Outpatient follow-up tests
After SAVR, all 109 patients underwent TTE and laboratory investigations at least once a year as a routine check. Signal averaged ECG (SAECG) and Holter ECG were performed if patients had suspected clinical symptoms of arrhythmias or they approved to undergo the tests to stratify the risk of arrhythmia. SAECG was considered positive if at least two of the following criteria were satisfied: filtered QRS duration > 114 ms; terminal (last 40 ms) QRS root means square (RMS) voltage < 20 μV; and low amplitude (<40 μV) signal (LAS) duration > 38 ms.