Left ventricular function in beta thalassaemia major

Changing trends in the prevalence of heart failure impairment with Thalassemias over three decades

BACKGROUND

To assess the prevalence trend and contributing factors of heart failure (HF) impairment with thalassemias at global, regional and national levels.

METHODS

Data on HF impairment with thalassemias was collected from the Global Burden of Disease study. The absolute number and prevalence of the disease were systematically collected for each year, and the estimated annual percentage changes (EAPC) in HF impairment were calculated by gender, region and country to measure temporal trends.

RESULTS

Thalassemias have caused a significant global burden since 1990, and the case number of HF related to thalassemias has been steadily increasing. The highest case number of HF impairments with thalassemias is observed in China (7739 cases) and the highest prevalence is in Pakistan (1.61 per 100,000) currently. Besides, the middle sociodemographic index (SDI) region carries the highest burden of comorbid disease yet exhibits the most evident trend for improvement across the five regions (EAPC = -.98). The burden of thalassemias and comorbid HF is generally higher in males than females with the gender gap growing chasm in the future. Besides, the hotspots of HF impairment with thalassemias have gradually shifted to low SDI regions, though middle SDI regions still hold a relatively higher prevalence (.37 per 100,000) across different regions.

CONCLUSIONS

The burden of thalassemias and accompanying HF, as well as their temporal trends, vary greatly across countries and regions. These findings can improve understanding of these conditions and guide policymakers in developing appropriate policies to address disparities between countries.

Early detection of ventricular dysfunction by tissue Doppler echocardiography related to cardiac iron overload in patients with thalassemia

Cardiac T2* MRI is used as a gold standard for cardiac iron quantification in patients with transfusion-dependent thalassemia (TDT). We hypothesized that left ventricular (LV) diastolic dysfunction would reflect the severity of iron overload and can serve as an early detection of cardiac iron deposits. A study was conducted on all patients with TDT. Hemoglobin, serum ferritin and non-transferrin bound iron, together with a complete echocardiography and cardiac T2* MRI, were performed on all patients. Seventy-seven patients with TDT were enrolled (median age 14 years). In the patient group with a mean serum ferritin of > 2500 ng/mL during the past 12 months, there were more patients with severe cardiac iron deposits than in the group with a mean serum ferritin of ≤ 2500 ng/mL. Diastolic dysfunction was absent in all patients with a serum ferritin of < 1000 ng/mL. All patients with cardiac T2* ≤ 20 ms had grade III LV diastolic dysfunction. However, twenty-one percent of patients with cardiac T2* > 20 ms had LV diastolic dysfunction. The differences observed in pulmonary vein atrial reversal duration and mitral A-wave (PVAR-MVA) duration ≥ - 1 ms and an E/E' ratio ≥ 11 were proven to be the associated factors with the cardiac T2* ≤ 20 ms. Increased PVAR-MVA duration and increased E/E' ratio reliably reflected a severe iron overload, according to a cardiac T2* in patients with TDT. LV diastolic dysfunction can occur prior to severe cardiac iron deposition. Tissue Doppler echocardiography has the potential for the early detection of cardiac involvement in patients with TDT .

Longitudinal Analysis of Echocardiographic Abnormalities in Children With Sickle Cell Disease

BACKGROUND

Cardiac abnormalities have been described in echocardiograms of children with sickle cell disease (SCD). However, longitudinal studies investigating progression of echocardiographic abnormalities across the pediatric age spectrum in SCD are lacking.

METHODS

A retrospective longitudinal analysis of 829 echocardiograms from pediatric patients with SCD at steady-state was performed. Left heart parameters included left ventricular end-systolic, end-diastolic diameters, fractional shortening, and mass. Right ventricular pressure was estimated by tricuspid regurgitation gradient. Tricuspid regurgitation gradient ≥25 mm Hg, a z-score ≥2 for LV parameters and ≤-2 for left ventricular fractional shortening were considered abnormal.

RESULTS

Kaplan-Meier analysis revealed that echocardiographic abnormalities were detected by 5 years of age, and the cumulative incidence progressively increased throughout childhood. Age, male gender, HbSS and Sβ thalassemia genotype, white blood cell count, platelet count, total bilirubin, admissions for pain crises and acute chest syndrome were positively, whereas hemoglobin was negatively associated with cardiac abnormalities.

CONCLUSION

Cardiac abnormalities began early in childhood and progressively increased with age. Our study highlights the high cumulative incidence of cardiac abnormalities in children with SCD, which could represent a marker of disease severity.

Haematological determinants of cardiac involvement in adults with sickle cell disease

AIMS

Cardiac involvement is common in sickle cell disease (SCD). Studies are needed to establish haematological determinants of this involvement and prognostic markers. The aim of the study was to identify haematological factors associated with cardiac involvement in SCD and their impact on prognosis.

METHODS AND RESULTS

This longitudinal observational study was performed on 1780 SCD patients with SS or S-β(0)-thalassemia referred to our centre. Six hundred fifty-six met our inclusion criteria (availability of a blood-workup and echocardiogram obtained <1 year apart, no heart valve surgery and no current pregnancy). Median age was 31 (interquartile range, 25-40) years, and median haemoglobin (Hb) was 87 (80-95)g/L. Left ventricular (LV) dilation, left atrial dilation, cardiac index (CI) >4 L/min/m(2), LV ejection fraction <55%, and tricuspid regurgitant velocity (TRV) ≥2.5 m/s were found in 35, 78, 23, 8.5, and 17% of patients, respectively. Compared with other patients, those in the fourth quartiles (Q4) of LV end-diastolic dimension index (LVEDDind) and left atrial dimension index (LADind) and those with high CI had significantly lower Hb, % foetal Hb (HbF), and red blood cell (RBC) counts; and significantly higher lactate dehydrogenase, bilirubin, and %dense RBCs. Independent haematologic determinants of Q4 LVEDDind and LADind were low RBC count and %HbF; high %dense RBCs were associated with LADind. Low %HbF and RBC count were associated with high CI. High %dense RBCs or no α-thalassemia gene deletion was associated with greater severity of anaemia and cardiac dilation and with higher CI. During the median follow-up of 48 (32-59) months, 50 (7.6%) patients died. Tricuspid regurgitant velocity ≥ 2.5 m/s was a predictor of mortality. The risk of death increased four-fold when left ventricular ejection fraction <55% was present also (P = 0.0001).

CONCLUSION

Cardiac dilation and CI elevation in patients with SCD are associated with haematologic variables reflecting haemolysis, RBC rigidity, and blood viscosity. Tricuspid regurgitant velocity ≥ 2.5 and LV dysfunction (even mild) predict mortality.

The effect of iron overload in the hearts of patients with beta-thalassemia

BACKGROUND AND HYPOTHESIS

An important complication of beta-thalassemia is iron deposition in cardiac tissues resulting in fibrosis and dysfunction. Our aim was the investigation of the possible clinical effect of iron loading in the heart of patients with beta-thalassemia prior to the appearance of symptoms of depressed systolic function.

METHODS

Thirty-five patients with beta-thalassemia, of whom 24 had the major type (Group 1) and 11 had the intermedia type (Group 2) were studied. Eleven age- and gender-matched controls were also studied (Group 3). All patients were evaluated echocardiographically and were shown to have normal left ventricular systolic function and dimensions. Serum ferritin, atrial natriuretic peptide (ANP), left atrial diameter (LAD), peak early mitral inflow velocity (E), peak late mitral inflow velocity (A), E/A ratio, deceleration time of the mitral inflow E wave (DT), and isovolumic relaxation time (IVRT) were measured.

RESULTS

Univariate analysis showed that both groups of patients had similarly increased LAD and ANP plasma levels. Group 1 had a higher E/A ratio (2.27 +/- 0.88) SS than Group 2 (1.69 +/- 0.47, p = 0.05) and Group 3 (1.50 +/- 0.38, p = 0.01). Serum ferritin was significantly higher in Group 1 (3.526 +/- 0.352) than in Group 2 (2.808 +/- 0.288, p < 10(-5) and Group 3 (2.139 +/- 0.124, p < 10(-5). Multivariate analysis showed that ANP is a factor that is affected by the LAD and E/A ratio and that serum ferritin levels affect the LAD and E/A ratio.

CONCLUSIONS

Although LAD and ANP levels are increased in patients with beta-thalassemia, the increased serum ferritin levels of patients seem to affect left atrial size and E/A ratio. ANP secretion is consecutively affected by these factors.

Thalassemia and its relevance to personalized medicine

Thalassemias are the most common monogenic gene disorders in the world. Patients present with a wide variability of clinical phenotypes ranging from severe phenotype (β-thalassemia major) to a very mild, almost symptomless, condition. This variability is owing to the presence of a large number of genetic modifiers affecting the disease. Patients are treated with blood transfusions and iron chelation therapy. Pharmacological therapies have varying degrees of success depending on the genetic modifiers of the disease present in the patients. Studies undertaken to identify all the modifiers that affect β-thalassemia will lead to more appropriate genetic counseling during prenatal diagnosis and enable targeted and personalized treatment regimens for patients in the future.

The relation between left ventricular diastolic indices and serum ferritin in thalassemia major

Iron-induced heart failure is the primary cause of death in thalassemia major patients who receive continuous transfusions. Recent studies have suggested that diastolic function is impaired prior to systolic function in process of hemochromatosis, but they did not come to agreement on the first impaired diastolic index. Additionally, serum ferritin concentration is not a reliable indicator of body iron storage since it increases in any simple inflammation. Accordingly, the authors undertook this study to assess any association between left ventricular diastolic indices and serum ferritin in thalassemic patients with normal systolic function to estimate the true amount of body iron storage and correct it in earlier stages. Serum ferritin concentration and diastolic indices were measured in 29 patients with normal left ventricular systolic function. Linear regression test was used to find any association between hematological and cardiac factors. No significant association was found between diastolic indices and serum ferritin concentration. But the results were quite different in patients above and below 15 years of age; standardized coefficients (r) for peak of E and A were increased in patients above 15, and the significance was close to .05, unlike those of younger group. Although no correlation was found between serum ferritin and diastolic indices, the results were noteworthy in patients above 15. To appropriately judge this relation, the study must be continued with a bigger sample size and having patients' mean serum ferritin concentration during the 2 past years.

Evaluation of Left Ventricular Systolic Function in Pediatric Sickle Cell Anemia Patients Using the End-Systolic Wall Stress-Velocity of Circumferential Fiber Shortening Relationship

OBJECTIVES

The aim of this work was to evaluate myocardial contractility using the end-systolic wall stress (ESSm)-velocity of circumferential fiber shortening (VCFc) relationship in sickle cell anemia (SCA) patients compared with a similar age group of African-American (AA) control patients.

BACKGROUND

Abnormalities of myocardial function have been documented in SCA patients using load-dependent echocardiographic indexes. Whether the systolic dysfunction results from impaired myocardial contractility or altered loading conditions is unknown because controlled studies using a load-independent measure of contractility have not been performed.

METHODS

Fifty healthy AA patients and 57 SCA patients age 3 months to 18 years were studied. Simultaneous indirect arterial pulse tracing, phonocardiogram, electrocardiogram, and M-mode tracing of the left ventricular (LV) short-axis were recorded. The LV dimensions, corrected ejection time (ETc), percent fractional shortening (%FS), VCFc, and ESSm were determined. The ESSm-VCFc relationship was calculated and compared between groups. Duration and severity of anemia and effects of exchange transfusion on the ESSm-VCFc relationship were determined.

RESULTS

The SCA patients had increased LV dimensions in systole and diastole, and increased indexed LV mass. Load-dependent measurements of LV function (ETc, %FS, and VCFc) were lower in SCA patients, and afterload, as measured by ESSm, was increased. The ESSm-VCFc relationship demonstrated reduced contractility in SCA patients compared with control subjects. Degree and duration of anemia along with exchange transfusions did not impact contractility.

CONCLUSIONS

Sickle cell anemia patients have significant LV dilatation and increased LV mass due to abnormal loading conditions. Contractility, measured by the ESSm-VCFc index, is lower in SCA patients and was not negatively impacted by severity or duration of anemia, or exchange transfusions. The underlying mechanism explaining these findings requires further investigation.

Splenectomy: a strong risk factor for pulmonary hypertension in patients with thalassaemia

OBJECTIVE

To determine the association between splenectomy and pulmonary hypertension in patients with thalassaemia with anaemia.

DESIGN

Prospective cross-sectional study.

METHODS

68 patients with thalassaemia, who had a haemoglobin concentration of less than 100 g/l, were recruited into this study. Echocardiography was performed before clinical data were reviewed. Pulmonary artery pressure was estimated by measuring the systolic transtricuspid pressure gradient from tricuspid regurgitation and adding it to the right atrial pressure, which was estimated by the response of the inferior vena cava to inspiration. Pulmonary hypertension was defined as systolic pulmonary artery pressure > 35 mm Hg. History of splenectomy and other clinical data were compared between patients with and without pulmonary hypertension.

RESULTS

29 patients had pulmonary hypertension and 39 did not. Patients with pulmonary hypertension had significantly more nucleated red blood cells and higher platelet counts, and a higher prevalence of splenectomy (75.8% v 25.6%, odds ratio 9.1, 95% confidence interval 3.0 to 27.7). In multivariate analysis, splenectomy was the only factor significantly related to pulmonary hypertension.

CONCLUSION

Splenectomy is a strong risk factor for pulmonary hypertension in patients with thalassaemia.

Heart failure in beta-thalassemia syndromes: a decade of progress

The thalassemias are common monogenic disorders of hemoglobin synthesis. beta-thalassemias are the most important among the thalassemia syndromes and have become a worldwide clinical problem due to an increasing immigrant population. In beta-thalassemia major, regular blood transfusions are necessary early in life. Beta-thalassemia intermedia refers to a less severe phenotype, whereas beta-thalassemia/hemoglobin E disease encompasses a broad phenotypic spectrum. Blood transfusions and increased gastrointestinal iron absorption result in iron overload and tissue damage. Among patients with beta-thalassemia major, biventricular, dilated cardiomyopathy remains the leading cause of mortality. In some patients, a restrictive type of left ventricular cardiomyopathy or pulmonary hypertension is noted. The clinical course, although variable and occasionally fulminant, is more benign in recent than in older series. Myocarditis has been described as a cause of left-sided heart failure in younger patients. Pulmonary arterial hypertension is the principal cause of heart failure in beta-thalassemia intermedia. Chelation therapy has improved prognosis in beta-thalassemia major both by reducing the incidence of heart failure and by reversing cardiomyopathy. Estimation of the patient's cardiac risk is mainly based on clinical criteria and serial echocardiography. A new cardiovascular magnetic resonance technique will probably fulfill the need for more precise risk stratification in beta-thalassemia syndromes. By increasing the proportion of patients on optimal chelation, survival in beta-thalassemia major may further improve. Recent advances in gene therapy are expected to result in the long-awaited cure of this disease.

Tricuspid regurgitation in patients with ?-thalassemia major

Although cardiac complications remain the main causes of death in thalassemic patients, right heart dysfunction has been little studied and the mechanism is still unclear. Echocardiography was performed in 39 patients with beta-thalassemia major and 35 aged-matched controls. The gender, age, heart rate, blood pressure, left ventricular ejection fraction (LVEF), acceleration time (AcT) of right ventricular outflow and right ventricular ejection time (RVET), AcT/RVET, and the presence of tricuspid regurgitation (TR) were compared between the two groups. We also compared the gender, age, age at first blood transfusion, serum ferritin level, alanine aminotransferase (ALT), the presence of antibodies to hepatitis C virus, liver fibrosis, splenectomy, platelet counts, diabetes mellitus, arrhythmia, cardiomegaly, LVEF, AcT, RVET, AcT/RVET, and signal intensity ratio (SIR) of myocardial magnetic resonance imaging (MRI) between thalassemic patients with and without TR. The incidence of TR in thalassemic patients was significantly higher than that in the control group (30.8 vs 11.4%, p=0.03). The incidences of splenectomy (p=0.03), platelet counts (p=0.01), and SIR of myocardial MRI (p=0.03) in thalassemic patients with TR were significantly higher than in those without TR. The AcT was shorter and the AcT/RVET ratio was smaller, suggesting higher pulmonary pressure in the thalassemic patients with TR. Occurrence of TR in patients with beta-thalassemia major may be a consequence of cardiac iron deposit, thrombocytosis, splenectomy, or pulmonary hypertension.

Pulmonary arterial hypertension in previously splenectomized patients with beta-thalassemic disorders

Our aim was to study the cause and describe the clinical features of pulmonary arterial hypertension (PHT) in splenectomized beta-thalassemia (beta-Thal) patients. Ten splenectomized beta-Thal patients with systolic pulmonary artery (PA) pressure >30 mm Hg were evaluated by echocardiography, right-heart catheterization, and pulmonary angiography. Five of these patients later underwent hemodynamic studies. Echocardiography and pulmonary angiography on the 10 patients showed normal values of left ventricular systolic function and no findings of acute or chronic pulmonary embolism. Hemodynamic evaluation showed very high PA pressures associated with markedly increased pulmonary vascular resistance indices (PVRIs). Hematological evaluation of the 10 patients showed marked anemia, markedly increased numbers of nucleated red blood cells (nRBCs), and serum ferritin. Mean platelet count, plasma beta2 thromboglobulin, and thrombin-antithrombin III complex levels were significantly increased. It was concluded that PHT can be found in splenectomized beta-Thal patients. Features associated with PHT were female sex, hemoglobin E/beta-Thal, status many years postsplenectomy, marked anemia, markedly increased nRBC count, thrombocytosis, and very high serum ferritin levels. PHT was not due to pulmonary emboli. Our findings suggested that severe PHT was due to increased PVRI from thrombotic pulmonary arteriopathy, likely from chronic low-grade hypercoagulability and platelet activation after splenectomy.

Heart failure in beta-thalassemia

Heart failure remains the main cause of death in beta-thalassemia despite the progress that has been made. Myocardial iron deposition alone does not affect left ventricular relaxation but directly causes left ventricular myocardial restriction with considerably elevated pulmonary pressure. This leads to symptoms and signs of predominantly right-sided heart failure, which is usually observed in elderly and severely hemosiderotic populations. Left ventricular systolic dysfunction and failure, which occurs in younger, less hemosiderotic populations, seems to be multifactorial in etiology. Apart from iron loading, immunogenetic risk factors trigger the mechanisms of left-sided heart failure development in the context of dilated-type cardiomyopathy. (c)2001 CHF, Inc.

An angiotensin-converting enzyme inhibitor improves left ventricular systolic and diastolic function in transfusion-dependent patients with beta-thalassemia major

BACKGROUND

Cardiac complications are the major cause of death in patients with beta-thalassemia major. The purpose of this study was to assess the impact of long-term treatment with the angiotensin-converting enzyme inhibitor enalapril on left ventricular (LV) performance, with an emphasis on diastolic LV function because diastolic dysfunction has been found to be an early event in an asymptomatic thalassemic population with only mild impairment of LV systolic function.

METHODS

We used echocardiography to study the impact of treatment with oral enalapril on the evolution of standard M-mode and Doppler indices, along with a recently introduced Doppler index of combined systolic and diastolic LV performance.

RESULTS

Patients were found to have significantly increased LV end-diastolic dimensions (LVEDD), LV end-systolic dimensions (LVESD), and left atrial dimensions and decreased LV fractional shortening (LVFS) compared with controls. After treatment with enalapril, LVESD decreased from 3.58 +/- 0.3 cm to 3.23 +/- 0.4 cm (P <.01) and LVFS increased from 32.6% +/- 4.0% to 38.0% +/- 3.1% (P <.001). Patients at baseline were found to have a significantly higher E-wave velocity, E/A ratio, and Doppler index compared with controls. The E-wave deceleration time was significantly shorter compared with that of controls. After treatment with enalapril, the E/A ratio decreased from 2.10 +/- 0.42 to 1.50 +/- 0.30 (P <.05), E-wave deceleration time increased from 0.12 +/- 0.02 seconds to 0.15 +/- 0.03 seconds (P <.01), and the Doppler index decreased from 0.46 +/- 0.10 to 0.37 +/- 0.14 (P <.05).

CONCLUSIONS

Enalapril was well tolerated in asymptomatic or minimally symptomatic patients with LV dysfunction resulting from beta-thalassemia major. Echocardiographically we demonstrated significant improvement in LV systolic and diastolic function. Whether this translates to improved long-term prognosis and survival remains to be further evaluated.

Left ventricular diastolic function in congenital myotonic dystrophy

OBJECTIVE

Examination of left ventricular function and conduction abnormalities in myotonic dystrophy.

DESIGN

Twelve patients (median age, 13.7 years) with myotonic dystrophy had detailed electrocardiography and echocardiography performed. Echocardiographic parameters were compared with body surface area (BSA) matched median normal values.

RESULTS

Fractional shortening was slightly reduced (by 28-29%) in three patients and three patients had mild mitral valve prolapse. Diastolic function was abnormal; isovolumic relaxation time (IVRT) and duration of early filling were prolonged compared with control values (median IVRT, 74 v 61 ms). Peak E velocity was increased (median, 0.82 v 0.78 m/s) but atrial phase filling was normal. Heart rate was reduced (median, 68 v 81 beats/min). Conduction abnormalities were common but showed no clear relations with diastolic abnormalities.

CONCLUSIONS

Young patients with myotonic dystrophy have myocardial diastolic dysfunction as well as abnormal electrophysiology. The prognostic implications of such abnormalities require further study.

Apolipoprotein E 4 Allele as a Genetic Risk Factor for Left Ventricular Failure in Homozygous β-Thalassemia

In homozygous β-thalassemia, the organ damage is mainly attributed to excessive iron deposition through the formation of oxygen free radicals. Despite appropriate transfusion and chelation therapy and low ferritin levels, patients still develop organ failure, heart failure being the main cause of death. This study was designed to determine whether the decreased antioxidant activity of the apolipoprotein E (APOE) 4 allele could represent a genetic risk factor for the development of left ventricular failure (LVF) in β-thalassemia homozygotes. A total of 251 Greek β-thalassemia homozygotes were studied. Patients were divided in three groups: group A (n = 151) with no cardiac impairment, group C (n = 47) with LVF, and 53 patients with LV dilatation and normal LV systolic function constituted the group B. DNA was obtained from all patients, and the polymerase chain reaction was used to analyze the polymorphism at the APOE locus. The APOE allele frequencies were compared with those of a Greek control sample of 216 healthy blood donors. Patients with no cardiac impairment had an APOE 4 allele frequency (7.9%) not different from population controls (6.5%, P &gt; .05), while patients with LVF had a significantly higher frequency of APOE 4 (12.8%) than the controls (P &lt; .05, odds ratio = 2.11, 95% confidence interval 1.03 to 4.32). The APOE 4 allele may represent an important genetic risk factor for the development of organ damage in homozygous β-thalassemia.

© 1998 by The American Society of Hematology.

Apolipoprotein E 4 Allele as a Genetic Risk Factor for Left Ventricular Failure in Homozygous β-Thalassemia

In homozygous β-thalassemia, the organ damage is mainly attributed to excessive iron deposition through the formation of oxygen free radicals. Despite appropriate transfusion and chelation therapy and low ferritin levels, patients still develop organ failure, heart failure being the main cause of death. This study was designed to determine whether the decreased antioxidant activity of the apolipoprotein E (APOE) 4 allele could represent a genetic risk factor for the development of left ventricular failure (LVF) in β-thalassemia homozygotes. A total of 251 Greek β-thalassemia homozygotes were studied. Patients were divided in three groups: group A (n = 151) with no cardiac impairment, group C (n = 47) with LVF, and 53 patients with LV dilatation and normal LV systolic function constituted the group B. DNA was obtained from all patients, and the polymerase chain reaction was used to analyze the polymorphism at the APOE locus. The APOE allele frequencies were compared with those of a Greek control sample of 216 healthy blood donors. Patients with no cardiac impairment had an APOE 4 allele frequency (7.9%) not different from population controls (6.5%, P > .05), while patients with LVF had a significantly higher frequency of APOE 4 (12.8%) than the controls (P < .05, odds ratio = 2.11, 95% confidence interval 1.03 to 4.32). The APOE 4 allele may represent an important genetic risk factor for the development of organ damage in homozygous β-thalassemia.

© 1998 by The American Society of Hematology.

Pulmonary hypertension in patients with thalassemia major

To evaluate the pulmonary artery pressure in patients with thalassemia major, Doppler echocardiography was performed in 33 patients with thalassemia major (aged 2 to 24 years) and 33 normal controls. Pulmonary artery pressure was estimated by (1) measuring the systolic transtricuspid gradient from tricuspid regurgitation and adding it to the right atrial pressure, estimated by the response of the inferior vena cava to deep inspiration, and (2) measuring the time to peak velocity of pulmonary flow. The results showed that of 33 patients, 28 had tricuspid regurgitation with a pulmonary systolic pressure ranging from 18 to 94 mm Hg (47 +/- 15 mm Hg). Pulmonary systolic pressure was > 30 mm Hg in all 22 patients > 10 years old and in four of six patients < 10 years old. Pressure correlated with left ventricular ejection fraction (r = -0.74), the ratio of mitral peak early diastolic flow velocity and peak velocity during the atrial contraction (r = 0.52), age (r = 0.56), and total blood transfusion units (r = 0.59). The pulmonary time to peak velocity was shortened compared with controls (p < 0.05). We concluded that pulmonary hypertension, as another cardiovascular complication of multiple factors of cause, seems to occur more frequently and at an early stage of the cardiac involvement in patients with thalassemia major.

Myocarditis in beta-thalassemia major. A cause of heart failure

BACKGROUND

Although acute pericarditis is a common complication of beta-thalassemia major, the prevalence and consequences of myocarditis in this disease have not been investigated.

METHODS AND RESULTS

A prospective 5-year follow-up study was carried out in all patients with beta-thalassemia major in whom the diagnosis of acute infectious myocarditis could be established between 1977 and 1986. A similar number of age- and sex-matched control subjects with beta-thalassemia and normal left ventricular function and no evidence of myocarditis were also followed for 5 years. Of 1048 patients with beta-thalassemia major, 47 patients (age, 15 +/- 2.5 years) with precordial chest pain were diagnosed as having acute infectious myocarditis. Myocardial biopsy was diagnostic in 26 patients, border-line in 14 patients, and nondiagnostic in 7 patients. Acute heart failure with left ventricular dysfunction (left ventricular ejection fraction, 25 +/- 11%) developed in 11 patients (23.4%) with myocarditis, and 8 of them died within 1 month to 1 year after diagnosis. Thirteen patients with myocarditis (27.6%) developed chronic heart failure (left ventricular ejection fraction, 26 +/- 13%) within 3 +/- 1.3 years, and 10 of them died within 8 +/- 3 months. Left ventricular systolic and diastolic functions of the control subjects did not change significantly during the 5-year period (left ventricular ejection fraction, 63 +/- 11% versus 65 +/- 7%; P = NS). However, left ventricular restrictive abnormalities (early diastole/late diastole, > 2.2; deceleration time, < 110 milliseconds) combined with right ventricular dilatation (> 30 mm internal diameter) and right-sided heart failure developed in 3 patients with extremely high mean serum ferritin levels. No significant difference was found in mean levels of serum ferritin and pretransfusion hemoglobin between patients with and those without myocarditis.

CONCLUSIONS

In patients with beta-thalassemia, myocarditis appears to be involved in the pathogenesis of left ventricular systolic dysfunction, being the main cause of death. Iron overload appears to provoke left ventricular restrictive abnormalities combined with right ventricular enlargement and dysfunction.