1
|
Relationship between Serum Ferritin and Outcomes in β-Thalassemia: A Systematic Literature Review. J Clin Med 2022; 11:jcm11154448. [PMID: 35956067 PMCID: PMC9369259 DOI: 10.3390/jcm11154448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 07/22/2022] [Accepted: 07/26/2022] [Indexed: 12/10/2022] Open
Abstract
Among the difficulties of living with β-thalassemia, patients frequently require blood transfusions and experience iron overload. As serum ferritin (SF) provides an indication of potential iron overload, we conducted a systematic literature review (SLR) to assess whether SF levels are associated with clinical and economic burden and patient-reported outcomes (PROs). The SLR was conducted on 23 April 2020 and followed by analysis of the literature. Dual-screening was performed at the title, abstract, and full-text levels using predefined inclusion and exclusion criteria. Ten studies identified by the SLR were eligible for inclusion in the analysis. Seven studies were conducted in Europe, and most were prospective or retrospective in design. The patient populations had a median age of 20.7–42.6 years, with a percentage of men of 38–80%. Sparse data were found on the correlation between SF levels and mortality, and hepatic, skeletal, and cardiac complications; however, in general, higher SF levels were associated with worsened outcomes. The bulk of the evidence reported on the significant association between higher SF levels and endocrine dysfunction in its many presentations, including a 14-fold increase in the risk of diabetes for patients with persistently elevated SF levels. No studies reporting data on PROs or economic burden were identified by the SLR. SF levels provide another option for prognostic assessment to predict a range of clinical outcomes in patients with β-thalassemia.
Collapse
|
2
|
Alis D, Asmakutlu O, Topel C, Sahin AA, Karaarslan E. Association between left ventricular strain and cardiac iron load in beta-thalassaemia major: a cardiac magnetic resonance study. Acta Cardiol 2022; 77:71-80. [PMID: 33685353 DOI: 10.1080/00015385.2021.1887585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
OBJECTIVE To evaluate the utility of cardiac magnetic resonance feature tracking-derived left ventricular strain in assessing cardiac dysfunction and investigate the correlation between left ventricular strain and myocardial T2* in patients with beta-thalassaemia major. METHODS Forty-two patients with beta-thalassaemia major, having a mean age of 22.49 ± 8.48 years, and age-matched healthy controls were enrolled in the study. The observer drew regions of interest on the interventricular septum, and T2* decay curves were calculated accordingly. The short-axis cine images were used to derive left ventricular circumferential and radial strains, and the long-axis four-chamber and two-chamber images were used to assess left ventricular longitudinal strain. RESULTS The mean global left ventricular strains were lower in beta-thalassaemia major patients than the controls (p < 0.05). Left ventricular strains of beta-thalassaemia major patients with cardiac T2* values of > 20 ms were also significantly reduced compared with the controls (p < 0.05); there was no difference between the mean left ventricular ejection fractions of the two groups (p = 0.84). Cardiac T2* showed a weak correlation with left ventricular ejection fraction (r = 0.33, p = 0.03), while the left ventricular circumferential strain showed a good positive correlation with cardiac T2* (r = 0.6, p < 0.0001). CONCLUSION Compared with healthy controls, patients with beta-thalassaemia major, including those with myocardial T2* values of >20 ms, showed reduced global left ventricular strains. Left ventricular circumferential strain was positively correlated with myocardial T2*. Left ventricular strain analysis using cardiac magnetic resonance feature tracking may have utility in beta-thalassaemia major assessment.Key FindingsPatients with beta-thalassaemia major, including those with myocardial T2* values of >20 ms, had reduced global left ventricular strains.Cardiac T2* showed a weak correlation with left ventricular ejection fraction, while the left ventricular circumferential strain showed a good positive correlation with cardiac T2*.ImportanceLeft ventricular strain using cardiac magnetic resonance feature tracking might be used as an adjunct in assessing cardiac functions in beta-thalassaemia major.
Collapse
Affiliation(s)
- Deniz Alis
- Department of Radiology, Acibadem Mehmet Ali Aydinlar University School of Medicine, Istanbul, Turkey
| | - Ozan Asmakutlu
- Department of Radiology, Istanbul Mehmet Akif Ersoy Thoracic and Cardiovascular Surgery Training and Research Hospital, Istanbul, Turkey
| | - Cagdas Topel
- Department of Radiology, Istanbul Mehmet Akif Ersoy Thoracic and Cardiovascular Surgery Training and Research Hospital, Istanbul, Turkey
| | - Ahmet Anil Sahin
- Department of Cardiology, Istanbul Mehmet Akif Ersoy Thoracic and Cardiovascular Surgery Training and Research Hospital, Istanbul, Turkey
| | - Ercan Karaarslan
- Department of Radiology, Acibadem Mehmet Ali Aydinlar University School of Medicine, Istanbul, Turkey
| |
Collapse
|
3
|
Kamperidis V, Vlachou M, Pappa Z, Pantelidou D, Karamitsos T, Papadopoulou D, Kartas A, Boutou A, Ventoulis I, Vlachaki E, Giannakoulas G, Karvounis H. Prediction of long-term survival in patients with transfusion-dependent hemoglobinopathies: Insights from cardiac imaging and ferritin. Hellenic J Cardiol 2021; 62:429-438. [PMID: 33524617 DOI: 10.1016/j.hjc.2021.01.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 12/24/2020] [Accepted: 01/14/2021] [Indexed: 11/19/2022] Open
Abstract
AIMS The current study evaluated the association of echocardiography, cardiac magnetic resonance (CMR), and ferritin data with 10-year survival in thalassemia patients. METHODS Demographics, ferritin, echocardiography, and CMR parameters of stable consecutive thalassemia patients were prospectively collected. RESULTS In total, 75 patients (mean age 37 ± 11 years, 45% male) with thalassemia were included and dichotomized based on their survival status after a median follow-up period of 10.3 [9.6-10.9] years. Older age (HR: 1.071, p = 0.001), ferritin ≥2000 ng/ml (HR: 4.682, p = 0.007) and ≥1700 ng/ml (HR: 7.817, p = 0.002), elevated LV end-diastolic pressure (HR: 1.019, p = 0.044), TR Vmax >2.8 m/s (HR: 6.845, p = 0.005), and CMR T2∗ ≤20 msec (HR: 3.602, p = 0.043) and ≤34 msec (HR: 5.854, p = 0.026) were associated with increased all-cause mortality (primary endpoint). A baseline model including age was created and became more predictive of worse survival by adding TR Vmax >2.8 m/s instead of elevated LV end-diastolic pressure (C index 0.767 vs. 0.760, respectively), ferritin ≥1700 ng/ml instead of ≥2000 ng/ml (C index 0.890 vs. 0.807, respectively), or CMR T2∗≤34 msec instead of ≤20 msec (C index 0.845 vs. 0.839, respectively). Parameters associated with the combined endpoint of cardiac mortality/cardiac hospitalization (secondary endpoint) after adjusting for age were ferritin ≥1700 ng/ml (HR 3.770, p = 0.014), ratio E/A wave >2 (HR 3.565, p = 0.04), TR Vmax >2.8 m/s (HR 4.541, p = 0.049), CMR T2∗ ≤20 ms (HR 9.462, p = 0.001), and CMR T2∗ ≤34 ms (HR 11.735, p = 0.002). The model including age and T2∗ ≤34 ms instead of T2∗ ≤20 ms was more predictive of the secondary endpoint (C-index 0.844 vs 0.838, respectively). CONCLUSIONS In thalassemia patients, TR Vmax >2.8 m/s, ferritin ≥2000 ng/ml, and CMR T2∗ ≤20 ms were associated with worse long-term survival. In the current era of advanced chelation therapy, aiming for ferritin ≤1700 ng/ml and CMR T2∗ ≥34 ms may improve their prognosis.
Collapse
Affiliation(s)
- Vasileios Kamperidis
- 1st Cardiology Department, Aristotle University of Thessaloniki, AHEPA University Hospital, Thessaloniki, Greece.
| | - Maria Vlachou
- 1st Cardiology Department, Aristotle University of Thessaloniki, AHEPA University Hospital, Thessaloniki, Greece
| | - Zoi Pappa
- 1st Cardiology Department, Aristotle University of Thessaloniki, AHEPA University Hospital, Thessaloniki, Greece
| | | | - Theodoros Karamitsos
- 1st Cardiology Department, Aristotle University of Thessaloniki, AHEPA University Hospital, Thessaloniki, Greece
| | | | - Anastasios Kartas
- 1st Cardiology Department, Aristotle University of Thessaloniki, AHEPA University Hospital, Thessaloniki, Greece
| | - Afroditi Boutou
- Pulmonary Department, Papanikolaou Hospital, Thessaloniki, Greece
| | - Ioannis Ventoulis
- 1st Cardiology Department, Aristotle University of Thessaloniki, AHEPA University Hospital, Thessaloniki, Greece
| | - Efthymia Vlachaki
- Thalassaemia Unit, Ippokratio University Hospital, Thessaloniki, Greece
| | - George Giannakoulas
- 1st Cardiology Department, Aristotle University of Thessaloniki, AHEPA University Hospital, Thessaloniki, Greece
| | - Haralambos Karvounis
- 1st Cardiology Department, Aristotle University of Thessaloniki, AHEPA University Hospital, Thessaloniki, Greece
| |
Collapse
|
4
|
Vlachou M, Kamperidis V, Giannakoulas G, Karamitsos T, Vlachaki E, Karvounis H. Biochemical and imaging markers in patients with thalassaemia. Hellenic J Cardiol 2020; 62:4-12. [PMID: 32387594 DOI: 10.1016/j.hjc.2020.04.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 04/06/2020] [Accepted: 04/15/2020] [Indexed: 11/15/2022] Open
Abstract
Beta-thalassaemia is a genetic disease with different clinical aspects, which can lead to heart failure with a multifactorial mechanism. Over the last years, growing interest has been reported for biomarkers that may help in the diagnosis, staging and prognosis of heart disease at an early stage, in patients with beta-thalassaemia. This review will highlight the current clinical value of cardiac biomarkers in patients with beta-thalassaemia and the ongoing research for a possible expanded future use.
Collapse
Affiliation(s)
- Maria Vlachou
- 1(st) Cardiology Department, Aristotle University of Thessaloniki, AHEPA University Hospital, Thessaloniki, Greece
| | - Vasileios Kamperidis
- 1(st) Cardiology Department, Aristotle University of Thessaloniki, AHEPA University Hospital, Thessaloniki, Greece.
| | - George Giannakoulas
- 1(st) Cardiology Department, Aristotle University of Thessaloniki, AHEPA University Hospital, Thessaloniki, Greece
| | - Theodoros Karamitsos
- 1(st) Cardiology Department, Aristotle University of Thessaloniki, AHEPA University Hospital, Thessaloniki, Greece
| | - Efthymia Vlachaki
- Thalassaemia Unit, Ippokratio University Hospital, Thessaloniki, Greece
| | - Haralambos Karvounis
- 1(st) Cardiology Department, Aristotle University of Thessaloniki, AHEPA University Hospital, Thessaloniki, Greece
| |
Collapse
|
5
|
Parsaee M, Pouraliakbar H, Azarkeivan A, Ghadrdoost B, Behjati M. The Role of Exercise Stress Echocardiography for Determination of Subclinical Cardiac Involvement in β-Thalassemia Major. Hemoglobin 2019; 43:34-37. [PMID: 31084365 DOI: 10.1080/03630269.2019.1572620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
β-Thalassemia major (β-TM) patients are at increased risk for cardiovascular diseases. Determination of subclinical cardiac involvement is essential for preventive measures. Thus, we aimed to evaluate the role of stress echocardiography for identification of subclinical cardiac dysfunction in β-TM patients. In this prospective study, 45 β-TM patients who were referred for cardiac evaluation, were enrolled. Exclusion criteria included non sinus rhythm and overt cardiac disease. Stress echocardiography levels and cardiac magnetic resonance imaging (MRI) results were obtained from β-TM patients. Patients were divided into two groups of normal vs. iron overload from cardiac T2* greater or less than 20 msec, respectively. Resting and peak exercise right ventricular stroke volume (RVSV) and left ventricular SV (LVSV) were significantly lower in iron overload vs. normal β-TM patients, respectively (p value <0.05). At peak LV global longitudinal strain (GLS) and myocardial performance index (MPI) were significantly decreased and increased compared with resting in iron overload vs. normal β-TM patients, respectively (p value <0.05). There was a significant relationship between inappropriate hemodynamic response to exercise and lower age (p value = 0.032). Resting LVSV and RVSV seemed better prognosticators for iron overload than LV ejection fraction (LVEF). Decreased GLS and increased MPI at peak exercise could also predict the presence of cardiac iron overload. These measurements by stress echocardiography could be evaluated when cardiac T2* could not be determined.
Collapse
Affiliation(s)
- Mozhgan Parsaee
- a Echocardiography Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences , Tehran , Iran
| | - Hamidreza Pouraliakbar
- b Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences , Tehran , Iran
| | - Azita Azarkeivan
- c Research Center of Iranian Blood Transfusion Organization, Thalassemia Clinic , Tehran , Iran
| | - Behshid Ghadrdoost
- b Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences , Tehran , Iran
| | - Mohaddeseh Behjati
- a Echocardiography Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences , Tehran , Iran
| |
Collapse
|
6
|
Mancuso L, Vitrano A, Mancuso A, Sacco M, Ledda A, Maggio A. Left Ventricular Diastolic Dysfunction in β-Thalassemia Major with Heart Failure. Hemoglobin 2018; 42:68-71. [PMID: 29633668 DOI: 10.1080/03630269.2018.1451341] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
We studied the clinical, electrocardiographic, echocardiographic, Doppler and T2* cardiac magnetic resonance (CMR) data of all adult β-thalassemia major (β-TM) patients with heart failure (HF) consecutively observed at our referral center of the Sicilian region between 2008 and 2016. There were 16 patients enrolled in the study. Echocardiographic examination showed that only one patient had HF with systolic dysfunction of the left ventricle (HFrEF), whereas the others had HF with preserved systolic function of the left ventricle (HFpEF). Systolic dysfunction of the right ventricle (RV) was observed in 13 cases. Furthermore, 30.0% of the patients presented T2* CMR values consistent with intermediate risk of systolic dysfunction of the left ventricle (LV) due to iron overload, whereas 70.0% had normal values. Typical electrocardiographic abnormalities (wide T wave inversion and low voltages) were observed in 11 out of 16 patients. In conclusion, in the adult β-TM patients with HF recently observed at our center, the predominant form was that with diastolic dysfunction of the LV, and with systolic dysfunction of the RV. Only 30.0% had low values of T2* CMR. Typical electrocardiographic abnormalities were found in 69.0%.
Collapse
Affiliation(s)
- Luigi Mancuso
- a Franco and Piera Cutino Campus di Ematologia , Ospedali Riuniti Villa Sofia-V. Cervello , Palermo Italia
| | - Angela Vitrano
- a Franco and Piera Cutino Campus di Ematologia , Ospedali Riuniti Villa Sofia-V. Cervello , Palermo Italia
| | - Andrea Mancuso
- b Medicina Interna, Azienda di Rilievo Nazionale ad Alta Specializzazione (ARNAS) Civico , Palermo , Italia.,c Epatologia e Gastroenterologia, Ospedale Niguarda Ca' Granda , Milano , Italia
| | - Massimiliano Sacco
- a Franco and Piera Cutino Campus di Ematologia , Ospedali Riuniti Villa Sofia-V. Cervello , Palermo Italia
| | - Antonietta Ledda
- d Cardiologia, Ospedali Riuniti Villa Sofia-V. Cervello , Palermo , Italia
| | - Aurelio Maggio
- a Franco and Piera Cutino Campus di Ematologia , Ospedali Riuniti Villa Sofia-V. Cervello , Palermo Italia
| |
Collapse
|
7
|
Farmakis D, Triposkiadis F, Lekakis J, Parissis J. Heart failure in haemoglobinopathies: pathophysiology, clinical phenotypes, and management. Eur J Heart Fail 2016; 19:479-489. [PMID: 28000341 DOI: 10.1002/ejhf.708] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 10/18/2016] [Accepted: 11/07/2016] [Indexed: 12/28/2022] Open
Abstract
Hereditary haemoglobinopathies, mainly beta-thalassemia and sickle cell disease, constitute the most common monogenic disorders in humans, and although once geographically confined, they are currently globally distributed. They are demanding clinical entities that require multidisciplinary medical management. Despite their genotypic and phenotypic heterogeneity, the haemoglobinopathies share several similarities in pathophysiology, clinical manifestations, therapeutic requirements, and complications, among which heart failure (HF) represents a leading cause of mortality and morbidity. However, haemoglobinopathies have generally been addressed in a rather fragmentary manner. A unifying approach focusing on the underlying similarities of HF attributes in the two main entities might contribute to their better understanding, characterization, and management. In the present review, we attempt such an approach to the pathophysiology, clinical phenotypes, and management of HF in haemoglobinopathies.
Collapse
Affiliation(s)
- Dimitrios Farmakis
- Heart Failure Unit, Department of Cardiology, Attikon University Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | | | - John Lekakis
- Heart Failure Unit, Department of Cardiology, Attikon University Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - John Parissis
- Heart Failure Unit, Department of Cardiology, Attikon University Hospital, National and Kapodistrian University of Athens, Athens, Greece
| |
Collapse
|
8
|
Pennell DJ, Udelson JE, Arai AE, Bozkurt B, Cohen AR, Galanello R, Hoffman TM, Kiernan MS, Lerakis S, Piga A, Porter JB, Walker JM, Wood J. Cardiovascular function and treatment in β-thalassemia major: a consensus statement from the American Heart Association. Circulation 2013; 128:281-308. [PMID: 23775258 DOI: 10.1161/cir.0b013e31829b2be6] [Citation(s) in RCA: 261] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
This aim of this statement is to report an expert consensus on the diagnosis and treatment of cardiac dysfunction in β-thalassemia major (TM). This consensus statement does not cover other hemoglobinopathies, including thalassemia intermedia and sickle cell anemia, in which a different spectrum of cardiovascular complications is typical. There are considerable uncertainties in this field, with a few randomized controlled trials relating to treatment of chronic myocardial siderosis but none relating to treatment of acute heart failure. The principles of diagnosis and treatment of cardiac iron loading in TM are directly relevant to other iron-overload conditions, including in particular Diamond-Blackfan anemia, sideroblastic anemia, and hereditary hemochromatosis. Heart failure is the most common cause of death in TM and primarily results from cardiac iron accumulation. The diagnosis of ventricular dysfunction in TM patients differs from that in nonanemic patients because of the cardiovascular adaptation to chronic anemia in non-cardiac-loaded TM patients, which includes resting tachycardia, low blood pressure, enlarged end-diastolic volume, high ejection fraction, and high cardiac output. Chronic anemia also leads to background symptomatology such as dyspnea, which can mask the clinical diagnosis of cardiac dysfunction. Central to early identification of cardiac iron overload in TM is the estimation of cardiac iron by cardiac T2* magnetic resonance. Cardiac T2* <10 ms is the most important predictor of development of heart failure. Serum ferritin and liver iron concentration are not adequate surrogates for cardiac iron measurement. Assessment of cardiac function by noninvasive techniques can also be valuable clinically, but serial measurements to establish trends are usually required because interpretation of single absolute values is complicated by the abnormal cardiovascular hemodynamics in TM and measurement imprecision. Acute decompensated heart failure is a medical emergency and requires urgent consultation with a center with expertise in its management. The first principle of management of acute heart failure is control of cardiac toxicity related to free iron by urgent commencement of a continuous, uninterrupted infusion of high-dose intravenous deferoxamine, augmented by oral deferiprone. Considerable care is required to not exacerbate cardiovascular problems from overuse of diuretics or inotropes because of the unusual loading conditions in TM. The current knowledge on the efficacy of removal of cardiac iron by the 3 commercially available iron chelators is summarized for cardiac iron overload without overt cardiac dysfunction. Evidence from well-conducted randomized controlled trials shows superior efficacy of deferiprone versus deferoxamine, the superiority of combined deferiprone with deferoxamine versus deferoxamine alone, and the equivalence of deferasirox versus deferoxamine.
Collapse
|
9
|
Risk factors and mortality associated with an elevated tricuspid regurgitant jet velocity measured by Doppler-echocardiography in thalassemia: a Thalassemia Clinical Research Network report. Blood 2011; 118:3794-802. [PMID: 21772051 DOI: 10.1182/blood-2010-11-319152] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
An elevated tricuspid regurgitant jet velocity (TRV) is associated with hemolysis and early mortality in sickle cell disease, yet risk factors, clinical parameters, and mortality associated with this biomarker in thalassemia are poorly defined. This report summarizes the prevalence of an elevated TRV in 325 patients screened by Doppler echocardiography in the Thalassemia Clinical Research Network. A documented TRV was reported in 148 of 325 (46%) of patients. Average age was 25.9 years (range, 5-56 years) and 97% were transfusion-dependent. Mean TRV was 2.3 ± 0.4 m/s (range, 0.2-3.5 m/s). An abnormal TRV ≥ 2.5 m/s was identified in 49 of 148 (33%) of patients with a documented TRV, 5% (8/148), with a TRV ≥ 3.0 m/s, suggesting significant PH risk. Older age was strongly associated with a high TRV; however, 16% of children had a TRV ≥ 2.5 m/s. A history of splenectomy, hepatitis C, smoking, or high white blood cell count was associated with TRV elevation. In summary, an elevated TRV is noted in one-third of transfusion-dependent thalassemia patients with a documented value and develops in both children and adults. Age, splenectomy, hepatitis C, and smoking are significant univariate risk factors, with splenectomy surfacing as the dominant risk factor over time. Mortality was low in this cohort. Prospective longitudinal studies are needed. This study is registered at http://www.clinicaltrials.gov as NCT00661804.
Collapse
|
10
|
Derchi G, Formisano F, Balocco M, Galanello R, Bina P, Dessi C, Piga A, Donato G, Cappellini MD, Cassinerio E, Quarta G, Melpignano A, Forni GL. Clinical management of cardiovascular complications in patients with thalassaemia major: a large observational multicenter study. EUROPEAN JOURNAL OF ECHOCARDIOGRAPHY 2011; 12:242-6. [DOI: 10.1093/ejechocard/jeq190] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
|