HISTORY, CURRENT ILLNESS AND PHYSICAL EXAMINATION
45-year-old woman with type 2 diabetes. In 2007 she was diagnosed with non-obstructive hypertrophic cardiomyopathy, initially with normal ventricular function, although since 2012 she had severe left ventricular dysfunction and moderate right ventricular dysfunction. He had also undergone ablation of three accessory pathways due to Wolff-Parkinson-White syndrome and in 2012 required pacemaker implantation due to high-grade AV block. Other antecedents include cochlear implantation in the right ear in 2004 for sensorineural deafness. Baseline: independent for activities of daily living, in NYHA functional class III, without angina. Usual treatment: bisoprolol 1.25 mg, eplerenone 25 mg, sitagliptin 25 mg, paracetamol on demand.
Admitted to our hospital in January 2016 due to worsening functional class, presenting dyspnoea at rest and bendopnoea, without orthopnoea or DPN.

Examination revealed BP 80/50 mmHg, HR 77 bpm, O2 saturation 96% on room air, with no evidence of congestion on pulmonary auscultation, and no oedema in the lower limbs.

COMPLEMENTARY TESTS
CBC: Hb 13.9 g/dl; leukocytes 8,240/ul; platelets 147,000/ul; urea 89 mg/dl; creatinine 0.96 mg/dl; Na 143 mEq/l; K 4.0 mEq/l; glucose 76 mg/dl, HbA1c 7.1 %. Total cholesterol 138 mg/dl; HDL 30 mg/dl; LDL 93 mg/dl; TG 75 mg/dl. INR 1.3. NT-proBNP 6,903 ng/dl. Normal liver and iron profile.
Chest X-ray: bicameral pacemaker. Cardiomegaly.
Free costophrenic sinuses, with no signs of pulmonary congestion.
ECG: sinus rhythm at 60 bpm with pacemaker-mediated ventricular pacing.
Echocardiogram: non-dilated LV, with severe asymmetric hypertrophy, with no evidence of dynamic obstruction at the outflow tract level. Severely depressed global systolic function (LVEF by Simpson biplane: 21%). Pseudonormal filling pattern. Hypertrophic RV with moderate systolic dysfunction (shortening fraction: 29%). Mild MI. Mild AoI. Mild TR, allowing estimation of a PSAP of 32 mmHg. No pericardial effusion.

EVOLUTION
During admission, diuretic treatment was adjusted and the patient was discharged from hospital after 7 days. The patient was asked about her family history and it was noted that three of her seven sisters were diabetic and had a cochlear implant. Therefore, this is a patient with hearing loss and diabetes (both at an early age and with a family history) and hypertrophic cardiomyopathy.
A genetic study was requested, which subsequently confirmed the existence of the 3243A>G mutation, establishing the diagnosis of MELAS syndrome (Mitochondrial Encephalomyopathy with Mitochondrial Encephalomyopathy with Mitochondrial Syndrome)
Encephalomyopathy with Lactic Acidosis and Stroke-like episodes).
Two months later, the patient showed subjective clinical improvement, started a cardiac rehabilitation programme and continued with a tendency to arterial hypotension.

Four months after hospital discharge, the patient was upgraded to a three-chamber ICD-CRT without complications. Better tolerance to physical activity since starting cardiac rehabilitation, but is in NYHA functional class II-III. She was assessed by Neurology, who considered that the neurological involvement did not seem to be significant, and that cases of stroke were more frequent at younger ages and in males affected by the disease, so the neurological prognosis did not seem to be limiting in this patient. In accordance with the poor functional class and the progressive nature of the cardiac involvement, as well as the scarce significant associated comorbidity, referral was made to another hospital for evaluation of cardiac transplantation. Virus serology, respiratory function tests and abdominal ultrasound were performed, with normal results. However, the patient was not placed on the transplant waiting list due to severe depressive disorder.

DIAGNOSIS
MELAS syndrome:
Non-obstructive hypertrophic cardiomyopathy in dilated phase. Biventricular involvement with severe LV systolic dysfunction and moderate RV systolic dysfunction. Heart failure in NYHA functional class II-III.
Wolff-Parkinson-White syndrome with ablation of 3 accessory pathways.
High degree AV block, carrier of a bicameral pacemaker with upgrade to ICD-CRT.
Sensorineural deafness, cochlear implant carrier.
Type 2 diabetes mellitus.
