HISTORY, CURRENT ILLNESS AND PHYSICAL EXAMINATION
An 86-year-old man came to the emergency department for dyspnoea.

History
No drug allergies. Cardiovascular risk factors: controlled arterial hypertension. Type 2 diabetes mellitus of five years of evolution in treatment with oral antidiabetics. Dyslipidaemia.

Previous cardiological history: chronic ischaemic heart disease which debuted in 2000 in the form of stable angina. Coronary angiography in 2005 for angina Class III/IV CCS and positive stress echocardiography for induction of ischaemia in the LAD territory. Three-vessel disease partially revascularised by drug-eluting stents to proximal LAD, middle DC and OM1. In 2008, again clinical angina II/IV CCS, with positive stress echocardiography for ischaemia in CX territory, opting for conservative management. Permanent non-valvular atrial fibrillation diagnosed in 2010, anticoagulated with acenocoumarol; echocardiography in that consultation ruled out significant valvulopathies and reported preserved LVEF. No studies or follow-up by Cardiology since then. Functional class II NYHA.
Other pathologies: intermittent gait claudication in Fontaine stage IIa.
Bilateral carpal tunnel syndrome.
Previous treatment: acenocoumarol, bisoprolol 2.5 mg/24h, ranolazine 750 mg/12h, isosorbide mononitrate 50 mg/24h, rosuvastatin 10 mg/24h, metformin 1000 mg/12h, sitagliptin 50 mg/12h.
Baseline: partially dependent for ABVD (Katz B). Walks with a walker.
Cognitive preserved.

Current illness
She attended the emergency department with progressive dyspnoea of one week's evolution accompanied by palpitations, unquantified weight gain, orthopnoea and episodes of DPN in the last few nights. The patient claimed adequate compliance with treatment and denied any dietary transgressions. The previous week he had felt a little more "cold", with cough, mucous expectoration and a feeling of dystrophy at home without thermometry. He consulted his health centre for this reason and was prescribed treatment with apyretics and mucolytics, with a partial response.

Physical examination
BP: 105/45 mmHg, HR: 110 bpm, Ta 36.7°C, Sat O2 96 %. Weight 70 kg. Cardiac auscultation: arrhythmic, with systolic ejection murmur predominantly in aortic focus, II/VI, with abolished R2. Pulmonary auscultation: crackles in both lung bases with scattered scattered rhonchi. Abdomen: soft and depressible, no masses or visceromegaly, no signs of peritoneal irritation. Extremities: pretibial oedema with fovea ++/+++; paedial pulses present but asymmetrical, no phlebitis.

COMPLEMENTARY TESTS
CBC: glucose: 130 mg/dl, urea 58 mg/dl, creatinine 1.38 mg/dl, CrCl (Cockcroft-Gault): 38 ml/min/, sodium: 138 mEq/l, potassium: 5.2 mEq/l, NT-proBNP: 10.055pg/ml; TnT US: 89 ng/l (normal value < 15 ng/l); haemoglobin: 10 g/dl, haematocrit: 30.8 %; MCV: 87.5 fl, platelets: 277,000/uL; INR: 1.5.
Emergency electrocardiogram: atrial fibrillation at 120 bpm; narrow QRS with normal axis; early transition in V2 and LV overload pattern by ST-segment depression in V2-V5 and inferior leads.
Chest X-ray: cardiomegaly, hilar congestion with vascular redistribution towards apexes, fluid in fissures and discrete pinching of the right costophrenic sinus.
Transthoracic echocardiogram: marked biauricular dilatation.
Severe concentric left ventricular hypertrophy with ejection fraction at the lower limit of normal (global LVEF by Simpson 52%). Thickened aortic valve with significant restriction to its opening and severe valvular stenosis by estimated area (area 0.65 cm2) although with low gradients (peak aortic transvalvular gradient 25 mmHg). Mitral filling pattern with single E wave by AF and increased filling pressures data: E/e" ratio 17 and shortened deceleration time (TD 115 ms). Mild mitral valve insufficiency. Myocardial deformation study with the following findings: Decreased GLS (-11 %) with preserved deformation parameters in apical segments and pathological in basal and middle segments (apical sparing).
Bone scan with 99mTc-DPD: study with cardiac uptake of notable intensity, much higher than bone uptake, which in SPECT-CT is diffusely distributed and coincides with LV, these findings being suggestive of amyloidosis due to transthyretin deposition. In the rest of the study, discrete hyperuptake in the sternoclavicular joints and large bilateral joints (shoulders, elbows, wrists, hips and knees) suggesting inflammatory/degenerative pathology.

EVOLUTION
The patient was admitted to the cardiology ward with a diagnosis of heart failure in the context of lower respiratory tract infection. He progressed well during the 72 hours following admission, achieving copious diuresis with treatment with intravenous furosemide and heart rate control with digoxin. After improvement of the congestive symptoms, a certain tendency to hypotension persisted, as well as bradycardia, despite a minimum dose of beta-blocker (bisoprolol 2.5 mg/24 h), but without significant clinical repercussions except for slight dizziness with an orthostatic profile coinciding with sudden postural changes.
Given the nature of the symptoms and the semiology, it was decided to update the echocardiographic study, with findings suggestive of infiltrative cardiomyopathy and severe aortic valve disease due to paradoxical low-flow stenosis previously unknown. In view of these results, it was decided to complete the study with immunofixation techniques aimed at ruling out the presence of a monoclonal component in blood and urine, a characteristic finding of the most frequent subtype of cardiac amyloidosis, secondary to light chain deposition (AL amyloidosis).
After ruling out the presence of Bence Jones proteinuria or elevated plasma light chains, a bone scintigraphy study with 99mTc-DPD was requested, which showed intense left ventricular uptake, significantly higher than bone uptake, a finding highly suggestive of cardiac amyloidosis due to transthyretin deposition. Finally, the study was completed with a biopsy of abdominal fat in which the diagnosis of senile amyloidosis due to free transthyretin deposition was confirmed.
After reaching a consensus with the patient on a conservative approach to the management of his aortic valve disease and given the clinical stability achieved, he was discharged home after pharmacological adjustment for outpatient clinical follow-up in cardiology consultations.

DIAGNOSIS
Decompensated heart failure in the context of lower respiratory tract infection. Preserved LVEF.
Senile cardiac amyloidosis due to abnormal transthyretin deposition.
Paradoxical" severe low-flow aortic valve stenosis.
