ABSTRACT
Cardiac amyloidosis (CA) is an infiltrative restrictive cardiomyopathy caused by the deposition of amyloid fibrils in the myocardium. It manifests in two primary subtypes: transthyretin cardiac amyloidosis (ATTR) and immunoglobulin light chain cardiac amyloidosis (AL). ATTR is further classified into wild-type (wtATTR) and hereditary (hATTR) based on transthyretin gene mutation. Advances in diagnostics and therapeutics have transformed CA from a rare and untreatable condition to a more prevalent and manageable disease. Non-invasive diagnostic tools such as electrocardiography, echocardiography, and cardiac magnetic resonance can raise suspicion for CA; bone scintigraphy can non-invasively confirm ATTR, while AL necessitates histological confirmation. The severity of ATTR and AL can be assessed through serum biomarker-based staging. Treatment approaches differ, ranging from silencing or stabilizing transthyretin and degrading amyloid fibrils in ATTR to employing anti-plasma cell therapies and autologous stem cell transplantation in AL.
ABSTRACT
Cardiac amyloidosis (CA) is an underdiagnosed disease that is caused by deposition of misfolded transthyretin (ATTR) or immunoglobulin light chain (AL) fibrils in the myocardium. Bradyarrhythmias are commonly seen in CA, due to disruption of conducting system by amyloid fibrils. Atrioventricular conduction defect is more common than sinus node dysfunction. Bradyarrhythmias are most prevalent in wtATTR, followed by hATTR and AL. Pacemaker implantation, when indicated, can help provide symptomatic relief but does not confer mortality benefit. Progression of conduction system disease is common and often leads to increased right ventricular pacing burden with time. Therefore, cardiac resynchronizing therapy (biventricular therapy) is often considered as a better and safer option in these patients. Finally, the role of prophylactic pacemaker implantation is controversial, and current guidelines do not recommend prophylactic pacemaker insertion in CA patients.
