Patient MSV, a 61-year-old woman born in Penteado, Alagoas, Brazil and residing in Sao Paulo was hospitalized for decompensated heart failure (HF). Approximately 1 year before, she experienced dyspnea with moderate effort, and there was marked worsening over the last 3 months associated with orthopnea and lower limb edema. Laboratory tests from when the patient was first seen at the InCor emergency unit (in March 2013) revealed: 3.3 million red blood cells/mm³; hemoglobin 10.9 g/dL; hemocyte 33%; MCV (mean corpuscular volume), 100 fL; leukocytes, 4,260/ mm³ (3,067 neutrophils, 213 eosinophils, 43 basophils, 809 lymphocytes and 128 monocytes); platelets, 146,000/mm³; CK-MB, 1.37 ng/mL; troponin I, 0.081 ng/mL; urea, 26 mg/ dL; creatinine, 0.92 mg/dL; sodium 140 mEq/L; potassium 4.9 mEq/L; magnesium, 1.5 mEq/L; C-reactive protein, 6.31 mg/L; B-type natriuretic peptide, 282 pg/mL; PT (INR), 1.2; APTT, 0.97 ratio. Radiography (in March 2013) showed an increase in the pulmonary vasculature and slightly increased cardiac area with middle arc rectification. (Figure 1). Figure 1 Patient chest X ray: increased pulmonary vasculature and slightly increased cardiac area, with middle arc rectification. After administration of medicines, HF improved; however, after 1 week, the symptoms worsened and the patient sought emergency medical attention and was hospitalized (on August 6, 2013). She also complained of burning precordial discomfort accompanying dyspnea on exertion. She stated that there were no palpitations, syncope, arterial hypertension, diabetes mellitus, or dyslipidemias. The patient reported use of anti-inflammatory drugs for treating carpal tunnel syndrome. The physical examination (on August 6, 2013) revealed increased jugular venous pressure, heart rate of 100 bpm, and blood pressure of 117 × 59 mmHg. Pulmonary auscultation revealed decreased vesicular breath sounds at the lung bases and sizzling rales until the middle third; cardiac auscultation revealed no changes. The abdomen had no visceromegaly or ascites, and there was discrete edema in the lower limbs. Chest radiography (on August 6, 2013) revealed bilateral opacification of the costophrenic sinuses, increased pulmonary vasculature, and increased heart size (Figure 2). Figure 2 Chest X ray: bilateral opacification of the costophrenic sinuses, increased pulmonary vascular markings, and increased heart area. The electrocardiogram (ECG, on August 7, 2013) showed sinus rhythm, a heart rate of 78 bpm, low voltage QRS complexes, and diffuse ventricular repolarization (Figure 3). Figure 3 ECG showing sinus rhythm, a heart rate of 78 bpm, low voltage QRS complexes, and diffuse ventricular repolarization. The following was revealed by the echocardiogram (on August 8, 2013): aortic sinus, 29 mm; left atrium, 42 mm; septal thickness, 16 mm and posterior wall thickness, 12 mm; left ventricle (diastole/systole), 42/29 mm; ejection fraction, 57% (Figure 4). The left ventricle showed marked hypertrophy without segmental changes. The filling pattern was restrictive and not reversible with the Valsalva maneuver (Figure 5). The right ventricle had preserved systolic function without valvular dysfunction. There were signs of pulmonary hypertension, and pulmonary artery pressure was estimated to be at 50 mmHg. The E (mitral protodiastolic speed)/E’ (protodiastolic velocity of the mitral annulus) ratio was 15 (normal value < 8), indicative of the left atrial pressure above 20 mmHg. Figure 4 Transthoracic ECHO: marked increase in the left atrium diameter. Figure 5 Left panel: Transthoracic ECHO M mode, mitral valve with the Christmas tree pattern, early closure of the mitral valve, and increased end diastolic pressure in the LV. Right panel: restrictive-type pattern ventricular filling. Laboratory tests revealed anemia, renal failure, and hypothyroidism (Table 1). Table 1 Laboratory tests Diuretics and intravenous dobutamine were administered with initial improvement in pulmonary congestion; however, congestion and oliguria worsened, with a marked increase in urea and creatinine levels (Table 1 and Figure 6). Dialysis was indicated, during which the patient showed signs of bacteremia, and the procedure was stopped. This was followed by worsening dyspnea and cardiac arrest by hypoxia. Resuscitation and orotracheal intubation for respiratory support were started, but there was no response, and the patient died (at 3:45 am on August 12, 2013). Figure 6 Left aspect of the atrial septum. Irregular yellowish areas correspond to the amyloid deposit.