Right Ventricular Dysplasia: Evaluation and Management in Relation to Sports Activities
Frank I. Marcus,
M.D.
Professor of Medicine
University of Arizona College of Medicine
Address Correspondence:
Frank I. Marcus, M.D.
University Medical Center
1501 N. Campbell Ave.
P.O. Box 24-5037
Tucson, AZ 85724
Telephone: 520-626-6358
Fax: 520-626-4333
Description of
the disease
Arrhythmogenic right ventricular dysplasia (ARVD) is a familial disease
in which the free wall of the right ventricle is partially or almost entirely
replaced by fat (1,2). The remaining muscle fibers are interspersed with
fatty tissue, providing a substrate for ventricular arrhythmias. The left
ventricle is usually not involved but may be minimally or moderately affected.
Typically ARVD occurs in young adults, particularly in men. At least 80%
are diagnosed before the age of 40 years. The physical examination is
usually not remarkable in young patients. There may be prominence of the
left precordium consistent with right ventricular enlargement. A chest
x-ray may show minimal cardiac enlargement or, in the advanced stage,
marked cardiomegaly.
In young normal individuals the T wave in lead V1 is usually upright but may be flat; however, it is almost always upright in lead V2. In patients with ARVD who have symptomatic arrhythmias, the electrocardiogram usually shows T wave inversion in leads V1 and V2 that can extend to V6 (3). Of particular importance for screening for ARVD is the observation that there is prolongation of the QRS complex in lead V1, V2 or V3, due to parietal block (4). In a series of 50 cases of ARVD compared with an age and sex matched control group, the diagnosis of ARVD could be determined by ECG with 84% sensitivity and 100% specificity if the QRS duration in leads V1, V2 or V3 was longer than 110 msec and the T wave was negative in V2 (4). Others have indicated that a QRS duration ratio V2 +V3/V4 + V5 > 1.2 is specific for this condition (5). Young athletes served as controls in this study. These same criteria distinguished patients with ARVD from those with right ventricular outflow tract tachycardia, provided that the QRS R/S transition occurred in V3 or V4 (6). Similar results were obtained in patients with incomplete right bundle branch block with T wave inversion in V1. In patients with complete right bundle branch block who have ARVD, 7 of 11 (64%) had a duration of the QRS complex in V1, V2 or V3 longer by 52+-36 msec than that in V6, consistent with parietal block in addition to right bundle branch block (7). In six airline pilots with RBBB and no cardiac condition this difference was 7+-10 msec (figure 1). There is data to indicate that a longer QRS duration in V1-V3 is associated with a greater risk of sudden death (8,9).
In 5-30% of the cases with ARVD one may observe a discreet wave just beyond the QRS complex, particularly in V1 which has been termed the epsilon wave. This represents potentials of small amplitude due to delayed right ventricular activation. The signal averaged electrocardiogram is positive in about 70% of patients with ARVD who have a history of ventricular fibrillation or sustained ventricular tachycardia (9). There appears to be a correlation of the degree of abnormality of the signal averaged ECG with the extent of the right ventricular disease (9, 10). The signal averaged ECG is normal in athletes without heart disease or ventricular arrhythmias (11). Other noninvasive tests to confirm selective right ventricular enlargement or a decrease in right ventricular function are the echocardiogram, radionuclide angiography and magnetic resonance imaging (MRI). This latter technique has the advantage of providing tissue characterization in addition to observing right and left ventricular volumes as well as wall motion abnormalities and is being used increasingly to aid in the diagnosis (2, 12).
The usual clinical presentation is that of palpitations, non-sustained or sustained ventricular tachycardia. Uncommonly, sudden cardiac death may be the first manifestation of this condition.
Sudden Cardiac
Death and ARVD
There is a marked variation in the reported incidence of sudden cardiac
death due to ARVD. This may be due to study differences in the regional
prevalence of the disease. In the Veneto region of Italy, 12 (20%) of
60 sudden deaths in patients below the age of 35 were due to right ventricular
dysplasia (13). None of the patients were diagnosed as having this condition
before death. In 5, sudden death was the first sign of the condition.
In 7, there was a history of palpitations or ventricular arrhythmias.
Ten of these individuals died during exertion. Of 1000 individuals who
died suddenly below age 65 and were examined at autopsy in Lyon, France,
50 cases (5%) had ARVD (14). None of these 1000 patients had a medical
cause of death due to homocide or recreational drug use and none had a
history of cardiac disease In contrast only 3 of 547 individuals (0.55%)
between the ages of 15-35 who died suddenly were found to have ARVD in
an autopsy series reported from Maryland (15). This marked difference
in the incidence of sudden cardiac death due to ARVD in the various reports
cited could be partly explained by the high prevalence of this condition
in the Veneto region of Italy, but the ten fold higher incidence of sudden
death due to ARVD between Lyon, France and Maryland is difficult to explain
on this basis. It is likely to be related to the lack of recognition of
this disease by forensic pathologists. At autopsy moderate or marked amount
of epicardial fat in the free wall of the right ventricle can be normal
(16). In an autopsy study (that was performed in Olmstead County, MN)
of 54 individuals who died suddenly between the ages of 20-40 years, adipose
tissue comprising > 75% of the right ventricular free wall was found
in 9 (17%) of these individuals (17). However, in 6 of the 9, the cause
of death was determined to be other than ARVD. The forensic pathologist
must differentiate a marked degree of adipose tissue in the free wall
of the right ventricle from the fatty replacement of myocardial tissue
in right ventricular dysplasia. The gross differentiation must be based
on careful examination of diffuse right ventricular enlargement in the
absence of left ventricular enlargement and/or aneurysmal bulges in the
right ventricular wall. These latter findings could readily be missed
unless specifically sought for. The histological confirmation requires
surviving strands of cardiac myocytes imbedded in fibrous tissue within
fat (18). It is hypothesized that the hearts in patients with right ventricular
dysplasia are more susceptible to myocarditis and it is not uncommon to
see evidence of a superimposed myocarditis on the above described histological
picture (12, 2).
It has been observed repeatedly that a majority of arrhythmic deaths due to ARVD occur during exertion (Figure 2). For example, in the report by Thiene et al 10 of the 12 patients with ARVD who died suddenly did so during exertion (13). These same investigators reported on the frequency of exercise related sudden death in 182 consecutive individuals < age 35 years (19). Eighteen of these 182 sudden deaths were due to ARVD; of these 8 (44%) were related to exercise. The incidence of exercise related sudden death was significantly greater than that found in individuals who died of other causes except for individuals who died due to an anomalous coronary artery. Therefore, it would be anticipated that ARVD would be well recognized as a cause of sudden cardiac death in athletes. In fact, this condition was the most common cause (6 0f 17 cases) of arrhythmic death in young competitive athletes in the Veneto Region of Italy (20). In a recent report by Maron, 4 of 134 athletes who died suddenly (3%) had ARVD (21). In one there was an associated myocarditis and in one there was also involvement of the left ventricle. In addition, it has been found that individuals with ARVD who perform intensive and regular sports activities have symptoms at a younger age and that palpitations, syncope or sudden death were more frequent in the athletic group than in patients with ARVD who were not athletically inclined (22). This higher incidence of arrhythmias during exertion could be due to several factors including increased catacholamines acting on a dilated right ventricle whose fibers are further stretched during exertion. Right ventricular dilatation may be further enhanced during exercise due to the fact that there is less of a decrease of pulmonary resistance than of peripheral vascular resistance (23). The combination of these factors can result in exercise induced ventricular tachycardia that can be extremely rapid. Since the rate of the tachycardia can exceed 200 beats/min during exertion, (Fig 1) it is understandable that ventricular fibrillation may ensue.
Since sudden cardiac death can be due to ARVD in a small but not insignificant number of athletes, how can this entity be detected? One approach may be based on the following observations: In a series of 10 victims with ARVD who died suddenly between the ages 15-35 and who were not diagnosed while alive, electrocardiograms obtained for unknown reasons prior to death showed that 8 had ECG changes (24). All of the 8 individuals had T wave inversion in the anterior precordial leads, 3 had T wave inversion in V1 and V2 and 5 in V1-V3. The duration of the QRS complex was greater than 110 msec in the right precordial leads in 70%. The same group of investigators found that the majority of individuals with ARVD below the age of 35 who died suddenly, had a history of palpitations or ventricular arrhythmias or syncope (13, 20). Based on this information, one approach would be to screen athletes for a history for palpitations and/or symptoms suggestive of arrhythmias such as near syncope. Since this condition is known to be genetic and is transmitted with the pattern of autosomal dominance with variable penetrance, a history of sudden death in immediate family members should be sought. If the individual has a suspicious clinical history, a 12 lead electrocardiogram could be obtained looking for T wave inversion in the anterior precordial leads and prolongation of the QRS in the right precordial leads. Further noninvasive investigation could then be performed on this selective population.
There needs to be increasing awareness of ARVD amongst pathologists as well as radiologists who perform MRI examinations. In the former case education needs to be directed to recognition of the pathological diagnosis of ARVD and to the latter group, there needs to be standardization of the technique of MRI as well as its interpretation. This, in part, could be accomplished through educational efforts directed at these specialists. In addition, the natural history of this condition needs to be elucidated. We need additional information as to how to counsel family members of those diagnosed as having ARVD; particularly, to determine whether or not the young individuals who are family members could safely participate in sports or competitive athletics. At the present time it would seem reasonable to suggest that family members who have a normal ECG and do not have non-sustained or sustained ventricular tachycardia on a 24 hour ambulatory ECG and during an exercise stress test could participate in sports. On the other hand, family members who are identified as having ARVD by echocardiogram and have sustained or non-sustained ventricular tachycardia at rest or with exercise should not be permitted to engage in competitive sports (25). In fact their exercise should be markedly limited and treatment should be initiated either with a beta blocker or with sotalol.
Recently an ARVD registry has been established both in Europe as well as the United States in an attempt to gather information to further answer the many questions that are still unresolved with regard to diagnosis, treatment and prognosis of this condition.
References:
1. Marcus F.I., Fontaine G.H., Guiraudon G., et al. Right ventricular dysplasia: A report of 24 adult cases. Circulation 1982;65:384-398.
2. Marcus F.I., Fontaine G.H. Arrhythmogenic right ventricular dysplasia/cardiomyopathy: A review. PACE 1995;18:1298-1314.
3. Fontaine G., Tsezana R, Lazarus A, et al. Troubles de la repolarisation et de la conduction intraventriculaire dans la dysplasie ventriculaire droite arhythmogene. Ann Cardiol. Angeiol 1994;43-5-10.
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5. Peters S., Reil GH., McKenna WJ. Different ECG algorithms for the differentiation of arrhythmogenic right ventricle and athlete's heart. June 16-18, 1996; First International Symposium on Arrhythmogenic Right Ventricular Dysplasia - Cardiomyopathy. Paris, France.
6. Peters S., Weber B., Reil GH. Conventional electrocardiogram in arrhythmogenic right ventricular dysplasia-cardiomyopathy and idopathic right ventricular outflow tract tachycardia. Annals of non Invasive Cardiology 1996;1(4):400-404.
7. Fontaine G., Sohal P., Piot O., et al. Parietal block superimposed on right bundle branch block: A new ECG marker of right ventricular dysplasia. JACC 1997;29:#2 suppl. A:110A: 934-54 (abstract).
8. Corrado D., Turrini P., Buja G., et al. Dispersion of depolarization-repolarization and sudden death in arrhythmogenic right ventricular cardiomyopathy. XVIIth Congress of the European society of Cardiology, Amserdam 20-24 August 1995. Eur Heart J 16 (Abstract Suppl):115.1995
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17. Shen W.K., Edwards D., Hammill S.C., et al. Right ventricular dysplasia: A need for precise pathological definition for interpretation of sudden death. JACC 1994; 34A: 847-65. (abstract)
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Legend
Figure 1: Electrocardiogram, V1-V6 during exercise in a 21 year old competitive cyclist with ARVD. There is one ventricular couplet of left bundle branch block configuration followed by the onset of sustained ventricular tachycardia of the same morphology at a rate of a 200 bpm. The paper speed is 10 mm/sec.
Figure 2: Electrocardiogram with right bundle branch block pattern is shown from a patient with ARVD (left) and from a patient with hypertension (right). In the patient with ARVD the difference in the duration of the QRS complex in V1-V6 = 60 msec while in the other patient it is 10 msec.