Viral coronary arteritis and myocardial infarction

Reversible impairment of coronary flow reserve in acute myocarditis

OBJECTIVE

Acute myocarditis is accompanied by an impaired coronary microcirculation. These microcirculatory disturbances are not well defined, and data are derived from complex invasive measurements. Therefore, this study aimed to evaluate the inflammation-induced microcirculatory dysfunction including its reversibility and association with markers of inflammation severity (extent of LGE on CMR imaging and laboratory markers of myocardial necrosis) using the noninvasive technique of echocardiographic CFR measurement.

METHODS

Patients (n = 14) with clinically suspected acute myocarditis in the absence of coronary artery disease were prospectively enrolled, and echocardiographic CFR was determined by measuring peak diastolic coronary blood flow velocity at rest (PDV1) and under adenosine-induced hyperemia (PDV2) at baseline and 3-month follow-up.

RESULTS

Eight of 14 (57.1%) patients showed an impaired baseline CFR (PDV2/PDV1 < 2). These patients were characterized by higher levels of cardiac troponin T (0.55 ± 0.39 vs 0.18 ± 0.08; P = 0.008) and larger areas of LGE on CMR. At 3-month follow-up, CFR was normal in all patients.

CONCLUSION

A reversibly impaired coronary microcirculation is a frequent finding in acute myocarditis and is associated with markers of inflammation severity. Echocardiographic CFR measurement represents a feasible and safe method for its assessment.

Infective coronary arteritis: a pathological analysis at autopsy

Coronary artery disease, one of the leading causes of worldwide adult mortality, is most commonly atherosclerotic in pathogenesis. Nonatherosclerotic etiologies are quite rare. In the latter category, infective arteritis or infective vasculitis of the coronary arteries is a very rare but well-recognized subtype, usually discovered at autopsy. In this article, we present the clinicopathologic necropsy data of 10 patients in whom infective coronary arteritis was the leading cause of death. Among the 10 cases, the male/female ratio was 6:4, and with the exception of a 2-year-old female child, all the other patients were adults with an age range of 26 to 59 years. Of the 10 cases, 6 had infective endocarditis along with history of rheumatic heart disease in 3 patients, whereas 2 other patients had strong clinical suspicion of bacteremia or septicemia. The remaining 2 cases had preexisting coronary atherosclerosis with a history of stent placement in 1 of them. All our cases showed on histopathology acute obliterative inflammatory infiltrate consisting mainly of neutrophils along with bacterial colonies (in most of them) involving the epicardial and intramural coronary arteries. To the best of our knowledge, this is the largest series of infective coronary arteritis to be reported in the world.

Neonatal myocardial infarction: case report and review of the literature

Myocardial infarction in a neonate is rare. We describe the case of a full-term male who presented with respiratory distress. A chest radiograph demonstrated cardiomegaly. An electrocardiogram revealed ST segment changes suggestive of ischemia. Cardiac enzymes were elevated and an echocardiogram revealed a regional wall motion abnormality. Cardiac catheterization was performed demonstrating occlusion of the ramus intermedius branch of the left main coronary artery. The patient decompensated, requiring extracorporeal membrane oxygenation (ECMO). The infant was able to be decannulated from ECMO support in 5 days and was ultimately discharged on hospital day 25. We review this case as well as the literature on neonatal myocardial infarction.

Neonatal myocardial infarction or myocarditis?

We report a 29 week-gestation preterm infant who presented during his second week of life with cardiogenic shock. Clinical presentation and first diagnostics suggested myocardial infarction, but echocardiographic features during follow-up pointed to a diagnosis of enteroviral myocarditis. The child died of chronic heart failure at 9 months of age. Autopsy showed passed myocardial infarction. No signs for active myocarditis were found. We discuss the difficulties in differentiating between neonatal myocardial infarction and myocarditis. Recognizing enteroviral myocarditis as cause for cardiogenic shock is of importance because of the therapeutic options.

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.

A rare case of acute 'infective' myocardial infarction triggered by acute parvovirus B19 myocarditis

BACKGROUND

A 25-year-old obese male (BMI 31.9 kg/m(2)) presented with atypical chest pain of sudden onset that was indistinguishable from acute myocardial infarction. He had tachycardia (104 beats/min) and dyspnea at a low level of exercise. He had no previous cardiac history, but his cardiovascular risk profile included a familial predisposition, smoking and hypertension.

INVESTIGATIONS

Electrocardiogram, laboratory testing, chest radiography, echocardiography, coronary angiography, intravascular ultrasonography and endomyocardial biopsy.

DIAGNOSIS

Acute myocardial infarction and parvovirus-B19-positive myocarditis.

MANAGEMENT

Percutaneous transluminal coronary angioplasty with intracoronary abciximab, heparin and nitroglycerin infusion.

Role of infection in atherosclerosis and coronary artery disease: a new therapeutic target?

There is growing evidence that inflammatory processes may be involved in the development of atherosclerosis and its complications. Viral and bacterial pathogens have been implicated as possible causative factors in the pathogenesis of coronary artery disease and postangioplasty restenosis. Antibiotic trials have been completed examining which treatment of infection can prevent the complications of coronary artery disease. In high-risk patients, the results of these most recent studies have not revealed any benefit of treatment.

Review of evidence for a connection between Chlamydia pneumoniae and atherosclerotic disease

BACKGROUND

Established risk factors account for no more than 50% of coronary artery disease cases; therefore, the search continues for other modifiable risk factors. In recent years, there has been renewed interest in the infectious theory of atherosclerosis. Chlamydia pneumoniae has been implicated as a potential cause of atherosclerotic disease.

OBJECTIVE

This review discusses possible mechanisms of C pneumoniae involvement in atherosclerosis, summarizes the case-control studies and antibiotic trials completed, and identifies remaining questions about future therapy.

METHODS

Published data were identified by a MEDLINE search of the English-language literature from 1966 through 2001 using the terms Chlamydia, atherosclerosis, and coronary artery disease. Relevant conference presentations and book chapters were also included.

RESULTS

C pneumoniae antibodies are found in approximately 50% of middle-aged adults world-wide. These antibodies have been detected in atherosclerotic tissue by various methods, including microimmunofluorescence, and several studies have linked high antibody titers with increased risk of cardiovascular events. A few possible mechanisms for this perceived increase in risk have been proposed, such as induction of atheroma through damage to the endothelium, expression of procoagulant factor leading to thrombus formation, and production of cytokines resulting in increased inflammatory response. Results of animal studies suggest that early antibiotic treatment may reduce cardiovascular risk, but the first human studies have not produced conclusive results.

CONCLUSIONS

Although a connection has been suggested, the precise mechanism by which C pneumoniae affects atherosclerosis has not yet been identified. Large-scale trials are needed to determine whether eradication of C pneumoniae reduces the incidence of cardiovascular events in humans.

Coronary arteritis diagnosed at autopsy: three case reports and review of the literature

Coronary arteritis is rare but can be fatal either by itself or in conjunction with other diseases. The authors report cases of three men in whom coronary arteritis was an interesting finding that may have caused or contributed to death. One 45-year-old man collapsed at work, another 56-year-old man was found dead in his parked car, and one 80-year-old man had a recent cerebrovascular accident. All three men had coronary arteritis, arteriosclerotic cardiovascular disease, some form of myocardial disease, and fatty liver change. Two had different lung diseases. The findings suggest that coronary arteritis may be an independent cause of death, part of a systemic disease, or, as these three cases illustrate, part of a constellation of cardiac and cardiovascular pathologies with a possible relation to other medical conditions. Coronary arteritis is an important finding in forensic pathology and merits consideration in a case of unexplained death.

Staphylococcal coronary arteritis as a complication of septicemia

We describe a case of staphylococcal coronary arteritis in the setting of sepsis due to arteriovenous fistula and dialysis catheter infection. The left circumflex coronary artery was the only vessel involved. The patient was a 77-year-old, insulin-dependent diabetic man with chronic renal failure. The immunosuppressed state in diabetes with subsequent septicemia may have facilitated a large number of bacteria to lodge in the atheromatous plaque of the coronary artery. We briefly review previously reported cases and suggest that bacterial arteritis may be an underrecognized cause of acute coronary occlusion.

Intense acute phase response in ischemic patients

The aim of this study was to estimate the qualitative and quantitative changes of acute phase proteins in patients suffering from coronary heart disease. The study was carried out on 74 patients and 12 healthy volunteers. The patients were divided into three groups as follows: patients with myocardial infarction (n=37), Group I--without heart failure, Group II--with heart failure (II-III NYHA), Group III--patients with unstable angina pectoris (n=35); controls-healthy volunteers (n=12). The immunological measurements were performed at the beginning of hospitalisation (point 0), after 4, 8, 12 and 72 h, and after 6, 9 and 12 days of hospitalisation. The concentrations of C-reactive protein (CRP), alpha1-acid glycoprotein (AGP) and alpha1-antichymotrypsin (ACT) were measured using rocket immunoelectrophoresis according to Laurell. Glycosylation profiles of AGP and ACT were determined using crossed affinity immunoelectrophoresis with Con A as ligand according to Bøg-Hansen. Between Groups I and II statistically significant differences were observed for all investigated parameters. Highest concentration values were observed for Groups II and III; for Group II they appeared earlier than for Group III. The maximal values for reactivity coefficients (AGP-RC and ACT-RC) were observed earlier than the respective maximal values of concentrations. Continuous activation occurring in unstable angina leads to a more rapid increase in the concentrations of acute phase proteins and more marked alterations in their glycosylation profiles. In a way these patients seem to be 'primed' with constant stimulation, so that they respond dramatically to the stimulus of ischemia.

Evidence of endothelial dysfunction of epicardial coronary arteries in patients with immunohistochemically proven myocarditis

BACKGROUND

Recent reports indicate that myocarditis can be associated with acute myocardial ischemia and even myocardial infarction in patients with normal arteriograms. We therefore tested the hypothesis that patients with biopsy-proven myocarditis have endothelial dysfunction despite angiographically smooth epicardial coronary arteries.

METHODS AND RESULTS

Graded concentrations of the endothelium-dependent vasodilator acetylcholine (10(-6) to 10(-4) mol/L) and for comparison, the non-endothelium-dependent vasodilator nitroglycerin (0.3 mg intracoronary), were infused into the left coronary arteries of 18 patients (mean age 47+/-9 years, 8 women and 10 men) with biopsy-proven myocarditis but without angiographically demonstrable coronary artery disease. Vascular responses were analyzed by quantitative coronary angiography. Three patients had an intact vasodilator response to acetylcholine concentrations of up to 10(-4) mol/L in all segments of the left coronary artery, with a mean dilatation of +9.9%+/-2%. In contrast, paradoxical constriction by acetylcholine occurred in 9 patients, who showed a mean change in coronary artery diameter of - 11%+/-3%. Six patients had no significant change in any segments in response to acetylcholine (-2.5%+/-4%). There was a significant inverse correlation between the number of T-lymphocytes in the myocardium and the response of the epicardial coronary arteries to acetylcholine (Pearson correlation coefficient -0.49, P=.03).

CONCLUSIONS

It can be assumed that the process of myocarditis is associated with impairment of endothelium-dependent vasodilation in response to acetylcholine in most patients. Vasoconstriction in the presence of acetylcholine in myocarditis is likely to reflect an abnormality of endothelial function. Endothelial dysfunction of coronary arteries may explain the occurrence of myocardial ischemia in patients with myocarditis.

"Infective" myocardial infarction

Four patients who developed acute myocardial infarction (AMI) in the setting of systemic febrile illness are described. They were all treated with anticoagulants or lytic agents (or both), demonstrating patient coronary arteries following infarction. We discuss the pathogenesis and therapeutic implications of AMI occurring in this setting.

Electrocardiographic criteria for diagnosis of acute myocardial infarction in childhood

Myocardial infarction (MI), a common occurrence in adults, is generally considered to be rare in children. Electrocardiographic criteria for diagnosis of MI in adults are well known and accepted, but no general criteria exist for children. We report 37 autopsy-proved cases of transmural MI and electrocardiographic evidence of MI in 30 of these cases. A variety of conditions previously reported to produce "pseudo-infarction" are included in these cases of MI, including myocarditis, hypertrophic cardiomyopathy, and the cardiomyopathy of Duchenne's muscular dystrophy. Compilation of the electrocardiographic data in all patients allowed for the development of criteria for this diagnosis of MI in childhood, and include wide Q waves (greater than 35 ms) with or without Q-wave notching, ST-segment elevation (greater than 2 mm), and prolonged QT interval corrected for heart rate (QTc greater than 440 ms) with accompanying Q-wave abnormalities. With use of these electrocardiographic criteria, an additional 3 patients were subsequently diagnosed prospectively with MI and confirmed on autopsy. Pathologic evaluation confirmed the location of infarction predicted by the electrocardiograms in all 3 cases.

Myocarditis presenting as acute myocardial infarction

Ten patients with acute myocarditis, who were initially seen with clinical signs of acute myocardial infarction, will be discussed. All had symptoms and seven had laboratory evidence of an acute viral infection. Acute cardiac findings consisted of chest pain in nine patients, compatible ECGs and elevated creatine kinase levels in 10, positive MB fractions in eight, and regional wall motion abnormalities in eight. Acutely, the left ventricular ejection fraction was less than 55% in six patients; ventricular ectopy occurred in five patients, bundle branch block in four, transient junctional escape rhythm in three, and congestive heart failure in three. Among the nine patients followed-up for 1 to 14 months there was one death, five patients had normal results of exercise tests, and three had normal coronary angiograms. Wall motion abnormalities persisted in four patients; ejection fraction improved in five and was less than 55% in three. These findings suggest that focal myocardial damage may occur during acute viral myocarditis and mimic acute myocardial infarction resulting from atherosclerotic coronary artery disease.

Infection and infarction. Acute viral (and other) infection in the onset, pathogenesis, and mimicry of acute myocardial infarction

Because a prospective controlled investigation showed a highly significant association of the onset of acute myocardial infarction with signs of preceding respiratory infection, the clinical, laboratory, experimental, and epidemiologic evidence more directly supporting this association was analyzed. Inflammation--specifically of infectious, usually viral, origin--has been shown by several lines of evidence to be capable of precipitating or mimicking clinical myocardial infarction. Myocardial biopsy is producing rapidly increasing confirmation that myocarditis can perfectly mimic clinical acute myocardial infarction. Coronary arteritis, with implications for vasospasm and thrombosis, is being increasingly demonstrated when deliberately sought in necropsy and biopsy material. Effects of blood-borne infectious agents, particularly viremia, on platelets in vivo and in vitro--aggregation and lysis with release of vasoactive substances--have even more serious potential for coronary thrombosis and vasospasm. It is not clear whether such mechanisms operate entirely independently or are more potent in high-risk patients, particularly in view of the demonstrable hypercoagulable state in many patients with coronary disease. Because of the great importance of confirming precipitating mechanisms for acute myocardial infarction (as well as its frequent mimic, myocarditis), intensive investigation of the relation between infection and infarction has important preventive and therapeutic implications.

Acute myocardial infarction associated with DF-2 bacteremia after a dog bite

This is the first reported case of an acute myocardial infarction probably secondary to DF-2 bacterial septicemia and presumed endocarditis. Selective coronary arteriography revealed a long filling defect causing 95% stenosis of the second diagonal branch of the left anterior descending coronary artery. Multiple blood cultures revealed Decarboxylase Fermentor-2 (DF-2) septicemia that responded to penicillin therapy. Two months status after myocardial infarction recatheterization revealed complete recanalization with slight irregularity of the vessel lumen at the site of previous obstruction.

An uncommon systemic arteritis--a case report

A 26-year-old male shortly after an acute respiratory disease was affected by a thrombophlebitis of the left leg. After a few days he had two syncopal attacks. Later on, a myocardial ischemia was diagnosed. Subsequently the patient began to complain of a bilateral claudication of the calves; after an attack of fever, the ischemia of the lower limbs worsened with recurring pain at rest. At the same time, in absence of any symptom, a myocardial ischemia occurred again and the presence of a thrombus was observed in the right atrium. After surgical removal of it, the ischemic troubles of the lower limbs once again began to worsen with the occurrence of bilateral gangrene of the feet. An amputation of both the legs was promptly performed at the level of the thighs. The histological examination of the arteries of the amputated legs showed segmental arteritis with partially recanalized thrombi of the popliteal, left femoral and tibioperoneal arteries. In the meantime, the titres for Coxsackie virus B2 and B6 were found slightly increased. One month later, the left radial pulse disappeared for a few days. The histopathological findings may relate this arteritis to a form of Buerger's disease even if a systemic thromboangiitis obliterans is not commonly accepted. In case that the acute respiratory infection represented the true onset of the sickness, it seems conceivable that the hypothesis of a viral infection gave raise to arteritis with morphological features recalling those of Buerger's disease.

Clinical aspects of virus/immune myocarditis

Although a cause-and-effect relationship between viral infection and myocarditis remains inferential, two distinct clinical syndromes can be identified. During the early viral phase, the cardiac manifestations emerge while the symptoms of active viral infection are also present. During the chronic phase, symptoms of the viral infection may be remote or nonexistent, and identification of active myocarditis is contingent upon an aggressive diagnostic approach with endomyocardial biopsy and gallium 67 imaging. The exact incidence of myocarditis in patients with heart failure of unknown cause is unclear due to lack of standardization of histologic parameters. There are no other clinical clues to the presence of myocarditis in those patients presenting with cardiomyopathy or ventricular arrhythmia. For further clarification of the incidence and various presentations of myocarditis a large multi-center trial is necessary.

Association of acute respiratory symptoms with onset of acute myocardial infarction: prospective investigation of 150 consecutive patients and matched control patients

Among 150 prospectively investigated patients with acute myocardial infarction (MI) and 150 control patients matched for age, sex and admission date, acute respiratory symptoms occurred in 42 MI patients and in 23 control patients (p less than 0.02). Matched-pairs analysis gave an odds ratio for a respiratory syndrome of 2.2:1 for MI. The statistically significant association of minor respiratory syndromes and the onset of MI must be further investigated to determine whether there is any pathogenetic relation of respiratory symptoms, presumably virally induced, to the onset of MI.

Pathogenesis of rheumatoid arthritis: a vascular hypothesis

Past research into the pathogenesis of RA has generally concerned itself with established inflammation. The present review summarizes alterations in microvascular anatomy and function which occur during the hypoxic state, in various experimental and disease conditions. It further shows that tissue hypoxia is a common finding in RA and that the microvascular alterations of RA are similar to those produced by experimental hypoxia. The available data suggest that microcirculatory compromise, concomitant with an increase in metabolic needs of synovial tissue, may initiate tissue injury via anoxia and acidosis, resulting in hydrolytic enzyme release, increased vascular permeability and acceleration of inflammatory processes. It is further believed that the microcirculatory abnormality may be generalized, accounting for the systemic manifestations often seen in RA. Factors effecting arteriolar blood flow obstruction are reviewed to identify areas for future investigation in RA and other disorders involving microvasculopathy. The multitude of longknown and newly recognized factors predisposing to vasospasm and vasodilatation have been outlined as a guide to possible mechanisms which may be operative in RA. An attempt has been made to gather and synthesize the available data in the hope that it may stimulate other investigators to pursue more definitive research into specific areas which may show early microvascular abnormalities in the pathophysiology of RA. Identification of factors operative early in the pathogenesis of RA, before it becomes self-perpetuating, may well be a step in the direction of preventing the ravages of this disease, or providing insight to more effective control.

Coxsackie B5 heart disease. Demonstration of inferolateral wall myocardial necrosis

A case of Coxsackie B5 viral myopericarditis is presented in which the diagnosis of inferolateral wall myocardial necrosis was made on the basis of specific cardiac enzyme changes and radionuclide myocardial imaging. This localized damage may have resulted from coronary arteritis with resulting infarction or necrosis secondary to preferential viral involvement of the inferolateral wall of the myocardium. Hepatitis and cerebral embolism complicated the case, with the latter suggesting endocardial disease.

On cerebral infarction in childhood and adolescence

This report is based on a retrospective analysis of clinical and angiographic findings in 14 children and adolescents suffering from cerebral infarction. They were all examined during the acute stage and selective angiography was performed within a day or two of the stroke. Pathogenesis is discussed and focuses particularly on the occurrence of segmental arteritis from unknown (infectious?) aetiology.