Unexplained Congestive Heart Failure Research Articles

PERIPATUM CARDIOMYOPATHY ; FIVE YEARS STUDY IN DIWANIYAH TEACHING HOSPITAL

Objective: Astudy was carried out to verify peri partum cardiomyopathy (PPCMP) frequency among other cardiomyopathy (CM)Patients and methods : From April 2001 to April 2005 , out and in patients (98) patients with clinically unexplained congestive heart failure had been subjected to careful echocardiographic study.Results : it was found that (13.2%) of dilated CM studied had PPCM. All the 13 patients of PPCM were multiparous ; had heart failure in stage 111-1V; and they were anemic and underweight.

Feminizing Adrenal Carcinoma Presenting with Heart Failure and Ventricular Tachycardia

We present a case of feminizing adrenal carcinoma with severe elevation in serum estradiol and otherwise unexplained congestive heart failure with ventricular arrhythmia and review the literature on feminizing adrenal tumors and the potential relationship between estrogen and cardiac problems. A 54-year-old man presented with congestive heart failure and ventricular arrhythmia. Imaging revealed a large adrenal mass. Hormonal evaluation revealed a very high serum level of estradiol, elevated DHEA-sulfate and androstenedione, and lack of cortisol suppression on a low-dose overnight dexamethasone suppression test. The patient underwent a left adrenalectomy with subsequent normalization of serum estradiol. Surgical pathology examination established adrenocortical carcinoma MacFarlane stage II. Upon 15-month followup, the patient continued to have a normal serum estradiol level, his cardiac function was significantly improved, and he had no further episodes of ventricular arrhythmia. To the best of our knowledge, the serum estradiol level that was detected in our case is the highest that has been reported. Further, we hypothesize that the very high serum concentration of estradiol in our case may have played a role in his cardiac presentation with congestive heart failure and arrhythmia, particularly as these problems resolved with normalization of his serum estradiol level.

A Prospective Study of Iron Overload Management in Allogeneic Hematopoietic Cell Transplantation Survivors

We report the results of a single-center, prospective evaluation for iron overload and subsequent treatment in 147 adult allogeneic hematopoietic cell transplantation (HCT) recipients who survived beyond 1 year after transplantation. Patients were screened by serum ferritin level; those with ferritin >1000 ng/mL underwent liver R2 magnetic resonance imaging to estimate liver iron concentration (LIC; normal < or =1.8 mg/g). Patients with significant iron overload (defined as LIC > or =5 mg/g), based on physician and patient preference, were offered observation only, phlebotomy, or enrollment in a pilot study of deferasirox. Sixteen patients had significant iron overload. Their median age was 51 years (range, 29-64 years), and they had survived a median of 21 months (range, 12-114 months). All 16 patients were transfusion-independent at study enrollment. Five patients received no treatment (median LIC, 6.4 mg/g; range, 5.1-28.3 mg/g), 8 underwent phlebotomy (median LIC, 13.1 mg/g; range, 7.8-43.0 mg/g), and 3 received daily deferasirox 20 mg/kg/day orally for 6 months (LIC, 6.3, 9.0, and 19.9 mg/g). Two patients had abnormal liver function tests, and 1 patient each had cirrhosis and unexplained congestive heart failure; all 4 of these patients underwent phlebotomy. Follow-up serum ferritin concentrations decreased spontaneously in 4 patients in the observation-only arm. Phlebotomy was generally well tolerated. Deferasirox also was well tolerated and led to decreased LIC after 6 months of therapy in all 3 patients. Phlebotomy is feasible in the majority of allogeneic HCT recipients who have survived for > or =1 year after HCT and have significant iron overload. Although the number of subjects is small, deferasirox may be a safe and effective alternative for allogeneic HCT survivors with iron overload who cannot undergo phlebotomy.

Estudo de 11 casos de fibroelastose endocárdica primária

INTRODUCAO: A fibroelastose endocardica (FEE) e definida como espessamento difuso do endocardio ventricular em funcao da proliferacao de fibras colagenas e elasticas. Pode ser classificada como primaria ou secundaria. A FEE primaria apresenta-se na forma dilatada, mais comum, ou na forma restritiva. Geralmente manifesta-se como insuficiencia cardiaca inexplicada, em criancas com menos de 12 meses de idade. OBJEIVOS: Avaliar aspectos epidemiologicos, clinicos e anatomopatologicos da FEE primaria. MATERIAL E METODO: Foram pesquisadas, entre 1960 e 2000, 6.211 necropsias perinatais e pediatricas do Hospital de Clinicas da Universidade Federal do Parana (UFPR), tendo sido verificados 11 casos de FEE. RESULTADOS: Em nove casos (81,8%), o surgimento dos sintomas ocorreu antes de 1 ano de idade. Em oito (72,7%), o obito ocorreu antes de 1 ano de idade. Dentre os sinais clinicos, destacaram-se taquipneia (54,5%), hepatomegalia (45,5%), tosse (36,4%), cianose (36,4%) e febre (36,4%). Todas as radiografias (n = 6) apresentavam cardiomegalia. O espessamento endocardico predominou no coracao esquerdo (90,9%). A causa de obito foi insuficiencia respiratoria aguda em cinco casos (45,5%) e choque cardiogenico em quatro (36,4%). DISCUSSAO E CONCLUSOES: Os resultados mostram acometimento predominante de criancas com menos de 1 ano de idade e rapida progressao para obito. Sinais clinicos frequentes, como taquipneia, tosse e febre, sugeriram infeccao respiratoria, que foi confirmada por necropsia em tres casos (27,3%). Os exames complementares mostraram apenas achados sugestivos de insuficiencia cardiaca. Os dados analisados neste estudo mostram que, em nosso meio, a FEE primaria nao difere significativamente do que e apresentado na literatura internacional em relacao a caracteristicas epidemiologicas, clinicas e anatomopatologicas.

A Newborn Who Has Previously Undiagnosed Hydrops Fetalis

A 36-week appropriate-for-gestational age male was born with hydrops fetalis that was not diagnosed prenatally. The birth hospital had a Level II nursery. Pertinent points in the history include: Born to a 24-year-old G2P0010 (previous first-trimester spontaneous abortionwoman by emergency cesarean section due to failure to progress and decreased fetal heart rate variability. ### Prenatal Laboratory Results Preterm labor occurred 1 week prior to delivery, but was stopped successfully with tocolysis, and the mother was sent home after 6 hours of observation. Rupture of membranes occurred 6 hours prior to delivery with clear fluid. At delivery, the infant appeared grossly edematous, dusky, and floppy, with no spontaneous respiratory effort. Endotracheal intubation was difficult because of airway edema. Resuscitation consisted of positive pressure ventilation, chest compressions, and epinephrine administration via an umbilical venous catheter. ### Initial Arterial Blood Gas Results A chest radiograph showed bilateral pleural effusions. A kidney-ureter-bladder (KUB) radiograph showed ascites. Pleurocentesis released 45 mL of straw-colored fluid from the left side of the chest, but none from the right side of the chest. A total of 15 mL of straw-colored fluid was removed from the abdomen via paracentesis. ### Follow-up Arterial Blood Gas Results On physical examination, the infant exhibited gross body edema but no dysmorphic features. A II/VI systolic murmur was heard at the left sternal border. The liver was palpable 3 cm below the costal margin. There was mild glandular hypospadias with a minimal chordee, but testes were descended bilaterally. The infant developed seizures and received a loading dose of 20 …

Amyloidosis: Recognition, Confirmation, Prognosis, and Therapy

Amyloidosis: Recognition, Confirmation, Prognosis, and Therapy

Clinicopathologic characteristics of elderly patients with persistent ST segment elevation and inverted T waves: Evidence of insidious or healed myocarditis?

Objectives. We sought to clarify the clinicopathologic characteristics of insidious or healed myocarditis in the elderly.Background. Myocarditis is the cause of unexplained congestive heart failure and dilated cardiomyopathy. However, acute myocarditis of the Fiedler type is rare, and the incidence and implication of insidious or healed myocarditis in the elderly are not yet known.Methods. In an autopsy study of 3,000 patients aged ⩾60 years, there were 12 (0.4%) with insidious or healed myocarditis, showing extensive and circumferential fibrosis and scattered lymphocytic infiltration of both ventricular walls without acute necrosis of the myocardial fibers.Results. Unexplained congestive heart failure was found in seven cases. In all cases, electrocardiography had demonstrated upward elevation of the ST segment and inverted T waves for durations ranging from 1 month to 12.7 years (mean 5.7 years). Mean (± SD) heart weight was 338 ± 81 g (range 220 to 470). In nine cases, fibrous lesions, which were scattered but extensive and circumferential, were located in the subepicardial and middle layers of the left ventricle. In the remaining three cases, the fibrous lesions were located predominantly in the subepicardial and middle layers, but the subendocardial layer was also locally involved. Fibrous lesions of the right ventricle were predominant in the subepicardial layer and involved the subendocardial layer in four cases. Scattered lymphocytic infiltration was found in the fibrous lesions.Conclusions. In more than half of the aged cases with insidious or healed myocarditis, unexplained congestive heart failure was also present. Fibrous lesions due to myocarditis were located predominantly in the subepicardial and middle layers and led to persistent upward elevation of the ST segment and inverted T waves.

Does endomyocardial biopsy aid in the diagnosis of active rheumatic carditis?

Carditis is the only component of rheumatic fever that leads to permanent disability. The diagnosis of carditis is presently made by using composite clinical criteria based on the revised Jones' criteria. Since myocardial involvement is an important component of rheumatic carditis, right ventricular endomyocardial biopsies were performed in 54 patients with clinical acute rheumatic fever and quiescent rheumatic heart disease to evaluate the role of biopsy for the diagnosis of rheumatic carditis. In 11 of the 54 patients, clinical consensus was certain about rheumatic fever and carditis based on the revised Jones' criteria (group 1). Histomorphological abnormalities in these patients were scarce. The diagnostic features of rheumatic myocarditis including Aschoff nodules or histiocytic aggregates were encountered in 3 patients (27%). Lymphocytic infiltration was sparse. A majority of patients demonstrated myocyte degeneration, interstitial degeneration, or occasional interstitial mononuclear cell infiltration, but since these histopathological lesions may occur in other conditions also, they were considered nondiagnostic. In 33 of the 54 patients with preexisting rheumatic heart disease, the diagnosis of carditis was suspected based on varied clinical presentations. Since previous cardiac findings were not available in these patients, the clinical diagnosis of carditis could not be made without equivocation (group 2). Twenty-three patients presented with unexplained acute onset of congestive heart failure and evidence of recent streptococcal infection (group 2A). While 13 of them had one or more other major manifestations, 10 patients had only minor manifestations. Mimetic carditis was suspected in the remaining 10 of 33 patients based on carditis having occurred in previous episodes of rheumatic fever (group 2B). The endomyocardial biopsy provided confirmatory evidence of rheumatic myocarditis in 9 patients of group 2A but in none of the 10 patients with suspected mimetic carditis. Nondiagnostic myocyte or interstitial alterations were frequently observed in group 2. Ten of the 54 patients had no clinical evidence of active carditis (group 3). No histological alterations diagnostic of rheumatic carditis were noted in these patients. Twenty-two follow-up biopsies were performed in the first 10 consecutive patients. Diagnostic histiocytic aggregates or Aschoff nodules were observed in initial biopsies in 4 of 10 patients, and nonspecific myocyte or interstitial alterations were observed in 9. All patients with diagnostic changes in initial biopsy demonstrated fibrohistiocytic nodules in 6- or 12-week biopsy samples. Nondiagnostic alterations, similar to those seen in acute cases, were present in 5 of 8 patients at 6 weeks, 5 of 8 patients at 12 weeks, and 3 of the 6 patients at 24 weeks despite the presumed adequate immunosuppressive therapy. No complications related to biopsy were encountered. The present study highlights the low frequency of diagnostic features in the biopsy specimens of patients with definite clinical rheumatic carditis. Although such alterations are not observed in patients with chronic rheumatic heart disease, endomyocardial biopsy does not appear to provide additional diagnostic information where clinical consensus is certain about diagnosis of rheumatic carditis. Our study, however, substantiates the concept of carditis underlying unexplained congestive heart failure of acute onset in patients with preexisting rheumatic heart disease and elevated antistreptolysin-O titers.

In situ detection of human cytomegalovirus immediate-early gene transcripts within cardiac myocytes of patients with HIV-associated cardiomyopathy.

Recent clinical and echocardiographic studies have identified dilated cardiomyopathy in 10-20% of HIV-infected adults. The purpose of this study was to determine the role of cardiotropic cytomegalovirus (CMV) infection in the development of HIV-associated cardiomyopathy. We generated sense and antisense digoxigenin-labeled riboprobes derived from the CMV immediate-early (IE) and delayed-early (DE) genes and applied them retrospectively to endomyocardial biopsy samples and control autopsy cardiac samples from HIV-infected patients. Tertiary care, referral hospital. Twelve consecutive HIV-infected patients with global left ventricular hypokinesis demonstrated on two-dimensional echocardiography; eight randomly selected control autopsy cardiac samples from HIV-infected patients without cardiac disease during life. Of the 12 endomyocardial biopsy specimens, six (50%) were found to have specific myocyte nuclear and perinuclear hybridization for transcripts of the CMV IE gene, consistent with non-permissive or latent infection. Similar patterns were not found in any of the eight autopsy control samples. All six patients presented with unexplained congestive heart failure and had CD4 counts less than 100 x 10(6)/l; all six biopsy samples had immunohistochemical evidence of increased myocardial major histocompatibility complex (MHC) class I expression, a finding typical of non-HIV myocarditis. None of the endomyocardial biopsy samples had characteristic CMV inclusions and no specific hybridization was noted with the DE gene riboprobe, suggesting that no active viral DNA replication was present. Only two of the six patients with myocyte hybridization with the IE riboprobe had clinical evidence of solid organ infection with CMV at the time of cardiovascular presentation. This study is the first to demonstrate the expression of the IE gene of CMV within myocytes from HIV-infected patients with cardiomyopathy, suggesting a non-permissive infection of myocytes without classical intranuclear inclusions. Myocyte infection may be necessary to trigger cellular and humoral-mediated cardiac injury and may be best identified using in situ hybridization techniques.

Transesophageal echocardiographic recognition of subaortic complications in aortic valve endocarditis. Clinical and surgical implications.

Secondary involvement of the mitral-aortic intervalvular fibrosa and the anterior mitral leaflet (subaortic structures) can occur in patients with aortic valve endocarditis. The secondary involvement of these structures occurs as a result of direct extension of the infection from the aortic valve or as a result of an infected aortic regurgitant jet striking the ventricular surfaces of the mitral-aortic intervalvular fibrosa and the anterior mitral leaflet. The abscess of mitral-aortic intervalvular fibrosa can expand to form an aneurysm. Subsequently, this mitral-aortic intervalvular fibrosa aneurysm can develop a perforation and communicate with the left atrium, resulting in the systolic regurgitation of blood from the left ventricular outflow tract into the left atrium. Secondary infection can also occur on the ventricular surface of the anterior mitral leaflet and result in the formation of an aneurysm or perforation of anterior mitral leaflet. This study examines the utility of transesophageal echocardiography in the detection of these subaortic complications in 55 consecutive patients with aortic valve endocarditis. A total of 24 patients (44%) had involvement of subaortic structures, including four with an abscess in the mitral-aortic intervalvular fibrosa, four with mitral-aortic intervalvular fibrosa aneurysm, seven with perforation of the mitral-aortic intervalvular fibrosa with communication into the left atrium, two with an aneurysm of the anterior mitral leaflet, and seven with perforation of the anterior mitral leaflet. The transesophageal echocardiographic findings were confirmed at surgery in 20 patients and at necropsy in two. By comparison, transthoracic echocardiography visualized these lesions in five of 24 patients (21%), including none of four with mitral-aortic intervalvular fibrosa abscesses, two of four with mitral-aortic intervalvular fibrosa aneurysms, one of seven with mitral-aortic intervalvular fibrosa perforations, one of two with anterior mitral leaflet aneurysms, and one of seven anterior mitral leaflet perforations. Eccentric mitral regurgitation-type systolic jets were noted in eight additional patients by transthoracic color flow imaging, and this finding suggested the possibility of these unusual subaortic complications. If these patients are included, then transthoracic echocardiography suggested the presence of these subaortic complications in 13 of 24 patients (54%). The results indicate that 1) involvement of the subaortic structures in patients with aortic valve endocarditis may be more common than previously recognized, 2) patients with aortic valve endocarditis and eccentric jets of mitral regurgitation on transthoracic echocardiography should undergo further evaluation by transesophageal echocardiography to exclude these unusual complications, 3) precise recognition of these complications is of value in the optimal medical and surgical management of these patients, and 4) these complications may be responsible for unexplained congestive heart failure and hemodynamic deterioration in some patients with aortic valve endocarditis.

Spectrum of renal vascular malformation

In summary, renal AVMs are rare. The possibility of these lesions should be raised in cases of hematuria of unknown etiology, prolonged hematuria following trauma or needle biopsy, unexplained congestive heart failure or abdominal/flank bruit, or hypertension after renal trauma. Selective renal arteriography is the study of choice for establishing the diagnosis, the hallmark being demonstration of an abnormal arterial communication with a vein. The goal of management should be maximum preservation of renal parenchyma. Observation with follow-up is indicated for asymptomatic AVMs.

Severe “Silent” Mitral Regurgitation: A Potentially Reversible Cause of Refractory Heart Failure

Hemodynamically critical ("severe") mitral regurgitation is usually associated with an audible (if not loud) systolic murmur and signs of left ventricular volume overload. However, "silent" severe mitral regurgitation is being increasingly recognized. We review the case histories of nine patients with silent hemodynamically important mitral regurgitation (associated with acute myocardial infarction and chronic valvular, hypertrophic, and ischemic heart disease), six of whom survived mitral valve replacement, of whom five are alive and functioning well more than three years postoperatively. Performance of left ventriculography early in the hospital course of patients with severe unexplained congestive heart failure (with normal or near-normal left ventricular systolic function assessed noninvasively) identifies patients with severe silent mitral regurgitation who may have long-term benefit from mechanical therapy.

Endomyocardial biopsy in patients with unexplained congestive heart failure.

To determine the incidence of myocarditis proved by biopsy findings in patients presenting with unexplained congestive heart failure. Retrospective review. General medical services of a Veterans Administration and university hospital. Ninety consecutive patients presenting with unexplained congestive heart failure who had endomyocardial biopsy as a part of their diagnostic evaluation. Classification of biopsy findings according to a recently proposed scheme for histologic diagnosis of myocarditis (Dallas criteria) showed myocarditis in only 4 of 90 (4.4%) patients (95% CI, 0.2 to 8.6), although two thirds of the patients had symptoms of congestive heart failure for less than 3 months. The incidence of myocarditis proved by endomyocardial biopsy findings is low in patients presenting with unexplained congestive heart failure and raises questions concerning the need for this procedure in this patient group.

ENDOMYOCARDIAL BIOPSY IN UNEXPLAINED HEART FAILURE.

Some investigators have advocated endomyocardial biopsy for patients with a new onset of unexplained congestive heart failure. The rationale is that immunosuppressive therapy might be appropriate for a subset of patients with biopsy-proven …

Profiles of biopsy-proven cases with myocarditis.

Fifty-seven patients with unexplained dilated hearts and congestive heart failure were studied clinically and by endomyocardial biopsy of the left ventricle. Of the patients, 61% had histologic evidence of active lymphocytic myocarditis. The sudden onset of heart failure, often with arrhythmias, if preceded by a viral-like illness indicated a high chance of finding inflammatory infiltration in the biopsy material. No abnormal accumulation of immunoglobulin was found in these patients with dilated cardiomyopathy and myocarditis. Immunosuppressive therapy did not always bring about improvement.

High incidence of myocarditis by endomyocardial biopsy in patients with idiopathic congestive cardiomyopathy

Thirty-five patients with unexplained congestive heart failure were evaluated with endomyocardial biopsy. Utilizing microscopic, ultrastructural and immunofluorescent studies, samples were classified as exhibiting either no inflammation (cardiomyopathy) or active lymphocytic myocarditis, grade I to IV. Twenty-two (63%) of the patients had inflammatory changes. Of these 22 patients, 18 had low grade I or II inflammation, 7 were treated with immunosuppressive agents with improvement in 5 and stabilization in 1. One patient died of progressive congestive heart failure. Three of four patients with high grade III or IV myocarditis died after a fulminant course. The results suggest that inflammatory myocarditis may be more common than previously suspected and add evidence that there may be ongoing inflammation in many cases of congestive cardiomyopathy.

Right ventricular endomyocardial biopsy: Clinicopathologic correlates in 100 consecutive patients

The first 100 consecutive patients to undergo right ventricular endomyocardial biopsy at the Mayo Clinic were divided retrospectively into five groups, depending on the prebiopsy clinical diagnosis, and the biopsies were review histologically in a single-blind format. Group 1 consisted of 34 patients with a diagnosis of unexplained congestive heart failure and a dilated heart; of these, 4 (12%) had active myocarditis by biopsy. Of the six patients in group 2 with a clinical diagnosis of myocarditis, only one (17%) had biopsy evidence of inflammation, but two (33%) had changes that, in the clinical setting, were suggestive of cardiomyopathy. Group 3 consisted of 27 patients with dysrhythmia, syncope, or cardiac arrest but without congestive heart failure; of these, 4 (15%) had active myocarditis by biopsy, and 8 (30%) had changes that, with the clinical history, were consistent with cardiomyopathy. Group 4 included 19 patients with unexplained congestive heart failure and a nondilated heart; 4 (21%) had cardiac amyloid on biopsy. Group 5 was a diverse group of 14 patients with possible cardiac involvement by a known systemic disease; myocardial disease was documented by biopsy in 7 (50%). On the basis of these findings, we recommend endomyocardial biopsy (1) in patients with dilated cardiomyopathy in whom myocarditis is suspected, (2) in patients with the clinical diagnosis of active myocarditis in whom tissue documentation is indicated before treatment with anti-inflammatory or immunosuppressive drugs, (3) in patients with clinically unexplained life-threatening dysrhythmias in whom myocarditis or cardiomyopathy may be present, and (4) in patients with apparent hypertrophic or restrictive cardiomyopathy in whom cardiac amyloid may be present.

The Use of 201Thallium for Myocardial Perfusion Imaging in Sarcoid Heart Disease

Cardiac dysfunction due to systemic sarcoidosis is most of ten due to severe restrictive pulmonary diseases. Although the diagnosis is frequently missed during life, direct granulomatous infiltration of the myocardium may occur with systemic sarcoidosis and, when present in the heart, is a major cause of death. To explore the possible use of radioactive 201thallium, a new agent for myocardial imaging, for improved clinical recognition of sarcoid heart disease, myocardial perfusion imaging with 201Tl was performed in six normal volunteers and in five patients with documented systemic sarcoidosis and clinically apparent cardiac dysfunction. Two of the patients with sarcoidosis had severe restrictive pulmonary disease. Their myocardial perfusion scans revealed relatively uniform uptake of 201Tl by the left ventricle, similar to that found in the normal volunteers; however, the right ventricular uptake of 201Tl and right ventricular thickness in these two patients with sarcoidosis was greater than normal. The other three patients with sarcoidosis had unexplained congestive heart failure, mitral regurgitation, or arrhythmias. Myocardial perfusion imaging in these patients revealed normal right ventricular uptake of radioactivity but segmental defects in the left ventricle compatible with an infiltrative disease of the myocardium. Segmental myocardial infiltration by sarcoid was confirmed by autopsy in one of these patients and at operation in another. Thus, myocardial imaging with 201Tl may provide a noninvasive technique for the improved clinical recognition of primary myocardial sarcoid and for distinguishing it from cardiac dysfunction secondary to pulmonary disease.

Pheochromocytoma without hypertension presenting as cardiomyopathy

Characteristically, a patient with pheochromocytoma presents with paroxysmal or sustained hypertension and related symptoms. Occasionally the predominant manifestation of such a tumor may be congestive heart failure associated with primary myocardial disease, and hypertension may be absent. A patient with pheochromocytoma whose symptoms and clinical course related to a primary cardiomyopathy, and who remained normotensive until the final month of illness, has been presented. Mechanisms implicated in the development of primary myocardial disease by a pheochromocytoma have been reviewed. Diagnostic and therapeutic measures have been briefly outlined. The physician must be alert to the relatively rare occurrence of a pheochromocytoma in a patient who presents with a primary cardiomyopathy or unexplained congestive heart failure, since removal of the tumor allows for regression, if not cure, of the associated heart disease.

Atrial fibrillation and hyperthyroidism in a 14-year-old boy

<h2>Summary</h2> Atrial fibrillation is reported in a 14-year-old boy with juvenile hyperthyroidism, who also developed congestive heart failure and mitral regurgitation. The atrial fibrillation and congestive heart failure responded to treatment with digitalis, diuretics, quinidine, and antithyroid therapy. The murmur of mitral regurgitation resolved after the hyperthyroidism was brought under control. Hyperthyroidism should be included in the differential diagnosis of the pediatric patient with unexplained atrial fibrillation and unexplained congestive heart failure.