P900Electrocardiographic findings in Anderson-Fabry disease versus sarcomeric hypertrophic cardiomyopathy

Abstract

Abstract Background Cardiac involvement is one of the most frequent and disabling organ damage in Anderson-Fabry (AF) disease, causing hypertrophic cardiomyopathy (HCM), conduction disturbances, arrhythmias and coronary disease. Differential diagnosis from sarcomeric HCM is often very challenging, especially for patients with exclusive cardiac involvement. Purpose To gain new insights from standard electrocardiogram (ECG) in AF disease, and identify ECG differences from sarcomeric HCM. Methods Sixty-two consecutive patients (27 males, mean age: 62±16 years) with definite diagnosis of AF disease from 2 Italian centres were evaluated for ECG analysis and divided in 2 groups, according to the presence (Group A, N=39) or the absence (Group B, N=26) of cardiac involvement [hypertrophy detected at echocardiogram or cardiac magnetic resonance (CMR)]. All ECGs were analysed by 2 independent investigators. For Group A, when CMR was performed, a correlation between CMR and ECG was assessed. Patients with cardiac involvement were matched with 78 sarcomeric HCM patients according to sex, age and septal wall thickness on echocardiogram. Results Two AF patients out 39 with cardiac involvement (5%) had normal ECG. Short PR and I degree atrio-ventricular (AV) block were both reported in 6 (15%) cases. Twenty-six (67%) patients showed left ventricular hypertrophy and the majority (85%) had abnormal repolarization. CMR was performed in 22 patients (56%); the 11 (50%) patients with replacement fibrosis had a higher mean Sokolow-Lyon score (4.1±1.8 vs 2.9±1.0 mV; p=0.05), more frequent ST segment depression (82 vs 27%; p=0.03) and negative T waves (91 vs 36%; p=0.027; sensitivity: 90%; specificity: 63%), compared with the 11 without replacement fibrosis. When compared with sarcomeric HCM, AF patients with cardiac involvement had a significantly wider QRS (120±30 vs 100±16 msec; p<0.0001), a higher frequency of right bundle branch block (RBBB) (18 vs 3%; p=0.01), ST segment depression (54 vs 20%; p<0.0001) and negative T waves (72 vs 46%; p=0.01), typically in the inferior leads (44 vs 14%; p<0.0001). No significant differences in terms of pseudo-necrosis and QRS voltages were found. Among Group B AF patients (26, mean age: 36±12 years), 4 had short PR and 5 incomplete RBBB. Four had an abnormal ECG (1 left atrial enlargement, 2 unspecific repolarization abnormalities, 1 Sokolow score of 3.5 mV). Conclusions Standard ECG can detect cardiac involvement in AF disease. A good correlation was reported between repolarization abnormalities and replacement fibrosis on CMR. Wide QRS and RBBB were more frequent among AF patients compared to age-sex-matched sarcomeric HCM ones, probably due to the different aetiology of the diseases (infiltrative disease vs pure hypertrophy).