Systemic amyloidosis is a multisystem disorder caused by the misfolding, aggregation, and deposition of certain proteins in various organs and tissues. Cardiac involvement is common and worsens the prognosis. Atrial fibrillation is the most frequent arrhythmia in cardiac amiloidosis (CA), but many cases of ventricular arrhythmias (VA) and sudden cardiac death (SCD) have been described.
We present a case of a 64-year-old man admitted following exertional syncope occurred after climbing a flight of stairs. His medical history included left gonarthrosis and surgery for right carpal tunnel syndrome one year before. Physical examination did not revealed signs of heart failure. A 12-lead electrocardiogram (ECG) showed a pseudoinfarction pattern with QS waves in V2 and V3 leads and low voltage in all limb leads. Routine blood tests revealed NT-pro-BNP 3436 pg/ml(n.v.0–125) and high-sensitive troponin T 67 pg/ml(n.v.< 58). A trans-thoracic echocardiogram showed left ventricle (LV) concentric thickening wall with granular and sparkling pattern, mild reduced ejection fraction, reduced global longitudinal strain with apical sparing, grade 3 diastolic disfunction, biatrial enlargement, mild mitral regurgitation, right ventricle free wall thickening (8 mm), mild reduced TAPSE, and mild pericardial effusion. Cardiac magnetic resonance (CMR) confirmed ventricular wall thickening with evidence at T1 mapping of interstitial infiltration more evident in the septum and inferior-lateral wall with apical savings. A total body 99mTc-HDP scintigraphy showed cardiac uptake with intensity similar to bone signal (Perugini Score 2) suggesting ATTR cardiac amyloidosis. Both kappa and lambda concentrations were normal. The genetic testing did not reveled mutations in the TTR gene. We concluded for a diagnosis of ATTR wild-type CA. The Holter ECG monitoring registered numerous ventricular ectopic beats and an episode of non-sustained ventricular tachycardia. A coronary angiography ruled out coronary artery disease. In consideration of the clinical-instrumental picture an ICD was implanted.
Conclusions: CA is still underdiagnosed. VA and SCD may further complicate the prognosis. Early diagnosis and adequate stratification of the arrhythmic risk are essential to ensure patients the best therapeutic strategies.