HISTORY, CURRENT DISEASE AND PHYSICAL EXAMINATION
A 53-year-old male, dyslipidaemic and ex-smoker, asymptomatic from a cardiovascular point of view, who was referred to the cardiology department for a chance finding on electrocardiogram.
As for his family history, his paternal family has a multiple history of heart disease at an early age: the patient's father received a heart transplant in 1995 for non-ischaemic dilated cardiomyopathy, his paternal grandfather died at the age of 60 due to an unspecified heart problem, and two of his father's siblings (one male and one female) suffer from dilated cardiomyopathy and are implantable cardioverter-defibrillator (ICD-CRT) cardiac resynchronisation therapy patients. Among the patient's siblings, the case of a woman with dilated cardiomyopathy associated with an atrial septal defect is documented. The rest of her siblings, as well as her daughters, are asymptomatic from the cardiovascular point of view.
Physical examination reveals no pathological findings.

COMPLEMENTARY TESTS
ELECTROCARDIOGRAM (ECG): sinus rhythm at 72 bpm. Intraventricular conduction disorder, with QRS 116 msec. Repolarisation alterations consisting of negative T from V3 to V6.
ANALYTICS: LDL (Friedewald estimation) 138 mg/dl, without other notable alterations.
Transthoracic echocardiogram (December 2014): left ventricle not dilated or hypertrophied. Moderately to severely depressed left ventricular ejection fraction (LVEF) (36% by Simpson biplane) overall. There was a slight increase in trabeculation at the level of the apex, without criteria of non-compaction cardiomyopathy (ecopotentiator administered).
Non-dilated right ventricle, increased trabeculation with slight hypokinesia in apical and basal segments with preserved contractility. Mild biauricular dilatation (left atrium 22 cm2, right atrium 17 cm2). Inferior vena cava not dilated. No pericardial effusion.
Slightly thickened aortic valve with preserved mobility, minimal insufficiency.
Mild mitral insufficiency. No tricuspid insufficiency allowing estimation of systolic pulmonary pressure (SPP). No pericardial effusion.
Cardiac MRI (2018): LV not dilated or hypertrophic. Normal global and segmental contractility. Apical hypertrabeculation without criteria of noncompaction cardiomyopathy.
No areas of uptake on late enhancement sequences suggestive of fibrosis.
HOLTER: stable sinus rhythm with good heart rate range. Low-medium intensity ventricular extrasystoles with right ventricular outflow tract morphology.
No pathological pauses or blockages.
CORONARYGRAPHY: coronary arteries without significant lesions. Right dominance.
GENETIC STUDY: the sample was sent for NGS study (panel of 81 genes). The study found a probably pathogenic variant: p.Arg5902* mutation in heterozygosis in the TTN gene: NP_003310.4: p.Arg5902*, M_003319.4: c.17704C>T, NC_000002.11g.179487411G>A). The G>A nucleotide substitution at chromosomal position g.179487411 results in the substitution of an arginine for a premature stop codon affecting most TTN isoforms.

CLINICAL COURSE
Following echocardiographic findings of moderate to severely depressed systolic function, treatment with low-dose bisoprolol and ramipril was initiated and well tolerated. Since his diagnosis, the patient has remained asymptomatic, with no episodes of heart failure decompensation and New York Heart Association (NYHA) functional class I. He is being followed up in cardiology consultations.
He was followed up in cardiology consultations with annual control echocardiograms, having recovered in the last one up to a LVEF of 53%. A genetic study was performed on relatives, finding mutations in the TTN gene in one of her paternal aunts and in one of her sisters, both affected by dilated cardiomyopathy, which demonstrates cosegregation and confirms the pathogenicity of the mutation found.

DIAGNOSIS
Non-ischemic familial dilated cardiomyopathy.
Carrier of p.Arg5902* mutation in heterozygosis in the TTN gene, probably associated with the disease.
Current LVEF 53%.
