ST-T Alternans and Myocardial Ischemia

Abstract

Previous studies using intracoronary electrocardiography have demonstrated that ST-T alternans can develop during standard balloon coronary angioplasty. Total occlusion with a large amount of myocardium in jeopardy is the postulated prerequisite. In this study, the authors used perfusion balloons instead of standard balloons, so coronary perfusion was maintained and ischemia was minimized. Fourteen patients with standard balloon technique and 11 patients with perfusion balloon technique were studied. The ST segment was less elevated during perfusion angioplasty (0.15 +/- 0.05 mV vs 1.04 +/- 0.19 mV, p<0.001). There were six (43%) patients with ST-T alternans with standard balloon technique compared with none in the perfusion balloon group (p<0.001). In this study, the authors found that there was less ischemia, less ST segment elevation, and lack of ST-T alternans on the intracoronary electrocardiogram during perfusion balloon angioplasty. These findings support the postulate that a large amount of ischemic myocardium is a prerequisite for ST-T alternans.

Cigarette Smoking Is Related to Endothelial Dysfunction of Resistance, but Not Conduit Arteries in the General Population—Results From the Gutenberg Health Study

“…These associations were shown to be less dose-dependent, but rather to reach a point where increasing exposure and prolonged cessation are not accompanied by further impairment or improvement. This observed pattern goes along with previous studies showing that smoking-attributable risk does not follow a monotone dose-dependent course ( 51 , 53 ). Moreover, these associations seen in the sex- and age-adjusted models were only marginally influenced by further adjustment for a comprehensive set of risk factors and thus it is likely that smoking-induced dysregulated resistance artery endothelial function constitutes an independent risk setting by displaying relevant early vascular damage.…”

Electrical alternans induced by a brief period of myocardial ischemia during percutaneous coronary intervention: The characteristic ECG morphology and relationship to mechanical alternans

“…However, the incidence of EA varies considerably, depending on the period of occlusion and the method employed to detect an EA. Most earlier studies induced EA by occluding the LAD for 1-2 min or longer (6,8,10,(12)(13)(14)(15)(16). However, in the current PCI protocol, the occlusion time is approximately 20 sec.…”

“…During percutaneous coronary intervention (PCI), alteration of the repolarization morphology, particularly T-wave alternans (TWA), has been studied (6)(7)(8)(9)(10)(11)(12)(13), which has yielded a variable incidence of electrical alternans (EA). The wide distribution of EA incidence is partly due to the changes in PCI procedures.…”

The Intracoronary Electrocardiogram in Percutaneous Coronary Intervention

“…ST‐alternans occurs during a proportion of coronary angioplasty procedures, and there is modest evidence that the IC‐ECG is more sensitive at detecting ST‐alternans than the S‐ECG 19–21 . ST‐alternans on IC‐ECG was shown to identify a large area of myocardial ischemia, 22 is associated with the occurrence of ventricular arrhythmias during angioplasty, 19 and may be abolished by preconditioning 21 . It is possible that persisting ST‐alternans on IC‐ECG could identify patients with unrecognized ongoing ischemia or patients requiring more intensive postprocedural monitoring.…”