The role of endomyocardial biopsy in the management of cardiovascular disease: a scientific statement from the American Heart Association, the American College of Cardiology, and the European Society of Cardiology

A transatrial pericardial access: lead placement as proof of concept

A safe, easy, and quick access into the pericardial space may provide a window for diagnostics and therapeutics to the heart. The objective of this study was to provide proof of concept for an engagement and access catheter that allows access to the pericardial space percutaneously. A multilumen catheter was developed to allow navigation and suction fixation to the right atrial appendage/wall in a normal swine model. Advancement through the multilumen catheter using a second catheter with a distal needle tip allows access to the pericardial space without pericardial puncture and advancement of a standard guide wire into the space. Navigation into the pericardial space was undertaken by fluoroscopy alone and was accomplished in 10 swine (5 acute and 5 chronic). As a specific application of this pericardial access method, a pacing lead was implanted on the epicardial surface. Five chronic swine experiments were conducted with successful pacing engagement verified by lead impedance and pacing threshold and sensing. Lead impedance exceeded 1,000 Ω preengagement and dropped by an average of 200 Ω upon implant (769 ± 498 Ω). Pacing thresholds at 0.4 ms ranged from ∼0.5 to 2.1 V acutely (1.03 ± 0.92 V). No cardiac effusion or tamponade was observed in any of the acute or chronic studies. The ability to engage, maintain, and retract the right atrial appendage/wall and to engage an epicardial lead was successfully demonstrated. These findings support the feasibility of safe access into the pericardial space in a normal swine model and warrant further investigations for clinical translation.

Viral myocarditis: diagnosis, aetiology and management

Myocarditis is an inflammatory disease of the cardiac muscle caused by myocardial infiltration of immunocompetent cells following any kind of cardiac injury. Classic myocarditis mainly occurs as a result of the host's immune response against organisms that cause common infectious illnesses, as a manifestation of hypersensitivity or as a toxic reaction to drug therapy. Chronic inflammatory events may survive successful clearance of initial cardiotoxic agents, be triggered or amplified by autoimmunological processes, or develop in the context of systemic diseases. If the underlying infectious or immune-mediated causes of the disease are carefully defined by clinical and biopsy-based tools, specific immunosuppressive and antiviral treatment options may improve the prognosis of patients with acute and chronic disease.

Right ventricular substrate mapping using the Ensite Navx system: Accuracy of high-density voltage map obtained by automatic point acquisition during geometry reconstruction

BACKGROUND

Contact point-to-point electroanatomic mapping (Pt-Map) is a validated tool to evaluate right ventricular (RV) substrate. When using the EnSite NavX system (St. Jude Medical, St Paul, Minnesota), geometry reconstruction by dragging the mapping catheter (Geo-Map) allows for quicker acquisition of a large number of points and better definition of anatomy, but it is not validated for substrate mapping.

OBJECTIVE

This study evaluates the feasibility and accuracy of Geo-Map.

METHODS

Thirteen patients (mean age 38 +/- 12 years) with RV arrhythmias and an apparently normal heart underwent cardiac magnetic resonance imaging (MRI), Pt-Map, and Geo-Map. The 2 maps were compared in terms of mapping procedural time, radiation time, and total number of points acquired. We finally compared the number and characteristics of low-potential areas on each patient's Pt-Map, Geo-Map, and cardiac MRI.

RESULTS

Geo-Map required significantly shorter mapping and radiation times in comparison to Pt-Map (12.4 +/- 4.6 vs. 31.9 +/- 10.1 and 5.8 +/- 2.1 vs. 12.1 +/- 3.9, P <.001). Furthermore, Geo-Map was based on a significantly higher density of points in comparison to Pt-Map (802 +/- 205 vs. 194 +/- 38, P <.001). Taking into consideration the total number of RV regions analyzed, the Pt-Map and Geo-Map disagreed in 2 of 65 (3%) regions (P = NS), which only Geo-Map identified as low-potential areas and indeed corresponded to wall motion abnormalities on MRI.

CONCLUSION

Voltage maps obtained through RV geometry acquisition have accuracy comparable to that of conventional point-by-point mapping in detecting low-voltage areas, have a good correlation with MRI wall motion abnormalities, and allow a significant reduction in procedural time and x-ray exposure.

Inflammation as a therapeutic target in heart failure? A scientific statement from the Translational Research Committee of the Heart Failure Association of the European Society of Cardiology

The increasing prevalence of heart failure poses enormous challenges for health care systems worldwide. Despite effective medical interventions that target neurohumoral activation, mortality and morbidity remain substantial. Evidence for inflammatory activation as an important pathway in disease progression in chronic heart failure has emerged in the last two decades. However, clinical trials of 'anti-inflammatory' therapies (such as anti-tumor necrosis factor-alpha approaches) have to date failed to show benefit in heart failure patients. The Heart Failure Association of the European Society of Cardiology recently organized an expert workshop to address the issue of inflammation in heart failure from a basic science, translational and clinical perspective, and to assess whether specific inflammatory pathways may yet serve as novel therapeutic targets for this condition. This consensus document represents the outcome of the workshop and defines key research questions that still need to be addressed as well as considering the requirements for future clinical trials in this area.

Myocarditis

Myocarditis may present with a wide range of symptoms, ranging from mild dyspnea or chest pain that resolves without specific therapy to cardiogenic shock and death. Dilated cardiomyopathy with chronic heart failure is the major long-term sequela of myocarditis. Most often, myocarditis results from common viral infections; less commonly, specific forms of myocarditis may result from other pathogens, toxic or hypersensitivity drug reactions, giant-cell myocarditis, or sarcoidosis. The prognosis and treatment of myocarditis vary according to the cause, and clinical and hemodynamic data usually provide guidance to decide when to refer a patient to a specialist for endomyocardial biopsy. The aim of this review is to provide a practical and current approach to the evaluation and treatment of suspected myocarditis.

[State of diagnostics and therapy of inflammatory cardiomyopathie]

Myocardial inflammation of cardiac muscle is caused by intramyocardial infiltration of immunological competent cells. Etiologically, the relevant factors are the direct or indirect influence of infectious pathogens, toxic, chemical or physical agents, allergic-hyperergic reactions and myocardial inflammatory events in the context of systemic diseases. Clinically significant infections include cardiotropic viruses, which are capable of causing acute or chronic damage to the myocardium under certain conditions. The wide variety of etiologies in inflammatory cardiomyopathy and its heterogeneous clinical presentations have impeded patients identification and consensus on the most appropriate diagnostic criteria and specific therapeutic strategies. Although the Dallas criteria have standardized the histological definition of active myocarditis, the recognition of true etiologies of acute and chronic stages of inflammatory cardiomyopathies require additional and more sensitive markers of tissue inflammation and molecular biological identification of responsible infectious agents. Actually, only biopsy-based diagnosis and characterization of patients allow identification of patients who may get benefit from specific immunosuppressive or anti-viral treatment strategies.

Cardiocyte nuclear chromatin density correlates with transplanted heart left ventricular mass

INTRODUCTION

Cardiocyte hypertrophy is accompanied by polyploidy, seen as a decrease in chromatin density in the enlarged nucleus. Repeated biopsies of a transplanted heart offer the possibility of a dynamic evaluation of these phenomena. The aim of this work was an evaluation of cardiocyte nuclear chromatin density in transplanted hearts during long-term follow-up.

MATERIALS AND METHODS

The material encompassed myocardial biopsy specimens taken during the first week, first month, and then on an annual basis up to 10 years after surgery. Only biopsy specimens with no rejection were considered (grade "0" International Society for Heart and Lung Transplantation [ISHLT] 122 biopsy specimens). The control group consisted of 7 donor heart specimens. We evaluated the optical density-mean gray level-of cardiomyocyte nuclear chromatin. We determined correlations of this index with the nuclear area, and with left ventricle ultrasound measurements, using correlation analysis.

RESULTS

The chromatin mean gray level decreased with time, correlating positively with interventricular septum thickness, left ventricle posterior wall diameter, and left ventricular mass. Analysis of individual periods showed a significant positive correlation of the mean grey level with the cardiocyte nuclear surface in year 3, 4, and 9 after transplantation, thereby suggesting the occurrence of polyploidy at those times. The significant negative correlation of these values (1 week and 1 year) indicated normalization of early cardiocyte hypertrophy.

CONCLUSIONS

With the passage of time chromatin condenses, leading to pyknosis. The activity of cardiocyte chromatin correlated with left ventricular hypertrophy. Compensatory cardiomyocyte polyploidy is a periodical phenomenon.

Reciprocal regulation of myocardial microRNAs and messenger RNA in human cardiomyopathy and reversal of the microRNA signature by biomechanical support

BACKGROUND

Much has been learned about transcriptional control of cardiac gene expression in clinical and experimental congestive heart failure (CHF), but less is known about dynamic regulation of microRNAs (miRs) in CHF and during CHF treatment. We performed comprehensive microarray profiling of miRs and messenger RNAs (mRNAs) in myocardial specimens from human CHF with (n=10) or without (n=17) biomechanical support from left ventricular assist devices in comparison to nonfailing hearts (n=11).

METHODS AND RESULTS

Twenty-eight miRs were upregulated >2.0-fold (P<0.001) in CHF, with nearly complete normalization of the heart failure miR signature by left ventricular assist device treatment. In contrast, of 444 mRNAs that were altered by >1.3-fold in failing hearts, only 29 mRNAs normalized by as much as 25% in post-left ventricular assist device hearts. Unsupervised hierarchical clustering of upregulated miRs and mRNAs with nearest centroid analysis and leave-1-out cross-validation revealed that combining the miR and mRNA signatures increased the ability of RNA profiling to serve as a clinical biomarker of diagnostic group and functional class.

CONCLUSIONS

These results show that miRs are more sensitive than mRNAs to the acute functional status of end-stage heart failure, consistent with important functions for regulated miRs in the myocardial response to stress. Combined miR and mRNA profiling may have superior potential as a diagnostic and prognostic test in end-stage cardiomyopathy.

[Sudden cardiac death 43 months after fulminant myocarditis and two-peaked myositis in non-typhoid salmonellosis]

HISTORY AND CLINICAL FINDINGS

A previously healthy 29-year-old male was hospitalized due to acute myalgia and high temperature following an uncomplicated gastroenteritis. Within 24 hours, he developed life-threatening hemodynamic shock with the need for inotropic support and sustained ventricular tachycardia.

INVESTIGATIONS

Echocardiography and electrocardiogram as well as lab tests were consistent with the diagnosis of fulminant myocarditis and acute myositis. Serological and bacteriological analysis yielded an acute infection with salmonella D.

TREATMENT AND COURSE

The patient's condition stabilized under conservative supportive care within a few days. Apart from a histologically confirmed recurrent myositis four weeks later, no further complications occurred and the patient was clinically and echocardiographically considered to be in complete functional remission. Three and a half years later, however, the patient unexpectedly and suddenly died.

CONCLUSIONS

Although fulminant myocarditis is a life-threatening condition in its initial phase, the prognosis after recovery is considered to be good. However, this case study suggests that sudden cardiac death as a late complication of fulminant myocarditis may occur.

Quantitative assessment of endomyocardial biopsy in arrhythmogenic right ventricular cardiomyopathy/dysplasia: an in vitro validation of diagnostic criteria

AIMS

To provide a standardized endomyocardial biopsy (EMB) protocol and diagnostic quantitative parameters for arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D). The Task Force criteria for the in vivo diagnosis of ARVC/D include tissue characterization by EMB as a major criterion.

METHODS AND RESULTS

EMBs were simulated in vitro with a Cordis bioptome in explanted hearts from six groups: diffuse (n = 10) and segmental (n = 10) ARVC/D, dilated cardiomyopathy (DC) (n = 10), controls (n = 10), adipositas cordis (n = 10), elderly >80 years (n = 10). Sampling sites were the RV inferior-subtricuspid, antero-apical, and mid-outflow tract (RVOT), the septum, and the left ventricle (LV). Histomorphometry was performed to evaluate the amount of myocardium and fibrous and fatty tissues. Myocyte diameters and abnormalities were also assessed. By selecting a 95% specificity, the ARVC/D diagnostic cut-offs on cumulative RV EMB samples are myocardium <59%, fibrosis >31% and fat >22% (80, 50, and 50% sensitivity, respectively). By excluding elderly and obese people groups a lower cut-off for fat was found (>9%). A high variability between different RV sampling sites was observed; the antero-apical was the most informative region although fat at this level is non-specific. No useful diagnostic cut-off for fatty tissue was identified at the antero-apical and RVOT area. No significant difference was found for any tissue parameter either in septal or in LV EMB. Increased RV myocyte diameters and cytological changes were detected in ARVC/D and DC.

CONCLUSION

The residual myocardium is the main diagnostic morphometric parameter in ARVC/D, whereas fat at the apex is non-specific. Sensitivity and specificity vary according to the RV region. Target sampling of the triangle of dysplasia is required, although only a single region is often informative, emphasizing the usefulness of imaging-guided EMB. There is no diagnostic value of either septal or LV EMB. Cardiomyopathic changes of the myocytes also appear important for establishing a pathological diagnosis.

Fulminant myocarditis

Fulminant myocarditis is an inflammatory process that occurs in the myocardium and causes acute-onset heart failure. If patients with fulminant myocarditis are aggressively supported in a timely manner, nearly all can have an excellent recovery. In this Review, we discuss the clinical and histological distinguishing features of fulminant myocarditis and contrast this disease entity with nonfulminant myocarditis. The epidemiology, pathophysiology, clinical presentation, methods of diagnosis, management options and prognosis of fulminant myocarditis are reviewed in detail.

Cardiac magnetic resonance imaging of myocardial contrast uptake and blood flow in patients affected with idiopathic or familial dilated cardiomyopathy

Idiopathic dilated cardiomyopathy (IDC) is characterized by left ventricular (LV) enlargement with systolic dysfunction, other causes excluded. When inherited, it represents familial dilated cardiomyopathy (FDC). We hypothesized that IDC or FDC would show with cardiac magnetic resonance (CMR) increased myocardial accumulation of gadolinium contrast at steady state and decreased baseline myocardial blood flow (MBF) due to structural alterations of the extracellular matrix compared with normal myocardium. CMR was performed in nine persons affected with IDC/FDC. Healthy controls came from the general population (n = 6) or were unaffected family members of FDC patients (n = 3) without signs or symptoms of IDC/FDC or any structural cardiac abnormalities. The myocardial partition coefficient for gadolinium contrast (lambda(Gd)) was determined by T1 measurements. LV shape and function and MBF were assessed by standard CMR methods. lambda(Gd) was elevated in IDC/FDC patients vs. healthy controls (lambda(Gd) = 0.56 +/- 0.15 vs. 0.41 +/- 0.06; P = 0.002), and correlated with LV enlargement (r = 0.61 for lambda(Gd) vs. end-diastolic volume indexed by height; P < 0.01) and with ejection fraction (r = -0.80; P < 0.001). The extracellular volume fraction was higher in IDC patients than in healthy controls (0.31 +/- 0.05 vs. 0.24 +/- 0.03; P = 0.002). Resting MBF was lower in IDC patients (0.64 +/- 0.13 vs. 0.91 +/- 0.22; P = 0.01) than unaffected controls and correlated with both the partition coefficient (r = -0.57; P = 0.012) and the extracellular volume fraction (r = -0.56; P = 0.019). The expansion of the extracellular space correlated with reduced MBF and ventricular dilation. Expansion of the extracellular matrix may be a key contributor to contractile dysfunction in IDC patients.

Predictors of outcome in patients with suspected myocarditis

BACKGROUND

The objective of this study was to identify the prognostic indicators in patients with suspected myocarditis who underwent endomyocardial biopsy.

METHODS AND RESULTS

Between 1994 and 2007, 181 consecutive patients (age, 42+/-15 years) with clinically suspected viral myocarditis were enrolled and followed up for a mean of 59+/-42 months. Endomyocardial biopsies were studied for inflammation with histological (Dallas) and immunohistological criteria. Virus genome was detected by polymerase chain reaction. The primary end point was time to cardiac death or heart transplantation. In 38% of the patients (n=69), the Dallas criteria were positive. Immunohistological signs of inflammation were shown in 50% (n=91). Genomes of cardiotropic virus species were detected in 79 patients (44%). During follow-up, 22% of the patients (n=40) reached the primary end point. Three independent predictors were identified for the primary end point, namely New York Heart Association class III or IV at entry (hazard ratio, 3.20; 95% confidence interval, 1.36 to 7.57; P=0.008), immunohistological evidence of inflammatory infiltrates in the myocardium (hazard ratio, 3.46; 95% confidence interval, 1.39 to 8.62; P=0.008), and beta-blocker therapy (hazard ratio, 0.43; 95% confidence interval, 0.21 to 0.91; P=0.027). Ejection fraction, left ventricular end-diastolic pressure, and left ventricular end-diastolic dimension index were predictive only in univariate, not in multivariate, analysis. Neither the Dallas criteria nor the detection of viral genome was a predictor of outcome.

CONCLUSIONS

For patients with suspected myocarditis, advanced New York Heart Association functional class, immunohistological signs of inflammation, and lack of beta-blocker therapy, but not histology (positive Dallas criteria) or viral genome detection, are related to poor outcome.

Transcriptomic biomarkers for individual risk assessment in new-onset heart failure

BACKGROUND

Prediction of prognosis remains a major unmet need in new-onset heart failure (HF). Although several clinical tests are in use, none accurately distinguish between patients with poor versus excellent survival. We hypothesized that a transcriptomic signature, generated from a single endomyocardial biopsy, could serve as a novel prognostic biomarker in HF.

METHODS AND RESULTS

Endomyocardial biopsy samples and clinical data were collected from all patients presenting with new-onset HF from 1997 to 2006. Among a total of 350 endomyocardial biopsy samples, 180 were identified as idiopathic dilated cardiomyopathy. Patients with phenotypic extremes in survival were selected: good prognosis (event-free survival for at least 5 years; n=25) and poor prognosis (events [death, requirement for left ventricular assist device, or cardiac transplant] within the first 2 years of presentation with HF symptoms; n=18). We used human U133 Plus 2.0 microarrays (Affymetrix) and analyzed the data with significance analysis of microarrays and prediction analysis of microarrays. We identified 46 overexpressed genes in patients with good versus poor prognosis, of which 45 genes were selected by prediction analysis of microarrays for prediction of prognosis in a train set (n=29) with subsequent validation in test sets (n=14 each). The biomarker performed with 74% sensitivity (95% CI 69% to 79%) and 90% specificity (95% CI 87% to 93%) after 50 random partitions.

CONCLUSIONS

These findings suggest the potential of transcriptomic biomarkers to predict prognosis in patients with new-onset HF from a single endomyocardial biopsy sample. In addition, our findings offer potential novel therapeutic targets for HF and cardiomyopathy.

Preamplification techniques for real-time RT-PCR analyses of endomyocardial biopsies

Background

Due to the limited RNA amounts from endomyocardial biopsies (EMBs) and low expression levels of certain genes, gene expression analyses by conventional real-time RT-PCR are restrained in EMBs. We applied two preamplification techniques, the TaqMan^® PreAmp Master Mix (T-PreAmp) and a multiplex preamplification following a sequence specific reverse transcription (SSRT-PreAmp).

Results

T-PreAmp encompassing 92 gene assays with 14 cycles resulted in a mean improvement of 7.24 ± 0.33 Ct values. The coefficients for inter- (1.89 ± 0.48%) and intra-assay variation (0.85 ± 0.45%) were low for all gene assays tested (<4%). The PreAmp uniformity values related to the reference gene CDKN1B for 91 of the investigated gene assays (except for CD56) were -0.38 ± 0.33, without significant differences between self-designed and ABI inventoried Taqman^® gene assays. Only two of the tested Taqman^® ABI inventoried gene assays (HPRT-ABI and CD56) did not maintain PreAmp uniformity levels between -1.5 and +1.5. In comparison, the SSRT-PreAmp tested on 8 self-designed gene assays yielded higher Ct improvement (9.76 ± 2.45), however was not as robust regarding the maintenance of PreAmp uniformity related to HPRT-CCM (-3.29 ± 2.40; p < 0.0001), and demonstrated comparable intra-assay CVs (1.47 ± 0.74), albeit higher inter-assay CVs (5.38 ± 2.06; p = 0.01). Comparing EMBs from each 10 patients with dilated cardiomyopathy (DCM) and inflammatory cardiomyopathy (DCMi), T-PreAmp real-time RT-PCR analyses revealed differential regulation regarding 27 (30%) of the investigated 90 genes related to both HPRT-CCM and CDKN1B. Ct values of HPRT and CDKN1B did not differ in equal RNA amounts from explanted DCM and donor hearts.

Conclusion

In comparison to the SSRT-PreAmp, T-PreAmp enables a relatively simple workflow, and results in a robust PreAmp of multiple target genes (at least 92 gene assays as tested here) by a mean Ct improvement around 7 cycles, and in a lower inter-assay variance in RNA derived from EMBs. Preliminary analyses comparing EMBs from DCM and DCMi patients, revealing differential regulation regarding 30% of the investigated genes, confirm that T-PreAmp is a suitable tool to perform gene expression analyses in EMBs, expanding gene expression investigations with the limited RNA/cDNA amounts derived from EMBs. CDKN1B, in addition to its function as a reference gene for the calculation of PreAmp uniformity, might serve as a suitable housekeeping gene for real-time RT-PCR analyses of myocardial tissues.