Prognostic role of on-line vectorcardiography as regards repeat revascularization after successful coronary angioplasty

Analysis of QRS loop changes in the beat-to-beat Vectocardiogram of ischemic patients undergoing PTCA

In the present work, we have studied dynamic changes of QRS loop in the Vectocardiogram (VCG) of 80 patients that underwent Percutaneous Transluminal Coronary Angioplasty (PTCA). The VCG was obtained for each patient using the XYZ orthogonal leads of their electrocardiographic (ECG) records acquired before, during and after PTCA procedure. In order to analyze the variations of VCG, it has been proposed in this study the following parameters a) Maximum module of the cardiac depolarization vector, b) Volume, c) and Area of vectocardiographic loop corresponding to the QRS complex of each beat, d) Maximum distance between Centroid and the Loop, e) Angle between the XY plane and the Optimum Plane, f) Relation between the Area and Perimeter. The results obtained indicate that the parameters proposed show significant statistics differences (p-value<0.05) before, during (with some exceptions at the first minute of balloon inflation) and after PTCA. We conclude that the variations observed in the proposed parameters correctly represent not only the morphological changes in the depolarization VCG but also they reflect the modifications in the levels of cardiac ischemia induced by PTCA.

Continuous 12-lead electrocardiographic ST monitoring and long-term prognosis after successful coronary stenting

BACKGROUND

The possible long-term prognostic value of transient ST ischemic episodes detected by continuous multilead electrocardiographic (ECG) monitoring after successful coronary stenting (CS) has not been thoroughly investigated.

METHODS

A total of 739 consecutive patients, who underwent a 24-hour, continuous 12-lead electrocardiographic (ECG) ST monitoring in the first day after successful CS, were studied. An ST ischemic episode was defined as a transient ST shift (depression or elevation) in any lead of > or = 0.10 mV compared with the reference ECG lasting for > or = 1 minute.

RESULTS

The incidence of the composite of death, nonfatal myocardial infarction, and recurrent angina by the first year was 28.7%. Patients with > or = 3 (defined by receiver operating characteristics analysis) ST ischemic episodes, detected by continuous 12-lead ECG ST monitoring, were at significantly higher risk for the 1-year composite primary end point than those with either 1 and 2 (52.7% vs 25.7%, hazard ratio [HR] 2.1, 95% CI 1.4-3.7, P < .001) or no (52.7% vs 25%, HR 2.2, 95% CI 1.2-2.9, P < .001) ST ischemic episodes. By multivariate Cox regression analysis, the occurrence of > or = 3 ST ischemic episodes in the first postprocedural day was independently associated with a significant increased risk of the 1-year composite primary end point (HR 1.9, 95% CI 1.4-3.9, P = .002).

CONCLUSIONS

The present study suggests that continuous 12-lead ECG ST monitoring in the first day after successful CS may serve as an affordable tool for the identification of patients with an increased risk of fatal or nonfatal ischemic complication during the first year after the procedure.