Acute myocarditis. A follow-up study

Contemporary National Trends of Mechanical Circulatory Support Among Myocarditis Hospitalizations Before the Pandemic: A National In-patient Database (2005-2019) Study

According to the Global Burden of Disease Project, the morbidity and mortality of myocarditis continue to be a significant worldwide burden. On October 1, 2015, hospital administrative data started using the International Classification of Diseases (ICD)-10 codes instead of the ICD-9. To our knowledge, nationwide trends of myocarditis have not been studied after this update. The NIS database from 2005-2019 was analyzed using ICD-9 and 10 codes. Our search yielded 141,369 hospitalizations due to myocarditis, with 40.9% females. There were 6627 (4.68%) patients who required mechanical circulatory support (MCS) using left ventricular assisted devices (LVAD), intra-aortic balloon pump (IABP), or extracorporeal membrane oxygenation (ECMO). The use of LVAD and ECMO increased significantly during the study period (p-trend 0.003 and <0.001, respectively), whereas the use of IABP decreased during the same period (p-trend 0.025). Our study demonstrated an overall increase in the use of MCS overall in myocarditis, with increasing utilization of more advanced MCS in the forms of LVAD and ECMO.

Trends in myocarditis incidence, complications and mortality in Sweden from 2000 to 2014

Investigate trends in myocarditis incidence and prognosis in Sweden during 2000–2014. Little data exist concerning population-trends in incidence of hospitalizations for myocarditis and subsequent prognosis. Linking Swedish National Patient and Cause of Death Registers, we identified individuals ≥ 16 years with first-time diagnosis of myocarditis during 2000–2014. Reference population, matched for age and birth year (n = 16,622) was selected from Swedish Total Population Register. Among the 8 679 cases (75% men, 64% < 50 years), incidence rate/100,000 inhabitants rose from 6.3 to 8.6 per 100,000, mostly in men and those < 50 years. Incident heart failure/dilated cardiomyopathy occurred in 6.2% within 1 year after index hospitalization and in 10.2% during 2000–2014, predominantly in those ≥ 50 years (12.1% within 1 year, 20.8% during 2000–2014). In all 8.1% died within 1 year, 0.9% (< 50 years) and 20.8% (≥ 50 years). Hazard ratios (adjusted for age, sex) for 1-year mortality comparing cases and controls were 4.00 (95% confidence interval 1.37–11.70), 4.48 (2.57–7.82), 4.57 (3.31–6.31) and 3.93 (3.39–4.57) for individuals aged < 30, 30 to < 50, 50 to < 70, and ≥ 70 years, respectively. The incidence of myocarditis during 2000–2014 increased, predominantly in men < 50 years. One-year mortality was low, but fourfold higher compared with reference population.

Autoimmunity in Acute Myocarditis: How Immunopathogenesis Steers New Directions for Diagnosis and Treatment

PURPOSE OF REVIEW

Over the last decade, myocarditis has been increasingly recognized as common cause of sudden cardiac death in young adults and heart failure overall. The purpose of this review is to discuss hypothesis of development of non-infectious myocarditis, to provide a description of the immunopathogenesis and the most common mechanisms of autoimmunity in myocarditis, and to provide an update on therapeutic options.

RECENT FINDINGS

A new entity of myocarditis is immune checkpoint inhibitor (ICI) induced myocarditis. ICIs are used in advanced cancer to "disinhibit" the immune system and make it more aggressive in fighting cancer. This novel drug class has doubled life expectancy in metastatic melanoma and significantly increased progression free survival in advanced non-small-cell lung cancer, but comes with a risk of autoimmune diseases such as myocarditis resulting from an overly aggressive immune system. Myocarditis is an inflammatory disease of the heart with major public health impact. Thorough understanding of its immunopathogenesis is crucial for accurate diagnosis and effective treatment.

Adult murine cardiomyocytes exhibit regenerative activity with cell cycle reentry through STAT3 in the healing process of myocarditis

Mammalian cardiomyocytes substantially lose proliferative capacity immediately after birth, limiting adult heart regeneration after injury. However, clinical myocarditis appears to be self-limiting with tissue-reparative properties. Here, we investigated the molecular mechanisms underlying the recovery from myocarditis with regard to cardiomyocyte proliferation using an experimental autoimmune myocarditis (EAM) model. Three weeks after EAM induction (EAM3w), cardiac tissue displayed infiltration of inflammatory cells with cardiomyocyte apoptosis. However, by EAM5w, the myocardial damage was remarkably attenuated, associated with an increase in cardiomyocytes that were positively stained with cell cycle markers at EAM3w. Cardiomyocyte fate mapping study revealed that the proliferating cardiomyocytes primarily derived from pre-existing cardiomyocytes. Signal transducer and activator of transcription 3 (STAT3) was robustly activated in cardiomyocytes during inflammation, accompanied by induction of interleukin-6 family cytokines. Cardiomyocyte-specific ablation of STAT3 gene suppressed the frequency of cycling cardiomyocytes in the recovery period without influencing inflammatory status, resulting in impaired tissue repair and cardiac dysfunction. Finally, microarray analysis revealed that the expression of regeneration-related genes, metallothioneins and clusterin, in cardiomyocytes was decreased by STAT3 gene deletion. These data show that adult mammalian cardiomyocytes restore regenerative capacity with cell cycle reentry through STAT3 as the heart recovers from myocarditis-induced cardiac damage.

Moesin is activated in cardiomyocytes in experimental autoimmune myocarditis and mediates cytoskeletal reorganization with protrusion formation

Acute myocarditis is a self-limiting disease. Most patients with myocarditis recover without cardiac dysfunction in spite of limited capacity of myocardial regeneration. Therefore, to address intrinsic reparative machinery of inflamed hearts, we investigated the cellular dynamics of cardiomyocytes in response to inflammation using experimental autoimmune myocarditis (EAM) model. EAM was induced by immunization of BALB/c mice with α-myosin heavy chain peptides twice. The inflammatory reaction was evoked with myocardial damage with the peak at 3 wk after the first immunization (EAM3w). Morphological and functional restoration started from EAM3w, when active protrusion formation, a critical process of myocardial healing, was observed in cardiomyocytes. Shotgun proteomics revealed that cytoskeletal proteins were preferentially increased in cardiomyocytes at EAM3w, compared with preimmunized (EAM0w) hearts, and that moesin was the most remarkably upregulated among them. Immunoblot analyses demonstrated that the expression of both total and phosphorylated moesin was upregulated in isolated cardiomyocytes from EAM3w hearts. Immunofluorescence staining showed that moesin was localized at cardiomyocyte protrusions at EAM3w. Adenoviral vectors expressing wild-type, constitutively active and inactive form of moesin (wtMoesin, caMoesin, and iaMoesin, respectively) were transfected in neonatal rat cardiomyocytes. The overexpression of wtMoesin and caMoesin resulted in protrusion formation, while not iaMoesin. Finally, we found that cardiomyocyte protrusions were accompanied by cell-cell contact formation. The expression of moesin was upregulated in cardiomyocytes under inflammation, inducing protrusion formation in a phosphorylation-dependent fashion. Moesin signal could be a novel therapeutic target that stimulates myocardial repair by promoting contact formation of cardiomyocytes.

Carditis associated with mycoplasma pneumoniae infection

Among 560 patients with serologically confirmed Mycoplasma pneumoniae infection, 25 (4.5%) had carditis (19 perimyocarditis, 6 pericarditis). During the acute phase 9 patients required intensive care. After an average of 16 months follow-up 11 patients with no previous signs of heart disease still had cardiac symptoms or signs. Thus carditis associated with M. pneumoniae infection is a serious disease, having cardiac sequelae more often than has hitherto been supposed. The pathogenesis of the carditis associated with M. pneumoniae infection is discussed, including the possibility that in some cases the elevated titre in the complement fixation test is non-specific. A summary is given of the 33 cases previously presented in the literature.

Stokes-Adams attacks requiring pacemaker treatment in three patients with acute nonspecific myocarditis

Three patients, aged 16--44 years, with complete heart block in acute myocarditis are reported. The diagnosis of myocarditis was based on the development of transitory repolarization disturbances on the ECG in association with clinical signs of acute infectious disease. All patients were brought to hospital due to repeated Stokes-Adams attacks and demonstrated ventricular asystoles for up to 25 sec. The patients were all successfully treated with temporary intracardiac pacing but one of them later turned out to require a permanent pacemaker. The possibility of differences in localization and in prognostic importance of conduction disturbances between infectious and ischemic myocardial disease is discussed.

Etiology of mild acute infectious myocarditis. Relation to clinical features

The etiology of mild myocarditis, diagnosed on the basis of serial ECG changes during an acute infection, was studied in 126 consecutive conscripts. A fourfold rise in the antibody titers in the paired serum samples was required for a positive etiologic diagnosis. An etiologic diagnosis was made probable in 47% of the patients. Adenovirus was incriminated in 19 patients, vaccinia in 12, influenza A in eight, beta-hemolytic Streptococcus in six, mononucleosis in five and Mycoplasma in three. Chlamydia, influenza B and Coxsackie B4 were each found in two patients; parainfluenza, mumps and adult Still's disease were each found in one patient. The incidence of vaccinia myocarditis was 1/10000 smallpox vaccinations. Clear-cut myopericarditis was usually noted during vaccinia, mononucleosis, Mycoplasma, Chlamydia and Coxsackie B4 infections. Adenovirus and influenza A myocarditis was most often subclinical, being mostly detected only because of ECG screening of patients without cardiac symptoms. Frequent recent ventricular extrasystoles were most often triggered by a beta-hemolytic Streptococcus infection. The etiology of infectious myocarditis seems to reflect the overall profile of viruses and other infective agents in the study population at that particular time. Cardiotrophic viruses such as Coxsackie B only rarely cause myocarditis outside epidemics.

Smallpox vaccination and myopericarditis: a clinical review

Smallpox is a devastating viral illness that was eradicated after an aggressive, widespread vaccination campaign. Routine U.S. childhood vaccinations ended in 1972, and routine military vaccinations ended in 1990. Recently, the threat of bioterrorist use of smallpox has revived the need for vaccination. Over 450,000 U.S. military personnel received the vaccination between December 2002 and June 2003, with rates of non-cardiac complications at or below historical levels. The rate of cardiac complications, however, has been higher than expected, with two confirmed cases and over 50 probable cases of myopericarditis after vaccination reported to the Department of Defense Smallpox Vaccination Program. The practicing physician should use the history and physical, electrocardiogram, and cardiac biomarkers in the initial evaluation of a post-vaccination patient with chest pain. Echocardiogram, cardiac catheterization, magnetic resonance imaging, nuclear imaging, and cardiac biopsy may be of use in further workup. Treatment is with non-steroidal anti-inflammatory agents, four to six weeks of limited exertion, and conventional heart failure treatment as necessary. Immune suppressant therapy with steroids may be uniquely beneficial in myopericarditis related to smallpox vaccination, compared with other types of myopericarditis. If a widespread vaccination program is undertaken in the future, many more cases of post-vaccinial myopericarditis could be seen. Practicing physicians should be aware that smallpox vaccine-associated myopericarditis is a real entity, and symptoms after vaccination should be appropriately evaluated, treated if necessary, and reported to the Vaccine Adverse Events Reporting System.

Coxsackie B virus infection in idiopathic dilated cardiomyopathy: clinical and pharmacological implications

Idiopathic dilated cardiomyopathy (IDC) is a myocardial disease characterised by ventricular dilatation, impaired contractility, and the symptoms of congestive heart failure. Although the causes of IDC remain uncertain, much interest has been focused on the enteroviral infection in the myocardium in the pathogenesis of this disease. Enteroviral RNA has been demonstrated in the myocardium at all stages of IDC. Recent studies using sequence analysis of enteroviral polymerase chain reaction (PCR) products have shown that the viruses detected in hearts of patients with IDC are coxsackie B. In addition, active coxsackieviral RNA replication in the myocardium has been demonstrated by strand-specific detection of viral RNA. Viral antigen has also been found in hearts with IDC by immunohistochemical techniques. In tissue culture experiments and transgenic mice, it has been shown that restricted coxsackieviral RNA replication, and not infectious virus progeny, in the myocardium can impair cardiac contractile function and lead to dilated cardiomyopathy. Coxsackieviral RNA in the myocardium can be a marker of a poor clinical outcome after partial left ventriculectomy, and might influence prognosis after heart transplantation. Therefore, there is a therapeutic need to detect replicating coxsackieviral RNA in the myocardium, and a specific therapy for coxsackie B viruses is indicated in the management of patients with virus-positive IDC.

The etiology of cardiac arrest in children and young adults: special considerations for ED management

Children and young adults rarely present to the emergency department (ED) in cardiac arrest. This review examines published series on nontraumatic, cardiac arrest for patients aged 1 to 45 years and discusses the differential diagnosis for cardiovascular collapse. Among the most common entities encountered are cardiac diseases (hypertrophic cardiomyopathy, myocarditis), airway diseases (pneumonia, epiglottitis, and asthma), epilepsy, hemorrhage (gastrointestinal bleeding, ectopic pregnancy), and drug toxicity (tricyclic antidepressants, cocaine). ED management of children and young adults in cardiac arrest requires an understanding of the heterogeneous pathophysiologic mechanisms and etiologies leading to cardiopulmonary dysfunction in these patients. The emergency physician should give particular focus to airway management for toddlers and preadolescents, because respiratory diseases predominate. When treating an adolescent or young adult, the resuscitation team should also consider toxic causes as well as occult hemorrhage. Management considerations unique to this patient population are discussed.

Antiviral treatment with WIN 54 954 reduces mortality in murine coxsackievirus B3 myocarditis

BACKGROUND

Coxsackieviruses B (CBVs) are dominant causative agents in myocarditis and are associated with pathogenesis is some cases of dilated cardiomyopathy, a clinical entity with a poor survival without heart transplantation.

METHODS AND RESULTS

In vitro, the antiviral agent WIN 54 954 was shown to inhibit replication of CBV3 at a minimal inhibitory concentration value of 0.02 mg/L. Administration of WIN 54 954, 100 mg/kg BID PO, beginning on the day of infection resulted in complete protection from enteroviral mortality (P < .01). WIN 54 954 treatment did not abrogate the inflammatory reaction in the myocardium. No difference was found in the expression of surface lymphocyte subset markers. At 3 weeks, macrophages seemed to dominate the inflammatory reaction, regardless of treatment. There was no difference in CBV3 antibody titers, indicating that WIN 54 954 does not interfere with the development of protective immunity. Complement factors C3 and B were synthesized at a higher level during infection and correlated well with the degree of inflammatory reaction.

CONCLUSIONS

The results show that WIN 54 954 is a potent antiviral agent with a highly significant effect on survival in CBV-induced myocarditis in the A/J mouse if treatment is started early. It is suggested that the reduction in mortality seen with WIN 54 954 administration is due to an inhibitory effect on virus replication in affected organs that does not interfere with cellular or humoral immunity.

Infectious and lymphocytic myocarditis: epidemiology and factors relevant to sports medicine

Myocarditis is a disease entity of permanent actuality and of special concern in the sports setting. This is because the probability of complications or sequelae increases if exercise is imposed. Myocarditis may pass unrecognized by the sufferer or be easily overlooked by the physician, especially in athletes, where electrocardiographic changes often exist normally. Furthermore, although the immune system of the conditioned individual may be more efficient than that of the sedentary individual, very strenuous and frequently repeated or long-lasting exercise may cause immunosuppression and an increased susceptibility to respiratory tract infections (RTI). Several causative agents of RTI can give rise to myocarditis as well. The true incidence of proven infectious myocarditis in society is unknown. Histopathologically defined myocarditis (lymphocytic myocarditis), on the other hand, has been found in about 1% of unselected routine autopsies. In general, the long-term prognosis in myocarditis is favorable but exercise stress may cause long-term sequelae or sudden death. It is thus essential to refrain from strenuous exercise during RTI.

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.

Electrocardiography of myocarditis revisited: clinical and prognostic significance of electrocardiographic changes

To clarify the clinical and prognostic value of the ECG, an ECG review was undertaken in 45 consecutive patients with a histologic diagnosis of active myocarditis (29 men and boys and 16 women and girls; age, 36.8 +/- 15 years; idiopathic myocarditis, 39 cases). In patients (21) with symptoms of recent onset (less than or equal to 1 month) AV block and repolarization abnormalities were the prevailing ECG features at the time of admission, and a pseudoinfarction pattern (Q waves plus ST-segment elevation) frequently heralded a rapidly fatal course ("fulminant myocarditis"). Left atrial enlargement and atrial fibrillation, left ventricular hypertrophy and LBBB, which prevailed in patients who had symptoms for longer periods, corresponded to the most severe degree of left ventricular dysfunction during the initial hemodynamic and echocardiographic evaluation. The overall mortality rate after 58 +/- 24 months from the time of diagnosis was 29%. Abnormal QRS complexes and LBBB were markers of poor survival, independently of initial indexes of left and right ventricular function, both of which indicate an increased propensity for sudden cardiac death.

Complete heart block from mycoplasma pneumoniae infection

Complete heart block (CHB) in infants and children is usually congenital. Nonsurgical acquired CHB is rare. Occasionally, transient acquired CHB is seen in association with viral myocarditis. We describe here an unusual case of transient CHB in a 12-year-old boy with endomyocardial biopsy-proven myocarditis and evidence of Mycoplasma pneumoniae infection.

Diagnosing and treating active myocarditis

The treatment of dilated cardiomyopathy is palliative and, hence, has little effect on the natural history. Therapy directed toward the cause rather than the effect will be necessary before mortality can be affected. Active myocarditis is postulated to be the cause of dilated cardiomyopathy in a subset of patients. A model of murine coxsackievirus B3 myocarditis has immunopathogenic parallels to the disease in humans and suggests that persistent autoimmune reactivity following viral clearance leads to progressive myocyte damage and dilated cardiomyopathy. In preliminary uncontrolled studies, patients with myocarditis have shown clinical and histologic improvement with the addition of immunosuppressive therapy, but there may also be a significant rate of spontaneous improvement. A multicenter study currently acquiring patients is designed to determine the efficacy of immunosuppression and the natural history of active myocarditis.

Streptococcal tonsillitis and acute nonrheumatic myopericarditis

Two young men with streptococcal tonsillitis had acute myopericarditis mimicking myocardial infarction. Subsequently, 264 consecutive army conscripts hospitalized with a fever and sore throat underwent throat cultures. Group A streptococci were found in 84 patients. When these patients were systematically screened by serial electrocardiography for myocarditis, one case of probable asymptomatic myocarditis was diagnosed. None had signs of acute rheumatic fever. All three patients received penicillin therapy when the signs of myocarditis appeared. Their recovery was good.

Dilated cardiomyopathy and myocarditis: natural history, etiology, clinical manifestations, and management

This monograph begins and ends with a statement of uncertainty regarding many aspects of dilated cardiomyopathy. Natural history studies identify patients with widely differing outcomes. A host of prognostic factors have emerged, yet it would appear that the major determinants of survival are as yet unrecognized. The diagnosis remains primarily one of exclusion, and management is largely nonspecific and supportive. The frequency of sudden cardiac death is well documented, but the ability to accurately identify patients at risk and the efficacy of antiarrhythmic therapy is unestablished. The emerging success of cardiac transplantation is a source of encouragement. The causes of dilated cardiomyopathy remain a source of intense investigation. Accumulating evidence (much of it circumstantial) does, however, implicate a viral etiology and perhaps altered function of the immunoregulatory system. However, the disparity between the severity of functional disturbance with the relative lack of histologic markers of cellular necrosis implies a disturbance at a cellular level. The etiology or etiologies remain elusive. Future investigation directed at fundamental aspects of cardiac cellular biology may provide the answers.

Long-term follow-up of patients with previous myocarditis using radionuclide ventriculography

A prospective long-term follow-up study is reported of 18 of 19 patients who survived a bout of presumed myocarditis 6-136 months (average 54 months) previously. The study included 14 males and four females, ranging from 27 to 63 years of age (mean, 44 years). Chest X-ray, ECG, echocardiogram, and resting and exercise radionuclide ventricular ejection fraction (RNVEF) for assessment of ventricular function were evaluated at follow-up. Resting and exercise RNVEF from seven control subjects were evaluated for comparison. Residual abnormalities were noted in chest X-ray (16%), echocardiogram (30%), and ECG (55%) in these predominantly asymptomatic patients (17/18 or 95%). The resting RNVEF (mean +/- SD) for the myocarditis group versus controls were 0.57 +/- 0.1 and 0.65 +/- 0.1 (P = NS), respectively. The exercise RNVED for the myocarditis group versus controls were 0.56 +/- 0.1 and 0.74 +/- 0.05 (P less than 0.01), respectively. Abnormal resting RNVEF was noted in six (33%) and exercise RNVEF in 14 (77%) patients in the myocarditis group. Two patients with abnormal exercise RNVEF subsequently developed findings consistent with dilated cardiomyopathy. It is unclear as to whether the abnormal ventricular function may serve as a marker for future development of dilated cardiomyopathy.

Functional and myocarditis-induced T-wave abnormalities. Effect of orthostasis, beta-blockade, and epinephrine

Negative T waves in the ECG during an acute infection may be due purely to functional variations, making the diagnosis of acute myocarditis difficult. The effects of orthostasis, beta-blockade, and intravenous epinephrine infusion (0.07-0.21 micrograms/kg/min) on T waves and the Q-T interval was studied in 28 young men with acute myocarditis, in 29 persons with functional T-wave abnormalities, and in 30 healthy subjects. Myocarditis-induced negative T waves were never normalized by beta-blockade. Functional T-wave inversions were normalized by beta-blockade in 22 subjects (76 percent). Orthostasis always augmented the T-wave abnormalities that were normalized by beta-blockade. Functional T-wave abnormalities responding to beta-blockade were augmented by epinephrine in 17 subjects (77 percent); but those unresponsive to beta-blockade were normalized in six of seven subjects. The Q-Tc interval was significantly (p less than 0.01) lengthened in subjects with myocarditis (410 +/- 36 ms) compared with controls (384 +/- 27 ms). The beta-blockade test is useful in differentiating between functional T-wave inversions and acute myocarditis. However, functional T-wave abnormalities are not constantly abolished by beta-blockade but may then be normalized by epinephrine. A clearly prolonged Q-Tc interval speaks for a diagnosis of myocarditis.

Acute and transient ST segment elevation during bacterial shock in seven patients without apparent heart disease

Acute elevation of the ST segment in several ECG leads was observed in seven patients with bacterial shock during the course of therapy. Six patients had bacterial pneumonia, one had acute cholecystitis, and none had a previous history of heart disease. At the onset of the ST elevation, all patients were receiving dopamine infusion, which in four of them was inadvertently increased shortly before the ECG changes, the ST elevation was not associated with chest pain, pericardial friction rub, or acute changes in the heart rate, or arterial blood pressure. In four patients the maximum ST elevation was greater than or equal to 5 mm. In each instance the ST segment returned to the isoelectric line within 24 hours, and subsequent development of Q waves or changes in the QRS was not observed. Although the existence of an acute pericarditis or an acute myocarditis as possible causes of the ST elevation cannot be fully ruled out, the sudden onset, prominent magnitude, and brief duration of the ST elevation are perhaps more indicative of an acute ischemic event, possibly related to a transient coronary vasoconstriction induced by the dopamine infusion.

Evaluation of mild acute infectious myocarditis

The diagnosis of acute mild myocarditis in vaguely defined. Therefore we studied 185 consecutive young men in military service with electrocardiographic changes arousing a suspicion of myocarditis in connection with an acute infectious disease. It was possible to classify 160 patients into seven electrocardiographic groups; definite or probable myocarditis was observed in 104 patients. The electrocardiographic patterns considered characteristic for acute myocarditis were: ST segment elevations followed by T wave inversions; gradually changing T wave inversions not corrected by beta blockade; and ventricular extrasystoles more than 10 per minute triggered by acute infection. Thirty-nine subjects without myocarditis had "functional" T wave abnormalities completely normalised by beta blockade, or stable T wave inversion. The leading symptoms in acute myocarditis were fatigue and chest pains; loud S3 gallop, paradoxical cardiac pulsation, pericardial friction rub, or enlargement of the heart were noted altogether in 50% of the patients. Echocardiography disclosed segmental wall motion abnormalities related to the T wave inversions. Serum creatine kinase MB fraction increased in 70% of the acute myopericarditis patients during the ST segment elevation stage. In the non-myocarditis groups the clinical and pertinent laboratory findings remained normal. Thus, we noted in clinically mild acute infectious myocarditis clear-cut and early signs of myocardial dysfunction, suggesting that the direct and often local viral invasion of the myocardium is the basic pathogenetic mechanism. The present electrocardiographic classification based on serial tracings and beta blockade proved useful in the evaluation of patients suspected of having mild acute myocarditis.

Clinical and laboratory manifestations in patients with serological evidence of Mycoplasma pneumoniae infection

139 cases of Mycoplasma pneumoniae infection (serological diagnosis) were treated at Aurora Hospital, Helsinki, between January 1975 and August 1977. In 123 patients the main diagnosis was respiratory infection; 114 of these had pneumonia. The frequency of complications was high: 8 patients had neurologic, 6 cardiac and 5 joint symptoms. Although a significant rise in titre of complement-fixing antibodies to M. pneumoniae was required, the low titre level in some patients who had manifestations less frequently associated with M. pneumoniae infection may suggest nonspecific reactions. Nearly half of the patients in this study had plasmocytosis in the peripheral blood suggesting a strong antibody response. This might be connected with some serological reactions detected in association with M. pneumoniae infections.

Coxsackie virus heart disease and cardiomyopathy

Twenty-two cases of Coxsackie virus heart disease diagnosed from November, 1969, to December, 1971, were re-examined after a period of 42 to 68 months from the acute illness. The patients with hypertension, diabetes, chronic alcohol intake, or aged over 35 were eliminated from the trial. With the purpose of assessing myocardial function, the systolic time intervals were recorded by a noninvasive standard technique. The differences in systolic time intervals between the group of patients with previous viral myocarditis and a group of normal control subjects were not statistically significant. However, the pre-ejection period was clearly prolonged in three patients out of 10, a modification consistent with a depressed myocardial function, as in patients with cardiomyopathy.

Acute myopericarditis. A long-term follow-up study

A follow-up study was made of 29 patients aged 21 to 45 years, some 15-158 months after acute myopericarditis. The mean follow-up period was 72.9 months. The follow-up investigation included recording of history, physical examination, laboratory tests, radiologic examination of the heart and lungs and electrocardiography. All but one of the patients were fit for fulltime work. Nine had residual cardiac symptoms, but the physical examination was negative in all but 2 of them. One patient had chronic cardiac insufficiency and hepatic enlargement. Another had sinus tachycardia and cardiac enlargement of moderate degree and impaired working capacity in relation to heart size. Cardiac murmurs without clinical significance were audible in three cases. The resting ECG was pathologic in only 6 cases. Orthostatic ECG evoked ECG abnormalities in 6 more cases. Exercise tolerance tests showed reduced working capacity in relation to heart volume in 5 of the 29 cases (17%). Four of these 5 patients had cardiac enlargement. There was thus good correlation between increase in heart volume and reduction of physical capacity. The prognosis in regard to cardiac function was good, as was also found in other comparable series in which the observation time was somewhat shorter.

The protean manifestations of Mycoplasma pneumoniae infection in adults

Mycoplasma pneumoniae is a well recognized respiratory pathogen in children and young adults. In addition, M. pneumoniae infections may also involve other organ systems. Reviewed here are the various clinical syndromes in adults caused by this infectious agent, with emphasis on those which have recently been seen at The New York Hospital. Two previously unreported manifestations of M. pneumoniae infection, cranial nerve mononeuropathy and hepatitis, are described, and the laboratory methods for diagnosis are discussed.

Three cases of acute ketotic diabetes mellitus with myocarditis: a common viral origin?

Focal electrocardiographic abnormalities have been noted in three young adults who developed acute diabetes after an illness bearing the hallmarks of a viral infection. The persistent S-T and T wave changes were inexplicable in terms of acute electrolyte imbalance or ischaemic heart disease and were ascribed to viral myocarditis. The significance of this is discussed.