ABC | Volume 114, Nº4, Suplement, April 2020

Case Report Nunes et al. Syncope in Val122Ile amyloidosis Arq Bras Cardiol 2020; 114(4Suppl.1):1-3 Figure 1 – A) Electrocardiogram: Sinus rhythm, HR: 88 bpm, indeterminate QRS axis. P-wave in the frontal plane with increased duration (160 ms), with partial Bachmann’s bundle block and tricuspid P wave in D2, D3 and aVF; qR pattern in V1 and Morris index are observed in the horizontal plane, which means right and left atrial enlargement. Pseudo-infarct pattern in precordial leads and presence of low voltage in the frontal plane are also observed. B and C) Resting Cardiac MRI shows diffuse LVH, with areas of diffuse subendocardial late enhancement in the LV (arrows), atria, and interatrial septum. D and E) 99mTc-PYP myocardial scintigraphy showing intense radiotracer uptake in the myocardium (Grade 3). CAD. Because gadolinium is a purely extracellular agent and does not penetrate the intact cardiomyocyte, the characteristic appearance of LE (Figure1) in non-coronary territory is extremely suggestive of CA and this was decisive in this case. 1,4,7 The evaluation of myocardial deformity by the GLS technique, performed after the CMRI, demonstrated a typical pattern of CA (Figure 2), which ruled out other causes of LVH and corroborated the diagnosis, which has been very useful in this scenario. 8 Among the CA types, the one caused by light chains Imunoglobulins (AL) is the one that most commonly affects the heart; therefore, we began with the search for hematological disease. 1,4,6 Since the definitive diagnosis of CA required tissue biopsy at that time, this was performed. More recent diagnostic algorithms reserve tissue biopsy only for suspected cases of AL, as the 99m-Tc-PYP myocardial scintigraphy replaced myocardial biopsy in ATTR-CA. 1,9 This technique has been used for a long time to diagnose bone diseases, of which radiotracer has a strong affinity for calcium, that is almost only present in ATTR deposits. Positive and negative predictive values for ATTR diagnosis by 99mTc-PYP myocardial scintigraphy with a score ≥ 2 are 88 and 100%, respectively. Diagnostic certainty is proposed when the score is ≥ 2 in the absence of an immunoglobulin monoclonal peak, which would be equivalent to a positive endomyocardial biopsy, 9 as in the case described (Figure1), witch was confirmed latter by the genetic testing. The most frequent cardiac symptoms in Val142Ile ATTR are: heart failure, dyspnea, arrhythmias and dizziness. Syncope, most frequently found in AL (20%), is unusual in ATTR (8%), andwhen it occurs on exertion it represents the inability to increase cardiac output, which confers high mortality. 5,10 Moreover, sensitivity to intravascular fluid depletion combined with autonomic neuropathy, depressed myocardial reserve, atrial dysfunction and stiffness, and the presence of arrhythmias contribute to the occurrence of syncope. 6 All these possibilities make syncope a multifactorial presentation in CA, as it may have occurred in the case described herein. THAOS, an open worldwid registry to all patients with ATTR, shows that the Val142Ile, also known as Val122Ile mutation, is the second most common genotype worldwide and the most common in the USA, accounting for 23% of the total mutations in the country and 1% in the rest of the world. The carriers of this mutation are mostly of African descent and males, being prevalent in 3 to 4% of African‑Americans at birth, with a penetrance of approximately 20%. 5 2