We are dealing with a 26-year-old male who presented to the Emergency Department for dyspnoea.

History, current illness and physical examination
Personal history: Allergic to ASA (development of urticaria and angioedema). Smoker of 1 pack/day, occasionally marijuana. No other toxic habits. Viral myocarditis about ten years ago, diagnosed in Colombia. Admitted the previous month to Cardiology for dyspnoea, diagnosed with rapid ACFA and HF, requesting voluntary discharge without completing the study.

Usual treatment: Digoxin (1.0.0.0), Acovil 5 (1.0.0.0), Seguril (1.1.0), which the patient reported not taking. Current illness: Progressive dyspnoea of 3-4 weeks' evolution, which in the last few days has become minimal effort, together with orthopnoea, cough and non-thermometric dysthermic sensation. He denies chest pain, palpitations or other accompanying organotropic symptoms.

General examination: BP 104/72 mm Hg, HR 176 bpm, Ta 36.7 oC, baseline Sat02 94%. The patient is conscious, oriented, well hydrated and perfused, normocholoured and eupneic at rest. C&C: No IY. AC: Arrhythmic, pansystolic murmur in mitral focus, with 3rd noise. AP: bibasal crackles. Abdomen: soft, depressible, not painful on palpation, sounds present. No liver or splenomegaly. No peritonism. Lower extremities: No oedema or signs of DVT. Pedial pulses present and symmetrical.

Complementary tests
- ECG: thick wave ACFA at 170-180 bpm. Axis a-60o. Rest of the tracing normal.
- Chest X-ray: Cardiomegaly ++, with aneurysmal LA. No obvious condensation. Interstitial pattern.
- Laboratory tests: Biochemistry and haemacytometry normal. INR 1.07. Chagas serology: Negative. Urine toxicity: Positive for Cannabis.
- Echocardiography: severely dilated LV, with increased wall thickness, and increased trabeculation, especially in the mid-apical segments of the entire ventricle, respecting the basal segments, with very severe trabeculation throughout the apex (the findings were confirmed after administration of echocardiographic contrast). Severe systolic dysfunction (EF by Simpson biplane 27%). DTD: 66; DTS: 55. Aneurysmal LA (80 mm). Fibrotic and thickened mitral valve with severe MR directed towards the posterolateral wall of the LV, secondary to annular dilatation and tenting with pseudoprolapse of the anterior leaflet. Normofunctioning trivalve aortic valve. Slightly dilated right chambers. RV with moderate-severe dysfunction (TAPSE of 14 mm and tricuspid annulus S wave of 6 cm/s). Mild TR with RV-AD gradient of 40 (estimated PSAP of 60 as the inferior vena cava is 26 mm, without inspiratory collapse). Slight pericardial effusion.
- MRI: LV severely dilated with severely depressed global and segmental systolic dysfunction with preserved diffuse hypokinesia. EF: 29%. Absence of compaction except in basal segments and medial septum with a ratio of non-compacted myocardium/compacted myocardium greater than 3:1 At the level of the lateral apical face, findings compatible with non-compacted cardiomyopathy. No RV involvement is demonstrated. No thrombi are visualised. Thinning of the compacted myocardium in the affected segments, especially in the mid anterior face with a thickness of 4 mm in the end-diastolic phase. Severe dilatation of the left atrium. Mitral insufficiency which appears significant. Small pericardial effusion. Non-dilated RV with moderate dysfunction. EF 31%. In the late enhancement sequences no pathological uptakes are seen.

Clinical course
The patient was diagnosed with non-compaction cardiomyopathy with severe LV dysfunction. Medical treatment was started with diuretics, ACE inhibitors, beta-blockers, aldosterone inhibitors and oral anticoagulants, with rapid clinical improvement. After completing the study, it was decided to discharge him home with the treatment described above, with subsequent appointments at our hospital's Heart Failure Department. First-degree relatives were contacted to perform a structural study, by means of echocardiography and genetic testing.

Diagnosis
- Non-compaction cardiomyopathy with severe left ventricular systolic dysfunction
- Severe mitral insufficiency
- Atrial fibrillation with rapid ventricular response
