HISTORY, CURRENT ILLNESS AND PHYSICAL EXAMINATION
We present the case of a 21-year-old girl, with no personal history of interest or usual treatment. Pregnancy at term with euthyphalic vaginal delivery in a private clinic 48 hours before being brought to the emergency department. The gestation was uncomplicated, as was the delivery. However, 48 hours after delivery, the patient began with pinkish expectoration and rapidly progressive dyspnoea and was referred to our hospital. On arrival at the ED, her vital signs were: Blood pressure 100/69 mmHg. Heart rate 140 bpm. Respiratory rate 24 rpm. O2 saturation 96% with FiO2 100%.
On physical examination she was pale and sweaty, with distal coldness. There was no jugular ingurgitation at 45o. Cardiac auscultation was rhythmic with a gallop rhythm on the third sound. Pulmonary auscultation with bibasal crackles. Abdomen distended. Upper and lower extremities without oedema, with palpable distal pulses.  

COMPLEMENTARY TESTS
Electrocardiogram (ECG): on arrival, sinus tachycardia, with normal PR, narrow QRS, without repolarisation disorders.
Blood tests: Baseline arterial blood gas on arrival: pH 7.44, pCO2 27.6 mmHg, pO2 55.9 mmHg, HCO3 18.6 mmol/l. Biochemistry: glucose 84 mg/dl, urea 47 mg/dl, creatinine 0.85 mg/dl, Na 140 mEq/l, K 4.3 mEq/l, chlorine 105 mEq/l, estimated glomerular filtration rate (CKD-EPI) > 60, troponin 0.06 > 0.09 > 0.03 ng/ml. Lactate 18.7 mg/dl, NT-proBNP 12442 pg/ml. Haemocytes: leucocytes 5.1 10e3/μl, haemoglobin 11.2 g/dl, MCV 70 fl, platelets 234 10e3/μl. Coagulation: prothrombin activity 81%, INR 1,16.
Chest X-ray: perihilar interstitial pattern compatible with acute pulmonary oedema. Transthoracic echocardiogram (TTE) on admission: slightly dilated left ventricle (LVED 57 mm) with very severe systolic dysfunction (LVEF 10-15%). Right ventricle of normal size and function. Tricuspid and normofunctioning aortic valve. Normal mitral valve with mild mitral regurgitation (MR). Indirect evidence of increased left filling pressures. Normal tricuspid valve without insufficiency. Type I pulmonary flow. Inferior vena cava (IVC) not dilated with inspiratory collapse. No coarctation of the aorta. Calculated GCS for continuity of 3.7 l/min. Pleural effusion in both lung bases.
Cardiac magnetic resonance imaging (MRI): dilated left ventricle (LV) with end-diastolic volume 164 ml (corrected for body surface area of 100 ml/m2). Telesystolic volume 132 ml (80 ml/m). EF 20%. Diffuse hypokinesia without clear segmental changes. No abnormal intramyocardial enhancement after contrast injection at early or late times. No evidence of significant pericardial effusion. Rest of the study without alterations. Severe LV systolic dysfunction (EF 20%). In the clinical context suggests peripartum cardiomyopathy.
Other tests: PCR adenovirus, enterovirus and herpes virus: negative. Serology for Toxoplasma, CMV, herpes zoster, Epstein-Barr, HSV 1 and 2, HIV and hepatitis: negative.
Transthoracic echocardiogram at discharge: left ventricle slightly dilated. Severe LV systolic dysfunction. LVEF 25%. Paradoxical septal motion. Right ventricle (RV) not dilated with preserved RV systolic function. Mitral regurgitation in the mild range. Normal diastolic Doppler pattern. Normal diastolic tissue Doppler pattern. Normal pulmonary artery pressure (PAP) (14 mmHg+PVC). Vena cava not dilated.

CLINICAL EVOLUTION
The coronary unit was notified due to suspicion of pulmonary thromboembolism (PTE), as the patient presented poor general condition, tachypnoea, desaturation and a tendency to hypotension. A transthoracic echocardiogram was performed at the bedside showing very severe LV systolic dysfunction (LVEF 15%) with hyperdynamic RV, so, on suspicion of acute pulmonary oedema triggered by peripartum cardiomyopathy, she was urgently transferred to our unit. After being urgently admitted to the coronary unit, inotropic treatment was started with dobutamine and diuretics, both at high doses. In the following hours the evolution was adequate, with significant negative balance, improved oxygenation and organ perfusion data. This allowed for a progressive decrease in inotropic and diuretic support. Dobutamine perfusion was suspended and neurohormonal treatment with bisoprolol and enalapril was started, with good tolerance. ten days after admission, she was discharged to the cardiology ward, where the study was completed with a cardiac magnetic resonance that ruled out pathological enhancements and an inflammatory component at cardiac level with an estimated LVEF of 20%. Based on these data, and given the high risk of ventricular arrhythmias in a very young patient, it was decided to implant an implantable cardioverter defibrillator (ICD). The subcutaneous route was chosen, given the possible improvement or recovery of ventricular function experienced by some patients with peripartum cardiomyopathy in the following months, as reported in the literature.
A genetic study was requested and a frameshift variant was found in the TTN gene (encoding titin), which is considered pathogenic.

DIAGNOSIS
Acute pulmonary oedema.
Peripartum cardiomyopathy with severe left ventricular dysfunction.
Subcutaneous ICD implantation as primary prevention of ventricular arrhythmias.
Positive genetic study for pathogenic variant in the titin gene.
