Israel Medical Association Journal

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.

Background: Trials have shown superiority of primary percutaneous intervention (PPCI) over in-hospital thrombolysis in ST-elevation myocardial infarction (STEMI) patients treated within 6-12 hours from symptom onset. These studies also included high-risk patients not all of whom underwent a therapeutic intervention. 

Objectives: To compare the outcome of early-arriving stable STEMI patients treated by thrombolysis with or without coronary angiography to the outcome of PPCI-treated STEMI patients.

Methods: Based on six biannual Acute Coronary Syndrome Israeli Surveys comprising 5474 STEMI patients, we analyzed the outcome of 1464 hemodynamically stable STEMI patients treated within 3 hours of onset. Of these, 899 patients underwent PPCI, 383 received in-hospital thrombolysis followed by angiography (TFA), and 182 were treated by thrombolysis only.

Results: Median time intervals from symptom onset to admission were similar while door-to-reperfusion intervals were 63, 45 and 52.5 minutes for PPCI, TFA and thrombolysis only, respectively (P < 0.001). The 30-day composite endpoint of death, post-infarction angina and myocardial infarction occurred in 77 patients of the PPCI group (8.6%), 64 patients treated by TFA (16.7%), and 36 patients of the thrombolysis only group (19.8%, P < 0.001), with differences mostly due to post-infarction angina. One-year mortality rate was 27 (3%), 13 (3.4%) and 11 (6.1%) for PPCI, TFA and thrombolysis only, respectively (P = 0.12).

Conclusions: PPCI was superior to thrombolysis in early-arriving stable STEMI patients with regard to 30-day composite endpoint driven by a decreased incidence of post-infarction angina. No 1 year survival benefit for PPCI over thrombolysis was observed in early-arriving stable STEMI patients.