Cardiac amyloidosis

Cardiac amyloidosis is an important cause of heart failure and cardiac arrhythmias, yet cardiologists often miss the diagnosis. Immunoglobulin light-chain amyloidosis (AL) is relatively rare, but likely underdiagnosed. The median survival of untreated patients with cardiac AL is 6 months after the onset of heart failure, highlighting the importance of early diagnosis. Wild-type transthyretin amyloidosis (ATTR) is increasingly recognized, especially in males over the age of 60 years. Although the clinical course of wild-type ATTR is more indolent, the median survival is approximately 3.5 years from diagnosis. Typical echocardiographic findings of increased left and right ventricular wall thickness, diastolic dysfunction, and pericardial effusion may suggest cardiac amyloidosis, along with abnormal delayed gadolinium enhancement and difficulty nulling the myocardium on cardiac magnetic resonance imaging. For AL, a tissue diagnosis is required. In contrast, ATTR may be diagnosed non-invasively with grade 2/3 uptake by nuclear scintigraphy in the absence of a monoclonal protein. Treatment of cardiac amyloidosis is entirely dependent on the type of amyloid and is directed at the underlying precursor protein or disrupting existing deposits. Cardiac care is supportive and challenging. Standard heart failure medications such as beta blockers and angiotensin-converting enzyme inhibitors are not routinely indicated and often cause haemodynamic deterioration. Outcomes of source-directed therapy for AL are improving and several clinical trials of treatment for ATTR are ongoing.