Case conference: complete heart block in a young man

A previously healthy 32-year-old man presented to the ED in complete heart block. Ischemic, infectious, and inflammatory conditions were considered in the differential diagnosis. Management options for complete heart block, the etiology of heart block in young adults, and treatment guidelines are reviewed.

Restricted usage of T cell receptor V alpha-V beta genes in infiltrating cells in the hearts of patients with acute myocarditis and dilated cardiomyopathy

Prolonged myocardial cell damage initiated by acute myocarditis is thought to be one of the most important etiology of dilated cardiomyopathy. To investigate the immunological mechanisms involved in the pathogenesis of dilated cardiomyopathy, we analyzed the phenotypes of infiltrating cells and examined the expression of perforin in infiltrating cells in the hearts of patients with dilated cardiomyopathy as well as acute myocarditis. We also examined the expression of HLA and intercellular adhesion molecule-1 (ICAM-1) in myocardial tissue of these patients. Furthermore, to evaluate the antigen specificity of infiltrating T cells and persistence of viral genomes in the myocardial tissue, we analyzed the expression of T cell receptor (TCR) V alpha and V beta genes as well as enterovirus genomes by PCR. We found infiltration of perforin-expressing killer cells and enhanced expression of HLA class I and ICAM-1 in the myocardial tissue. We also found that the repertoires of TCR V alpha as well as V beta gene transcripts were restricted, indicating that a specific antigen in the hearts was targeted. Because no enterovirus genomes were detected in all patients, it is strongly suggested that a cell-mediated autoimmune mechanism triggered by virus infection may play a critical role in the pathogenesis of dilated cardiomyopathy. However, we could not exclude the possibility that viruses other than enteroviruses could be pathogenic in these patients.

Advanced atrioventricular block associated with atrial tachycardia caused by Mycoplasma pneumoniae infection

Atrial tachycardia with atrioventricular (AV) block has been recognized as a common manifestation of digitalis toxicity. We describe here an unusual case of transient advanced AV block associated with atrial tachycardia in a 6 year old boy with evidence of Mycoplasma pneumoniae infection.

[Left ventricular systolic function in patients with infectious allergic myocarditis]

Examination of 26 patients with infectious-and-allergic myocarditis and of 12 cases with myocarditic cardiosclerosis, performed with the aid of radionuclide ventriculography revealed signs of impairement of left ventricular systolic function, with both end-systolic volume and the mean myocardial fiber circular shortening rate measurements showing a downward tendency. A relationship was established between alterations in systolic function of the heart and clinical pattern of the medical condition.

Molecular identification of viruses in sudden infant death associated with myocarditis and pericarditis

A subset of infants dying suddenly and unexpectedly have myocarditis with or without pericarditis found at autopsy. To address whether viruses known to cause infantile myocarditis and pericarditis might be present in such infants, we examined myocardium, liver and skeletal muscle for the presence of genomic sequences from adenovirus, cytomegalovirus, enterovirus and echovirus 22/23 in infants enrolled in a comprehensive evaluation protocol. We studied eight infants who died suddenly and unexpectedly with histologic evidence of myocarditis and/or pericarditis detected at postmortem examination. One infant with myocarditis and pericarditis had adenovirus genome detected in the myocardium. In an additional infant with severe pericarditis alone, enterovirus genome was detected in the liver. Although echovirus 22/23 has been associated with myopericarditis in young infants, no previous studies have used molecular methods to search for the genomic sequences of these viruses in clinical samples. No echovirus 22/23 genome was detected in the patients reported here. The significance of enterovirus and adenovirus genome in the tissues of two patients dying suddenly and unexpectedly remains speculative but raises the possibility that pathogenic viruses may cause little or no clinical symptoms and yet be contributory to sudden death in young infants.

Coronary artery thromboembolism and unexpected death in childhood and adolescence

Two cases of unexpected death in childhood and adolescence associated with coronary artery thromboembolism are reported involving a 6-year-old girl with acute rheumatic fever and left ventricular vegetations, and an 18-year-old adolescent with Down syndrome and congenital heart disease. Although coronary artery thromboembolism is rarely reported in childhood or adolescence, these cases demonstrate that careful examination of the coronary arteries during pediatric autopsy may be helpful in determining factors contributing to death, even at quite young ages. This is particularly so in the presence of predisposing cardiac pathology.

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 > or = 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.

Feline endomyocarditis and left ventricular endocardial fibrosis

A retrospective study was conducted of all feline necropsies over a 7-year period. Of a total of 1,472 necropsies, 37 cases of endomyocarditis (EMC) and 25 cases of left ventricular endocardial fibrosis (LVEF) (previously called restrictive or intermediate cardiomyopathy) were identified. There was a subset of four cats with EMC that had histologic features of both diseases. Interstitial pneumonia was seen in 25 of 35 cats (71%) with EMC but in only seven of 25 cats (28%) with LVEF. Thrombi or thromboemboli were seen in 14 of 25 cats (56%) with LVEF but in only six of 37 of cats (16%) with EMC. In both LVEF and EMC, thromboemboli were located in the abdominal aorta, left atrium and ventricle of the heart, femoral artery, cranial mesenteric artery, liver, pulmonary artery, jugular vein, or a meningeal vessel. Each cat had a single thrombus/thromboembolus, except for four cats with LVEF that had more than one. The histologic and clinical findings suggest that EMC and LVEF represent temporally different manifestations of a single disease entity.

Transseptal decompression of the left heart during ECMO for severe myocarditis

A 16-month-old boy suffered a cardiac arrest as a result of acute myocarditis, and venoarterial extracorporeal membrane oxygenation was instituted. Twelve hours later, acute left heart distention developed with cessation of left ventricular ejection. Under transesophageal echocardiographic guidance, a long introducer was placed into the left atrium through a transseptal puncture and connected in-line to the venous circuit. Within hours, left ventricular function improved and ejection returned. Left heart decompression was continued for 5 days, and the patient was weaned from extracorporeal membrane oxygenation after 6 days with normal cardiac and neurologic function.

Myocarditis in enteric fever

1. Myocarditis in the course of enteric fever is a common occurrence. In a series of 100 bacteriologically or serologically proved enteric fever, we found 7 cases with clinical evidence of myocarditis and 46 cases with ECG evidence of myocarditis. 2. Commonest ECG abnormality was Q-Tc prolongation (29%) followed by ST-T changes (20%) bundle branch block (7%) first degree A-V Block (%) and arrhythmia (2%). 3. All the ECG changes were transient except bundle branch block which persisted in 3 cases. 4. Those with other systemic complications had a higher chance of having myocarditis (P < 0.01). 5. Autopsy evidence of myocarditis was found in 2 cases. With our results, it is obvious that ECT must be recorded in all cases of enteric fever. Those with ECG changes must be observed carefully for clinical evidence of myocarditis. All these patients must have absolute bed rest. Judicious use of corticosteroids is indicated in selected cases of selected cases of severe myocarditis. Diuretics are indicated in cases with evidence of congestive cardiac failure.

Corticosteroid therapy for ventricular tachycardia in children with silent lymphocytic myocarditis

OBJECTIVE

The objective of our study was to describe the efficacy of corticosteroids for ventricular tachycardia in four children with structurally normal hearts in whom endomyocardial biopsy revealed histologic changes of lymphocytic myocarditis.

PATIENTS

The four patients had unexplained ventricular tachycardia. Three dysrhythmias were sustained, and one was inducible by exercise. Patient ages ranged from 4 months to 12 years. Three of the four patients had no symptoms. In two of them, ventricular tachycardia was identified by mass screening for heart disease. Two patients received oral steroids and two received pulse steroid therapy.

RESULTS

In all four patients, significant underlying diseases were not found by noninvasive evaluation. Right ventricular endomyocardial biopsy revealed abnormal histologic findings of chronic lymphocytic myocarditis in all patients. Steroid therapy was effective in all four patients, two of whom received methylprednisolone pulse therapy.

CONCLUSIONS

We conclude that unexplained ventricular tachycardia may be the only manifestation of clinically silent myocarditis. Steroid therapy should therefore be considered if conventional antiarrhythmic medication is not effective and histologic findings confirm the presence of lymphocytic myocarditis.

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.

Giant cell myocarditis: monocytic immunophenotype of giant cells in a case associated with ulcerative colitis

Giant cell myocarditis (GCM) is a rare condition whose histologic hallmark, the multinucleate giant cell, is of debated origin (monocytic v myogenic). We report the case of a 46-year-old woman with a previous diagnosis of ulcerative colitis who rapidly deteriorated and died as the result of refractory ventricular tachyarrhythmias. Postmortem examination showed a diffuse infiltration of the myocardium by round cells and multinucleate giant cells. Immunohistochemically, round cells were demonstrated to be T lymphocytes admixed with monocytes. Multinucleate giant cells expressed monocytic markers (MAC 387, lysozyme) and were negative for muscle markers (actin, desmin, myoglobin). This case illustrates the monocytic and macrophagic nature of multinucleate giant cells and lends support to the autoimmune hypothesis of GCM by the concurrence of the latter with ulcerative colitis.

Antibody-mediated imbalance of myocardial energy metabolism. A causal factor of cardiac failure?

The ADP-ATP carrier of the inner mitochondrial membrane is an autoantigen in myocarditis and dilated cardiomyopathy. Sera of patients with these diseases contain carrier-specific autoantibodies that inhibit the transmembrane nucleotide transport on isolated mitochondria. Guinea pigs immunized with the isolated ADP-ATP carrier protein also generate specific carrier-inactivating antibodies. In this study, we measured the cardiac function of guinea pigs immunized with the ADP-ATP carrier by determining the external heart work (EHW) of their isolated perfused spontaneously beating hearts stimulated by 4.0 mmol/L calcium and aortic ligature. Further, the electrogenic transport activity of the ADP-ATP carrier was estimated by calculating the cytosolic-mitochondrial difference of the phosphorylation potential of ATP [delta G(cyt-mit)] in the freeze-clamped isolated hearts by nonaqueous fractionation. The EHW of immunized guinea pigs was seen to be reduced by 54% (P < .005) compared with nonimmunized control guinea pigs, and delta G(cyt-mit) declined from 4.9 kJ/mol ATP in nonimmunized control hearts to 2.3 kJ/mol ATP in the hearts of the immunized guinea pigs (P < .005). The decisive result of this study, however, is the close relation observed between the magnitude of reduction of delta G(cyt-mit) and the size of the decrease in EHW (r = .87). Therefore, it seems plausible that antibody-mediated carrier dysfunction (creating the observed imbalance in myocardial energy metabolism) is responsible for the impairment of cardiac function. Our data support the hypothesis that immunopathic mechanisms in myocarditis and dilated cardiomyopathy can trigger subsequent heart failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Myocarditis-associated ventricular fibrillation. An unusual cause of syncope in Wolff-Parkinson-White syndrome

We report the case of a 60-year-old man with long-standing symptomatic Wolff-Parkinson-White syndrome who presented with recurrent syncope and documented spontaneous ventricular fibrillation. This primary ventricular fibrillation, which was not preceded by atrial fibrillation, was associated with lymphocytic myocarditis and not with Wolff-Parkinson-White syndrome. The patient was treated with radiofrequency ablation of the accessory pathway and a drug regimen of prednisone, amiodarone, and metoprolol. At the 6-month follow-up, he was asymptomatic and had returned to work. To our knowledge, the association of acute lymphocytic myocarditis and Wolff-Parkinson-White syndrome has not been previously reported.

Ventricular tachycardia and myocardial dysfunction in a horse

Ventricular tachycardia develops less frequently than supraventricular dysrhythmias and generally is more indicative of cardiac disease. The horse in this report had clinical signs of lethargy and hypophagia and was determined to have sustained ventricular tachycardia. Echocardiography was a valuable diagnostic tool and revealed an echodense area in the left ventricle that had subnormal ventricular performance. A primary heart problem of an inflammatory nature was suspected. The horse responded favorably to treatment with lidocaine, antimicrobials, and aspirin, as well as stall rest. The horse was used successfully as a sire and hunter-jumper after treatment, but subsequently died 2.2 years later of massive hemoperitoneum. Necropsy revealed an extensive area in the left ventricle that appeared thin and fibrotic.

Hemopump fails as bridge to transplantation in postinfarction ventricular septal defect

From 1990, six patients were bridged to transplantation with a catheter-mounted axial flow pump (Hemopump). Indications were graft failure (two patients), postinfarction ventricular septal defect (two patients), myocarditis (1 patient), and myocardial infarction (1 patient). The 21F cannula, inserted via the groin, was used as a partial assist in four patients, and the 31F cannula, inserted via the ascending aorta, was used to assist the other two patients completely. Hemodynamic recovery was achieved in all patients (mean cardiac index rose from 2.1 L/gm/m2 to 3.85 L/gm/m2 after 1 hour assist). Sudden pump failure occurred in the two patients with postinfarction ventricular septal defect and a piece of necrotic tissue blocking the catheter was found. Both patients died. The other four patients were successfully bridged to transplantation. One of these patients died during his postoperative hospital stay; the three remaining patients were discharged and were well at follow-up (46, 40, and 3 months). The Hemopump device provides sufficient organ perfusion to be used as a bridge to transplantation. No conclusions can be drawn for the long-term use (longest run in this series was 102 hours). Postinfarction ventricular septal defect is a contraindication for the use of the Hemopump device.

Serial electrocardiographic findings in acute myocarditis

The purpose of the present study was to clarify the characteristic findings of electrocardiogram (ECG) in 11 patients with acute myocarditis. ST elevation without reciprocal ST depression was one of the conspicuous findings in the acute stage. Total QRS amplitudes at the acute stage were significantly decreased as compared to those before illness and during the convalescent stage. Abnormal Q waves were present in 7 patients and disappeared in a short period. The number of leads showing Q waves was inversely correlated to left ventricular (LV) ejection fraction (r = -0.87, p < 0.01). Conduction disturbances were present in 7 patients. Second degree and advanced AV block was transient while bundle branch block remained over months. Corticosteroid treatment was effective for patients who had edematous myocardial thickening and AV conduction disturbances. As the serial ECG findings in acute myocarditis are so characteristic, and this help to differentiate it from acute myocardial infarction (AMI).