Managing HIV. Part 5: Treating secondary outcomes. 5.9 HIV-related cardiovascular disease

Heart disease is common in HIV, but often asymptomatic. As improved therapies prolong the lives of HIV-infected patients, an increase in symptomatic heart disease can be expected.

[Arrhythmogenic right ventricular dysplasia]

Arrhythmogenic right ventricular dysplasia is a cardiomyopathy with autopsy evidence of fibrous and fatty infiltration of the right ventricular. The disease, which shows familial clustering, causes electrical instability that may place affected subjects at risk of sudden death. It is characterized by ECG changes and right ventricular dysfunction. Death can occur due to ventricular arrhythmia. We describe a 46-year-old female Cypriot who presented with recurrent syncope and palpitation due to ventricular tachycardia with the LBBB pattern; T waves were inverted in V1-V3. Echocardiogram and cardiac catheterization revealed severe right ventricular dysfunction. Her sister had died several years before of a similar syndrome, including ventricular tachycardia. Family members should be screened for right ventricular dysplasia. Those currently asymptomatic should be given prophylactic therapy to prevent sudden death. Treatment is either medical: sotalol, beta-blockers or verapamil; or surgical: ablation of the arrhythmogenic focus in the right ventricle, total disconnection of the right ventricular free wall; or implantation of a cardioverter defibrillator.

Molecular genetics of dilated cardiomyopathies

The application of molecular genetics in cardiology is currently producing important results in the study of the pathogenetic mechanisms underlying cardiomyopathies. Recent clinical surveys have indicated that genetic factors play a major pathogenetic role in idiopathic dilated cardiomyopathy (IDC). Familial IDC is frequent (20-30%) and is probably a heterogeneous entity, as suggested by the clinical variability and the different pattern of inheritance in the affected families. Molecular genetic studies have demonstrated the existence of heterogeneity also at the genetic level. In a series of families with X-linked IDC, the disease gene has been identified as the dystrophin gene. In familial right ventricular cardiomyopathy (or right ventricular dysplasia), a new nosological entity characterized by isolated right ventricular involvement that can mimic IDC, the disease gene has been localized in the long arm of chromosome 14. In families with matrilineal transmission, the cardiomyopathy could be linked to mitochondrial DNA alterations. Autosomal dominant familial IDC, considered to be the most frequent form, is currently under active investigation. Our preliminary data have excluded a large series of candidate genes, among which are the cardiac beta-myosin heavy chain and several other genes encoding for cardiac contractile proteins, genes of the HLA region, and about 60 genes involved in the immune regulation.

Cardiac status and health-related quality of life in the long term after surgical repair of tetralogy of Fallot in infancy and childhood

The long-term results of surgical repair of tetralogy of Fallot were assessed by means of extensive cardiologic examination of 77 nonselected patients 14.7 +/- 2.9 years after surgical repair of tetralogy of Fallot in infancy and childhood. Because of the frequent use of a transannular patch (56%) for the relief of right ventricular outflow tract obstruction, the prevalence of elevated right ventricular systolic pressure was low (8%), but the prevalence of substantial right ventricular dilation with severe pulmonary regurgitation was high (58%). The exercise capacity of patients with a substantially dilated right ventricle proved to be significantly decreased (83% +/- 19% of predicted) when compared with that of patients with a near normal sized right ventricle (96% +/- 13%). Eight out of 10 patients who had needed treatment for symptomatic arrhythmia had supraventricular arrhythmia, which makes supraventricular arrhythmia--in numbers--a more important sequela in the long-term survivors than ventricular arrhythmia. Older age at the time of the operation and longer duration of follow-up were not associated with an increase in prevalence or clinical significance of sequelae.

Arrhythmogenic right ventricular dysplasia/cardiomyopathy: a review

Right ventricular dysplasia is being recognized with increasing frequency. It should be considered as a cause of ventricular tachycardia of left bundle branch block configuration and/or sudden unexpected death particularly during exercise in young men. The electrocardiogram (ECG) may show anterior precordial T wave inversion, particularly in lead V2 and/or a QRS complex duration > or = 110 ms in the right precordial leads. Echocardiographic studies focusing on the size and wall-motion abnormalities of the right ventricle are useful in confirming the diagnosis. Radionuclide angiography usually shows a moderately or markedly depressed right ventricular ejection fraction with normal or relatively well preserved left ventricular function. Cinemagnetic resonance imaging demonstrates abnormal fatty infiltration of the right ventricular myocardium and can show increased right ventricular dimensions as well as wall-motion abnormalities. Contrast ventricular angiography remains the gold standard to establish the diagnosis but must be performed with appropriate views and with care to avoid ventricular premature beats. Quantitative analysis of right ventricular dimensions can be performed in selected centers. Three-dimensional echocardiography is a promising approach to evaluate right ventricular wall-motion abnormalities as well as to demonstrate enlargement. The etiology and pathogenesis of this condition is not clear. A familial incidence has been well-documented in certain areas and an abnormal gene has been identified. Sporadic cases are the most common. In contrast to Uhl's anomaly, characterized pathologically by areas of paper thin myocardium, the right ventricular free wall is minimally decreased in thickness. Histologically there appears to be a replacement of musculature by fatty tissue. Medical therapy with sotalol or amiodarone, or combination therapy (Class Ic drugs plus beta-blocking drugs, or amiodarone plus beta-blocking drugs) is frequently effective in preventing recurrent ventricular tachycardia. Ablation using radiofrequency (RF) or direct current (DC) energy is reserved for patients who are unresponsive or intolerant of antiarrhythmic drugs. Ventricular arrhythmia recurrence of different morphology is not uncommon after apparent successful ablation. There appears to be a lower rate of successful ablation using RF energy. However, patients with this condition who have been resuscitated from sudden cardiac death or those refractory to medical treatment are candidates for ablation, implantation of an automatic cardioverter defibrillator, or cardiac transplantation. Surgery consisting of total disconnection of the right ventricle is a promising therapeutic modality.

Right ventricular dysplasia: the Mayo Clinic experience

OBJECTIVE

To determine the initial clinical manifestations and echocardiographic features of right ventricular dysplasia as encountered in a major cardiovascular referral center in the United States.

DESIGN

We conducted a retrospective study of cases of right ventricular dysplasia diagnosed at the Mayo Clinic between January 1978 and January 1993.

MATERIAL AND METHODS

In an institutional data-base search, we identified 20 patients with right ventricular dysplasia. Echocardiographic, electrophysiologic, Holter monitoring, cardiac catheterization, and endomyocardial biopsy results were analyzed. The mean duration of follow-up was 7 years.

RESULTS

In the 12 female and 8 male patients (mean age, 30 years; range, 3 to 60), the initial manifestations of right ventricular dysplasia included ventricular arrhythmia (45%), congestive heart failure (25%), heart murmur (10%), asymptomatic (10%), complete heart block (5%), and sudden death (5%). First-order relatives were affected in 30% of the patients. Ventricular tachycardia with morphologic features of left bundle branch block was inducible in seven of nine patients. On Holter monitoring, all but 2 of 15 patients studied had frequent ventricular ectopic activity (Lown grade 2 or more). Characteristic fatty infiltration of the myocardium was present in 7 of 13 right ventricular biopsy specimens. Inordinate right ventricular enlargement was present in 60% of the patients at first echocardiographic assessment and in two other patients on follow-up assessment. Variable left ventricular involvement was noted in 50% of the cases. During the follow-up period, four patients died: two died suddenly, one died of congestive heart failure, and one died of respiratory failure after a coronary artery bypass operation. Of the 16 living patients, 8 are doing well, 3 have an implanted cardiac defibrillator, 3 are receiving antiarrhythmic agents, and 2 have undergone cardiac transplantation because of progressive biventricular failure.

CONCLUSION

Patients with right ventricular dysplasia have varied initial manifestations and a high frequency of serious cardiovascular symptoms and complications.

Cor pulmonale in children with human immunodeficiency virus infection

A cross-sectional echocardiographic study of 50 black Zimbabwean children with clinical human immunodeficiency virus (HIV) infection was carried out. The median age was 9 months. Seventy per cent had chronic cough, 60% respiratory distress and 40% cyanosis. Sixty per cent had pericardial effusion and 48% right ventricular hypertrophy (RVH) and dilation. However, the clinical diagnosis of heart failure was difficult as most of these children (80%) had hepatomegaly. These findings suggest that respiratory disease plays a role in the causation of RVH in these children. As cardiac causes of RVH were absent, this was presumed to be due to cor pulmonale. HIV-infected children presenting with respiratory distress may have clinically unapparent cor pulmonale. Early and appropriate management may by beneficial.

Reproducibility of MRI-derived measurements of right ventricular volumes and myocardial mass

Magnetic resonance (MR) imaging has been shown to provide accurate measurements of right ventricular (RV) volumes and myocardial mass. The purpose of this study was to evaluate the reproducibility of MR imaging, which in clinical practice may be as important as its absolute accuracy. The reproducibility of MR imaging measurements of the right ventricle was assessed by analyzing 40 serial functional MR imaging examinations of the right ventricle with variance component analysis. Standard deviations and 95% ranges for change were: for RV myocardial mass, 5.9 and 16 g; and for RV ejection fraction, 6.0% and 16%, respectively. Reproducibility was similar for cine and spin-echo MR imaging. The intraobserver and interobserver errors were especially large, indicating that observer subjectivity is the limiting factor in the interpretation of the MR images. This study suggests that the reproducibility of RV measurements is adequate to detect RV hypertrophy and a low ejection fraction in the individual patient. For accurate follow-up examinations, whereby smaller changes are to be detected, the reproducibility of MR imaging measurements may not be sufficient. More effort is needed to improve the reproducibility of MR imaging measurements.

The state of body surface mapping in Japan

In Japan, body surface mapping (BSM) started in 1974. A huge amount of data has been accumulated regarding basic researches and clinical applications. Recent work on BSM in Japan is summarized here, with the goals of establishing a normal database and diagnostic criteria by using the standardized mapping system. The standard systems used in Japan are the HPM-7100 and the VCM-3000, manufactured by Fukuda-Denshi (Tokyo, Japan) under the supervision of a committee of the Japanese Circulation Society. The number of leads in this system is 87 (59 on front, 28 on back). As a basic study, a computer simulation was carried out on bundle branch block with myocardial infarction (MI), on late potentials in MI, and finally, on the solution of the inverse problem. The database of 606 normal subjects was established regarding age and sex, and a "departure index" (the grade of deviation from normal: the difference between a patient's data the normal mean divided by the normal SD) was proposed. Using the departure index, diagnostic criteria were proposed for the ischemic site, MI site, hypertrophic site of the ventricle, etc. The origin of the ventricular premature contractions was determined by the site of minima and maxima of the QRS and QRST isointegral maps. The site of accessory pathways was determined by the site of minimum less than -0.15 mV on the BSM. For the prediction of patients prone to ventricular tachycardia (VT), several approaches were tried such as multipolar patterns of QRST isointegral maps, Wigner distribution, late potentials with relation to endo- or epicardial delayed potentials, body surface distribution of specific frequency band (25-50 Hz) obtained from fast Fourier transform analysis, and nondipolarity of the QRST isointegral map. To improve the ablation procedure of VT, the author developed a technique to determine the precise location of the VT focus in pace mapping using a correlation matrix between VT and pace maps. To ensure the longevity of the BSM, a reduction of the number of leads has been proposed. The usefulness of BSM has been confirmed and the technique accepted in Japan for daily clinical diagnosis.

[The evaluation of systolic right ventricular pressure and right ventricular hypertrophy using body surface mapping (isointegral map, isochrone map)]

We studied QRS and QRST isointegral maps, and isochrone map for the diagnosis of right ventricular hypertrophy and its severity in atrial septal defects and primary pulmonary hypertensions. The discriminant analysis in QRS isointegral map showed better results for differential diagnosis between atrial septal defects and both normal subjects and incomplete right bundle branch block patients than these in QRST isointegral map and isochrone map. Three parameters (Qp/Qs, systolic right ventricular pressure, right ventricular ejection fraction) for right ventricular overload showed significant correlation with QRS isointegral map and QRS isopotential map. Thus body surface map was an useful method for the evaluation of right ventricular hypertrophy.

[The role of magnetic resonance in studying hypertrophic cardiomyopathy: the echocardiographic correlations and clinical implications]

Clinical studies evaluating the role of magnetic resonance imaging (MRI) in patients with hypertrophic cardiomyopathy are scanty. To assess the capability of MRI to define the presence, distribution and severity of left ventricular hypertrophy, the prevalence and clinical implications of right ventricular hypertrophy, the prevalence and clinical implications of myocardial structural abnormalities, MRI and echocardiography were performed in 37 unselected patients (age 10-72 years, mean 38 +/- 19) with hypertrophic cardiomyopathy. The concordance between the two methods was 100% in the diagnosis and classification of left ventricular hypertrophy as asymmetric, concentric or apical. A significant linear correlation was found between echocardiography and MRI measurements of interventricular septum (r = 0.69, p < 0.0001, SEE = 4) and left ventricular posterior wall (r = 0.67, p < 0.0001, SEE = 2.4). Right ventricular hypertrophy (right anterior wall diastolic thickness > 5 mm) was disclosed by MRI in 23/33 patients (70%). In this group, left posterior wall thickness and left atrial diameter were higher (15 +/- 4 versus 11 +/- 2 mm, p < 0.01 and 45 +/- 9 versus 38 +/- 5 mm, p < 0.05 respectively). On T2 weighted sequences, areas of reduction of signal intensity, probably caused by myocardial fibrosis, were detected in 16 cases (43%). This group was characterized by a higher value in maximal septal thickness (26 +/- 7 versus 21 +/- 6 mm, p < 0.05) and in maximal left posterior wall thickness (15 +/- 9 versus 7 +/- 8 mm, p < 0.01). All the 3 cases with dilated and hypokinetic left ventricle showed this type of tissue abnormality.(ABSTRACT TRUNCATED AT 250 WORDS)

Connection between right ventricular pressure and the ECG

According to the literature, electrocardiographic signs of right ventricular hypertrophy have low sensitivity. The cause of this low sensitivity may be attributed to the original studies that were performed mostly in children with hypoplastic left ventricles or congenital heart abnormalities. In adulthood cases of normal or hypertrophic left ventricles, electrocardiographic right ventricular hypertrophy can only be detected during the late phase of ventricular depolarization. Two hundred four adult cardiac patients with complete noninvasive and invasive records were systematically studied by conventional and vectocardiographic methods. The terminal QRS (S wave) of the standard lead I has proved to be informative for detecting electrocardiographic signs in the presence of elevated right ventricular pressure. In cases of chronic right ventricular pressure overload (right ventricular hypertrophy) the terminal depolarization QRS vectors pointed posteriorly and to the right; therefore, a characteristic terminal S wave was represented in the standard lead I. If right and left ventricular hypertrophy were simultaneously present, the same resultant vectors pointed posteriorly and slightly to the left. In these cases, notching of the declining phase of the R wave was frequent, and a flatness of the terminal R wave portion was characteristic. The latter electrocardiographic sign has been called "simultaneous overloading of both ventricles" by the authors. The clinical utility of the new signs have also been proved by statistical methods.

[Arrhythmogenic right ventricular dysplasia. Case report and review of the literature]

Two cases of arrhythmogenic right ventricular dysplasia are described. The most important clinical features of the disease are malignant ventricular arrhythmia and sudden death. It is characterized by the loss of right ventricular musculature and by the fatty and connective tissue infiltration of the right ventricular wall. The diagnosis is based on the typical echocardiographic appearance of right ventricular dilatation, on the presence of negative T waves in leads V1-4 on the resting ECG and on ventricular tachycardia of left bundle branch block pattern. Right heart failure develops only in the late phase of the disease. Genetic defect might be an etiologic factor. In conclusion authors suggest that in case of left bundle branch block ventricular tachycardia or Adams-Stokes syndrome in young adults echocardiography and family screening are necessary.

Clinical course of isolated ventricular septal defect: an Indian experience

To define the clinical course of ventricular septal defect, 410 consecutive patients with isolated ventricular septal defect were evaluated over a period of 13 years. Their age ranged from 12 days to 24 years at the time of first visit to the hospital. Patients with less than 2 years follow-up period were excluded. One hundred and fifty seven patients were one year of age or less. The left to right shunt size remained the same in 52.4% of cases. In 34.4% the shunt size decreased, with complete closure of ventricular septal defect in 8.8%. Closure of ventricular septal defect was observed even in patients who had initially presented with large left to right flow, and congestive heart failure in infancy. Right ventricular outflow tract obstruction developed in 8.5% of patients usually between 2 and 10 years of age. Murmur of aortic regurgitation appeared in 8.9% on follow-up. Infective endocarditis developed in 6 cases. The unfortunate complication of Eisemenger's complex was seen in 3 patients; they had not returned for follow up for a long period of time. Hence, our data show that the left to right shunt across the ventricular septal defect decreases in about one-third of patients. However, a regular follow up is essential to prevent development of Eisenmenger's complex and for early detection of other complications like aortic regurgitation and right ventricular outflow tract obstruction.

Diagnostic value of ECG patterns of right ventricular hypertrophy in children

OBJECTIVE

To determine the diagnostic value of traditional criteria of right ventricular hypertrophy (RVH) in children.

PATIENTS

The electrocardiograms (ECGs) of 1000 consecutive pediatric patients were reviewed. Children under three months old were excluded as were patients with QRS prolongation.

RESULTS

Four hundred and thirty-four patients met all inclusion criteria. The medical records were then reviewed for diagnosis. Sixty-seven per cent had a diagnosis compatible with RVH. Of the ECG patterns evaluated, a precociously upright T wave in lead V1 was most predictive with 99% specificity. Presence of a QR complex in lead V1 had a 96% specificity but R:S ratio, voltage criteria and rSR' incomplete right bundle branch block pattern had intermediate specificities of 66%, 66% and 52%, respectively. Sensitivities of 12.6%, 13.2%, 34.0%, 63.3% and 74.2% were calculated for upright T, QR complex, R:S ratio, voltage criteria and rSR', respectively.

CONCLUSIONS

An upright T wave or qR pattern are highly specific but insensitive markers of RVH in children. In contrast, when an incomplete right bundle branch block exists, the rSR' pattern is a relatively sensitive but nonspecific predictor of RVH.

The body surface QRST isointegral maps in infants with right ventricular overload

Electrocardiographic criteria for right ventricular (RV) hypertrophy in infants generally exhibit low sensitivity in terms of diagnostic accuracy. We studied the QRST isointegral map (QRST-Imap) of body surface potential distribution for the diagnosis of RV overload in patients less than 2 years old. Patients with atrial septal defect (ASD), pulmonary stenosis (PS) and tetralogy of Fallot (TOF) were examined (RV overload group) and the findings of their QRST-Imaps were compared to those of age-matched healthy infants (NOR). QRST-Imaps in RV overload showed abnormal findings, with two maxima or a rightward shift of the maximum with increased amplitude, in contrast to one maximum at the left anterior chest with a single dipole pattern in the NOR group. ASD patients had two maxima with a decreased integral value between them. In PS, two maxima were also observed, with increased integral values of the right maximum as the RV systolic pressure was elevated. TOF patients showed a single maximum shifted to the anterior median line with increased amplitude. These results indicate that the findings of QRST-Imaps are of value in detecting the presence and pattern of RV overload in infants.