Enhancement of Standard ECGs by a New Method for Multi-Cycle Superimposition and Summation.

BACKGROUND: Since the introduction of the electrocardiogram (ECG) in 1902, the fundamentals of ECG data acquisition, display, and interpretation in the clinical arena have not changed much.

OBJECTIVES: To present a new method to enhance and improve acquisition, analysis, and display of the standard ECG.

METHODS: We performed ECG enhancement by superimposition and summation of multiple standard ECG cycles of each lead, by temporal alignment to peak R wave and voltage alignment to an improved baseline, at the T-P segment.

RESULTS: We enhanced ECG recordings of 504 patients who underwent coronary angiograms for routine indications. Several new ECG features were noted on the enhanced recordings. Examination of a subgroup of 152 patients with a normal rest 12-lead ECG led to the discovery of a new observation, which may help to distinguish between patients with and without coronary artery disease (CAD): namely, a spontaneous cycle-to-cycle voltage spread (VS) at the S-T interval, normalized to VS at the T-P interval. The mean normalized VS was significantly greater in those with CAD (n=61, 40%) than without (n=91, 60%), 5.61 ± 3.79 vs. 4.01 ± 2.1 (P < 0.05).

CONCLUSIONS: Our novel method of multiple ECG-cycle superimposition enhances the ECG display and improves detection of subtle electrical abnormalities, thus facilitating the standard rest ECG diagnostic power. We describe, for the first time, voltage spread at the S-T interval, an observed phenomenon that can help detect CAD among individuals with normal rest 12-lead ECG.