The patient was a 22-year-old male marathoner with fatal heart failure for 1 year. The clinical data reported were dyspnea and precordial discomfort on exertion. The patient maintained his trainings and running practice less intensely due to lower limb pain and weakness in the last months, until he was hospitalized due to chest pain, dyspnea, hemoptysis, mental confusion and syncope. During hospitalization, his clinical findings rapidly and progressively deteriorated. His electrocardiogram on admission revealed signs of right atrial overload, left ventricular overload and secondary ventricular repolarization changes. The left ventricle was diffusely hypokinetic and the diastolic function pattern was restrictive. There was moderate mitral and tricuspid valve regurgitation. These findings suggest cardiomyopathy with important hemodynamic repercussion.

The causes of cardiomyopathy in young individuals are: idiopathic cardiomyopathy, infectious myocarditis and autoimmune myocarditis.1 Cardiotoxicity can also be observed in exposure to certain agents, such as alcohol, cocaine, heavy metals and antineoplastic drugs, such as anthracyclines and cyclophosphamide.

Idiopathic dilated cardiomyopathy is the most common cause of heart failure in young individuals, 30% to 50% of the cases being familial and associated with inherited genetic mutations.2^,3 Some patients have heart failure of rapid progression and refractory to treatment, one of the most frequently found etiologies in heart transplant lists.4

Lymphocytic myocarditis can be triggered by different infectious agents, viruses being the most frequent ones. Lymphocytic myocarditis can progress with acute, subacute or chronic heart failure. More than 20 viruses, such as Coxsackievirus B, adenovirus, parvovirus B19, cytomegalovirus and human herpesvirus 6, have been related to the risk for myocarditis.5 Some groups, such as children and immunocompromised patients, are at higher risk to develop rapidly progressive or fulminant heart failure related to viral myocarditis. Other infectious agents, such as bacteria, rickettsia and fungi, are occasionally associated with myocarditis, but less commonly than viruses. In Brazil, where Chagas disease is endemic in some regions, some patients can have rapidly progressive myocardial impairment. Although our patient was born in an area potentially endemic for Chagas disease, his serology was negative.

Autoimmune myocarditis can lead to acute or subacute heart failure with rapid decompensation. Giant cell myocarditis is a rare disease, mediated by abnormalities in T lymphocyte function, affects mainly young and middle-aged individuals, has a rapid course and high mortality rate. The initial presentation in 75% of the cases is rapidly progressive heart failure, while the rest present with cardiac arrhythmias and findings similar to acute myocardial infarction. Around 20% of the patients with giant cell myocarditis have associated autoimmune conditions, such as inflammatory intestinal disease, thyroiditis, celiac disease, rheumatoid arthritis.6 Similarly to giant cell myocarditis, eosinophilic myocarditis can be characterized by rapidly progressive and potentially fatal heart failure, being occasionally related to exposure to drugs or exogenous agents. Cardiac sarcoidosis is also a differential diagnosis, although there was no report of previous impairment of organs, such the lungs and liver. Usually, patients with cardiac sarcoidosis have changes in the cardiac conduction system, with total atrioventricular block in up to 30% of the cases, related to the presence of granulomas and scars in the basal region of the interventricular septum.2

Acute myocardial infarction is a frequent cause of acute heart failure, is more common in middle-aged and old patients with atherosclerotic risk factors and/or established disease. In our case, the patient was young, had no classical risk factor for cardiovascular disease, and his clinical and laboratory findings did not suggest acute coronary syndrome.

Between the fifth and sixth days of hospitalization, the patient had a significant clinical deterioration, with respiratory and hemodynamic failure, change in his level of consciousness, requiring invasive ventilatory support and vasoactive drugs. His physical exam showed signs of acute heart failure with the third heart sound and pulmonary congestion, poor peripheral perfusion with elevated capillary filling time and increased central venous pressure, characterized by the presence of jugular venous distention. His laboratory tests on the occasion revealed several data of poor prognosis due to organic dysfunctions, such as elevation of nitrogen compounds, arterial lactate, liver enzymes, acidosis, hypoxemia, as well as increased levels of inflammatory markers, such as C-reactive protein, leukocytosis and D dimer. His electrocardiogram evidenced atrial fibrillation with high response, left ventricular overload and ventricular repolarization changes. The comparison of the new echocardiography with the previous one showed right ventricular dilatation and hypokinesis, and indirect signs of pulmonary hypertension. The transesophageal echocardiogram revealed a pedunculated thrombus on the left ventricular anterior wall, which increased his cardioembolic risk, being probably related to the presence of right frontal and parietal cerebral ischemic lesions later observed on skull tomography.

In some patients with acute or chronic heart failure, some conditions, such as underlying disease, infections, pulmonary thromboembolism (PTE), arrhythmias, myocardial ischemia and anemia, can trigger or worsen decompensation. Infection and PTE might have contributed to our patient's clinical deterioration. A recent study has reported a 17.8% PTE prevalence in individuals hospitalized due to syncope.7 In our patient, the new right ventricular dilatation and dysfunction associated with worsening of the respiratory findings, hypoxemia and shock might suggest PTE as the possible cause of decompensation. Viral and bacterial infections are among the most common causes of decompensation in patients hospitalized with heart failure.4 This higher incidence of infectious diseases in patients with heart failure is multifactorial, resulting from the interaction of different abnormalities, such as immunological changes in critically ill patients, nutritional deficiencies and higher need for invasive diagnostic and therapeutic procedures. Despite the treatment with large spectrum antibiotics because of fever and suggestive signs of sepsis, in addition to the hemodynamic support during hospitalization, the patient experienced hemodynamic instability and refractory shock. (Hilda Sara Montero Ramirez, MD, and Rafael Amorim Belo Nunes, MD)

Diagnostic hypotheses: congestive heart failure; myocarditis (autoimmune? viral?); cardioembolic ischemic stroke; nosocomial bronchopneumonia; cardiogenic and septic shock. (Hilda Sara Montero Ramirez, MD, and Rafael Amorim Belo Nunes, MD)

The heart weighed 590 g (normal, up to 350 g), was moderately enlarged and had a globose shape (Figure 3). The epicardial surface had small pericoronary fibrous thickenings. When opened, dilatation of all chambers with mild hypertrophy of the ventricular and atrial walls was observed (Figures 4 and 5). Neither the atrioventricular nor the arterial valves had abnormalities. There were neither cavitary thrombi nor endocardial thickening. The coronary arteries had usual origins and showed no significant obstructive lesion.

Figure 3 Figure 4 Figure 5

The microscopic exam showed moderate to marked hypertrophy of cardiomyocytes, with focal myocardial interstitial fibrosis (Figure 6) and areas of organizing microinfarcts (Figure 7). There were signs of terminal shock, such as centrilobular liver necrosis, renal acute tubular necrosis and recent pulmonary alveolar hemorrhage (Figure 8), in addition to signs of systemic embolism, such as recent infarcts in the brain (right parietal and occipital) and spleen. (Prof. Vera Demarchi Aiello, MD)

Figure 6 Figure 7 Figure 8

Diagnosis: Cause of death: cardiogenic shock. Main disease: idiopathic dilated cardiomyopathy. (Prof. Vera Demarchi Aiello, MD)

The patient was a marathoner with symptoms compatible with heart failure in the preceding year. He had syncope after physical training, being hospitalized. During his hospitalization, dilated cardiomyopathy was identified. The postmortem examination revealed moderate hypertrophy and dilatation of cardiac chambers. Clinically speaking, there was doubt regarding the etiology of the cardiomyopathy, and whether it would be related to the so-called "athlete's heart". Data from the literature have shown that, although some athletes, mainly practitioners of aerobic sports, can have dilated cardiac chambers, most have ventricular dimensions within the normal range. In around 10% of those athletes, the intensity of the dilatation is similar to that occurring in dilated cardiomyopathy, the differential diagnosis being established by the lack of systolic dysfunction, with maintenance of ventricular ejection fraction or even its increase. The same European authors have demonstrated that ventricular dilatation is positively related to the athlete's body surface and height.8^,9 Therefore, although our patient was an athlete (marathoner) and had myocardial dilatation and hypertrophy, there was cardiac dysfunction, characterizing dilated cardiomyopathy. In addition, the microscopic exam evidenced marked pathological myocardial changes, such as cardiomyocyte hypertrophy and myocardial interstitial fibrosis, as well as organized or organizing microinfarcts.

Although infarcts were identified in the territories of the cerebral and splenic arteries, cardiac thrombi, a possible embolic source, were not evidenced. The postmortem exam showed no infection sign. Despite the report of rheumatic disease during childhood, his heart valves showed no lesion compatible with sequelae of that disease. (Prof. Vera Demarchi Aiello, MD)