Dilated cardiomyopathy: diagnostic accuracy of endomyocardial biopsy

Histopathological Aspects of the Myocardium in Dilated Cardiomyopathy

Dilated cardiomyopathy is the most common form of cardiac muscle disease, accounting for approximately 60% of all cardiomyopathies. We proposed to identify histopathological changes of the myocardium in dilative cardiomyopathy. This study comprised a total of 19 cases, represented by myocardial fragments from deceased patients with diagnosis of dilated cardiomyopathy. Histopathological analysis allowed changes to be observed for both myocytes and myocardial interstitial components. We have found a combination of hypertrophic, atrophic and normal myocardocytes, or associated with the presence of hydropic changes. We rarely identified the aspect of myocytosis, cytoplasmic accumulation of lipofuscin pigment or mucinous material, and variable nuclear pleomorphism. At the interstitial level we noticed changes in fibrosis, lipomatosis and rarely the presence of inflammatory infiltrate. Histopathological characteristics of the myocardium in dilated cardiomyopathy are numerous but nonspecific, similar to those in the terminal stages of other cardiac diseases.

Cardiomyopathy in the pediatric patients

Pediatric cardiomyopathies are a group of myocardial diseases with complex taxonomies. Cardiomyopathy can occur in children at any age, and it is a common cause of heart failure and heart transplantation in children. The incidence of pediatric cardiomyopathy is increasing with time. They may be associated with variable comorbidities, which are most often arrhythmia, heart failure, and sudden death. Medical imaging technologies, including echocardiography, cardiac magnetic resonance, and nuclear cardiology, are helpful in reaching a diagnosis of cardiomyopathy. Nevertheless, endomyocardial biopsy is the final diagnostic method of diagnosis. Patients warrant surgical operations, such as palliative operations, bridging operations, ventricular septal maneuvers, and heart transplantation, if pharmaceutical therapies are ineffective. Individual therapeutic regimens due to pediatric characteristics, genetic factors, and pathogenesis may improve the effects of treatment and patients' survival.

Impact of diabetes mellitus on myocardial lipid deposition: an autopsy study

Lipid accumulation in the cardiac parenchyma has historically been known as fatty heart. Myocardial lipotoxicity and cardiac steatosis have been shown to be involved in the pathogenesis of obesity and diabetic mellitus (DM). Mutated adipose triglyceride lipase (ATGL), a key catalytic enzyme of triglyceride, has been found to cause human triglyceride deposit cardiomyovasculopathy (TGCV). Nevertheless, the significance of fatty heart in the disease process is still unclear. Here, we investigated myocardial lipid deposition (LD) in 73 autopsy cases. Nile blue staining revealed seven cases (9.5%) showing LD with elevated tissue triglyceride content, all of which suffered from DM. Immunohistochemically, ATGL expression was preserved in all tested cases. Rates of myocardial infarction and heart failure were higher in LD/DM cases than in non-LD cases. Semi-quantitative histological analysis revealed no significant differences in the degree of myocardial hypertrophy, myofibrillar loss, fibrosis, small vascular disease, inflammation or fat invasion between LD/DM and non-LD cases. However, more severe histological damage was seen in DM cases than in non-DM cases. Our data suggest that DM is a major risk for fatty heart with myocardial LD based on recent autopsy cases.

Biopsy-proven myocardial sequels in Kawasaki disease with giant coronary aneurysms

BACKGROUND

Although most Kawasaki disease with giant coronary aneurysms is asymptomatic, conventional investigations might not identify previous lesions, or all Kawasaki disease with giant aneurysms at risk of future myocardial lesions. We evaluated the long-term histopathology of the myocardium, especially of intramural small vessels in asymptomatic Kawasaki disease with giant aneurysms.

METHOD

The initial study comprised 16 consecutive Kawasaki patients - male-to-female ratio was 12:4 - aged from 2 to 12 years, and in the subsequent study, the same patients were aged from 4.9 to 16 years. Endomyocardial biopsies were histopathologically evaluated. Microangiopathies, mitochondrial abnormalities, and loss or disarray of myofibrils were compared by electron microscopy.

RESULTS

The incidence of histopathological abnormalities such as degeneration, hypertrophy, and inflammatory cell infiltration was quite high in the initial study, and inflammatory cell infiltration, interstitial fibrosis, and disarray were very noticeable at follow-up biopsies. The area of fibrous tissue was significantly higher in patients administered with intravenous immunoglobulin at follow-up biopsies. Electron microscopy showed microangiopathies including microthrombi within intramural small vessels in some patients at follow-up biopsies. The sites of the coronary aneurysms did not seem to have an impact on the biopsy findings, suggesting that the underlying pathophysiology is related to the original disease process.

CONCLUSIONS

Whether the abnormalities were due to direct myocardial injury, chronic ischaemia, repeated small-vessel thrombosis, or other problems associated only with biopsies, is difficult to determine. However, this subgroup had residual abnormal lesions in the myocardium. Follow-up should be more aggressive in this group of patients to identify myocardial damage that could be asymptomatic.

Histology of the explanted hearts of children transplanted for dilated cardiomyopathy

There is little information as to the histology of the explanted hearts of children transplanted for presumed dilated cardiomyopathy. We therefore aimed to describe the histology of these explants. Thirty-six children [mean age 7.4 years (range 0.1-17)] transplanted for dilated cardiomyopathy were identified. Based on histological examination of the explanted hearts patients were classified into three groups: severe inflammation, mild to moderate inflammation, and minimal or no inflammation. Cell death/damage and fibrosis were also scored. Duration of symptoms and degree of support at transplant were ascertained from the case notes. Two patients had severe confluent inflammation, nine mild or moderate focal inflammation, and 25 minimal or no inflammation. The degree of inflammation and fibrosis did not correlate with the interval between presentation and transplant (p = 0.37 and p = 0.78). Patients requiring inotropes or ventricular assist had a shorter time interval between presentation and transplant (p = 0.017) although these levels of support were not associated with the degree of inflammation or fibrosis (p = 0.90 and 0.5). We conclude that the explanted hearts of one-third of children transplanted for presumed cardiomyopathy have some degree of inflammation. Histological findings are not associated with symptom duration or support required.

Discordance between pre and post cardiac transplant diagnosis: implications for pre- and postoperative decision making

A correct clinical diagnosis in end-stage patients undergoing cardiac transplantation may have important prognostic and therapeutic implications. A retrospective clinico-pathologic study was carried out in 257 patients who had undergone cardiac transplantation at the University of Padua. A discrepancy between clinical and pathological diagnosis was found in 20 cases (8%). Among 126 patients with the clinical diagnosis of dilated cardiomyopathy, seven were found eventually to have ischemic heart disease (IHD), five myocarditis, one arrhythmogenic right ventricular cardiomyopathy (ARVC), and one non-compacted myocardium. Among the 87 patients with clinical diagnosis of IHD, three turned out to be dilated cardiomyopathy and one granulomatous myocarditis. Among the 10 patients with the clinical diagnosis of hypertrophic-restrictive cardiomyopathy, one had ARVC and one had cardiac fibroma. Altogether, only 24.5% underwent endomyocardial biopsy (EMB) and 75% coronary angiography before transplantation. Missed diagnosis of myocarditis occurred in patients in whom EMB was not carried out. EMB and coronary angiography might be indicated routinely in patients with apparent dilated cardiomyopathy, before proceeding to cardiectomy.

Clinical and histopathological studies in children with supraventricular tachycardia

To determine whether myocardial changes in patients with supraventricular tachycardia (SVT) are primary or secondary to persistent tachycardia, 11 patients with SVT were studied. These patients were divided into 2 groups with respect to the type of SVT. Group I consisted of 5 patients with incessant SVT and one with multifocal atrial tachycardia, while group II consisted of 4 patients with paroxysmal supraventricular tachycardia and one with short-run supraventricular premature contraction. All of the patients underwent electrophysiological study and endomyocardial biopsy from the right ventricle following routine cardiac catheterization. In group II, there were no significant abnormalities in the clinical and hemodynamic parameters. In group I, 3 patients had clinical features of dilated cardiomyopathy including abnormal ECG, chest X-ray and hypokinesis on left ventriculography. Induction and termination of SVT were possible in 2 patients in group I and in 4 of the 5 patients in group II. The only significant histologic difference between group I and group II was fibrosis. A high incidence of histopathological abnormalities, such as hypertrophy, degeneration, interstitial fibrosis and disarray was observed in both groups. The incidence of significant pathology was higher in group I than in group II. Almost all of the patients were given antiarrhythmic drugs. One patient underwent a successful surgical procedure and normal cardiac function returned after resection of the foci of the right atrium. Our present results suggest that patients with SVT who have incessant or recurrent SVT should undergo not only intracardiac electrophysiologic study but also endomyocardial biopsy for the evaluation of myocardial damage, since SVT might be the initial sign of cardiomyopathy.

Myocardial blood flow response to pacing tachycardia and to dipyridamole infusion in patients with dilated cardiomyopathy without overt heart failure. A quantitative assessment by positron emission tomography

BACKGROUND

Myocardial blood flow (MBF) impairment has been documented in advanced dilated cardiomyopathy (DCM) in which hemodynamic factors, secondary to severe ventricular dysfunction, may limit myocardial perfusion. To assess whether MBF impairment in DCM may also be present independent of hemodynamic factors, the present study was designed to quantify myocardial perfusion in patients with mild disease without overt heart failure.

METHODS AND RESULTS

Absolute regional MBF (milliliters per minute per gram) was measured by positron emission tomography and 13N-ammonia in resting conditions, during pacing-induced tachycardia, and after dipyridamole infusion (0.56 mg/kg over 4 minutes) in 22 DCM patients and in 13 healthy subjects. Patients were in New York Heart Association functional class I-II and showed depressed left ventricular (LV) ejection fraction by radionuclide angiography (35 +/- 8%; range, 21% to 48%), normal coronary angiography, and normal or moderately increased LV end-diastolic pressure (9.2 +/- 5.5 mm Hg; range, 2 to 20 mm Hg). There were no differences in arterial blood pressure, heart rate, and rate-pressure product between patients and control subjects in the three study conditions. Compared with control subjects, DCM patients had lower mean MBF at rest (0.80 +/- 0.25 versus 1.08 +/- 0.20 mL.min-1.g-1, P < .01), during atrial pacing tachycardia (1.21 +/- 0.59 versus 2.03 +/- 0.64 mL.min-1.g-1, P < .01), and after dipyridamole infusion (1.91 +/- 0.76 versus 3.78 +/- 0.86 mL.min-1.g-1, P < .01). LV MBF values were related to baseline LV end-diastolic pressure at rest (r = -.57, P < .01) and during pacing (r = -.67, P < .01) but not after dipyridamole infusion (r = .19, P = .40). Five patients had LV end-diastolic pressure > 12 mm Hg; in 4, myocardial perfusion was severely depressed both at baseline and in response to stress.

CONCLUSIONS

In patients with DCM without overt heart failure, myocardial perfusion is impaired both at rest and in response to vasodilating stimuli. The abnormalities in vasodilating capability can be present despite normal hemodynamics; progression of the disease is associated with more depressed myocardial perfusion.

The incidence of myocarditis in endomyocardial biopsy samples from patients with congestive heart failure

We present the combined experience of three Yugoslavian cardiovascular centers in the application of endomyocardial biopsy for the diagnosis of myocarditis in patients who present clinically with congestive heart failure. The study group comprised 107 patients (mean age, 40.8 years; range, 19 to 61 years). On the basis of patient history and diagnostic tests, the following clinical diagnoses were established: dilated cardiomyopathy (85), myocarditis (16), and alcohol-induced heart disease (6). EMB samples were taken from the left ventricle (95) or both ventricles (12) by use of a King's College bioptome, with a mean of 3.2 samples per patient. Histologic evidence of myocarditis was noted in 10 of 85 patients (12%) with a clinical diagnosis of dilated cardiomyopathy, in 2 of 6 patients (33%) with alcohol-induced heart disease, and in 12 of 16 patients (75%) with a clinical diagnosis of myocarditis. There was confirmation of the clinically suspected diagnosis in 63% of cases, a change of diagnosis based on histology in 15% of cases, and nonspecific findings in 22%. However, useful information was obtained in 78% of the cases, and there was a 22% incidence of histologically proven myocarditis for the entire group. Our results indicate that endomyocardial biopsy is beneficial in determining the true incidence of myocarditis in patients with a clinical presentation of dilated cardiomyopathy.

Endomyocardial biopsy in children with Kawasaki disease

To study the histopathology of the myocardium in Kawasaki Disease (KD) with various coronary angiographic findings, right endomyocardial biopsy specimens were evaluated on 20 boys and 16 girls with this disorder. KD with coronary artery lesions (CAL) showed various histopathological abnormalities, such as myocellular hypertrophy in 44%, degeneration in 61%, interstitial fibrosis in 44% and endomyocardial changes in 22%. KD without CAL revealed myocellular hypertrophy in 44%, degeneration in 50%, disarray in 28% and interstitial fibrosis in 6%. As in patients with long-standing KD, more than three years after onset, myocardial changes such as myocellular hypertrophy, disarray and interstitial fibrosis persisted, it is suggested that cardiomyopathy may develop in some patients with KD.

The morphologic spectrum of dilated cardiomyopathy and its relation to immune-response genes

Endomyocardial biopsies from 174 patients with dilated cardiomyopathy (DC) were examined. Eight patients with histologically proven myocarditis were excluded from the study. A peculiar pattern of oversized and bizarre nuclei was observed in only some of the remaining patients. Two groups were identified: those with and without this feature (groups A and B, respectively). Myocyte width, nuclear diameter and nuclear/sarcoplasmic ratio were significantly higher in group A. The mean respective values were 36 +/- 5 mu, 14 +/- 3 mu and 0.41 +/- 0.08 for group A versus 20 +/- 8 mu, 7 +/- 2 mu and 0.37 +/- 0.08 for group B. Interstitial fibrosis was similarly present in groups A and B. Endocardial thickness was significantly increased in all patients, with group A showing the highest mean value. The morphologic features showed no correlation with the clinical condition of the patients at time of presentation. HLA typing was performed in 50 consecutive patients, 38 from group A and 12 from group B. DR4 and DR5 antigens were significantly more frequent in DC patients than in a normal population control (400 blood donors), while DR3 was less frequent. Group A was more strongly associated with the DR5 antigen than group B (55.3 vs 25.0%, respectively). It was less strongly associated with the DR4 antigen compared with group B (21.5 vs 41.7%, respectively). No difference was observed between the 2 groups concerning negative association with the DR3 antigen. Endomyocardial biopsies from DC patients reveal marked morphologic changes from patient to patient.(ABSTRACT TRUNCATED AT 250 WORDS)