Dilated cardiomyopathy (DCM) is associated with a high incidence of malignant ventricular arrhythmias and sudden death. Abnormalities in repolarization of ventricular myocardium have been implicated ...in the development of these arrhythmias. Spatial heterogeneity in repolarization has been studied in DCM, but temporal fluctuations in repolarization in this setting have been largely ignored. We sought to test the hypothesis that beat-to-beat QT interval variability is increased in DCM patients compared with control subjects.
Eighty-three patients with ischemic and nonischemic DCM and 60 control subjects served as the study population. Beat-to-beat QT interval variability was measured by automated analysis on the basis of 256-second records of the surface ECG. A QT variability index (QTVI) was calculated for each subject as the logarithm of the ratio of normalized QT variance to heart rate variance. The coherence between heart rate and QT interval fluctuations was determined by spectral analysis. In patients, ejection fractions were assessed by echocardiography or ventriculography, and spatial QT dispersion was determined from the standard 12-lead ECG. DCM patients had greater QT variance than control subjects (60.4+/-63.1 versus 25.7+/-24.8 ms2, P<.0001) despite reduced heart rate variance (6.7+/-7.8 versus 10.5+/-10.4 bpm2, P=.01). The QTVI was higher in DCM patients than in control subjects, with a high degree of significance (-0.43+/-0.71 versus -1.29+/-0.51, P<10-12). QTVI did not correlate with ejection fraction or spatial QT dispersion but did depend on New York Heart Association functional class. QTVI did not differ between DCM patients with ischemic and those with nonischemic origin. Coherence between heart rate and QT interval fluctuations at physiological frequencies was lower in DCM patients compared with control subjects (0.28+/-0.14 versus 0.39+/-0.18, P<.0001).
DCM is associated with beat-to-beat fluctuations in QT interval that are larger than normal and uncoupled from variations in heart rate. QT interval variability increases with worsening functional class but is independent of ejection fraction. These data indicate that DCM leads to temporal lability in ventricular repolarization.
Drs. Kenneth Baughman and John Jarcho discuss the mechanisms of action of cardiac-support devices and the clinical factors involved in the selection of a ventricular assist device.
Even with ...well-managed care, many patients with severe heart failure reach a stage at which medical therapy is insufficient to sustain an acceptable level of cardiac function. It is estimated that 0.2% of persons over 45 years of age in the United States, or nearly 200,000 people, may fit this description.
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Since only approximately 2000 donor hearts are available in the United States each year for transplantation, the need for another approach to cardiac replacement is well established.
Investigators and the medical-device industry have been pursuing the development of mechanical cardiac support for more than four decades. The earliest forms . . .
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.
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.
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.
The etiology of cardiomyopathy is usually inferred from clinical information and preliminary laboratory studies. Patients with unexplained cardiomyopathy may be referred for endomyocardial biopsy ...(EMBx). It is unknown whether pathological information obtained from EMBx is beneficial or alters the diagnosis established clinically. This study was undertaken to evaluate the utility of EMBx in confirming or excluding a clinically suspected diagnosis.
We evaluated 845 patients with initially unexplained cardiomyopathy who underwent EMBx between 1982 and 1997 at The Johns Hopkins Hospital. For each patient, an initial clinical diagnosis, an EMBx diagnosis, and a final diagnosis prior to discharge based on all available data were established.
The final diagnosis differed from the initial clinical diagnosis in 264 (31%) of these patients; EMBx made the diagnosis in 196 (75%) of these cases. Initial diagnoses most frequently altered were myocarditis (34%) and idiopathic cardiomyopathy (25%). Initial diagnoses least likely to be altered were those in which biopsy was used to confirm or grade a previously documented illness, such as hemochromatosis (11%), amyloidosis (18%), or cardiomyopathy secondary to doxorubicin toxicity (0%). EMBx was more sensitive than clinical diagnosis in detecting myocarditis and amyloidosis, and proved to be very specific in detecting ischemic cardiomyopathy, myocarditis, amyloidosis, and hemochromatosis.
In patients with unexplained cardiomyopathy after a standard evaluation, the clinical assessment of the etiology is inaccurate in 31% of patients. EMBx establishes the final diagnosis in 75% of these patients with a high degree of specificity.
Paragangliomas: Etiology, Presentation, and Management Joynt, Karen E; Moslehi, Javid J; Baughman, Kenneth L
Cardiology in review,
2009-July/August, 2009 Jul-Aug, 2009-07-00, 20090701, Letnik:
17, Številka:
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Journal Article
Paragangliomas are catecholamine-secreting tumors arising from the chromaffin cells of the sympathetic ganglia, and are known as extra-adrenal pheochromocytomas. These tumors commonly present with ...episodic hypertension, tachycardia, headache, and diaphoresis, and can be either benign or malignant. Diagnosis is made by serum and urine analysis for catecholamines and metanephrines, and confirmed with imaging studies including computed tomography scanning, magnetic resonance imaging, or 123-I metaiodobenzylguanidine imaging. Although the majority of paragangliomas are sporadic, a growing percentage of cases are found to be part of a familial genetic syndrome. Genetic testing should be offered to patients diagnosed with paraganglioma, particularly in patients who are young, have multiple tumors, or have a family history of malignancy. Management of paraganglioma is predicated on surgical resection, and careful perioperative management with alpha- and beta-adrenergic blockade is imperative for optimal outcomes. The majority of these tumors are benign, but for patients with malignant disease, chemotherapy, and radiation therapy may provide modest benefit. Long-term follow-up is essential, as paragangliomas can recur many years after initial diagnosis. Ongoing research into the genetic underpinnings of this tumor may allow for more targeted molecular therapies in the future.
Background The reported mortality rate of peripartum cardiomyopathy (PPCM) is high, although the potential for spontaneous recovery of ventricular function is well established. The prevalence of ...myocarditis in PPCM has varied widely between studies. The purposes of this study were to define the long-term prognosis in a referral population of patients with PPCM, to determine the prevalence of myocarditis on endomyocardial biopsy in this population, and to identify clinical variables associated with poor outcome. Methods We analyzed clinical, echocardiographic, hemodynamic, and histologic features of 42 women with PPCM evaluated at our institution over a 15-year period. Each patient underwent an extensive evaluation, including echocardiography, endomyocardial biopsy, and right heart catheterization. Data were analyzed to identify features at initial examination associated with the combined end point of death or cardiac transplantation by the use of Kaplan-Meier survival curves and a Cox proportional hazards model. Results Three (7%) patients died and 3 (7%) patients underwent heart transplantation during a median follow-up of 8.6 years. Endomyocardial biopsy demonstrated a high prevalence of myocarditis (62%), but the presence or absence of myocarditis was not associated with survival. Of the prespecified variables assessed, only decreased left ventricular stroke work index was associated with worsened outcome. Conclusions In patients with PPCM, (1) long-term survival is better than has been historically reported, (2) the prevalence of myocarditis is high, and (3) decreased left ventricular stroke work index is associated with worse clinical outcomes. (Am Heart J 2000;140:785-91.)
Multiple viruses have been isolated from the heart, but their significance remains controversial. We sought to determine the prevalence of cardiotropic viruses in endomyocardial biopsy (EMB) samples ...from adult patients with heart failure (HF) and to define the clinicopathologic profile of patients exhibiting viral positivity.
EMB from 100 patients (median ejection fraction, 30%; interquartile range IQR, 20% to 45%) presenting for cardiomyopathy evaluation (median symptom duration, 5 months; IQR, 1 to 13 months) were analyzed by polymerase chain reaction for adenovirus, cytomegalovirus, enteroviruses, Epstein-Barr virus, and parvovirus B19. Each isolate was sequenced, and viral load was determined. Parvovirus B19 was the only virus detected in EMB samples (12% of subjects). No patient had antiparvovirus IgM antibodies, but all had IgG antibodies, suggesting viral persistence. The clinical presentation of parvovirus-positive patients was markedly heterogeneous with both acute and chronic HF, variable ventricular function, and ischemic cardiomyopathy. No patient met Dallas histopathologic criteria for active or borderline myocarditis. Two patients with a positive cardiac MRI and presumed "parvomyocarditis" had similar viral loads to autopsy controls without heart disease. The oldest parvovirus-positive patients were positive for genotype 2, suggesting lifelong persistence in the myocardium.
Parvovirus B19 was the only virus isolated from EMB samples in this series of adult patients with HF from the United States. Positivity was associated with a wide array of clinical presentations and HF phenotypes. Our studies do not support a causative role for parvovirus B19 persistence in HF and, therefore, advocate against the use of antiviral therapy for these patients.
Pulmonary hypertension is a clinically useful predictor of death in patients with heart failure. Whether pulmonary hypertension has the same prognostic value among specific underlying causes of ...cardiomyopathy is unknown. Using a diverse cohort of cardiomyopathy patients, we tested the hypotheses that (1) elevated mean pulmonary arterial pressure is the most important hemodynamic predictor of death and (2) the prognostic value of mean pulmonary pressure varies among different cardiomyopathies.
Patients (n=1134) with new cardiomyopathy were prospectively assigned a specific diagnosis on the basis of clinical evaluation and endomyocardial biopsy. All patients underwent right heart catheterization at baseline and were followed for an average of 4.4 years. In multivariate Cox models that allowed for nonlinear relations between hemodynamics and death, mean systemic pressure (mSP) and mean pulmonary arterial pressure (mPA) emerged as the most important hemodynamic predictors of death. Moreover, there was a statistically significant positive interaction between mPA and the diagnosis of myocarditis. For each 5-mm Hg increase in baseline mSP, mortality rates decreased with relative hazard (RH) of 0.89 (0.86 to 0.92). For a 5-mm Hg increase in baseline mPA, mortality rates increased in patients who did not carry the diagnosis of myocarditis with RH 1.23 (1.17 to 1.29); among patients with myocarditis, mortality rates increased substantially with RH of 1.85 (1.50 to 2.29; P<0.001 for interaction).
Baseline mPA is particularly important for stratifying risk in myocarditis. These findings suggest that secondary pulmonary hypertension may have different biological features in myocarditis and that patients with pulmonary hypertension and myocarditis should be targeted for aggressive medical therapy.
Current implantable left ventricular assist devices (LVAD) improve survival and function for patients with very late stage heart failure (HF) but may also offer benefit before inotrope dependence. ...Debate continues about selection of HF patients for LVAD therapy. We sought to determine what level of personal risk and disability HF patients thought would warrant LVAD therapy.
The study included 105 patients with symptomatic HF and an LV ejection fraction (EF) < 35% who were given a written paragraph about LVADs and asked about circumstances under which they would consider such a device. New York Heart Association (NYHA) functional class, time trade-off utility, and patient-assessed functional score were determined.
Participants (mean age, 58 years) had an LVEF of 21%. The median duration of HF was 5 years, and 65% had a primary prevention implantable cardioverter defibrillator. Presented with a scenario of bed-ridden HF, 81% stated they would definitely or probably want an LVAD; 50% would consider LVAD to prolong survival if HF survival were predicted to be < 1 year and 75% if < 6 months. Meanwhile, 44% would consider LVAD if they could only walk < 1 block and 64% if they could not dress without stopping. Anticipated thresholds did not differ by NYHA class, time trade-off, or functional score.
Patient thresholds for LVAD insertion parallel objective survival and functional data. HF patients would be receptive to referral for discussion of LVAD by the time expected mortality is within 6 to 12 months and activity remains limited to less than 1 block.
Summary Over the last decades, beta-blockers have been a key component of heart failure therapy. However, currently there is no method to identify patients who will benefit from beta-blocking therapy ...versus those who will be unresponsive or worsen. Furthermore, there is an unmet need to better understand molecular mechanisms through which heart failure therapies, such as beta-blockers, improve cardiac function, in order to design novel targeted therapies. Solving these issues is an important step towards personalized medicine. Here, we present a comprehensive transcriptomic analysis of molecular pathways that are affected by beta-blocking agents and a transcriptomic biomarker to predict therapy response.
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