Influence of diabetes mellitus on T wave and QRS complex alternans during stress ECG testing

The aim of the study is to evaluate the influence of diabetes mellitus (DM) on T-wave and QRS-complex alternans (TWA&QRSA) during stress ECG testing. Principal component analysis, combined with wave amplitude computation was used for TWA&QRSA quantification. We studied 77 patients (64±1 1 years, 44% male). DM was present in 43% and angiographically significant coronary artery disease (AS_CAD) in 51%. Patients with DM had higher QRSA compared to non-diabetics (p=0.026); TWA did not differ significantly. Patients with positive stress ECG tests had higher TWA&QRSA compared to those with negative stress tests (p<;0.001 for TWA and p=0.001 for QRSA), no matter of the presence or absence of DM. In the subgroup of patients with negative stress test, diabetics had higher TWA values (p=0.001). With positive stress test this difference was no longer present.