Rare variant mutations in pregnancy-associated or peripartum cardiomyopathy

Peripartum cardiomyopathy: a contemporary review

Peripartum cardiomyopathy is a rare and potentially fatal disease. Though approximately half of the patients recover, the clinical course is highly variable and some patients develop refractory heart failure and persistent left ventricular systolic dysfunction. It is diagnosed when women present with heart failure secondary to left ventricular systolic dysfunction towards the end of pregnancy or in the months following delivery, where no other cause of heart failure is found. Etiology remains unclear, and treatment is similar to other cardiomyopathies and includes evidence-based standard heart failure management strategies. Experimental strategies such as intravenous immunoglobulin and bromocriptine await further clinical validation.

Cardiovascular disorders in pregnancy: diagnosis and management

Cardiovascular diseases (CVDs) are a major cause of complications in pregnancy worldwide and the number of patients who develop cardiac problems during pregnancy is increasing. This review summarises recent literature on the aetiology and the underlying pathophysiology, diagnostic tools, risk stratification and prognosis in women who develop heart failure during pregnancy and in the peri-partum phase as well as in patients with pre-existing cardiomyopathies undergoing pregnancy. We specifically highlight peri-partum cardiomyopathy, valvular disease and Marfan's syndrome. Furthermore, we provide overviews on established treatment concepts and novel therapeutic strategies for these different disease types, stressing the point that pregnancy-associated cardiac disease requires interdisciplinary concepts for diagnosis, management and treatment.

Phenotyping and outcome on contemporary management in a German cohort of patients with peripartum cardiomyopathy

Peripartum cardiomyopathy (PPCM) is a life-threatening heart disease developing towards the end of pregnancy or in the months following delivery in previously healthy women in terms of cardiac disease. Enhanced oxidative stress and the subsequent cleavage of the nursing hormone Prolactin into an anti-angiogenic 16 kDa subfragment emerged as a potential causal factor of the disease. We established a prospective registry with confirmed PPCM present in 115 patients (mean baseline left ventricular ejection fraction, LVEF: 27 ± 9 %). Follow-up data (6 ± 3 months) showed LVEF improvement in 85 % and full recovery in 47 % while 15 % failed to recover with death in 2 % of patients. A positive family history of cardiomyopathy was present in 16.5 %. Pregnancy-associated hypertension was associated with a better outcome while a baseline LVEF ≤ 25 % was associated with a worse outcome. A high recovery rate (96 %) was observed in patients obtaining combination therapy with beta-blocker, angiotensin-converting enzyme (ACE) inhibitors/angiotensin-receptor-blockers (ARBs) and bromocriptine. Increased serum levels of Cathepsin D, the enzyme that generates 16 kDa Prolactin, miR-146a, a direct target of 16 kDa Prolactin, N-terminal-pro-brain-natriuretic peptide (NT-proBNP) and asymmetric dimethylarginine (ADMA) emerged as biomarkers for PPCM. In conclusion, low baseline LVEF is a predictor for poor outcome while pregnancy-induced hypertensive disorders are associated with a better outcome in this European PPCM cohort. The high recovery rate in this collective is associated with a treatment concept using beta-blockers, ACE inhibitors/ARBs and bromocriptine. Increased levels of Cathepsin D activity, miR-146a and ADMA in serum of PPCM patients support the pathophysiological role of 16 kDa Prolactin for PPCM and may be used as a specific diagnostic marker profile.

Recent advances in the epidemiology, pathogenesis and prognosis of acute heart failure and cardiomyopathy in Africa

This review addresses recent advances in the epidemiology, pathogenesis and prognosis of acute heart failure and cardiomyopathy based on research conducted in Africa. We searched Medline/PubMed for publications on acute decompensated heart failure and cardiomyopathy in Africa for the past 5 years (ie, 1 January 2008 to 31 December 2012). This was supplemented with personal communications with colleagues from Africa working in the field. A large prospective registry has shown that acute decompensated heart failure is caused by hypertension, cardiomyopathy and rheumatic heart disease in 90% of cases, a pattern that is in contrast with the dominance of coronary artery disease in North America and Europe. Furthermore, acute heart failure is a disease of the young with a mean age of 52 years, occurs equally in men and women, and is associated with high mortality at 6 months (∼18%), which is, however, similar to that observed in non-African heart failure registries, suggesting that heart failure has a dire prognosis globally, regardless of aetiology. The molecular genetics of dilated cardiomyopathy, hypertrophic cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy in Africans is consistent with observations elsewhere in the world; the unique founder effects in the Afrikaner provide an opportunity for the study of genotype-phenotype correlations in large numbers of individuals with cardiomyopathy due to the same mutation. Advances in the understanding of the molecular mechanisms of peripartum cardiomyopathy have led to promising clinical trials of bromocriptine in the treatment of peripartum heart failure. The key challenges of management of heart failure are the urgent need to increase the use of proven treatments by physicians, and the control of hypertension in primary care and at the population level.

Sex and gender differences in myocarditis and dilated cardiomyopathy

Heart failure due to nonischemic dilated cardiomyopathy (DCM) contributes significantly to the global burden of cardiovascular disease. Myocarditis is, in turn, a major cause of acute DCM in both men and women. However, recent clinical and experimental evidence suggests that the pathogenesis and prognosis of DCM differ between the sexes. This seminar provides a contemporary perspective on the immune mediators of myocarditis, including interdependent elements of the innate and adaptive immune response. The heart's acute response to injury is influenced by sex hormones that appear to determine the subsequent risk of chronic DCM. Preliminary data suggest additional genetic variations may account for some of the differences in epidemiology, left ventricular recovery, and survival between men and women. We highlight the gaps in our knowledge regarding the management of women with acute DCM and discuss emerging therapies, including bromocriptine for the treatment of peripartum cardiomyopathy.

Family history of dilated cardiomyopathy among patients with heart failure from the HF-ACTION genetic ancillary study

BACKGROUND

The value of family history (FH) is well established, but its sensitivity to detect familial dilated cardiomyopathy (FDC) has been infrequently examined.

METHODS

A genetic ancillary study was created as a component of the HF-ACTION trial, a multicenter, prospective, randomized clinical trial of exercise in patients with heart failure and an ejection fraction <35%. A FH-based study using a structured questionnaire mailed to all consenting individuals was incorporated into the genetic ancillary. FH responses were analyzed for dilated cardiomyopathy (DCM) in family members.

RESULTS

Of the 741 individuals with data available, 358 (48.3%) had nonischemic and 383 (51.6%) had ischemic etiology, and of these 164 (45.8%) and 201 (52.4%), respectively, returned evaluable questionnaires. Of those with nonischemic etiology, 14/164 (8.5%) reported at least one first-degree family member with DCM or an enlarged heart; another 21/164 (12.8%) reported a FH of "cardiomyopathy," a less specific term to indicate DCM.

CONCLUSION

At least 8.5% of patients with nonischemic etiology in the HF-ACTION genetic ancillary study provided FH indicating familial DCM, information important to inform further genetic analyses of this cohort and to plan other studies.

[Peripartum cardiomyopathy: interdisciplinary challenge]

Peripartum cardiomyopathy (PPCM) is a rare type of heart failure which presents towards the end of pregnancy or in the first 5 months after delivery. Depending on the geographical location the incidence is reported in the literature as 1:300 up to 1:15,000. There are a number of known risk factors, such as multiparity and age of the mother over 30 years. The symptoms of PPCM correspond to those of idiopathic cardiomyopathy. The diagnosis is mainly carried out using echocardiography which shows a clear reduction of systolic left ventricular function. The therapeutic approach is the same as for idiopathic cardiomyopathy and in this context it is absolutely necessary to show caution concerning the state of pregnancy and the resulting contraindications for therapeutic drugs. The prognosis is dependent on recovery from the heart failure during the first 6 months postpartum. The lethality of the disease is high and is given in the literature as up to 28 %. Because of its complexity PPCM is an interdisciplinary challenge. In the peripartum phase a close cooperation between the disciplines of cardiology, cardiac surgery, neonatology, obstetrics and anesthesiology is indispensable. For anesthesiology the most important aspects are the mostly advanced unstable hemodynamic condition of the mother and the planning and implementation of the perioperative management. This article presents the case of a patient in advanced pregnancy with signs of acute severe heart failure and a suspected diagnosis of PPCM. The patient presented as an emergency case and delivery of the child was carried out using peridural anesthesia with a stand-by life support machine.

Article Commentary: Acute Heart Failure: Is it Peripartum Cardiomyopathy or Not?

Peripartum cardiomyopathy (PPCM) is a potentially life-threatening disease that occurs in women of childbearing age.

16-kDa prolactin and bromocriptine in postpartum cardiomyopathy

Peripartum cardiomyopathy (PPCM) is a potentially life-threatening heart disease emerging toward the end of pregnancy or in the first postpartal months in previously healthy women. Recent data suggest a central role of unbalanced peri-/postpartum oxidative stress that triggers the proteolytic cleavage of the nursing hormone prolactin (PRL) into a potent antiangiogenic, proapoptotic, and proinflammatory 16-kDa PRL fragment. This notion is supported by the observation that inhibition of PRL secretion by bromocriptine, a dopamine D2-receptor agonist, prevented the onset of disease in an animal model of PPCM and by first clinical experiences where bromocriptine seem to exert positive effects with respect to prevention or treatment of PPCM patients. Here, we highlight the current state of knowledge on diagnosis of PPCM, provide insights into the biology and pathophysiology of 16-kDa PRL and bromocriptine, and outline potential consequences for the clinical management and treatment options for PPCM patients.

Natural history, management, and outcomes of peripartum cardiomyopathy: an Irish single-center cohort study

AIM

To describe the natural history, management and outcomes of peripartum cardiomyopathy (PPCM) in an unselected Northern European population.

METHODS

A retrospective single-center observational study was performed at a tertiary referral heart failure and transplantation unit. Outcomes measured were baseline demographics, clinical presentation, course, and treatment. Echocardiographic findings were compared at baseline, 2 months, and 6 months.

RESULTS

Twelve cases of PPCM were identified between 2002 and 2008. Mean age was 34.7 years. Nine patients were multiparous and nine had preeclampsia. Ten patients presented in the first week postpartum. Two patients required inotropic support. Mean ejection fraction (EF) at presentation was 27% (SD = 8%) which improved to 47% (SD = 13%) at 6 months. At this time, 10 patients were asymptomatic and 6 had recovered normal cardiac function. Left ventricular (LV) function improved but did not reach normal limits in five cases. One case with persistent severe LV dysfunction required cardiac transplantation. One patient suffered an arrhythmic death several years after the 6 months follow-up period.

CONCLUSIONS

PPCM is a rare condition. With appropriate therapy, a good clinical outcome is common but not universal. Continued deterioration requiring ventricular support and cardiac transplantation can occur. In our cohort, older maternal age, multiparity, and preeclampsia appeared to be risk factors.

Return of genetic results in the familial dilated cardiomyopathy research project

The goal of the Familial Dilated Cardiomyopathy (FDC) Research Project, initiated in 1993, has been to identify and characterize FDC genetic cause. All participating individuals have been consented for the return of genetic results, an important but challenging undertaking. Since the inception of the Project we have enrolled 606 probands, and 269 of these had 1670 family members also enrolled. Each subject was evaluated for idiopathic dilated cardiomyopathy (IDC) and pedigrees were categorized as familial or sporadic. The coding regions of 14 genes were resequenced in 311 to 324 probands in five studies. Ninety-two probands were found to carry nonsynonymous rare variants absent in controls, and with Clinical Laboratory Improvement Amendment of 1988 (CLIA) compliant protocols, relevant genetic results were returned to these probands and their consented relatives by study genetic counselors and physicians in 353 letters. In 10 of the 51 families that received results >1 year ago, at least 23 individuals underwent CLIA confirmation testing for their family's rare variant. Return of genetic results has been successfully undertaken in the FDC Research Project. This report describes the methods utilized in the process of returning research results. We use this information as a springboard for providing guidance to other genetic research groups and proposing future directions in this arena.

Escape capture bigeminy: phenotypic marker of cardiac sodium channel voltage sensor mutation R222Q

BACKGROUND

Electrocardiographic signature of escape capture bigeminy that spans generations and clusters in a family has not been linked to a sodium channel voltage sensor mutation.

OBJECTIVE

To characterize the clinical and biophysical consequences of the R222Q mutation in the voltage sensor of cardiac sodium channels.

METHODS

Comprehensive clinical assessment, invasive electrophysiologic study, genetic analysis, and patch-clamp studies were undertaken.

RESULTS

Uniquely, 5 members had the same electrocardiographic pattern of a junctional escape ventricular capture bigeminy. Genetic analysis of 3 family members revealed the same mutation (R222Q) in the cardiac sodium channel gene, SCN5A (nucleotide change was 665 G→A that led to missense amino acid substitution Arg 222 Gln, located in the S4 voltage sensor in domain I). Catheterization and mapping revealed that there was no consistent evidence of bundle branch reentry or fascicular potentials preceding ectopic beats. The bigeminy was suppressed by the intravenous administration of the sodium channel blocker, lidocaine. Patch-clamp studies revealed unique differential leftward voltage-dependent shifts in activation and inactivation properties of human voltage-gated Na(+) channels with the R222Q mutation, consistent with increasing channel excitability at precisely the voltages corresponding to the resting membrane potential of cardiomyocytes.

CONCLUSIONS

The R222Q mutation enhances cardiac sodium channel excitability, resulting in an unusual, highly penetrant phenotype of escape capture bigeminy and cardiomyopathy. These findings support the conclusion that a mutation in the voltage sensor of cardiac sodium channels can cause bigeminal arrhythmia associated with cardiomyopathy.

Risk factors for maternal outcome in pregnancy complicated with dilated cardiomyopathy

OBJECTIVE

The goal of the study was to determine risk factors for maternal cardiac failure in pregnancy complicated with dilated cardiomyopathy (DCM).

STUDY DESIGN

The subjects were 29 patients diagnosed with DCM before conception or during the first 7 months of pregnancy. DCM was defined as left ventricle end-diastolic dimension (LVDd)≥48 mm and/or fractional shortening (%FS)≤30% on echocardiography. Patients were followed until at least 1 year after delivery and were categorized into a poor prognosis group (n=6; death or end stage heart failure of New York Heart Association (NYHA) class III and IV) and a good prognosis group (n=23; all other cases).

RESULT

DCM was initially diagnosed during pregnancy in 6/6 and 8/23 patients in the poor and good prognosis groups, respectively (P<0.005). The %FS of the first test during pregnancy was 17.5±6.2 and 27.4±9.3% in the respective groups (P<0.005). In eight abortion cases with %FS 15.2±3.1%, %FS, cardiac function and NYHA class were maintained until 20 months after abortion. There was no relationship between LVDd and maternal outcome.

CONCLUSION

Onset during pregnancy and decreased %FS are risk factors for a poor maternal outcome in patients with DCM. Abortion prevents further deterioration of cardiac function in patients with a very low %FS.

Myocardial recovery in peripartum cardiomyopathy: prospective comparison with recent onset cardiomyopathy in men and nonperipartum women

BACKGROUND

Whether myocardial recovery occurs more frequently in peripartum cardiomyopathy (PPCM) than in recent onset cardiomyopathies in men and nonperipartum women has not been prospectively evaluated. This was examined through an analysis of outcomes in the Intervention in Myocarditis and Acute Cardiomyopathy 2 (IMAC2) registry.

METHODS AND RESULTS

IMAC2 enrolled 373 subjects with recent onset nonischemic dilated cardiomyopathy. Left ventricular ejection fraction (LVEF) was assessed at entry and 6 months, and subjects followed for up to 4 years. Myocardial recovery was compared between men (group 1), nonperipartum women (group 2) and subjects with PPCM (group 3). The cohort included 230 subjects in group 1, 104 in group 2, and 39 in group 3. The mean LVEF at baseline in groups 1, 2, and 3 was 0.23 ± 0.08, 0.24 ± 0.08, and 0.27 ± 0.07 (P = .04), and at 6 months was 0.39 ± 0.12, 0.42 ± 0.11, and 0.45 ± 0.14 (P = .007). Subjects in group 3 had a much greater likelihood of achieving an LVEF >0.50 at 6 months than groups 1 or 2 (19 %, 34%, and 48% respectively, P = .002).

CONCLUSIONS

Prospective evaluation confirms myocardial recovery is greatest in women with PPCM, poorest in men, and intermediate in nonperipartum women. On contemporary therapy, nearly half of women with PPCM normalize cardiac function by 6 months.

Peripartum cardiomyopathy: a review

Peripartum cardiomyopathy is idiopathic heart failure occurring in the absence of any determinable heart disease during the last month of pregnancy or the first 5 months postpartum. The incidence varies worldwide but is high in developing nations; the cause of the disease might be a combination of environmental and genetic factors. Diagnostic echocardiographic criteria include left ventricular ejection fraction <0.45 or M-mode fractional shortening <30% (or both) and end-diastolic dimension >2.7 cm/m(2). Electrocardiography, magnetic resonance imaging, endomyocardial biopsy, and cardiac catheterization aid in the diagnosis and management of peripartum cardiomyopathy. Cardiac protein assays can also be useful, as suggested by reports of high levels of NT-proBNP, cardiac troponin, tumor necrosis factor-α, interleukin-6, interferon-γ, and C-reactive protein in peripartum cardiomyopathy. The prevalence of mutations associated with familial dilated-cardiomyopathy genes in patients with peripartum cardiomyopathy suggests an overlap in the clinical spectrum of these 2 diseases.Treatment for peripartum cardiomyopathy includes conventional pharmacologic heart-failure therapies-principally diuretics, angiotensin-converting enzyme inhibitors, vasodilators, digoxin, β-blockers, anticoagulants, and peripartum cardiomyopathy-targeted therapies. Therapeutic decisions are influenced by drug-safety profiles during pregnancy and lactation. Mechanical support and transplantation might be necessary in severe cases. Targeted therapies (such as intravenous immunoglobulin, pentoxifylline, and bromocriptine) have shown promise in small trials but require further evaluation. Fortunately, despite a mortality rate of up to 10% and a high risk of relapse in subsequent pregnancies, many patients with peripartum cardiomyopathy recover within 3 to 6 months of disease onset.

Clinical characteristics of peripartum cardiomyopathy in the United States: diagnosis, prognosis, and management

Peripartum cardiomyopathy is a pregnancy-associated myocardial disease characterized by the development of heart failure due to marked left ventricular systolic dysfunction. Although the disease is relatively uncommon, its incidence is increasing, and it can be associated with important and lasting morbidity and with mortality. Peripartum cardiomyopathy seems to affect women in different parts of the world but with considerable differences in clinical presentation. The purposes of this review are to describe the clinical profile of peripartum cardiomyopathy in the United States and to provide recommendations for the diagnosis and the management of this disease.

Next-generation sequencing entering the clinical arena

Over the last decade the genetic etiology of many heritable diseases could be resolved. For heart muscle diseases, so called cardiomyopathies, mutations in more than 40 different genes have been identified. Due to this large genetic heterogeneity and missing of adequate gene-diagnostic tools, most patients are not genetically characterized, which would be important for individualized patient care. Currently, next-generation sequencing technologies are revolutionizing genetic and epigenetic research, since they are capable to produce billions of bases of sequence information in a single experiment. Accordingly, this powerful technology can now also open avenues for genetic diagnostics. The scope of this article is to illustrate technical approaches, clinical applications, and yet unsolved problems of next-generation sequencing entering the clinical arena.

Familial dilated cardiomyopathy associated with congenital defects in the setting of a novel VCL mutation (Lys815Arg) in conjunction with a known MYPBC3 variant

Idiopathic dilated cardiomyopathy (DCM) is a primary myocardial disorder characterized by ventricular chamber enlargement and systolic dysfunction. Twenty to fifty percent of idiopathic DCM cases are thought to have a genetic cause. Of more than 30 genes known to be associated with DCM, rare variants in the VCL and MYBPC3 genes have been reported in several cases of DCM. In this report, we describe a family with DCM and congenital abnormalities who carry a novel missense mutation in the VCL gene. More severely affected family members also possess a second missense variant in MYBPC3, raising the possibility that this variant may be a disease modifier. Interestingly, many of the affected individuals also have congenital defects, including two with bicuspid aortic valve with aortic regurgitation. We discuss the implications of the family history and genetic information on management of at-risk individuals with aortic regurgitation.

Different characteristics of peripartum cardiomyopathy between patients complicated with and without hypertensive disorders. -Results from the Japanese Nationwide survey of peripartum cardiomyopathy-

BACKGROUND

There has been no nationwide survey concerning peripartum cardiomyopathy (PPCM) among the Asian population, and clinical profiles of PPCM complicated with hypertensive disorders complicating pregnancy (HD) as the major risk factor of PPCM have not been characterized.

METHODS AND RESULTS

A retrospective, nationwide survey of PPCM in 2007 and 2008 all over Japan was performed and the clinical characteristics were compared between patients with and without HD. We obtained data for 102 patients. HD during pregnancy occurred in 42 patients (41%). Patients with HD were older than those without HD (33.8 vs. 31.9 years old, P<0.05) and babies were delivered more frequently by Caesarean section (81% vs. 52%, P<0.01). Although cardiac parameters at diagnosis were similar in patients with and without HD, patients with HD were hospitalized for a shorter period and had better cardiac function after 7 months. Multivariate regression analysis revealed that HD was independently associated with a shorter hospital stay and a higher left ventricular ejection fraction at last follow up.

CONCLUSIONS

PPCM complicated with HD had different clinical characteristics from those without HD. This condition might be a unique subset of PPCM that is characterized by relatively swift recovery except in the cases of death. In order to prevent severe heart failure and maternal death, peripartum women should be treated with HD cautiously and must immediately undergo a cardiac examination as needed.

The genomic architecture of sporadic heart failure

Common or sporadic systolic heart failure (heart failure) is the clinical syndrome of insufficient forward cardiac output resulting from myocardial disease. Most heart failure is the consequence of ischemic or idiopathic cardiomyopathy. There is a clear familial predisposition to heart failure, with a genetic component estimated to confer between 20% and 30% of overall risk. The multifactorial etiology of this syndrome has complicated identification of its genetic underpinnings. Until recently, almost all genetic studies of heart failure were designed and deployed according to the common disease-common variant hypothesis, in which individual risk alleles impart a small positive or negative effect and overall genetic risk is the cumulative impact of all functional genetic variations. Early studies used a candidate gene approach focused mainly on factors within adrenergic and renin-angiotensin pathways that affect heart failure progression and are targeted by standard pharmacotherapeutics. Many of these reported allelic associations with heart failure have not been replicated. However, the preponderance of data supports risk-modifier effects for the Arg389Gly polymorphism of β1-adrenergic receptors and the intron 16 in/del polymorphism of angiotensin-converting enzyme. Recent unbiased studies using genome-wide single nucleotide polymorphism microarrays have shown fewer positive results than when these platforms were applied to hypertension, myocardial infarction, or diabetes, possibly reflecting the complex etiology of heart failure. A new cardiovascular gene-centric subgenome single nucleotide polymorphism array identified a common heat failure risk allele at 1p36 in multiple independent cohorts, but the biological mechanism for this association is still uncertain. It is likely that common gene polymorphisms account for only a fraction of individual genetic heart failure risk, and future studies using deep resequencing are likely to identify rare gene variants with larger biological effects.

Peripartum cardiomyopathy

Peripartum cardiomyopathy (PPCM) is a potentially devastating disease that affects women during the last months of pregnancy or the first months after delivery. The aetiology and pathogenesis of this disease remain unclear, but oxidative stress and the generation of a cardiotoxic fragment of prolactin may play key roles. Diagnosing PPCM remains a challenge, as symptoms may mimic those women experience during normal pregnancy and the peripartum period. A high index of suspicion is thus necessary to make the diagnosis. Patients with PPCM have a varied clinical course, as some patients achieve full recovery while others progress to end-stage heart failure and even death. Standard heart failure treatment is indicated, although special provisions are necessary in pregnant and lactating women. Additional research into the pathophysiology of this disease, including possible genetic contributions, may lead to novel treatment strategies that can improve outcomes.

Genetics of sudden cardiac death syndromes

PURPOSE OF REVIEW

To survey recent developments in the field of genetics encompassing discovery of new candidate genes, new diagnostic strategies, and new therapies for sudden cardiac death (SCD) syndromes.

RECENT FINDINGS

In addition to new mutations in known SCD genes, several novel genes not previously implicated in SCD causation have been found, particularly in long QT syndrome (e.g., KCNJ5, AKAP9, SNTA1), idiopathic ventricular fibrillation (e.g., DPP6, KCNJ8), dilated cardiomyopathy (e.g., NEBL), and hypertrophic cardiomyopathy (HCM; e.g., NEXN). Genetic SCD animal models have provided novel insights into the cellular mechanism and pathogenesis of nearly all the major SCD syndromes, which has led to several new drug therapies for patients with genetic arrhythmia syndromes (e.g., flecainide in catecholaminergic polymorphic ventricular tachycardia). Furthermore, genetic contributions to acquired heart diseases are increasingly being recognized. For example, a 21q21 locus is strongly associated with ventricular fibrillation after myocardial infarction. Near this locus is CXADR, a gene encoding a viral receptor implicated in myocarditis and dilated cardiomyopathy. Finally, common variants in cardiac ion channels and proteins likely contribute to common cardiac phenotypes.

SUMMARY

Major strides have been made in uncovering new genes, mechanisms, and syndromes that have significantly advanced the diagnosis and treatment of genetic SCD disorders.

Update 2011: clinical and genetic issues in familial dilated cardiomyopathy

A great deal of progress has recently been made in the discovery and understanding of the genetics of familial dilated cardiomyopathy (FDC). A consensus has emerged that with a new diagnosis of idiopathic dilated cardiomyopathy (IDC), the clinical screening of first-degree family members will reveal FDC in at least 20% to 35% of those family members. Point mutations in 31 autosomal and 2 X-linked genes representing diverse gene ontogeny have been implicated in causing FDC but account for only 30% to 35% of genetic causes. Next-generation sequencing methods have dramatically decreased sequencing costs, making clinical genetic testing feasible for extensive panels of dilated cardiomyopathy genes. Next-generation sequencing also provides opportunities to discover additional genetic causes of FDC and IDC. Guidelines for evaluation and testing of FDC and IDC are now available, and when combined with FDC genetic testing and counseling, will bring FDC/IDC genetics to the forefront of cardiovascular genetic medicine.

Systematic review of pregnancy in women with inherited cardiomyopathies

Pregnancy exposes women with inherited cardiomyopathies to increased risk for heart failure and arrhythmias. In this paper, we review the clinical course and management of pregnant women with the following inherited cardiomyopathies: hypertrophic cardiomyopathy, dilated cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, left ventricular non-compaction cardiomyopathy, and restrictive cardiomyopathy. We also discuss peripartum cardiomyopathy. Pregnancy is generally well tolerated in asymptomatic patients with inherited cardiomyopathies. However, worsening of the clinical condition can occur during pregnancy, despite intensive medical treatment. If prior cardiac events, poor functional class (New York Heart Association class III or IV), or advanced left ventricular systolic dysfunction are present, the risk of maternal cardiac complications during pregnancy are markedly increased. The postpartum condition is generally no worse than the antepartum condition, but no long-term follow-up studies have been reported. Preconception evaluation and counselling are important aspects of managing women with inherited cardiomyopathies. Genetic counselling and DNA testing should be offered to all women following the diagnosis of an inherited cardiomyopathy.

Acute and critically ill peripartum cardiomyopathy and 'bridge to' therapeutic options: a single center experience with intra-aortic balloon pump, extra corporeal membrane oxygenation and continuous-flow left ventricular assist devices

INTRODUCTION

Peripartum cardiomyopathy (PPCM) patients refractory to medical therapy and intra-aortic balloon pump (IABP) counterpulsation or in whom weaning from these therapies is impossible, are candidates for a left ventricular assist device (LVAD) as a bridge to recovery or transplant. Continuous-flow LVADs are smaller, have a better long-term durability and are associated with better outcomes. Extra corporeal membrane oxygenation (ECMO) can be used as a temporary support in patients with refractory cardiogenic shock. The aim of this study was to evaluate the efficacy and safety of mechanical support in acute and critically ill PPCM patients.

METHODS

This was a retrospective search of the patient database of the Ghent University hospital (2000 to 2010).

RESULTS

Six PPCM-patients were treated with mechanical support. Three patients presented in the postpartum period and three patients at the end of pregnancy. All were treated with IABP, the duration of IABP support ranged from 1 to 13 days. An ECMO was inserted in one patient who presented with cardiogenic shock, multiple organ dysfunction syndrome and a stillborn baby. Two patients showed partial recovery and could be weaned off the IABP. Four patients were implanted with a continuous-flow LVAD (HeartMate II, Thoratec Inc.), including the ECMO-patient. Three LVAD patients were successfully transplanted 78, 126 and 360 days after LVAD implant; one patient is still on the transplant waiting list. We observed one peripheral thrombotic complication due to IABP and five early bleeding complications in three LVAD patients. One patient died suddenly two years after transplantation.

CONCLUSIONS

In PPCM with refractory heart failure IABP was safe and efficient as a bridge to recovery or as a bridge to LVAD. ECMO provided temporary support as a bridge to LVAD, while the newer continuous-flow LVADs offered a safe bridge to transplant.

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.

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.

Targeted next-generation sequencing for the molecular genetic diagnostics of cardiomyopathies

BACKGROUND

Today, mutations in more than 30 different genes have been found to cause inherited cardiomyopathies, some associated with very poor prognosis. However, because of the genetic heterogeneity and limitations in throughput and scalability of current diagnostic tools up until now, it is hardly possible to genetically characterize patients with cardiomyopathy in a fast, comprehensive, and cost-efficient manner.

METHODS AND RESULTS

We established an array-based subgenomic enrichment followed by next-generation sequencing to detect mutations in patients with hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM). With this approach, we show that the genomic region of interest can be enriched by a mean factor of 2169 compared with the coverage of the whole genome, resulting in high sequence coverage of selected disease genes and allowing us to define the genetic pathogenesis of cardiomyopathies in a single sequencing run. In 6 patients, we detected disease-causing mutations, 2 microdeletions, and 4 point mutations. Furthermore, we identified several novel nonsynonymous variants, which are predicted to be harmful, and hence, might be potential disease mutations or modifiers for DCM or HCM.

CONCLUSIONS

The approach presented here allows for the first time a comprehensive genetic screening in patients with hereditary DCM or HCM in a fast and cost-efficient manner.

Rare variant mutations identified in pediatric patients with dilated cardiomyopathy

Dilated cardiomyopathy (DCM) in infants and children can be partially explained by genetic cause but the catalogue of known genes is limited. We reviewed our database of 41 cases diagnosed with DCM before 18 years of age who underwent detailed clinical and genetic evaluation, and summarize here the evidence for mutations causing DCM in these cases from 15 genes (PSEN1, PSEN2, CSRP3, LBD3, MYH7, SCN5A, TCAP, TNNT2, LMNA, MYBPC3, MYH6, TNNC1, TNNI3, TPM1, and RBM20). Thirty-five of the 41 pediatric cases had relatives with adult-onset DCM. More males (66%) were found among children diagnosed after 1 year of age with DCM. Nineteen mutations in 9 genes were identified among 15 out of 41 patients; 3 patients (diagnosed at ages 2 weeks, 9 and 13 years) had multiple mutations. Of the 19 mutations identified in 12 families, mutations in TPM1 (32%) and TNNT2 (21%) were the most commonly found. Of the 6 patients diagnosed before 1 year of age, 3 had mutations in TPM1 (including a set of identical twins), 1 in TNNT2, 1 in MYH7, and 1 with multiple mutations (MYH7 and TNNC1). Most DCM was accompanied by advanced heart failure and need for cardiac transplantation. We conclude that in some cases pediatric DCM has a genetic basis, which is complicated by allelic and locus heterogeneity as seen in adult-onset DCM. We suggest that future prospective comprehensive family-based genetic studies of pediatric DCM are indicated to further define mutation frequencies in known genes and to discover novel genetic cause.

Impact of Mendelian inheritance in cardiovascular disease

Cardiovascular disease is a leading cause of mortality worldwide. While the etiology for the majority of cardiovascular disease is presumed to be a combination of genetic and environmental factors, developments in understanding the basic biology of cardiac disorders have been greatly advanced through discoveries made studying heart diseases that exhibit Mendelian forms of inheritance. Most of these diseases primarily affect children and young adults and include cardiomyopathies, arrhythmias, aortic aneurysms, and congenital heart defects. The discovery of the genetic etiologies for these diseases have had significant impact on our understanding of more complex forms of cardiovascular disease and in some cases have led to novel diagnostic and treatment modalities. In this review, we will summarize these seminal genetic discoveries, highlighting a few that have resulted in significant impact on human disease, and discuss the potential utility of studying Mendelian-inherited heart disease with the development of new genetic technologies and our increased understanding of the human genome.

Familial occurrence of peripartum cardiomyopathy presages a genetic rather than an environmental cause

Peripartum cardiomyopathy (PPCM) is an uncommon form of left ventricular dysfunction associated with pregnancy and triggered by a number of obstetric factors including pre-eclampsia, plural gestations and multiparity. PPCM is the most frequent cause of pregnancy-related maternal death. Although the clinical outcome of PPCM has been determined, its patho-etiology has not been elucidated. Two recent studies have demonstrated for the first time in a small proportion of patients, convincing evidence of a genetic predisposition for PPCM, activated by modifier genes responding to biochemical and hemodynamic signals during mid to late pregnancy.