycardia. Eight patients had a history of spontaneous SVTA several years before ventricular tachycardia occurrence. Protocol of the study consisted of programmed atrial stimulation with one and two extrastimuli delivered during sinus rhythm and two driven rhythms (600 and 400 msec), programmed ventricular stimulation with up to three extrastimuli and was performed in the control state and after infusion of isoproterenol. The results of programmed atrial stimulation were compared with those obtained in 36 asymptomatic subjects without heart disease and with a mean age of 50 +/- 18 years (control group). Sustained SVTA (> 1 minute) was induced in seven of eight patients with spontaneous SVTA, in 27 (69%) of those with ARVD, who did not have spontaneous SVTA, and in two control subjects (5.5%) (p < 0.001). SVTA was inducible in the control state, but ventricular tachycardia induction required isoproterenol in 11 of 27 patients. Two patients without SVTA history but with inducible SVTA developed later spontaneous SVTA. ARVD was associated with a significantly higher incidence of inducible SVTA than in a control population. Supraventricular tachycardias may precede ventricular tachycardias. This association argues for a diffuse myocardial disorder in ARVD.

Arrhythmogenic right ventricular dysplasia and anterior polar cataract

Arrythmogenic right ventricular dysplasia (ARVD) is an autosomal dominant inherited cardiomyopathy with incomplete penetrance and variable expressivity. Recently, the gene was mapped to 14q23-24. It is being increasingly investigated as a major cause of sudden death at a young age. Anterior polar cataract (APC) is a rare hereditary form of lens opacity. The locus for an APC gene was located tentatively on 14q24qter. We describe a patient with a severe form of ARVD in whom asymptomatic APC was detected by an ophthalmologic examination. His sister had ARVD and similar cataracts. Parents were second cousins but were healthy. This is the first report of possible autosomal recessive inheritance of ARVD. This is also the first time that the combination of ARVD and APC is reported. Three possibilities may explain this concurrence: pleiotropy, contiguous gene syndrome, or coincidence. Our findings suggest placement of an APC gene at 14q23-24.

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.