The findings of electrocardiography in patients with cardiac amyloidosis.

Objective The electrocardiography (ECG) was the simplest and common adjunctive diagnostic tool for cardiac amyloidosis (CA). We sought to clarify the findings of ECG in patients with CA in order to early identification of CA according to the findings of ECG. Methods A total of 276 patients with diagnosis of systemic amyloidosis admitted to Peking Union Medical College Hospital from January 2000 to December 2011, were enrolled. Two groups were classified according to the cardiac involvement or not, namely CA (n = 189) and control (n = 87) groups. The low voltage on limb leads defined by the amplitude of the QRS complex in each limb leads 0.5 mV. The pseudo-infarct pattern defined by the presence of pathologic Q waves on at least two contiguous leads on ECG without obstructive coronary artery disease. Results The mean age was 55 +/- 12 (1588) years, 168 patients (61%) were male. Atrial arrhythmia (15.9% vs 3.4%, P = 0.003), low voltage on limb leads (54.5% vs 20.7%, P<0.001), atrioventricular block (14.8% vs 1.1%, P = 0.001) and pseudo-infarct pattern (40.2% vs 4.6%, P<0.001) were more prevalent in CA than control groups. The combination of low voltage on limb leads and pseudo-infarct pattern was more common (28.0% vs 2.3%, P<0.001) in CA than control groups. The sensitivity, specificity, positive and negative predictive values of the presence of low voltage on limb leads and pseudo-infarct pattern for the diagnosis of CA were 28%, 98%, 96%, and 39%, respectively. Conclusion In CA patients, low voltage on limb leads and pseudo-infarct pattern were the most common ECG findings. Atrial arrhythmia and atrioventricular block were the most common arrhythmias in CA patients. The combination of low voltage on limb leads and pseudo-infarct pattern had high specificity and positive predictive value for the diagnosis of CA.