Exploratory mediastinotomy in primary myocardial disease

Myocarditis

Viruses are the most common cause of myocarditis in economically advanced countries.

Enteroviruses and adenoviruses are the most common etiologic agents.

Viral myocarditis is a triphasic process. Phase 1 is the period of active viral replication in the myocardium during which the symptoms of myocardial damage range from none to cardiogenic shock. If the disease process continues, it enters phase 2, which is characterized by autoimmunity triggered by viral and myocardial proteins. Heart failure often appears for the first time in phase 2. Phase 3, dilated cardiomyopathy, is the end result in some patients. Diagnostic procedures and treatment should be tailored to the phase of disease.

Viral myocarditis is a significant cause of dilated cardiomyopathy, as proved by the frequent presence of viral genomic material in the myocardium, and by improvement in ventricular function by immunomodulatory therapy.

Myocarditis of any etiology usually presents with heart failure, but the second most common presentation is ventricular arrhythmia. As a result, myocarditis is one of the most common causes of sudden death in young people and others without preexisting structural heart disease.

Myocarditis can be definitively diagnosed by endomyocardial biopsy. However, it is clear that existing criteria for the histologic diagnosis need to be refined, and that a variety of molecular markers in the myocardium and the circulation can be used to establish the diagnosis.

Treatment of myocarditis has been generally disappointing. Accurate staging of the disease will undoubtedly improve treatment in the future. It is clear that immunosuppression and immunomodulation are effective in some patients, especially during phase 2, but may not be as useful in phases 1 and 3. Since myocarditis is often selflimited, bridging and recovery therapy with circulatory assistance may be effective. Prevention by immunization or receptor blocking strategies is under development.

Giant cell myocarditis is an unusually fulminant form of the disease that progresses rapidly to heart failure or sudden death. Rapid onset of disease in young people, especially those with other autoimmune manifestations, accompanied by heart failure or ventricular arrhythmias, suggests giant cell myocarditis.

Peripartum cardiomyopathy in economically developed countries is usually the result of myocarditis.

Background and current knowledge of Chlamydia pneumoniae and atherosclerosis

Attributes of Chlamydia pneumoniae of potential importance to a relationship with atherosclerosis are described. Among these are that C. pneumoniae is not new. It is unique. It is a pathogen with which everyone is infected, and it is difficult to treat. It causes immunopathology, myocarditis, and endocarditis and chronicity is a hallmark of Chlamydia infection. Current knowledge of the relation of C. pneumoniae and atherosclerosis comes from observational (e.g., seroepidemiology and tissue studies) and experimental studies. The limitations of the serologic studies of chronic infection are noted as is the conclusive demonstration of an association of C. pneumoniae and atherosclerosis by the repeated and frequent finding of the organism in atherosclerotic tissue. Experimental studies are needed to determine if the association is causal. Such studies should include animal models, basic mechanisms, and secondary prevention antibiotic treatment trials.

Endomyocardial biopsy--technical aspects experience and current status. An Indian perspective

Our study ellucidates the utility of endomyocardial biopsy (EMB) in various cardiac-muscle disorders seen in a tropical country like India. The procedure has been successfully performed in 501 patients (572 procedures) at our centre from April 1985 to December 1992. This included 60 infants and children. The indications were dilated cardiomyopathy (DCM) in 214, non-specific aortoarteritis in 91, rheumatic heart disease in 75, restrictive cardiomyopathy in 45, constrictive pericarditis in 14 and miscellaneous in 62 patients. There was no mortality, however, one patient developed cardiac tamponade and another sustained ventricular tachycardia requiring cardioversion. There was transient atrial fibrillation in six patients and all these had acute rheumatic heart disease. Transient complete heart block occurred in six patients with underlying left-bundle branch-block. Histological examination of EMB revealed myocarditis in 34/214 (15.4%) patients in DCM group and helped in following up these cases on immunosuppressive treatment. In the presence of restrictive haemodynamics it could identify amyloidosis in four patients. It was also helpful in differentiating between endomyocardial fibrosis and chronic constrictive pericarditis. In patients with non-specific aorto-arteritis significant histological changes of inflammatory myocarditis were observed in patients especially in congestive heart failure. Furthermore, it was helpful in identifying the nature of cardiac tumour in one patient. Its utility has also been evaluated in disorders, including rheumatic heart disease, peripartum cardiomyopathy and systemic disorders like systemic lupus erythematosis. Even in the absence of cardiac-transplant programmes at national level we have found EMB to be a useful investigation in a tropical country like India.

Endomyocardial biopsy with a modified bioptome introducer sheath: focus on diagnostic yield and prevention of complications

With a focus directed on the potential diagnostic yield of tissue biopsy in suspected myocardial disease, transvascular endomyocardial biopsies were carried out prospectively in 130 patients. In 149 out of 153 consecutive procedures, where the number of associated major complications was less than 1%, King's bioptome and a specially designed radiopaque long introducer catheter were used. The rather thickwalled sheath had a conical tip which facilitated percutaneous entry and a preshaped distal bending which was particularly useful in the right ventricle for obtaining a steady and safe position in the direction of the interventricular septum. With respect to the histopathological information from an average of 4.2 biopsies per patient, a high clinical yield was gained in 28% of the patients, in the form of specific diagnoses and/or findings influencing subsequent therapy, and useful diagnostic information was gleaned from a further 53%. Thus, the procedure appears safe as a part of routine cardiac catheterization, and biopsy may contribute to a more accurate and clinically relevant classification of a substantial number of patients with suspected myocardial disease.

Endomyocardial biopsy: a review of the literature

A review of the literature relating to endomyocardial biopsy (EMB) is presented. This is considered important at this time since EMB is being utilized with increasing frequency, particularly for the diagnosis of myocarditis. The development of the technique is briefly outlined. Emphasis is placed on the clinical application of EMB in the various primary cardiomyopathies (dilated, hypertrophic, restrictive, and obliterative), the infiltrative secondary cardiomyopathies (amyloidosis, sarcoidosis, hemochromatosis), myocarditis, as well as such conditions as adriamycin cardiotoxicity, cardiac transplant rejection, and Kawasaki disease. More controversial application of EMB in primary mitral valve prolapse (Barlow's syndrome), idiopathic ventricular arrhythmias, and the elucidation of the enigmatic finding of angina with angiographically normal coronary arteries is detailed. Experience with immunological and biochemical investigation of biopsy material, as well as with virus isolation and drug assays in the myocardium, is alluded to. Complications encountered with this procedure are also discussed, and its future role is contemplated.

Critical assessment of diagnostic value of endomyocardial biopsy. Assessment of cardiac biopsy

Right or left ventricular endomyocardial biopsy with the Konno or the Olympus bioptome was attempted in 73 patients aged 5 months to 61 years, with 82 per cent success. Light and electron microscopy showed non-specific features in over half the biopsies with new or diagnostically useful information in only 10 per cent of cases, usually as a result of electron microscopy. The method is safe but is of strictly limited diagnostic value and is likely to be of most help as a research tool in the biochemical study of cardiomyopathies.

Pathophysiologic significance of S-T and T wave abnormalities in patients with the intermediate coronary syndrome

The frequent association of new ST-T wave changes without Q waves in the surface electrocardiogram of patients with the intermediate coronary syndrome necessitates a better understanding of the pathophysiologic significance of this finding. A previous study in patients with stable coronary artery disease indicated that the surface electrocardiogram is insensitive in detecting epicardial Q waves. This relation was evaluated in 21 patients with the intermediate syndrome, characterized by recurrent chest pain at rest associated with significant new S-T or T wave abnormalities, or both, and no new Q waves in the surface electrocardiogram at the time of open heart coronary bypass surgery. Unipolar electrograms were recorded from the epicardial surface of the left ventricle before the bypass procedure. In 19 patients, epicardial electrograms revealed initial R waves over areas of the left ventricle in which the acute S-T and T wave abnormalities were evident in the surface electrocardiogram. Two patients had epicardial Q waves (one laterally and one inferiorly). In seven patients, a transmural biopsy specimen was also obtained from the ischemic area. All showed histologically normal myocardium without evidence of early inflammatory or necrotic tissue. Of the 19 patients discharged, only one demonstrated new postoperative Q waves that had been detected by epicardial recordings before bypass. In summary, patients with the intermediate syndrome exhibiting S-T or T wave abnormalities, or both without new Q waves in the surface electrocardiogram generally do not have Q waves either in the intraoperative epicardial or postoperative surface electrocardiogram. In addition, no histopathologic abnormalities are apparent in biopsy specimens taken from the ischemic area.

Local characteristics of the normal and asynergic left ventricle in man

The significance of ventricular asynergy in determining medical prognosis and surgical risk in patients with coronary artery disease and its delineation by ventriculography have been of increasing interest. To determine the underlying histopathologic and electrographic features of left ventricular asynergy, 39 patients undergoing open heart surgery were studied. Thirty-six histopathologic specimens were obtained in 31 patients (26 as transmural needle biopsies and 10 as aneurysm resections). In four normally contracting areas and 12 hypokinetic areas, neither fibrosis nor early changes of myocardial damage was evident. In contrast, of eight akinetic areas there was more than 50 per cent muscle loss in four and from 30 to 35 per cent muscle loss in three, in only one area was there less than 10 per cent muscle loss. Of 12 dyskinetic zones there was more than 75 per cent muscle loss in 10 zones, 35 per cent in one and no pathologic abnormalities in one. Epicardial electrograms were obtained from 35 areas in 29 patients. Of 10 normally contracting ventricles, in one, pathologic Q waves were demonstrated only over the inferior area. Progressive increases in the severity of asynergy were associated with a progressive increase in frequency of initial abnormal Q waves. In only one of nine hypokinetic areas were epicardial Q waves exhibited, but they were present in six of 10 akinetic and five of six dyskinetic areas. Both histopathologic and electrographic data were available from 20 asynergic areas in 16 patients. Initial epicardial R waves were associated with normal biopsy specimens in seven of eight hypokinetic areas. Of seven akinetic areas, initial R waves were associated with 30 to 35 per cent muscle loss in three; of four areas with initial Q waves, there was a 35 per cent muscle loss in one and more than 50 per cent muscle loss in three. Similarly, of five dyskinetic segments, a QS pattern was associated with more than 75 per cent fibrosis in four. In one dyskinetic area there was an intial R wave in association with a normal appearing biopsy specimen. In summary, a good correlation exists between the severity of asynergy by ventriculography, the degree of muscle loss and the presence of epicardial Q waves. However, a significant amount of histologically and electrographically normal myocardium may be present even in severely asynergic areas.

Reversible asynergy. Histopathologic and electrographic correlations in patients with coronary artery disease

Histopathologic-electrographic studies of ventriculography depicted nitroglycerin responsive and unresponsive asynergic areas were performed in 25 patients. Of 29 areas, 12 improved with nitroglycerin, showing less than 10% muscle loss. Seventeen unimproved zones demonstrated significant fibrosis. Epicardial electrograms showed R waves in eight of nine improved zones. Of 11 unimproved zones, eight had Q waves. Histopathologic-electrographic data from five responders showed less than 10% muscle loss, of whom four had epicardial R waves. Six unresponsive areas had significant fibrosis, with a QS over four. Thus, nitroglycerin responsive asynergic areas are generally comprised of histologically intact myocardium and are associated with epicardial R waves.

Technique of endomyocardial biopsy--including a description of a new form of endomyocardial bioptome

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Natural course of peripartum cardiomyopathy

Twenty-seven patients presented in the puerperium with cardiomegaly, abnormal `ECG, and congestive cardiac failure and were considered to have peripartum cardiomyopathy (PPCM). The incidence of PPCM was significantly higher in women over 30 years of age, in women in their third or subsequent pregnancy, and in the presence of twins or toxemia. Within 6 months, 14 patients had normal sized hearts (group A), and 13 patients maintained cardiomegaly (group B).

The 14 patients in group A have been followed for 3 to 21 years (average 10.7 years). Two have died of unrelated causes. Of the remaining 12, eight are functional class I and four are functional class II. Eight patients had 21 subsequent pregnancies, with no permanent deterioration of cardiac function. Of 13 patients in group B, 11 (85%) have died of congestive cardiac failure. Their average survival was 4.7 years; six of 11 were dead in 3 years. Their clinical course was punctuated by repeated admissions for congestive cardiac failure. Six had pulmonary emboli, one had a systemic embolus, and three of six patients with subsequent pregnancies deteriorated in the puerperium. Of the two surviving patients, one is functional class I and the other is functional class II.

Therefore, in those patients in whom cardiomegaly persisted, the prognosis was poor, and subsequent pregnancies were likely to lead to permanent deterioration. In those in whom the heart size returned to normal the prognosis was excellent.

Pericardial and myocardial disease associated with serological evidence of infection by agents of the psittacosis-lymphogranuloma venereum group (Chamydiaceae)

Nine patients with acute pericarditis or myocarditis, or both, were found to have serological evidence of concurrent infection by a psittacosis agent. Three patients had conclusive epidemiological and clinical evidence of complicating pulmonary psittacosis and demonstrated that psittacosis agent does produce inflammatory heart disease in this geographic area.

Six patients had imperfect corroborative evidence of psittacosis and their clinical manifestations were atypical. Indeed, half of these patients were initially believed to have some form of idiopathic myocardial disease. Studies of these patients suggest that psittacotic infection m ay be causal in certain forms of heart disease commonly designated primary myocardial disease.

Primary myocardial disease and alcoholism. The clinical manifestations and course of the disease in a selected population of patients observed for three or more years

The course of primary myocardial disease (PMD) was observed in 39 alcoholics. After initial examination 3 years or more before this report, we classified the severity of each patient's illness as stage I, II, or III. Stage I patients had minimal symptoms and normal-sized hearts. Stage II patients had evidence of concentric left ventricular hypertrophy and clinical manifestations like those of hypertensive heart disease. Stage III patients had left, and frequently right, ventricular hypertrophy and dilatation associated with persistent congestive heart failure, and clinical manifestations typical of patients with PMD. Only the duration of congestive heart failure differed significantly between stages II and III. Eight patients had exploratory mediastinotomy and myocardial biopsy. Gross and microscopic findings supported the diagnosis of PMD and our classification of severity and revealed diffuse interstitial fibrosis. Fifteen patients have been observed for 3 or more years; 10 have died and 14 have disappeared. These studies emphasize alcoholism's importance in the genesis of this form of PMD. Correlations were positive between abstention from alcohol and waning of clinical severity, and between persistent drinking and waxing of clinical severity.