Familial cardiomyopathy underlies syndrome of right bundle branch block, ST segment elevation and sudden death

OBJECTIVES

We sought to assess whether structural heart disease underlies the syndrome of right bundle branch block, persistent ST segment elevation and sudden death.

BACKGROUND

Ventricular fibrillation and sudden death may occur in patients with a distinctive electrocardiographic (ECG) pattern of right bundle branch block and persistent ST segment elevation in the right precordial leads.

METHODS

Sixteen members of a family affected by this syndrome underwent noninvasive cardiac evaluation, including electrocardiography, Holter ambulatory ECG monitoring, stress testing, echocardiography and signal-averaged electrocardiography; two patients had electrophysiologic and angiographic study. Endomyocardial biopsy was performed in one living patient, and postmortem examination, including study of the specialized conduction system, was performed in one victim of sudden death.

RESULTS

Five years before a fatal cardiac arrest, the proband had been resuscitated from sudden cardiac arrest due to recorded ventricular fibrillation. Serial ECGs showed a prolonged PR interval, right bundle branch block, left-axis deviation and persistent ST segment elevation in the right precordial leads, in the absence of clinical heart disease. Postmortem investigation disclosed right ventricular dilation and myocardial atrophy with adipose replacement of the right ventricular free wall as well as sclerotic interruption of the right bundle branch. A variable degree of right bundle branch block and upsloping right precordial ST segment was observed in seven family members; four of the seven had structural right ventricular abnormalities on echocardiography and late potentials on signal-averaged electrocardiography. A sib of the proband also had a prolonged HV interval, inducible ventricular tachycardia and fibrofatty replacement on endomyocardial biopsy.

CONCLUSIONS

An autosomal dominant familial cardiomyopathy, mainly involving the right ventricle and the conduction system, accounted for the ECG changes and the electrical instability of the syndrome.

Detection of salivary and seric IgG and IgA antipooled pigeon sera activities in patients with pigeon breeder's disease

Pigeon breeder's disease (PBD) is an interstitial lung disease induced by exposure to pigeon antigens. Search of antipigeon antigen antibodies (APSA) in serum or bronchoalveolar lavage is generally used for auxiliary diagnostic purposes. However, APSA can be present in a number of exposed but asymptomatic individuals as well as in patients with other interstitial lung diseases who live in areas where keeping pigeons is a common domestic habit. In this study, saliva was evaluated as an alternative means to serum for APSA detection by ELISA using pooled pigeon sera as antigen. Serum and saliva samples obtained from 17 patients with PBD, 14 with idiopathic pulmonary fibrosis (IPF), 19 asymptomatic relatives (AR) exposed to pigeon antigens, and 27 clinical healthy voluntary subjects (CHVS) were tested for IgG and IgA APSA. Our results showed that both fluids obtained from PBD patients exhibited a significantly higher specific IgG antibody activity compared to the other groups. Serum optical density (O.D.) values for PBD were 1.187 +/- 0.738 vs. 0.024 +/- 0.033, 0.255 +/- 0.471, and 0.204 +/- 0.346 for CHVS, AR and IPF, respectively (P < 0.05). Salivary O.D. for PBD were 0.801 +/- 0.447 vs 0.010 +/- 0.011, 0.104 +/- 0.151, and 0.22 +/- 0.447 (P < 0.05). In contrast, serum specific IgA did not discriminate between PBD and IPF patients. In addition, although the PBD group exhibited the highest values of IgA salivary APSA, high levels were also observed in saliva specimens from CHVS, a group of normal individuals who deny pigeon exposure. These findings suggest that measurement of IgG salivary APSA can play a role in the evaluation process of patients with pigeon breeder's disease.

Organ-specific circulating heart autoantibodies in Chagas' cardiomyopathy: exploratory study

Chagas' disease can evolve to a chronic phase with cardiomyopathy that may include autoimmune mechanisms, among others. Recently an organ-specific anti-heart muscle antibody was detected in idiopathic cardiomyopathy, using human heart muscle as antigen. We decide to standardize an indirect immunofluorescence assay using rat organs in order to evaluate frequency of organ-specific anti-heart antibodies in chagasic cardiomyopathy. We tested 18 patients with chagasic cardiomyopathy for serum organ-specific anti-heart muscle antibodies. Nine patients were positive for organ-specific anti-heart antibodies (positive in heart muscle but negative in tongue muscle) and one was positive for non-organ-specific anti-heart muscle antibodies (positive in both heart and tongue muscle). We conclude that organ-specific anti-heart muscle antibodies can be detected using rat organs as antigens. Organ-specific anti-heart muscle antibodies are present in patients with chagasic cardiomyopathy.

A new locus for arrhythmogenic right ventricular cardiomyopathy (ARVD2) maps to chromosome 1q42-q43

Autosomal dominant arrhythmogenic right ventricular cardiomyopathy (ARVD, MIM 107970) is one of the major causes of juvenile sudden death. We have previously assigned the disease locus to chromosome 14q23-q24. Here we report on a novel variant of ARVD, which is transmitted associated to 1q42-q43 and is characterized by a concealed form, showing effort-induced polymorphic tachycardias. Since both loci ARVD1 and ARVD2 map in proximity of alpha-actinin genes, the possible implication of these myofibrillar proteins in the pathogenesis of ARVD is discussed. Two additional ARVD families, tested with markers of chromosomes 1q42-q43 and 14q23-q24, failed to show linkage, providing evidence of further genetic heterogeneity.

Antiphospholipid syndrome in patients with cyanotic congenital heart disease

Patients with cyanotic congenital heart disease exhibit an increased incidence of thrombotic episodes and are frequently thrombocytopenic. We studied the sera of 15 patients with this type of heart malformation, searching for anticardiolipin antibodies. 3/15 had positive results. The three of them were adult females; two had thrombotic episodes and a false positive VDRL. Thus, cyanotic congenital heart disease may be another disease entity associated with the antiphospholipid syndrome.

[The prevalence of the Wolff-Parkinson-White syndrome in a population of 116,542 young males]

Since 1988 to 1992 we analyzed 116,452 consecutive 12-lead electrocardiograms belonging to the entire cohort of 18-year old young boys resident in Padova, Treviso, Rovigo, Venezia, Belluno area (2,834,000 inhabitants). We identified 173 cases of overt WPW pattern (short PR interval, delta wave, anomalous configuration of QRS complex) with a calculated incidence of 1.48/1000. Accessory pathway location was: left free wall (70 patients), right free wall (39 patients), postero-septal (37 patients), antero-septal (15 patients) and undetermined (12 patients). Sixty patients (34.6%) complained of different symptoms as palpitations, near syncope and dizziness. Fifty-three patients (30.6%) went in a regular sport activity. Twenty-four hour Holter monitoring (41 patients) and exercise stress test (43 patients) did not show sustained tachyarrhythmias; intermittent preexcitation was recorded in 23 and 32 patients, respectively. Two-dimensional echocardiogram (68 out of 173) was normal in 44 patients, while 24 showed minor cardiac abnormalities with two major disease; mitral valve prolapse was diagnosed in 8 patients. On the basis of transesophageal (24 patients) or intracardiac (5 patients) electrophysiologic study, 11 patients were considered at high risk for sudden death. Eight of them suffered from spontaneous symptoms.

Signal-averaged electrocardiography in familial form of arrhythmogenic right ventricular cardiomyopathy

This study was performed to establish whether signal-averaged electrocardiography can aid in the diagnosis of the familial form of arrhythmogenic right ventricular cardiomyopathy in order to determine the severity of the disease and to predict ventricular arrhythmias. In arrhythmogenic right ventricular cardiomyopathy there is a fatty fibrous substitution of myocardium, which is the substrate for delayed myocardial activation; this is responsible for the abnormalities seen on the signal-averaged electrocardiogram (SAECG). Seventy-five members of 11 families, both healthy and with various forms of the disease, were studied using a signal-averaged electrocardiographic technique. Forty-seven members, 16 with a severe and 31 with a minor form of the disease, were found to be affected. Forty-three subjects had abnormal results on the SAECG; of these, 39 had the disease (100% in patients with widespread disease and 74.1% in patients with a minor form), whereas the other 4 had no sign of the disease. Only 44.1% of the subjects with an abnormal SAECG had ventricular arrhythmias, whereas 76% of the subjects with ventricular arrhythmias had an abnormal SAECG. In contrast, 90.6% of patients with an abnormal SAECG had the disease, and only subjects with arrhythmogenic right ventricular cardiomyopathy had ventricular arrhythmias. The abnormality on the SAECG appears to be correlated with the severity of the disease. Signal-averaged electrocardiography does not seem useful in diagnosing the minor forms of the disease and it does not give precise information about electrical instability in these patients.

The effects of sympathetic stimulation induced by mental stress on signal-averaged electrocardiogram

We evaluated the influence of sympathetic stimulation, induced by mental stress test, on signal-averaged ECG in 30 healthy subjects and in 30 patients with previous myocardial infarction. Both patient and control groups underwent three consecutive signal-averaged ECG: under basal conditions, during a continuous mental stress test, and 5 min after the mental stress test. The signal-averaged ECG parameters, analyzed by mean of a bandpass filter of 25-250 and 40-250 Hz, were: the filtered QRS duration, the duration of the low-amplitude high frequency signals in the terminal portions of the QRS complex below 40 microV (HFLA), and the root mean square voltage in the last 40 ms of the filtered QRS (RMS). The mathematical stress test was considered effective when the heart rate increased by at least 15 beats/min, remaining stable for the total duration of the signal-averaged ECG acquisition. A significant reduction of the filtered QRS duration and HFLA with a simultaneous increase of RMS were found in control group, while no significant changes occurred in patient group. These results indicate that the sympathetic nervous system may affect the results of signal-averaged ECG, probably by influences on intraventricular conduction, in healthy subjects. On the contrary, myocardial alterations in ischemic heart disease induce modification of signal-averaged ECG not influenced by autonomic nervous system activity.

Arrhythmogenic right ventricular cardiomyopathy in young versus adult patients: similarities and differences

OBJECTIVES

This study was designed to evaluate and compare the patterns of arrhythmogenic right ventricular cardiomyopathy in young people and adults.

BACKGROUND

Few data are available on this cardiomyopathy in young people because clinical and morphologic findings considered pathognomonic are normally based on observations in adults. However, a familial occurrence with a probable genetic transmission led to the study of children and to early detection of this disease, in which sudden death has been reported even in young people.

METHODS

Seventeen young patients with arrhythmogenic right ventricular cardiomyopathy diagnosed at a mean age +/- SD of 14.9 +/- 4.9 years were studied. Clinical, electrocardiographic, echocardiographic, cineangiographic and biopsy findings were compared with those of 19 adult patients whose condition was diagnosed at a mean age of 38.1 +/- 13.4 years.

RESULTS

Syncope occurred in 23.5% of the young patients but in none of the adults (odds ratio of familial sudden death 5.54, p = 0.1). Ventricular couplets (odds ratio 16.0, p = 0.004) and subtricuspid bulging on echocardiography (odds ratio 5.95, p = 0.036) were prevalent in the young group. Cineangiographic data in the two groups were similar, except that more hypokinetic areas were found in adults (odds ratio 4.44, p = 0.05). Morphometric analysis of biopsy sections showed a greater amount of fibrous tissue in the young patients (p = 0.04) and a prevalence of fatty tissue in the adults (odds ratio 12, p = 0.005). During an equivalent follow-up time (mean 7 years), two young patients died suddenly, and two had ventricular fibrillation in the absence of antiarrhythmic therapy.

CONCLUSIONS

The pathognomonic criteria for the diagnosis of arrhythmogenic right ventricular cardiomyopathy in adults are also valid for young people. Sudden or aborted death occurred frequently in young untreated patients.

Ocular vaso-occlusive disease in primary antiphospholipid syndrome

PURPOSE

To evaluate the ocular involvement in patients with the primary antiphospholipid syndrome.

METHODS

The authors performed a cross-sectional ophthalmologic study of 17 patients with the primary antiphospholipid syndrome. Retinal fluorangiography was performed in 13 patients.

RESULTS

Visual symptoms were described by ten patients. Visual acuity was markedly decreased in five eyes. Conjunctival telangiectases and microaneurysms, in addition to single instances of bilateral episcleritis and limbal keratitis, were the anterior segment findings. Fundus abnormalities were present in 15 patients. Venous tortuosity was the most common finding but there were instances of optic disc edema, vitreous hemorrhages, cotton-wool spots, vitreous bands, serous detachment of the macula, and retinal capillary abnormalities. Fluorangiography showed vaso-occlusive retinopathy in six eyes (5 patients, 29%). Choriocapillary vessel occlusion was observed in two eyes (1 patient) and binocular reticular degeneration of pigmentary epithelium was present in another case.

CONCLUSION

The eye is frequently involved in the primary antiphospholipid syndrome, and serious ocular damage may occur. Detailed ophthalmologic evaluation is warranted in these patients.

[High-resolution electrocardiography in 102 young healthy subjects]

BACKGROUND

The aim of this study was to evaluate the normal values of the most common indexes used in the analysis of ventricular late potential in 102 young male subjects.

METHODS

The recordings were performed by means of a Marquette electronics Hi-Resolution ECG Mac 15, with filters at 25-250 Hz, 40-250 Hz and 80-250 Hz. The parameters obtained were: filtered QRS duration (QRSD), high-frequency low-amplitude signals duration (HFLA), and the root mean square of the signal expressed in the terminal portion of QRS (RMS). The body surface was also evaluated.

RESULTS

QRSD (121.23 ms-113.9 ms-99.9 ms); RMS (105 uV-42.77 uV-34.3 uV); HFLA (17.5 ms-29.3 ms-29.3 ms). The comparison between our results and those proposed by other authors for normal subjects showed different results, particularly concerning the filtered QRS duration. We suppose that these discrepancies may be due to the different instrumentations used and to the different age and sex of the study population.

CONCLUSIONS

From these results we confirm that a normal range for each index must be done for homogeneous groups of subjects for age and sex, in healthy subjects as well as for different heart disease.

Long-term follow-up of patients with single lead VDD stimulation

The purpose of this study was to assess the long-term results of a single lead VDD pacing system (Phymos MPS) in 85 patients (48 males, 37 females, mean age 74 +/- 9 years). The system, which incorporates two atrial floating electrodes (Phymos 830-S), was implanted for second- or third-degree Mobitz II AV block. The percentage of AV synchronized pacing, the presence of fusion beats due to short AV delay, and the occurrence of supraventricular arrhythmias was evaluated by Holter monitoring at 6-month intervals. Over a mean period of follow-up of 44 months (range 2-56), over 90% of AV synchronized pacing events were noted in 74 patients (87%). The presence of persistent fusion beats was detected in 12 patients (14%). In ten patients the pacemaker was reprogrammed to VVI mode for supraventricular arrhythmias (7 patients, 8.2%) or unsatisfactory atrial sensing (3 patients, 3.5%). One pacemaker was removed for pocket infection and two for battery depletion. These observations support the use of VDD single lead pacing to combine a physiological mode of stimulation with simple implantation techniques.

QT-interval variability in hypertrophic cardiomyopathy patients with cardiac arrest

We studied long-term variability of QT-dispersion in three patients with hypertrophic cardiomyopathy (Maron III) and ventricular fibrillation. Late potentials were absent on signal-averaged electrocardiogram. ST-segment depression was recorded in all three patients at Holter monitoring, and in two during exercise stress testing, nonsustained ventricular tachycardia was present in only one patient. The maximal correct QT-interval and corrected QT-dispersion (QTcd) were measured retrospectively, both off-drug and under treatment with amiodarone and beta-blocker (two patients), or sotalol alone (one patient). Ten age- and sex-matched normal subjects, and 13 hypertrophic cardiomyopathy patients without ventricular arrhythmias formed the control groups. QTcd-values in the control groups never exceeded 80 ms and mean values of 30.1 +/- 10.1 ms and 44.1 +/- 7.9 ms respectively, were found. During long-term follow-up, QTcd increased progressively in two of the three patients with ventricular fibrillation, and at the time of the event all showed a value > 100 ms. Sotalol, but not the amiodarone reduced QTcd. QTcd seems to be a powerful predictor of ventricular electrical instability in the absence of other specific markers, and a promising guide for effective pharmacological therapy.

The gene for arrhythmogenic right ventricular cardiomyopathy maps to chromosome 14q23-q24

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVD) is a dominantly inherited disorder progressively affecting the myocardium and it is one of the major causes of juvenile sudden death. The chromosomal localization of the disease gene is reported here for the first time. A maximum lod score of 6.04 was obtained at theta = 0 for linkage with the polymorphic marker D14S42 (14q23-q24) in two families, one of which has 82 subjects (19 affected) in four generations. The pre-symptomatic identification of ARVD carriers by linkage analysis in the affected families strongly increases the possibility of prevention of life-threatening complications.

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

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Right ventricular cardiomyopathy in identical and nonidentical young twins

We describe the first sets of identical and nonidentical twins with right ventricular cardiomyopathy (RVC). Pair A: A 12-year-old boy was referred because of palpitation and syncope. Clinical and instrument examinations revealed an enlarged and depressed right ventricle (end-diastolic volume = 110 ml/m2; ejection fraction = 44%), spontaneous ventricular tachycardia, and fatty-fibrous infiltrates in the biopsy specimens. His asymptomatic, monozygotic twin showed localized involvement of the right ventricle with isolated, ventricular extrasystoles. Pair B: These 18-year-old nonidentical twin boys showed diffuse right ventricular involvement (end-diastolic volume = 110 ml/m2 and 114 ml/m2; ejection fraction = 30% and 24%, respectively), induction of sustained and nonsustained ventricular tachycardia, respectively, and fibrosis on endomyocardial biopsy. One of the boys died suddenly at rest after documented ventricular fibrillation. These cases support the hypothesis of a genetic etiology with a minor role for genotype and point to the important influence of environmental factors in determining the clinical features of the disease.

Endomyocardial biopsy in right ventricular cardiomyopathy

Right ventricular cardiomyopathy is characterized by a progressive myocyte loss and fibro-fatty substitution of the right ventricle. The aim of our study was to assess the diagnostic accuracy of right ventricular endomyocardial biopsy. Using an imaging analyser system, histomorphometric parameters of myocytes, interstitium, fibrous tissue and fatty tissue were evaluated on endomyocardial biopsy from 30 patients with arrhythmogenic right ventricular cardiomyopathy, 29 patients with dilated cardiomyopathy and 30 control patients. The percent area of myocytes decreased from 78.10 +/- 7.34 in control to 63.39 +/- 9.22 in dilated cardiomyopathy (P < 0.05) and to 47.28 +/- 15.01 in arrhythmogenic right ventricular cardiomyopathy (P < 0.01). Fibrous tissue increased from 8.10 +/- 3.89 in control to 21.80 +/- 9.29 in dilated cardiomyopathy (P < 0.05) and to 24.60 +/- 11.37 in arrhythmogenic right ventricular cardiomyopathy (P < 0.05). Fatty tissue varied from 0.33 +/- 1.44 in control and 0.07 +/- 0.31 in dilated cardiomyopathy to 13.30 +/- 17.30 in arrhythmogenic right ventricular cardiomyopathy (P < 0.05). Fatty tissue was a feature of arrhythmogenic right ventricular cardiomyopathy (67% of patients vs. 6% of control and dilated cardiomyopathy patients). Diagnostic values typifying arrhythmogenic right ventricular cardiomyopathy, obtained by excluding any overlapping between confidence intervals in the three groups, were: myocytes < 44.95%; fibrous tissue > 40.38%, and fatty tissue > 3.21%, with 67% sensitivity and 91.53% specificity for at least one parameter. In conclusion, a significant difference between arrhythmogenic right ventricular cardiomyopathy, dilated cardiomyopathy and control exists in terms of amount of myocytes, fibrous tissue and fatty tissue. Presence of fatty tissue and fibrous tissue exceeding 3.21% and 40.38%, respectively should be considered highly suspect for arrhythmogenic right ventricular cardiomyopathy in right ventricular endomyocardial biopsy.

Heart rate variability in patients with orthotopic heart transplantation: long-term follow-up

To evaluate heart rate variability (expressed as the standard deviation of RR intervals) within 5 years of follow-up, we studied 20 patients (14 males, 6 females, mean age 44 +/- 12 years) who underwent orthotopic heart transplantation. Six measurements were taken: one in the first 3 weeks after transplantation, and the others once annually, for 5 years. Twenty healthy subjects (mean age 44 +/- 7 years) constituted the control group. Heart rate variability increased significantly in the first 3 years of follow-up (7.2 +/- 1 vs. 11.1 +/- 4, p < 0.001; 11.1 +/- 4 vs. 15.2 +/- 4, p < 0.01; 15.2 +/- 4 vs. 18.9 +/- 5, p < 0.05); in the following years this trend slackened and values did not reach a statistically significant difference (18.9 +/- 5 vs. 21.4 +/- 5; 21.4 +/- 5 vs. 22.5 +/- 5). The mean standard deviation was invariably greater in the control group (63.6 +/- 12). These findings show that sinus rhythm variability in the denervated heart progressively increased over 5 years of follow-up. The absence of presynaptic uptake, which is responsible for adrenergic hypersensitivity to circulating catecholamines and intrinsic cardiac reflexes, does not appear to cause this phenomenon, since these mechanisms are not able to evolve in time after cardiac transplantation. Therefore, an enhanced beta-adrenergic receptors density or affinity to circulating catecholamines or a limited sympathetic reinnervation may be the more probable underlying mechanism.

Multinucleated hepatocytes induced by rifabutin in rats

Rifabutin is an antibiotic of the rifamycin class, which is particularly active against mycobacteria, including those that occur in AIDS patients. Because clinical use will include long-term therapy, an extensive battery of long-term toxicity studies was carried out by the oral route, including carcinogenicity studies. An interesting feature was the occurrence of multinucleated hepatocytes (MNHs) in the rat. In some instances, as many as 25 nuclei occurred in a single cell. Light microscopy revealed a large hepatocyte with normal eosinophilic staining. The multiple nuclei stained like those present in the surrounding normal cells. Electron microscopy showed no abnormalities of the nuclei and no cell membranes within the cytoplasm. The customary organelles were present. MNHs were dose- and sex-related, starting from 10 mg/kg/day and being more evident in males. They began to appear after 5 wk of treatment and persisted over long periods of recovery (12 mo), without showing any tendency for cell proliferation. The life-span of MNHs was similar to that of normal hepatocytes. MNHs were present in the carcinogenicity study, but there was no increase in liver tumors. MNHs did not occur in mice or monkeys treated with rifabutin, nor did they occur in response to treatment with rifampin. The effect appears to be specific to the rat.