The Bottom Line: These clinical signs were found in 46% of patients in the cited study below.
Summary: Murtagh et al. from the Mayo Clinic provide the largest report to date of ECG findings in a population of patients with AL amyloidosis and biopsy-proven cardiac involvement. In 127 patients, they found that low ECG voltage (presence of QRS voltage amplitude 0.5 mV in all limb leads or 1 mV in all precordial leads) was
present in 46% of patients, and a pseudo-infarct pattern (i.e., no infarct actually evident on echocardiography) was present in 47% of patients. The pseudo-infarct patterns were anterior (36%), inferior (12%), and lateral (14%). Both low ECG voltage and pseudo-infarct pattern were present in 25% of patients. There was a moderate correlation between the presence of low voltage and pericardial effusion
but no correlation between voltage and the ejection fraction. Atrial fibrillation and flutter was the most common arrhythmia. It was present in 25% of patients with LV hypertrophy, whereas 7% of patients without LV hypertrophy were identified as having atrial fibrillation. None of the electrocardiographic variables correlated with survival.