Frequency of familial nature of dilated cardiomyopathy and usefulness of cardiac transplantation in this subset

Contemporary characteristics and outcomes of adults with familial dilated cardiomyopathy listed for heart transplantation

BACKGROUND

Familial dilated cardiomyopathy (FDCM) account for 20%-30% of non-ischemic cardiomyopathies (NICM). Previous published data showed that some patients with FDCM tend to have rapidly progressive disease; however, five-year mortality was not significantly different in the familial and non-familial forms of NICM with optimal medical therapy.

AIM

To better define the characteristics and clinical outcomes of FDCM patients listed for heart transplantation (HT).

METHODS

We queried the United Network for Organ Sharing Registry to identify FDCM patients listed for HT between January 2008 and September 2015 and compared them to NICM and ischemic cardiomyopathy (ICM) patients. We included all patients ≥ 18 years old and we separated patients to three groups: FDCM, NICM and ICM. Chi-square test was used to compare between categorical variables, the t-test was used to compare between continues variables, and Cox-proportional hazards model was used to perform time-dependent survival analyses.

RESULTS

Of the 24809 adults listed for HT, we identified 677 patients (2.7%) with the diagnosis of FDCM. Compared to patients with NICM and ICM, FDCM patients were younger (FDCM 43.9 ± 13.5 vs NICM 50.9 ± 12.3, P < 0.001, vs ICM 58.5 ± 8.1, P < 0.001), more frequently listed as status 2 (FDCM 35.2% vs NICM 26.5%, P < 0.001), with significantly lower left ventricular assist device (LVAD) utilization (FDCM 18.4% vs NICM 25.1%, P < 0.001; vs ICM 25.6%, P < 0.001), but higher use of total artificial heart (FDCM 1.3% vs NICM 0.6%, P = 0.039; vs ICM 0.4%, P = 0.002). Additionally, patients with FDCM were less frequently delisted for clinical deterioration or death and more likely to be transplanted compared to those with NICM [hazard ratio (HR): 0.617, 95% confidence interval (CI): 0.47-0.81; HR: 1.25, 95%CI: 1.14-1.37, respectively], and ICM (HR: 0.5, 95%CI: 0.38-0.66; HR: 1.18, 95%CI: 1.08-1.3, respectively). There was more frequent rejection among patients with FDCM (FDCM 11.4% vs NICM 9.8%, P = 0.28; vs ICM 8.4%, P = 0.034). One, three, and five post-transplant survival of patients with FDCM (91%, 88% and 80%) was similar to those with NICM (91%, 84%, 79%, P = 0.225), but superior to those with ICM (89%, 82%, 75%, P = 0.008), respectively.

CONCLUSION

End-stage FDCM patients are more likely to be transplanted, more likely to have early rejection, and have similar or higher survival than patients with other cardiomyopathies.

A novel alpha-tropomyosin mutation associates with dilated and non-compaction cardiomyopathy and diminishes actin binding

BACKGROUND

Dilated cardiomyopathy (DCM) is characterized by idiopathic dilatation and systolic contractile dysfunction of the ventricle(s) leading to an impaired systolic function. The origin of DCM is heterogeneous, but genetic transmission of the disease accounts for up to 50% of the cases. Mutations in alpha-tropomyosin (TPM1), a thin filament protein involved in structural and regulatory roles in muscle cells, are associated with hypertrophic cardiomyopathy (HCM) and very rarely with DCM.

METHODS AND RESULTS

Here we present a large four-generation family in which DCM is inherited as an autosomal dominant trait. Six family members have a cardiomyopathy with the age of diagnosis ranging from 5 months to 52 years. The youngest affected was diagnosed with dilated and non-compaction cardiomyopathy (NCCM) and died at the age of five. Three additional children died young of suspected heart problems. We mapped the phenotype to chromosome 15 and subsequently identified a missense mutation in TPM1, resulting in a p.D84N amino acid substitution. In addition we sequenced 23 HCM/DCM genes using next generation sequencing. The TPM1 p.D84N was the only mutation identified. The mutation co-segregates with all clinically affected family members and significantly weakens the binding of tropomyosin to actin by 25%.

CONCLUSIONS

We show that a mutation in TPM1 is associated with DCM and a lethal, early onset form of NCCM, probably as a result of diminished actin binding caused by weakened charge-charge interactions. Consequently, the screening of TPM1 in patients and families with DCM and/or (severe, early onset forms of) NCCM is warranted. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Cardiac Pathways of Differentiation, Metabolism and Contraction.

Early predictors of survival to and after heart transplantation in children with dilated cardiomyopathy

BACKGROUND

The importance of clinical presentation and pretransplantation course on outcome in children with dilated cardiomyopathy listed for heart transplantation is not well defined.

METHODS AND RESULTS

The impact of age, duration of illness, sex, race, ventricular geometry, and diagnosis of myocarditis on outcome in 261 children with dilated cardiomyopathy enrolled in the Pediatric Cardiomyopathy Registry and Pediatric Heart Transplant Study was studied. End points included listing as United Network for Organ Sharing status 1, death while waiting, and death after transplantation. The median age at the time of diagnosis was 3.4 years, and the mean time from diagnosis to listing was 0.62±1.3 years. Risk factors associated with death while waiting were ventilator use and older age at listing in patients not mechanically ventilated (P=0.0006 and P=0.03, respectively). Shorter duration of illness (P=0.04) was associated with listing as United Network for Organ Sharing status 1. Death after transplantation was associated with myocarditis at presentation (P=0.009), nonwhite race (P<0.0001), and a lower left ventricular end-diastolic dimension z score at presentation (P=0.04). In the myocarditis group, 17% (4 of 23) died of acute rejection after transplantation.

CONCLUSIONS

Mechanical ventilator use and older age at listing predicted death while waiting, whereas nonwhite race, smaller left ventricular dimension, and myocarditis were associated with death after transplantation. Although 97% of children with clinically or biopsy-diagnosed myocarditis at presentation survived to transplantation, they had significantly higher posttransplantation mortality compared with children without myocarditis, raising the possibility that preexisting viral infection or inflammation adversely affects graft survival.

Review and metaanalysis of the frequency of familial dilated cardiomyopathy

Several studies have investigated the frequency of familial dilated cardiomyopathy (FDC). However, no systematic review and meta-analysis on this topic are available. Therefore, using the PubMed, MEDLINE, Cochrane, and the ISI Web of Science databases, relevant reports published through December 2010 were identified. For the summation of prevalence findings, prevalence point estimates and 95% confidence intervals were computed using the logit transformation formula. An aggregate estimate of clinically confirmed FDC of 23% (95% confidence interval 0.17 to 0.31) was found. However, the prevalence rates reported across these studies varied widely, ranging from 2% to 65%, and the analysis showed very high heterogeneity (Q = 295, p <0.001, I(2) = 93%). Meta-regression analysis between logit event rate and year of publication explained 23% of between-study variance (p <0.05). Cumulative meta-analysis confirmed the influence of year of publication on the reported prevalence of FDC among the different studies. However, most of the observed heterogeneity may be explained by the fact that the various studies used different preselected criteria for the diagnosis of FDC. In conclusion, data obtained from trials performed using standardized criteria are needed to better define the true prevalence of FDC.

Clinical and genetic issues in dilated cardiomyopathy: a review for genetics professionals

Dilated cardiomyopathy (DCM), usually diagnosed as idiopathic dilated cardiomyopathy (IDC), has been shown to have a familial basis in 20-35% of cases. Genetic studies in familial dilated cardiomyopathy (FDC) have shown dramatic locus heterogeneity with mutations identified in >30 mostly autosomal genes showing primarily dominant transmission. Most mutations are private missense, nonsense or short insertion/deletions. Marked allelic heterogeneity is the rule. Although to date most DCM genetics fits into a Mendelian rare variant disease paradigm, this paradigm may be incomplete with only 30-35% of FDC genetic cause identified. Despite this incomplete knowledge, we predict that DCM genetics will become increasingly relevant for genetics and cardiovascular professionals. This is because DCM causes heart failure, a national epidemic, with considerable morbidity and mortality. The fact that early, even pre-symptomatic intervention can prevent or ameliorate DCM, coupled with more cost-effective genetic testing, will drive further progress in the field. Ongoing questions include: whether sporadic (IDC) disease has a genetic basis, and if so, how it differs from familial disease; which gene-specific or genetic pathways are most relevant; and whether other genetic mechanisms (e.g., DNA structural variants, epigenetics, mitochondrial mutations and others) are operative in DCM. We suggest that such new knowledge will lead to novel approaches to the prevention and treatment of DCM.

Genetics of dilated cardiomyopathy

Dilated cardiomyopathy (DCM) is a myocardial disease characterized by dilatation and impaired systolic function of the left or both ventricles. The etiology of DCM is multifactorial, and many different clinical conditions can lead to the phenotype of DCM. During recent years it has become evident that genetic factors play an important role in the etiology and pathogenesis of idiopathic DCM. The genetics of DCM have been under intensive investigation lately, and thereby the knowledge on the genetic basis of DCM has increased rapidly. The genetic background of the disease seems to be relatively heterogeneous, and the disease-associated mutations concern mostly single families and only few affected patients. Disease-associated mutations have been detected e.g. in genes encoding sarcomere, cytoskeletal, and nuclear proteins, as well as proteins involved with regulation of Ca(2+) metabolism. The mechanisms, by which mutations eventually result in clinical heart failure, are complex and not yet totally resolved. DCM causes considerable morbidity and mortality. Better knowledge of the genetic background and disease-causing mechanisms would probably help us in focusing early treatment on right subjects and potentially also developing new treatment modalities and improving cardiac outcome in the affected patients. This review deals with DCM of genetic origin.

Clinical characteristics of 304 kindreds evaluated for familial dilated cardiomyopathy

BACKGROUND

Familial dilated cardiomyopathy (FDC) is dilated cardiomyopathy of unknown cause occurring in 2 or more closely related family members.

METHODS AND RESULTS

Members of 304 families suspected to have FDC were evaluated by family history (FH) and medical record review and were categorized as affected with idiopathic dilated cardiomyopathy (IDC), unaffected, unknown, or no data. Pedigrees were categorized with confirmed FDC, probable FDC, possible FDC or IDC based on strength of evidence. Of the 304 pedigrees, 125 were categorized as confirmed FDC, 48 were probable FDC, 72 were possible FDC, and 59 had sporadic, nonfamilial IDC. Numbers of living first- and second-degree family members, and median number of relatives available for FH was greatest with confirmed FDC, and diminished for probable and possible FDC, and IDC categories. LV dimensions increased and LV function worsened in index patients along the spectrum from confirmed FDC, probable FDC, possible FDC and IDC, and a greater proportion of IDC patients underwent heart transplant. However, the age of onset, duration of disease, the time to death or heart transplant, and most other findings were similar among the 4 categories.

CONCLUSION

Clinical characteristics of IDC and FDC are similar, precluding an FDC diagnosis from clinical features only.

Progression of familial and non-familial dilated cardiomyopathy: long term follow up

BACKGROUND

It is unknown whether progression of familial idiopathic dilated cardiomyopathy differs from progression in the non-familial form. It has been suggested that familial disease indicates a worse prognosis, and that this should be considered when planning the timing of heart transplantation.

OBJECTIVE

To compare five year survival or time to heart transplantation in an unselected series of patients with dilated cardiomyopathy who had been evaluated for familial v non-familial disease through the echocardiographic investigation of first degree relatives.

DESIGN

Medical records were reviewed and questionnaires were mailed to all patients who had previously participated in a family based study of dilated cardiomyopathy. Information was gathered about survival, heart transplantation, and left ventricular ejection fraction (LVEF) measurements. Survival data were censored at the time of cardiac transplantation.

RESULTS

Follow up data were obtained for 99 of 101 patients (69 with non-familial and 30 with familial disease). Five year survival was 55% for non-familial and 51% for familial patients (NS). The main predictor of mortality was an LVEF of < 30%. Familial status did not predict mortality. There was no significant difference in follow up LVEF values between the groups.

CONCLUSIONS

Five year survival is not significantly different in the familial and non-familial forms of dilated cardiomyopathy.

[Familial dilated cardiomyopathy in patients transplanted for idiopathic dilated cardiomyopathy]

OBJECTIVE

To evaluate the prevalence, clinical features, and pattern of inheritance of familial dilated cardiomyopathy (DCM) in heart transplant patients.

PATIENTS AND METHOD

Patients with idiopathic DCM who had undergone heart transplantation were invited to participate. Patients with alcohol abuse were excluded. A clinical evaluation, 12-lead ECG, echocardiogram, blood tests, and DNA extraction were performed in patients and relatives. Familial DCM was defined as the presence of at least one relative with idiopathic DCM. Possible familial DCM was considered when at least one relative had left ventricular enlargement (LVE) (> 112% predicted LVEDD).

RESULTS

One hundred and ninety-nine relatives of 43 families were studied. DCM was familial in 11 probands (25.6%) and possibly familial in 11 (25.6%). Fifteen relatives had DCM (7.5%), 26 (13.1%) LVE, and 5 (2.5%) hypertrophic cardiomyopathy. The pattern of inheritance was autosomal dominant in most families. Five probands (3 with familial DCM) had antecedents of consanguinity and possible recessive inheritance. Six probands (14%, 1 with familial DCM) had relatives with conduction system defects. Creatine kinase was moderately increased in 9 relatives (4.5%), 3 of them with LVE. Fifteen patients had at least moderate alcohol intake. Three of them had familial DCM (relatives without alcohol abuse) and 6 had possible familial DCM.

CONCLUSIONS

The prevalence of familial DCM is high in patients who undergo heart transplant. Left ventricular enlargement, conduction system abnormalities, and elevated creatine kinase may be early markers of familial disease. Hypertrophic cardiomyopathy is present in some relatives of patients with idiopathic DCM. Familial DCM is present in patients with a previous diagnosis of alcoholic DCM.

Construction of a high-resolution physical map of the chromosome 10q22-q23 dilated cardiomyopathy locus and analysis of candidate genes

Dilated cardiomyopathy (DCM) is a major cause of morbidity and mortality and a leading cause of cardiac transplantation worldwide. Multiple loci and three genes encoding cardiac actin, desmin, and lamin A/C have been described for autosomal dominant DCM. Using recombination analysis, we have narrowed the 10q21-q23 locus to a region of approximately 4.1 cM. In addition, we have constructed a BAC contig, composed of 199 clones, which was used to develop a high-resolution physical map that contains the DCM critical region (approximately 3.9 Mb long). Seven genes, including ANX11, PPIF, DLG5, RPC155, RPS24, SFTPA1, and KCNMA1, have been mapped to the region of interest. RPC155, RPS24, SFTPA1, and KCNMA1 were excluded from further analysis based on their known functions and tissue-specific expression patterns. Mutational analysis of ANX11, DLG5, and PPIF revealed no disease-associated mutations. Multiple ESTs have also been mapped to the critical region.

New theories. Causes of dilated cardiomyopathy

Dilated cardiomyopathy is a heterogeneous disease, both clinically and genetically. Two genes responsible for X-linked DCM have been identified. Five genetic loci responsible for X-linked DCM have been identified. Five genetic loci responsible for autosomal dominant DCM have also been mapped but no genes identified so far. New paradigms may be necessary in order to elucidate the etiology of primary dilated cardiomyopathy.

Frequency and phenotypes of familial dilated cardiomyopathy

OBJECTIVES

This prospective study was performed to analyze the frequency and clinical characteristics of idiopathic dilated cardiomyopathy (DCM).

BACKGROUND

Despite several previous reports on families with DCM, most cases are still believed to be sporadic, and specific clinical findings of the familial form are not well defined.

METHODS

In 445 consecutive patients with angiographically proven DCM, we obtained detailed family histories to construct pedigrees and examined 970 first- and second-degree family members.

RESULTS

Familial DCM was confirmed in 48 (10.8%) of the 445 index patients and was suspected in 108 (24.2%). The 156 patients with suspected or confirmed familial disease were younger at the time of diagnosis (p < 0.03) and more often revealed electrocardiographic changes (p = 0.0003) than patients with nonfamilial disease. Among the families of the 48 index patients with confirmed familial disease, five phenotypes of familial DCM could be identified: 1) DCM with muscular dystrophy; 2) juvenile DCM with a rapid progressive course in male relatives without muscular dystrophy; 3) DCM with segmental hypokinesia of the left ventricle; 4) DCM with conduction defects; and 5) DCM with sensorineural hearing loss.

CONCLUSIONS

Up to 35% of patients with DCM may have an inherited disorder. Distinct clinical phenotypes can be observed in some families, suggesting a common molecular cause of the disease.

Gene mapping of familial autosomal dominant dilated cardiomyopathy to chromosome 10q21-23

Dilated cardiomyopathy (DCM) is the most common form of primary myocardial disorder, accounting for 60% of all cardiomyopathies. In 20-30% of cases, familial inheritance can be demonstrated; an autosomal dominant transmission is the usual type of inheritance pattern identified. Previously, genetic heterogeneity was demonstrated in familial autosomal dominant dilated cardiomyopathy (FDCM). Gene localization to chromosome 1 (1p1-1q1 and 1q32), chromosome 3 (3p25-3p22), and chromosome 9 (9q13-9q22) has recently been identified. We report one family with 26 members (12 affected) with familial autosomal dominant dilated cardiomyopathy in which linkage to chromosome 10 at the 10q21-q23 locus is identified. Using short tandem repeat polymorphism (STR) markers with heterozygosity > 70%, 169 markers (50% of the genome) were used before linkage was found to markers D10S605 and D10S201 with a pairwise LOD score = 3.91, theta = 0, penetrance = 100% for both markers. Linkage to 1p1-1q1, 1q32, 3p25-3p22, and 9q13-9q22 was excluded. We conclude that a new locus for pure autosomal dominant FDCM exists, and that this gene is localized to a 9 cM region of 10q21-10q23. The search for the disease causing gene and the responsible mutation(s) is ongoing.

Left ventricular enlargement is common in relatives of patients with dilated cardiomyopathy

Idiopathic dilated cardiomyopathy is characterized by dilation and impaired contractility of one or both ventricles. Long-term prognosis is poor. Early diagnosis has the potential for substantial reduction of morbidity and mortality. Recent studies, based on echocardiographic assessment of relatives of the patients have shown that familial dilated cardiomyopathy is relatively common. The authors studied 215 relatives (mean age, 27 years; 111 male) of 38 index patients with idiopathic dilated cardiomyopathy by clinical examination, electrocardiography, and two-dimensional, M-mode and Doppler echocardiography. Seven relatives (3%) from six families were shown to have dilated cardiomyopathy. Thus, 6 of the 38 index patients (16%) had familial disease. Furthermore, left ventricular enlargement either during diastole or systole was found in 66 of 174 healthy relatives (38%). This is significantly more frequent than in our normal control population of 100 unrelated subjects studied in the same way (18%; P < .0001). These 66 relatives with left ventricular enlargement belonged to 27 of the 38 examined families (71%). Dilated cardiomyopathy was found to be familial in 16% of patients. Of the relatives examined, 41% had left ventricular abnormalities. These findings provide further evidence for a genetic background of dilated cardiomyopathy. Relatives with left ventricular enlargement may have an early stage and/or latent form of the disease.

Familial dilated cardiomyopathy: a worse prognosis compared with sporadic forms

OBJECTIVE

To establish the time of onset of dilated cardiomyopathy (DCM) by review of annual chest x rays, which are obligatory in Hungary.

DESIGN

A retrospective survey of chest x rays of a cohort of confirmed cases of DCM, to assess time of onset of cardiomegaly. Clinical course was compared by follow up over a mean of six years from the time of diagnosis.

SUBJECTS

240 patients with DCM (31 familial, 209 non-familial). Diagnosis was made by echocardiography in all cases and confirmed by coronary angiography and heart biopsy in some cases.

MAIN RESULTS

At diagnosis, the mean age of the patients was 31.8 years in the familial group and 39.6 years in the non-familial group (P < 0.05). The time between the onset of cardiomegaly (cardiothoracic ratio > 0.45) and clinical diagnosis was 8.0 and 10.1 years respectively (P < 0.05). The six year survival was 6% in the familial group and 23% in the non-familial group (P < 0.05).

CONCLUSIONS

The familial form of DCM is the more malignant form: it occurs at an earlier age and progresses more rapidly than non-familial DCM.

A mutation in the dystrophin gene selectively affecting dystrophin expression in the heart

We have previously shown in a large X-linked pedigree that a deletion removing the dystrophin muscle promoter, the first muscle exon and part of intron 1 caused a severe dilated cardiomyopathy with no associated muscle weakness. Dystrophin expression was present in the muscle of affected males and transcription studies indicated that this dystrophin originated from the brain and Purkinje cell isoforms, upregulated in this skeletal muscle. We have now studied dystrophin transcription and expression in the heart of one member of this family. In contrast to the skeletal muscle, dystrophin transcription and expression were absent in the heart, with the exception of the distal Dp71 dystrophin isoform, normally present in the heart. The 43- and 50-kD dystrophin-associated proteins were severely reduced in the heart, despite the presence of Dp71, but not in skeletal muscle. The absence of dystrophin and the down-regulation of the dystrophin-associated proteins in the heart accounted for the severe cardiomyopathy in this family. The mutation present in these males selectively affects dystrophin expression in the heart; this could be secondary to the removal of cardiac-specific regulatory sequences. This family may represent the first example of a mutation specifically affecting the cardiac expression of a gene, present physiologically in both the skeletal and cardiac muscles.

Hereditary dilated cardiomyopathy

Dilated cardiomyopathy (DCM) is a common and important cause of morbidity and mortality. Many factors can contribute to the development of this disorder, although most commonly the etiology is unexplained. However, recent studies in individuals with idiopathic DCM now reveal a heritable cause in 20-30% of individuals. Diverse modes of inheritance have been demonstrated, encompassing an autosomal dominant type (by far the most common), together with recessive and X-linked forms, and maternal inheritance through mitochondrial DNA. The hereditary forms of DCM (HDCM) predominantly affect the left ventricle, although inherited abnormalities affecting primarily the right ventricle also are described. HDCM may occur as a primary cardiomyopathy, or secondary to inherited systemic metabolic or neuromuscular disorders. The causative genes for primary HDCM of the autosomal dominant and recessive types have not yet been discovered, but the combination of family pedigree analysis and phenotyping by echocardiography, together with new genetic techniques, should now allow their identification. Knowledge of the gene or genes responsible for HDCM would improve diagnostic accuracy, facilitate genetic counseling, advance understanding of pathogenesis, and provide the starting point for new methods of treatment. Because of the frequently heritable nature of DCM, it is of great importance that a diligent search for all potentially affected family members be undertaken.

Familial dilated cardiomyopathy

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Mitochondrial DNA deletions in dilated cardiomyopathy: a clinical study employing endomyocardial sampling

OBJECTIVES

The aim of this study was to assess the occurrence of the two most commonly encountered mitochondrial DNA (mtDNA) deletions in the hearts of patients with idiopathic dilated cardiomyopathy.

BACKGROUND

The mutation frequency of mtDNA is high, and sporadic cases of cardiomyopathies associated with mtDNA deletions have been described. Reports of increases in mtDNA deletions with advancing age also exist.

METHODS

We studied 15 consecutive patients with typical signs of idiopathic dilated cardiomyopathy, without a family history, together with 16 control hearts obtained at autopsy from patients who died of noncardiac causes. The patients underwent both right and left heart catheterization, during which endomyocardial biopsy samples were taken. The mtDNA in these samples and in the control hearts was analyzed by the polymerase chain reaction technique for the occurrence and proportion of 5- and 7.4-kilobase (kb) deletions (Cambridge sequence map positions from nucleotides 8469 to 13447 and 8637 to 16084, respectively).

RESULTS

The 5-kb mtDNA deletion was observed in the hearts of all of the patients with idiopathic dilated cardiomyopathy, accounting for 0.32 +/- 0.05% (mean +/- SEM) of the total mtDNA. The 7.4-kb deletion was found in 7 of the 15 patients with idiopathic dilated cardiomyopathy and comprised 0.28 +/- 0.08% of the total. The 5- and 7.4-kb deletions were detected in 12 and 9 control hearts, respectively, quantitatively similar to the patients with idiopathic dilated cardiomyopathy. A sigmoidal age dependency of the mtDNA deletions was found both in the patients with cardiomyopathy and in the control hearts, but after elimination of the confounding age variable, there was no difference between these groups.

CONCLUSIONS

Because of the similarity of the age-dependent increase in the frequency of mtDNA deletions in cardiomyopathic and control hearts, the deletions have no causal relation with idiopathic dilated cardiomyopathy. The present results confirm the notion of an increase in mtDNA deletions with advancing age and show that endomyocardial tissue sampling is a feasible method for detecting mtDNA defects in affected hearts.

The causes of dilated cardiomyopathy: a clinicopathologic review of 673 consecutive patients

OBJECTIVES

The purpose of this study was to document the various causes of dilated cardiomyopathy in a large group of adult patients with congestive heart failure.

BACKGROUND

Previous reports of the causes of dilated cardiomyopathy have usually been case reports of a single specific etiology or review articles. The frequency of any single specific heart muscle disease is largely unknown.

METHODS

We evaluated 673 patients referred for congestive heart failure due to dilated cardiomyopathy. The evaluation included medical history, physical examination, routine blood chemistry and hematologic measurements, electrocardiography and echocardiography. Thyroid function tests, antinuclear antibody tests and urinary vanillylmandelic acid and metanephrine levels were also obtained. Endomyocardial biopsy with right heart catheterization was performed in every patient. Coronary arteriography was performed in patients who had at least two standard cardiovascular risk factors or a history suggestive of myocardial ischemia. The cases were retrospectively reviewed, and a final cause for dilated cardiomyopathy was listed for each patient.

RESULTS

The most common causes of dilated cardiomyopathy were idiopathic origin (47%), idiopathic myocarditis (12%) and coronary artery disease (11%). The other identifiable causes of dilated cardiomyopathy made up 31% of the total cases.

CONCLUSIONS

Idiopathic dilated cardiomyopathy is a common cause of congestive heart failure. Specific heart muscle diseases occur with much less frequency.

Trends in patient selection for heart transplantation

OBJECTIVES

The purpose of this study was to review specific outcomes of patient referrals and the utility of selection criteria for heart transplantation at a single transplant center and to assess important trends over a 5-year period.

BACKGROUND

Although patient selection criteria are important for the clinical success of heart transplantation and the optimal utilization of the limited supply of donor organs, there are few data regarding actual outcomes and whether selection criteria are facilitating the identification of the most appropriate patients.

METHODS

We retrospectively reviewed 511 consecutive referrals of adult patients with heart failure from January 1, 1987 to December 31, 1991. Patients were followed up to one of five end points: 1) acceptance onto the transplant waiting list, 2) rejection from the transplant waiting list, 3) death, 4) referral to another program, and 5) still pending evaluation.

RESULTS

Of the 511 referred patients, 221 (43%) were accepted onto the waiting list, 222 (43%) were rejected, 39 (8%) died before the evaluation was completed, 15 (3%) were referred to another program and 14 (3%) are still pending evaluation. The rates for acceptance and rejection each year ranged between 30% and 51% and there were no consistent trends in the acceptance/rejection ratio from 1987 to 1991. Of the 221 patients accepted onto the waiting list, 115 (52%) underwent transplantation, 50 (22%) died, 12 (5%) were removed from the list because of clinical improvement, 9 (4%) were referred to another program and 35 (16%) are still on the waiting list. The continuing shortage of donor organs resulted in a marked increase in the size of the waiting list from 12.6 patients in 1987 to 36.5 in 1991, as well as a marked increase in the time on the waiting list before transplantation. Over 5 years, 50 patients were considered "too well" for transplantation (23% of all rejections). Of these 50 patients, 43 (86%) are alive and 7 were lost to follow-up during a mean period of 28.6 months (range 4 to 62). All 12 patients who were taken off the active transplant list because of improvement in symptoms, ejection fraction or peak exercise oxygen consumption are alive with a mean follow-up period of 27.7 months (range 11 to 61).

CONCLUSIONS

These data confirm the fact that transplant referrals are a selected group of patients with a high mortality rate, as 8% died before the evaluation could be completed and 22% died while waiting for a suitable donor organ. Furthermore, patient selection criteria are able to identify a small subset of patients with a low mortality risk as patients who were rejected because they were too well or taken off the list for clinical improvement have a reasonably good prognosis.

Familial aggregation of idiopathic dilated cardiomyopathy: clinical features and pedigree analysis in 14 families

OBJECTIVE

A recent prospective study in patients with dilated cardiomyopathy has reported that the disease is familial in at least 20% of cases, but the pattern of inheritance could not be ascertained. The presence of an autosomal dominant pattern, such as seen in hypertrophic cardiomyopathy, could make it possible to search for single gene defects with linkage analysis, whereas polygenic inheritance would be consistent with the autoimmune hypothesis. To assess the pattern of inheritance, we retrospectively identified patients with familial disease and assessed their first degree relatives (parents, siblings and children) for dilated cardiomyopathy.

DESIGN AND PATIENTS

The family history of 105 consecutive patients with dilated cardiomyopathy was reviewed and 14 who had at least one first degree relative with documented disease were identified as probands. Their healthy relatives (109) were studied by physical examination, electrocardiography, M mode and cross sectional echocardiography, and were classified as unequivocally normal or as potential carriers. The potential carriers had abnormal electrocardiography with either at least one echocardiographic measurement of left ventricular cavity dimension or percentage fractional shortening outside 2 SDs of normal values (based on age and body surface area). The potential carriers underwent 24 hour Holter monitoring and maximal treadmill exercise.

RESULTS AND CONCLUSION

Twenty three relatives (21%) were classified as potential carriers: 12 had an increased left ventricular end diastolic dimension, with reduced percentage fractional shortening in three; 11 had an abnormal electrocardiogram and increased end diastolic dimension, with reduced percentage fractional shortening in five. Such abnormalities were very mild and follow up is necessary to find whether such changes represent early disease. Pedigree analysis was most consistent with polygenic inheritance.

The frequency of familial dilated cardiomyopathy in a series of patients with idiopathic dilated cardiomyopathy

BACKGROUND

Dilated cardiomyopathy is characterized by an increase in ventricular size and impairment of ventricular function. Most cases are believed to be sporadic, and familial dilated cardiomyopathy is usually considered to be a rare and distinct disorder. We studied the proportion of cases of idiopathic dilated cardiomyopathy that were familial in a large sequential series of patients whose first-degree relatives were investigated regardless of whether these relatives had cardiac symptoms.

METHODS

We studied relatives of 59 index patients with idiopathic dilated cardiomyopathy of obtaining a family history and performing a physical examination, electrocardiography, and two-dimensional, M-mode, and Doppler echocardiography. A total of 315 relatives were examined.

RESULTS

Eighteen relatives from 12 families were shown to have dilated cardiomyopathy. Thus, 12 of the 59 index patients (20.3 percent) had familial disease. There was no difference in age, sex, severity of disease, exposure to selected environmental factors, or electrocardiographic or echocardiographic features between the index patients with familial disease and those with nonfamilial disease. A noteworthy finding was that 22 of 240 healthy relatives (9.2 percent) with normal ejection fractions had increased left ventricular diameters during systole or diastole (or both), as compared with 2 of 112 healthy control subjects (1.8 percent) who were studied separately.

CONCLUSIONS

Dilated cardiomyopathy was found to be familial in at least one in five of the patients in this study, a considerably higher percentage than in previous reports. This finding has important implications for family screening and provides direction for further investigation into the causes and natural history of dilated cardiomyopathy.

Familial dilated cardiomyopathy: a transverse and longitudinal clinical and echocardiographic study

The familial occurrence of hypertrophic cardiomyopathy is well known; familial dilated cardiomyopathy has so far received less attention. Ten families with two or more members affected by dilated cardiomyopathy were studied by echocardiography. In 3 out of 10 families, a transverse study extended to even apparently healthy subjects was carried out, which included a total of 45 subjects. In 19 out of the 45, dilated cardiomyopathy (either symptomatic or asymptomatic) was diagnosed at echocardiography. Three more relatives, already dead of the disease, were identified through hospital records. A clinical and echocardiographic longitudinal study, lasting up to 11 years, was carried out in 5 of the 10 families. During the follow-up, 8 out of 19 patients who, at first examination were affected by dilated cardiomyopathy, died, one improved, 3 remained in stable condition and 7 were lost at follow-up. One of two patients who presented echocardiographic findings suggestive of border-line dilated cardiomyopathy returned to normality and the other developed dilated cardiomyopathy. The clinical and echocardiographic findings in our patients, and in their relatives, suggest the possibility that idiopathic dilated cardiomyopathy may be a multifactorial disease in which genetic factors might play a variable role.

Clinical and pathologic study of familial dilated cardiomyopathy

To evaluate the occurrence of familial cases of dilated cardiomyopathy (DC), 165 consecutive patients were studied. Diagnosis of myocardial disease was based on clinical, hemodynamic, bioptic, postmortem or a combination of these criteria. Twelve patients (7% of cases) showed evidence of myocardial disease in greater than or equal to 1 relative; 27 patients with myocardial disease were detected in the 12 families, but a suspected history of myocardial involvement was present in a further 16 cases. In 6 families proband and relatives were affected by DC (total 14 cases); in 1 of these families the disease began with an atrioventricular block. In 4 families the relatives showed the presence of myocarditis at the endomyocardial biopsy. In 2 families the relatives presented a right ventricular cardiomyopathy. The mode of inheritance was autosomal dominant in 7 families, recessive in 4; X-linked pattern may be hypothesized in 1. Nine patients died under the age of 45 years: 2 of sudden death, 6 of chronic heart failure and 1 of cerebral embolism. Familial transmission is not rare. Different modes of genetic transmission (autosomal dominant, recessive and X-linked) and different forms of myocardial disease suggest that familial DC may be a multifactorial disease.